Agent for increasing polyphenol content in leaves of plant of family theaceae, and agent for increasing theanine content

Abstract

Provided are an agent for increasing polyphenol content and an agent for increasing theanine content in leaves of a plant of the family Theaceae, these agents making it possible to safely increase the amount of polyphenols, such as catechins, and / or theanine contained in the tea tree by appropriately spraying or irrigating the plant without adversely affecting the biological tissue of the plant. The agent for increasing the polyphenol content and / or the theanine content in leaves of a plant of the family Theaceae contains at least one compound selected from the group consisting of oxo fatty acids or salts thereof and fatty acid hydroxides or salts thereof.

Description

An agent for increasing the polyphenol content and theanine content in the leaves of plants of the family Theaceae

[0001] The present invention relates to an agent for increasing the polyphenol content in leaves of plants of the family Theaceae, as well as an agent for increasing the theanine content.

[0002] Many plants contain various functional components, such as vitamins, carotenoids, and polyphenols. In recent years, health-conscious trends have led to growing interest in these functional components in agricultural crops. There is particularly high demand for agricultural products rich in antioxidant functional components that remove radicals, such as reactive oxygen species, which are thought to damage cells and tissues and contribute to cancer, lifestyle-related diseases, and accelerated aging. These components also contain amino acids and peptides, which are building blocks of biological proteins and function as various neurotransmitters. Therefore, efforts have been made to significantly enhance the production of useful functional components within plants. In particular, the leaves of the tea plant, a member of the Theaceae family, contain catechins, a type of polyphenol. These catechins have antioxidant properties that help prevent aging and immune dysfunction. Other potential benefits include reducing body fat and combating dental caries-causing bacteria. Another functional component found in the leaves of the tea plant, a member of the Theaceae family, is the non-protein amino acid theanine. Theanine is the most abundant amino acid in tea and is considered one of the umami components of tea, so tea with a high theanine content has high market value. Therefore, one tea cultivation method known to increase the theanine content is cover cultivation (shade cultivation), in which tea plants are covered with a covering material to block sunlight for a certain period of time. When tea plants are covered and sunlight is blocked by cover cultivation, enzyme activity decreases, suppressing the synthesis of theanine into catechins. Theanine has also been reported to have effects such as relaxation, improving sleep, and preventing high blood pressure.

[0003] As a method for increasing the yield of functional components contained in such plants, Patent Document 1 discloses a technology for increasing the amount of polyphenols using unsaturated fatty acids of a specific structure. Patent Document 2 also discloses a fertilizer for improving the quality of tea, which contains stevia extract as an active ingredient, and also describes an increase in the theanine content. Patent Document 3 discloses a tea leaf cultivation method in which betaine is applied to tea plants before dormancy or after budding, and also describes an increase in the theanine content.

[0004] International Publication No. 2020 / 054630 Japanese Patent Application Laid-Open No. 2006-56761 Japanese Patent Application Laid-Open No. 2006-87323

[0005] However, there was no mention of a method for increasing the catechin content in tea plant leaves. Also, in order to increase theanine in tea plant leaves, stevia extract or betaine is required, but these substances can only be obtained from specific plants and are difficult to obtain.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide an agent for increasing the polyphenol content and theanine content in the leaves of plants of the Theaceae family that are easily available, have no adverse effects on the living tissues of plants, and can be safely sprayed or irrigated onto plants as appropriate to increase the amounts of polyphenols such as catechins and / or theanine contained in tea plants.

[0007] A first aspect of the present invention is an agent for increasing the polyphenol content in leaves of a Theaceae plant, comprising at least one compound selected from the group consisting of an oxo fatty acid or a salt thereof, and a hydroxylated fatty acid or a salt thereof. The agent for increasing the polyphenol content in leaves of a Theaceae plant preferably comprises an oxo fatty acid or a salt thereof, and a hydroxylated fatty acid or a salt thereof. The at least one compound selected from the group consisting of an oxo fatty acid or a salt thereof, and a hydroxylated fatty acid or a salt thereof is preferably an unsaturated fatty acid having 18 carbon atoms and not having an α-ketol structure.

[0008] The oxo fatty acid is preferably 13-oxo-9,11-octadecadienoic acid or a salt thereof, or 9-oxo-10,12-octadecadienoic acid or a salt thereof, and the hydroxylated fatty acid is preferably 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid.

[0009] The agent for increasing the polyphenol content in the leaves of a Theaceae plant is preferably used as a spray or dipping agent that is brought into contact with the stems, leaves, or roots of a Theaceae plant, or as a soil drench agent.

[0010] In the agent for increasing the polyphenol content in leaves of plants of the family Theaceae, the polyphenol is preferably a catechin.

[0011] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are preferably 0.0001 ppm or more and 1 ppm or less when sprayed as a plant activator containing a polyphenol content increaser.

[0012] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are preferably 0.001 ppm or more and 0.1 ppm or less when sprayed as a plant activator containing a polyphenol content increaser.

[0013] The weight ratio of the oxo fatty acid or its salt to the hydroxylated fatty acid or its salt is preferably 100 parts by weight of the oxo fatty acid or its salt to 5 to 100 parts by weight of the hydroxylated fatty acid or its salt.

[0014] The polyphenol content increaser contains the 13-oxo-9,11-octadecadienoic acid and the 9-oxo-10,12-octadecadienoic acid, and the ratio of the content of the 9-oxo-10,12-octadecadienoic acid to the content of the 13-oxo-9,11-octadecadienoic acid is preferably 0.1 to 10 by weight.

[0015] The polyphenol content increaser preferably contains the 13-oxo-9,11-octadecadienoic acid and the 9-oxo-10,12-octadecadienoic acid, and the ratio of the content of the 9-oxo-10,12-octadecadienoic acid to the content of the 13-oxo-9,11-octadecadienoic acid is 0.3 to 2.5 by weight.

[0016] In the agent for increasing the polyphenol content in leaves of plants of the family Theaceae, the catechin is preferably epigallocatechin gallate.

[0017] In the agent for increasing the polyphenol content in leaves of a Theaceae plant, the Theaceae plant is preferably a tea plant.

[0018] A second aspect of the present invention is an agent for increasing theanine content in leaves of plants of the family Theaceae, comprising at least one compound selected from the group consisting of oxo fatty acids or salts thereof, and hydroxylated fatty acids or salts thereof. The agent for increasing theanine content in leaves of plants of the family Theaceae preferably comprises an oxo fatty acid or salt thereof, and a hydroxylated fatty acid or salt thereof. The at least one compound selected from the group consisting of oxo fatty acids or salts thereof, and hydroxylated fatty acids or salts thereof is preferably an unsaturated fatty acid having 18 carbon atoms and not having an α-ketol structure.

[0019] The oxo fatty acid is preferably 13-oxo-9,11-octadecadienoic acid or a salt thereof, or 9-oxo-10,12-octadecadienoic acid or a salt thereof, and the hydroxylated fatty acid is preferably 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid.

[0020] The agent for increasing the theanine content in the leaves of Theaceae plants is preferably used as a spray or dipping agent that is brought into contact with the stems, leaves, or roots of Theaceae plants, or as a soil drench agent.

[0021] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are preferably 0.0001 ppm or more and 1 ppm or less when sprayed as a plant activator containing a theanine content increaser.

[0022] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are preferably 0.001 ppm or more and 0.1 ppm or less when sprayed as a plant activator containing a theanine content increaser.

[0023] The weight ratio of the oxo fatty acid or its salt to the hydroxylated fatty acid or its salt is preferably 100 parts by weight of the oxo fatty acid or its salt to 5 to 100 parts by weight of the hydroxylated fatty acid or its salt.

[0024] The theanine content increaser preferably contains the 13-oxo-9,11-octadecadienoic acid and the 9-oxo-10,12-octadecadienoic acid, and the weight ratio of the 9-oxo-10,12-octadecadienoic acid to the 13-oxo-9,11-octadecadienoic acid is preferably 0.1 to 10.

[0025] The ratio of the content of the 9-oxo-10,12-octadecadienoic acid to the content of the 13-oxo-9,11-octadecadienoic acid is preferably 0.3 to 2.5 by weight.

[0026] In the agent for increasing the theanine content in leaves of a Theaceae plant, the Theaceae plant is preferably the tea plant.

[0027] The agent for increasing the theanine content is preferably used in cover cultivation of plants of the family Theaceae.

[0028] The agent for increasing the polyphenol content in the leaves of a Theaceae plant of the present invention can be appropriately sprayed or irrigated onto the Theaceae plant to increase the polyphenol content in the leaves of the plant, even without stressful cultivation or the use of a cultivar with high polyphenol content.The agent for increasing the theanine content in the leaves of a Theaceae plant of the present invention can be appropriately sprayed or irrigated onto the Theaceae plant to increase the theanine content in the leaves of the plant, even without stressful cultivation or the use of a cultivar with high theanine content.

[0029] Fig. 1 is a graph showing a comparison of the catechin content in tea leaves between Example 1 and Comparative Example 1. Fig. 2 is a graph showing a comparison of the theanine content in tea leaves between Example 2 and Comparative Example 2.

[0030] (Regarding the agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention) The plant activator for leaves of Theaceae plants of the present invention comprises an agent for increasing the polyphenol content in leaves of Theaceae plants, which comprises at least one compound selected from the group consisting of oxo fatty acids or salts thereof, and hydroxylated fatty acids or salts thereof.

[0031] Contacting a portion of the stems, leaves, or roots of a Theaceae plant with an oxo fatty acid or its salt or a hydroxylated fatty acid or its salt can increase the amount of polyphenols contained in the plant. Since the increase in the plant was confirmed to be the same components as those typically increased in stressful cultivation, the oxo fatty acid or its salt of the present invention is believed to contain a substance and / or its precursor that, when absorbed into the Theaceae plant, acts in the plant similarly to the molecules naturally produced and acting as signals in Theaceae plants in response to environmental stress. In other words, the oxo fatty acid or its salt or hydroxylated fatty acid or its salt of the present invention can enhance the inherent stress resistance function of Theaceae plants. As a result, polyphenol production is promoted and / or degradation is inhibited in the Theaceae plant, thereby increasing polyphenols in the Theaceae plant. The agent for increasing polyphenol content in the leaves of the Theaceae plant of the present invention preferably contains both an oxo fatty acid or its salt and a hydroxylated fatty acid or its salt. In particular, the oxo fatty acids and hydroxylated fatty acids are preferably unsaturated fatty acids having 18 carbon atoms and not having an α-ketol structure. Unsaturated fatty acids having 18 carbon atoms are involved in the metabolism of living organisms, have a high affinity with Theaceae plants, and are present in the plant body, so they can minimize the environmental burden. Note that an α-ketol structure refers to a structure in which an OH group is bonded to the carbon atom adjacent to the carbonyl group carbon. Fatty acids having an α-ketol structure are susceptible to oxidation and have poor stability, so are not preferred as fatty acids for use in the present invention.

[0032] Oxo fatty acids are so-called rare fatty acids that are known to be produced as intermediates in the metabolism of unsaturated fatty acids. 13-oxo-9,11-octadecadienoic acid or 9-oxo-10,12-octadecadienoic acid or a salt thereof, used as an example of an oxo fatty acid or a salt thereof in the present invention, is a compound having 18 carbon atoms and a structure in which two double bonds form a conjugated system within the molecule. 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid are oxo fatty acids produced from linoleic acid, an unsaturated fatty acid, by enzymatic reaction or other means, and are among the rare fatty acids. 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid are known to exist naturally in plants such as tomatoes.

[0033] Hydroxylated fatty acids are fatty acids present in living organisms that are produced by the metabolism of linoleic acid by intestinal bacteria such as lactic acid bacteria. In the present invention, it is desirable to use 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid as the hydroxylated fatty acid.

[0034] However, it was not known that oxo fatty acids such as 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid or their salts, or hydroxylated fatty acids such as 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid, have the effect of increasing the amount of polyphenol components contained in the leaves of plants of the family Theaceae.

[0035] The agent for increasing polyphenol content in leaves of Theaceae plants of the present invention may contain an oxo fatty acid or a salt thereof or a hydroxylated fatty acid or a salt thereof, and the origin of the oxo fatty acid or a salt thereof is not particularly limited. Specifically, the oxo fatty acid or a salt thereof or the hydroxylated fatty acid or a salt thereof may be commercially available, or may be derived from plants such as tomatoes, either directly or after extraction and / or purification. Alternatively, the oxo fatty acid or a salt thereof or the hydroxylated fatty acid or a salt thereof may be obtained by the action of an enzyme, such as a plant-derived enzyme, on a substrate such as an unsaturated fatty acid, as described above, or may be obtained by chemical synthesis. For example, the oxo fatty acid or a salt thereof or the hydroxylated fatty acid or a salt thereof may be produced by enzymatic conversion of linoleic acid as a raw material using lipoxygenase (LOX) and / or a dehydrogenase, such as alcohol dehydrogenase (ADH), or via a catalytic reaction using a metal catalyst. The oxo fatty acid or its salt thus obtained can be used at a desired concentration or after being appropriately diluted as needed to increase the polyphenol content in the leaves of a Theaceae plant.

[0036] It is known that oxo fatty acids and hydroxylated fatty acids exist in isomers such as (E,E), (Z,E), (E,Z), and (Z,Z), but these isomers have similar effects in the agents for increasing the polyphenol content in the leaves of Theaceae plants. Therefore, in the present invention, for example, 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid, which can be used as examples of oxo fatty acids or salts thereof, or 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid, which can be used as examples of hydroxylated fatty acids or salts thereof, are considered to include all of their isomers. In other words, the oxo fatty acids and hydroxylated fatty acids contained in the agents for increasing the polyphenol content in the leaves of Theaceae plants of the present invention exhibit similar effects as agents for increasing the polyphenol content in the leaves of Theaceae plants, regardless of the isomer present in the agent.

[0037] In the present invention, the oxo fatty acid may be (9Z,11E)-13-oxo-9,11-octadecadienoic acid and / or (10E,12Z)-9-oxo-10,12-octadecadienoic acid, and the hydroxylated fatty acid may be 9(S),10(S),13(S)-trihydroxy-11(E)-octadecenoic acid and / or 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acid.

[0038] The agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention may contain a desired concentration of oxo fatty acids or salts thereof, or hydroxylated fatty acids or salts thereof. For example, a mixture containing oxo fatty acids and hydroxylated fatty acids may be used as the oxo fatty acids or salts thereof or hydroxylated fatty acids or salts thereof.

[0039] The agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention preferably contains water as a solvent, and may further contain a pH adjuster, an emulsifier, an antifoaming agent, a thixotropic agent, an antifreeze agent, a fertilizer component, or the like, as needed.

[0040] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt contained in the agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention are desirably 0.0001 to 1 ppm and 0.0001 to 1 ppm, respectively, and more preferably 0.001 to 0.1 ppm and 0.001 to 0.1 ppm, respectively, when sprayed as a plant activator containing a polyphenol content increaser. This is because at these concentrations, the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are easily absorbed by Theaceae plants, and are within the ranges that provide the greatest effect in increasing the polyphenol content.

[0041] When both the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are contained, the weight ratio of the compound consisting of the oxo fatty acid or its salt to the compound consisting of the hydroxylated fatty acid or its salt is preferably 5 to 100 per 100 of the compound consisting of the oxo fatty acid or its salt. This is because if the content of the compound consisting of the hydroxylated fatty acid or its salt exceeds 100 per 100 of the compound consisting of the oxo fatty acid or its salt, the polyphenol-increasing effect may be reduced.

[0042] Furthermore, when the oxo fatty acid or its salt contains 13-oxo-9,11-octadecadienoic acid or its salt and 9-oxo-10,12-octadecadienoic acid or its salt, the weight ratio of the content of 9-oxo-10,12-octadecadienoic acid or its salt to the content of 13-oxo-9,11-octadecadienoic acid or its salt is about 0.1 to 10, preferably about 0.3 to 2.5, and more preferably about 0.3 to 2.0.

[0043] In the agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention, the oxo fatty acids or hydroxylated fatty acids may be present in the form of a salt. Examples of salts include ammonium salts and metal salts. Metal salts that generate monovalent metal ions are preferred, and for example, sodium salts and potassium salts can be preferably used, although this is not limited thereto.

[0044] The agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention contains a naturally occurring oxo fatty acid or a salt thereof, or a hydroxylated fatty acid or a salt thereof, and therefore can increase the amount of polyphenols contained in Theaceae plants without causing problems related to soil contamination or toxicity.In other words, by using the agent for increasing the polyphenol content of the present invention, the polyphenol content in the leaves of Theaceae plants can be increased safely and simply.

[0045] The agent for increasing polyphenol content in the leaves of Theaceae plants of the present invention can induce the expression of stress response genes such as PR1, PR2, and PDF1.2 in the plants to which it is applied. For example, it can induce the expression of stress response genes such as PR1a and LOXD in Theaceae plants. That is, the agent for increasing polyphenol content in the leaves of Theaceae plants of the present invention enhances the stress resistance function inherent in Theaceae plants. Furthermore, it can increase polyphenols in Theaceae plants without the need for stressful cultivation. This avoids problems such as reduced yield and reduced resistance to pests that occur with stressful cultivation. Furthermore, it is believed that the agent for increasing polyphenol content in the leaves of Theaceae plants of the present invention can activate genes encoding enzymes necessary for the biosynthesis of catechins, such as chalcone synthase, chalcone isomerase, and flavonoid synthase. Therefore, it is possible to promote the synthesis of catechins in Theaceae plants and increase the catechin content in the leaves. Furthermore, since the applicant's tests did not confirm that the agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention has the effect of increasing caffeine content, it is believed that the agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention can selectively activate genes encoding enzymes of the shikimic acid pathway.The agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention can improve the stress resistance function of Theaceae plants through a simple treatment without changing conventional cultivation methods, and can increase the amount of polyphenol components contained in Theaceae plants.

[0046] The agent for increasing the polyphenol content in leaves of Theaceae plants of the present invention may contain at least one selected from the group consisting of amino acids, nucleic acids, and terpenes. These substances have the effect of promoting the growth of Theaceae plants. The amino acid is not particularly limited and may be appropriately selected from isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, histidine, tyrosine, cysteine, aspartic acid, asparagine, serine, glutamic acid, glutamine, proline, glycine, alanine, and arginine, or may be a mixture of two or more of these.

[0047] The nucleic acid may be at least one selected from a nucleic acid base, a nucleoside, a ribonucleoside, a deoxyribonucleoside, a ribonucleotide, and a deoxyribonucleotide. The nucleic acid is not particularly limited and may be any of the following: five common nucleic acid bases, i.e., adenine, guanine, thymine, cytosine, and uracil; five ribonucleosides in which ribose is bound to a nucleic acid base, i.e., adenosine, guanosine, 5-methyluridine, cytidine, and uridine; five deoxyribonucleosides in which deoxyribose is bound to five nucleic acid bases, i.e., deoxyadenosine, deoxyguanosine, thymidine, deoxycytidine, and deoxyuridine; and 15 ribonucleotides in which one to three phosphoric acid groups are ester-linked to five ribonucleosides (AMP (adenosine monophosphate), ADP (adenosine diphosphate), ATP (adenosine triphosphate), GMP (guanosine monophosphate), GDP (guanosine diphosphate), and GTP (guanosine triphosphate). phosphate), TMP (thymidylic acid / thymidine phosphate), TDP (thymidine diphosphate), TTP (thymidine triphosphate), CMP (cytidine monophosphate), CDP (cytidine diphosphate), CTP (cytidine triphosphate), UMP (uridine monophosphate), UDP (uridine diphosphate), UTP (uridine triphosphate)), or 15 types of deoxyribonucleotides in which the hydroxy group at the 2-position of the ribose of these ribonucleotides has been substituted with hydrogen (dAMP, dADP, dATP, dGMP, dGDP, dGTP, dTMP, dTDP, dTTP, dCMP, dCDP, dCTP, dUMP, dUDP, dUTP), or modified bases of these nucleic acid bases, or a mixture of two or more of these.

[0048] Any terpene may be suitably used, but monoterpenes, sesquiterpenes, diterpenes, and combinations thereof are preferred. Particularly preferred examples include monoterpenes such as α-pinene, β-pinene, silvestrene, and limonene, which are core plant hormones. Terpineol may also be included. Terpineol includes its isomers α-terpineol, β-terpineol, and γ-terpineol, with α-terpineol being more preferred. However, for example, commercially available terpineol may be a mixture of β-terpineol and γ-terpineol, with α-terpineol being the primary component. In other words, as long as it primarily contains α-terpineol, the mixture of isomers can be used as is. Pine oil containing α-pinene as the primary component may be suitably used in the present invention.

[0049] Examples of polyphenols whose amounts contained in plants of the family Theaceae are increased by the present invention include anthocyanins, catechins, cocoa polyphenols, rutin, ferulic acid, chlorogenic acid, curcumin, etc. Tea plants, which are the most widely cultivated of the plants of the family Theaceae, contain a large amount of catechins, and the effect of the present invention in increasing the polyphenol components is particularly notable for catechins.

[0050] Catechins are known to have various structures, and specific examples thereof include catechin (C), epicatechin (EC), epigallocatechin (EGC), gallocatechin (GC), epicatechin gallate (ECg), catechin gallate (Cg), epigallocatechin gallate (EGCg), and gallocatechin gallate (GCg). In the examples of this specification, the content of epigallocatechin gallate (EGCg) is measured.

[0051] The plants of the family Theaceae to which the present invention can be applied are not particularly limited, but for example, camellia, sasanqua, tea (camellia), summer camellia, etc. can be used.

[0052] Theaceae plants may be cultivated in any manner, i.e., planted in soil or submerged in a hydroponic solution.

[0053] Furthermore, the agent for increasing the polyphenol content in the leaves of a Theaceae plant of the present invention can be applied to a Theaceae plant by any method. The application method is not particularly limited as long as it contacts the plant body, such as the roots, stems, or leaves, of the Theaceae plant. The agent for increasing the polyphenol content in the leaves of a Theaceae plant of the present invention may be applied so as to come into direct contact with the plant body, or may be applied to a cultivation carrier, such as soil or medium, in which the plant body is established. For example, the agent for increasing the polyphenol content in the leaves of a Theaceae plant of the present invention can be used as a spray or immersion agent that comes into contact with the stems, leaves, or roots of the Theaceae plant, or as a soil drench agent. The specific application method can be appropriately selected depending on the cultivation form of the Theaceae plant to be applied, and examples include aboveground liquid application, aboveground solid application, aerial liquid application, aerial solid application, liquid surface application, indoor application, soil incorporation application, soil drench application, surface treatment such as painting treatment, seedling box application, single flower treatment, and base treatment. Furthermore, the agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention may be mixed with plant fertilizer components and used as a plant fertilizer. Furthermore, the agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention may be contained in a porous structure or capsule, or impregnated into a sheet or the like and used as a sustained-release drug. The form of the agent for increasing the polyphenol content in the leaves of Theaceae plants of the present invention is not particularly limited. For example, it may be in the form of a liquid or gel, or may be in the form of a solid (block, powder, granules, etc.). In the case of a liquid composition, it may be a concentrated type that can be used as is or diluted.

[0054] The present invention also relates to a Theaceae plant cultivated by the aforementioned cultivation method and having an increased polyphenol content. Such Theaceae plant can be used either as the plant itself or by extracting polyphenols from the Theaceae plant, and is thought to be useful as food or as a raw material for cosmetics, pharmaceuticals, supplements, etc.

[0055] (Regarding the agent for increasing theanine content in leaves of Theaceae plants of the present invention) The plant activator of the present invention comprises an agent for increasing theanine content in leaves of Theaceae plants, which comprises at least one compound selected from the group consisting of oxo fatty acids or salts thereof, and hydroxylated fatty acids or salts thereof.

[0056] Contacting a portion of the stems, leaves, or roots of a Theaceae plant with an oxo fatty acid or its salt or a hydroxylated fatty acid or its salt can increase the amount of theanine contained in the Theaceae plant. Since the increase in the plant was confirmed to be the same components as those typically increased in stressful cultivation, the oxo fatty acid or its salt of the present invention is believed to contain a substance and / or its precursor that, when absorbed into the Theaceae plant, acts in the plant similarly to the molecules naturally produced and acting as signals in Theaceae plants in response to environmental stress. In other words, the oxo fatty acid or its salt or hydroxylated fatty acid or its salt of the present invention can enhance the inherent stress resistance function of Theaceae plants. As a result, theanine production is promoted and / or degradation is inhibited in the Theaceae plant, thereby increasing theanine in the Theaceae plant. The agent for increasing theanine content in Theaceae plant leaves of the present invention preferably contains both an oxo fatty acid or its salt and a hydroxylated fatty acid or its salt. In particular, the oxo fatty acids and hydroxylated fatty acids are preferably unsaturated fatty acids having 18 carbon atoms and not having an α-ketol structure. Unsaturated fatty acids having 18 carbon atoms are involved in the metabolism of living organisms, have a high affinity with Theaceae plants, and are present in the plant body, so they can minimize the environmental burden. Note that an α-ketol structure refers to a structure in which an OH group is bonded to the carbon atom adjacent to the carbonyl group carbon. Fatty acids having an α-ketol structure are susceptible to oxidation and have poor stability, so are not preferred as fatty acids for use in the present invention.

[0057] Oxo fatty acids are so-called rare fatty acids that are known to be produced as intermediates in the metabolism of unsaturated fatty acids. 13-oxo-9,11-octadecadienoic acid or 9-oxo-10,12-octadecadienoic acid or a salt thereof, used as an example of an oxo fatty acid or a salt thereof in the present invention, is a compound having 18 carbon atoms and a structure in which two double bonds form a conjugated system within the molecule. 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid are oxo fatty acids produced from linoleic acid, an unsaturated fatty acid, by enzymatic reaction or other means, and are among the rare fatty acids. 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid are known to exist naturally in plants such as tomatoes.

[0058] Hydroxylated fatty acids are fatty acids present in living organisms that are produced by the metabolism of linoleic acid by intestinal bacteria such as lactic acid bacteria. In the present invention, it is desirable to use 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid as the hydroxylated fatty acid.

[0059] However, it was not known that oxo fatty acids such as 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid or their salts, or hydroxylated fatty acids such as 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid, had the effect of increasing the amount of theanine contained in the leaves of plants of the family Theaceae.

[0060] The agent for increasing theanine content in leaves of Theaceae plants of the present invention may contain an oxo fatty acid or a salt thereof, or a hydroxylated fatty acid or a salt thereof, and the origin of the oxo fatty acid or a salt thereof is not particularly limited. Specifically, the oxo fatty acid or a salt thereof, or the hydroxylated fatty acid or a salt thereof may be commercially available, or may be derived from plants such as tomatoes, either directly or after extraction and / or purification. Alternatively, the oxo fatty acid or a salt thereof, or the hydroxylated fatty acid or a salt thereof, may be obtained by the action of an enzyme, such as a plant-derived enzyme, on a substrate such as an unsaturated fatty acid, as described above, or may be obtained by chemical synthesis. For example, the oxo fatty acid or a salt thereof, or the hydroxylated fatty acid or a salt thereof, may be produced by enzymatic conversion of linoleic acid as a raw material using lipoxygenase (LOX) and / or a dehydrogenase, such as alcohol dehydrogenase (ADH), or by catalytic reaction using a metal catalyst. The oxo fatty acid or its salt thus obtained can be used at a desired concentration or after being appropriately diluted as needed to increase the theanine content in the leaves of Theaceae plants.

[0061] It is known that oxo fatty acids and hydroxylated fatty acids exist in isomers such as (E,E), (Z,E), (E,Z), and (Z,Z), but these isomers have the same effect as agents for increasing theanine content in the leaves of Theaceae plants. Therefore, in the present invention, for example, 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid, which can be used as examples of oxo fatty acids or salts thereof, or 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid, which can be used as examples of hydroxylated fatty acids or salts thereof, are considered to include all of their isomers. In other words, the oxo fatty acids and hydroxylated fatty acids contained in the agent for increasing theanine content in leaves of Theaceae plants of the present invention exert the same effect as agents for increasing theanine content in leaves of Theaceae plants, regardless of the isomers present in the agent.

[0062] In the present invention, the oxo fatty acid may be (9Z,11E)-13-oxo-9,11-octadecadienoic acid and / or (10E,12Z)-9-oxo-10,12-octadecadienoic acid, and the hydroxylated fatty acid may be 9(S),10(S),13(S)-trihydroxy-11(E)-octadecenoic acid and / or 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acid.

[0063] Furthermore, the agent for increasing the theanine content in leaves of Theaceae plants of the present invention may contain a desired concentration of oxo fatty acids or salts thereof, or hydroxylated fatty acids or salts thereof. For example, a mixture containing oxo fatty acids and hydroxylated fatty acids may be used as the oxo fatty acids or salts thereof or hydroxylated fatty acids or salts thereof.

[0064] The agent for increasing theanine content in leaves of Theaceae plants of the present invention preferably contains water as a solvent, and may also contain pH adjusters, emulsifiers, antifoaming agents, thixotropic agents, antifreeze agents, fertilizer components, etc., as needed.

[0065] The concentrations of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt contained in the agent for increasing the theanine content in leaves of Theaceae plants of the present invention are desirably 0.0001 to 1 ppm and 0.0001 to 1 ppm, respectively, when sprayed as a plant activator containing the theanine content increaser, and are preferably 0.001 to 0.1 ppm and 0.001 to 0.1 ppm, respectively. This is because at these concentrations, the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are easily absorbed by Theaceae plants, and are the ranges within which the effect of increasing the theanine content is greatest.

[0066] When both the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt are contained, the weight ratio of the compound consisting of the oxo fatty acid or its salt to the compound consisting of the hydroxylated fatty acid or its salt is desirably 5 to 100 per 100 of the compound consisting of the oxo fatty acid or its salt. This is because if the content of the compound consisting of the hydroxylated fatty acid or its salt exceeds 100 per 100 of the compound consisting of the oxo fatty acid or its salt, the theanine-increasing effect may be reduced.

[0067] Furthermore, when the oxo fatty acid or its salt contains 13-oxo-9,11-octadecadienoic acid or its salt and 9-oxo-10,12-octadecadienoic acid or its salt, the weight ratio of the content of 9-oxo-10,12-octadecadienoic acid or its salt to the content of 13-oxo-9,11-octadecadienoic acid or its salt is about 0.1 to 10, preferably about 0.3 to 2.5, and more preferably about 0.3 to 2.0.

[0068] In the agent for increasing theanine content in leaves of Theaceae plants of the present invention, the oxo fatty acid or hydroxylated fatty acid may be present in the form of a salt. Examples of salts include ammonium salts and metal salts. Metal salts that generate monovalent metal ions are preferred, and examples of suitable metal salts include, but are not limited to, sodium salts and potassium salts.

[0069] The agent for increasing theanine content in the leaves of Theaceae plants of the present invention contains a naturally occurring oxo fatty acid or a salt thereof, or a hydroxylated fatty acid or a salt thereof, and therefore can increase the amount of theanine contained in Theaceae plants without causing problems related to soil contamination or toxicity.In other words, by using the agent for increasing theanine content of the present invention, the content of theanine in the leaves of Theaceae plants can be increased safely and simply.

[0070] The agent for increasing theanine content in the leaves of Theaceae plants of the present invention can induce the expression of stress response genes such as PR1, PR2, and PDF1.2 in the plants to which it is applied. For example, it can induce the expression of stress response genes such as PR1a and LOXD in Theaceae plants. That is, the agent for increasing theanine content in the leaves of Theaceae plants of the present invention enhances the stress resistance function inherent in Theaceae plants. Furthermore, it can increase theanine in Theaceae plants without the need for stressful cultivation. This avoids problems such as reduced yield and reduced resistance to pests that occur with stressful cultivation. Furthermore, it is believed that the agent for increasing theanine content in the leaves of Theaceae plants of the present invention can activate genes encoding enzymes in the theanine synthesis pathway within Theaceae plants. This makes it possible to promote theanine synthesis in Theaceae plants and increase the theanine content in the leaves. The agent for increasing the theanine content in the leaves of Theaceae plants of the present invention can improve the stress resistance function of Theaceae plants through simple treatment without changing conventional cultivation methods, and can increase the amount of theanine contained in Theaceae plants.

[0071] The agent for increasing theanine content in leaves of Theaceae plants of the present invention may contain at least one selected from amino acids, nucleic acids, and terpenes, as these substances have the effect of promoting the growth of Theaceae plants. The amino acid is not particularly limited and may be appropriately selected from isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, histidine, tyrosine, cysteine, aspartic acid, asparagine, serine, glutamic acid, glutamine, proline, glycine, alanine, and arginine, or may be a mixture of two or more of these.

[0072] The nucleic acid may be at least one selected from a nucleic acid base, a nucleoside, a ribonucleoside, a deoxyribonucleoside, a ribonucleotide, and a deoxyribonucleotide. The nucleic acid is not particularly limited and may be any of the following: five common nucleic acid bases, i.e., adenine, guanine, thymine, cytosine, and uracil; five ribonucleosides in which ribose is bound to a nucleic acid base, i.e., adenosine, guanosine, 5-methyluridine, cytidine, and uridine; five deoxyribonucleosides in which deoxyribose is bound to five nucleic acid bases, i.e., deoxyadenosine, deoxyguanosine, thymidine, deoxycytidine, and deoxyuridine; and 15 ribonucleotides in which one to three phosphoric acid groups are ester-linked to five ribonucleosides (AMP (adenosine monophosphate), ADP (adenosine diphosphate), ATP (adenosine triphosphate), GMP (guanosine monophosphate), GDP (guanosine diphosphate), and GTP (guanosine triphosphate). phosphate), TMP (thymidylic acid / thymidine phosphate), TDP (thymidine diphosphate), TTP (thymidine triphosphate), CMP (cytidine monophosphate), CDP (cytidine diphosphate), CTP (cytidine triphosphate), UMP (uridine monophosphate), UDP (uridine diphosphate), UTP (uridine triphosphate)), or 15 types of deoxyribonucleotides in which the hydroxy group at the 2-position of the ribose of these ribonucleotides has been substituted with hydrogen (dAMP, dADP, dATP, dGMP, dGDP, dGTP, dTMP, dTDP, dTTP, dCMP, dCDP, dCTP, dUMP, dUDP, dUTP), or modified bases of these nucleic acid bases, or a mixture of two or more of these.

[0073] Any terpene may be suitably used, but monoterpenes, sesquiterpenes, diterpenes, and combinations thereof are preferred. Particularly preferred examples include monoterpenes such as α-pinene, β-pinene, silvestrene, and limonene, which are core plant hormones. Terpineol may also be included. Terpineol includes its isomers α-terpineol, β-terpineol, and γ-terpineol, with α-terpineol being more preferred. However, for example, commercially available terpineol may be a mixture of β-terpineol and γ-terpineol, with α-terpineol being the primary component. In other words, as long as it primarily contains α-terpineol, the mixture of isomers can be used as is. Pine oil containing α-pinene as the primary component may be suitably used in the present invention.

[0074] The plants of the family Theaceae to which the present invention can be applied are not particularly limited, but for example, camellia, sasanqua, tea (camellia), summer camellia, etc. can be used.

[0075] Theaceae plants may be cultivated in any manner, i.e., planted in soil or submerged in a hydroponic solution.

[0076] Furthermore, the agent for increasing theanine content in the leaves of a Theaceae plant of the present invention can be applied to the Theaceae plant by any method. The application method is not particularly limited as long as it contacts the plant body, such as the roots, stems, or leaves of the Theaceae plant. The agent for increasing theanine content in the leaves of a Theaceae plant of the present invention may be applied so as to come into direct contact with the plant body, or may be applied to a cultivation carrier, such as soil or medium, in which the plant body is established. For example, the agent for increasing theanine content in the leaves of a Theaceae plant of the present invention can be used as a spray or immersion agent that comes into contact with the stems, leaves, or roots of the Theaceae plant, or as a soil drench agent. Specific application methods can be appropriately selected depending on the cultivation form of the Theaceae plant to be applied, and include, for example, aboveground liquid application, aboveground solid application, aerial liquid application, aerial solid application, liquid surface application, indoor application, soil incorporation application, soil drench application, surface treatment such as painting treatment, seedling box application, single flower treatment, and base treatment. Furthermore, the agent for increasing theanine content in the leaves of Theaceae plants of the present invention may be mixed with plant fertilizer components and used as a plant fertilizer. The agent for increasing theanine content in the leaves of Theaceae plants of the present invention may be contained in a porous structure or capsule, or impregnated into a sheet or the like and used as a sustained-release agent. The form of the agent for increasing theanine content in the leaves of Theaceae plants of the present invention is not particularly limited. For example, it may be in the form of a liquid or gel, or may be in the form of a solid (block, powder, granules, etc.). In the case of a liquid composition, it can be used as is or diluted to form a concentrated type.

[0077] The present invention also relates to a Theaceae plant cultivated by the aforementioned cultivation method and having an increased theanine content. The Theaceae plant itself or the theanine extracted from the Theaceae plant can be used, and the plant is considered to be useful as food or as a raw material for cosmetics, pharmaceuticals, supplements, etc.

[0078] The polyphenol content increaser and theanine content increaser of the present disclosure, as well as at least one compound selected from the group consisting of oxo fatty acids or their salts and hydroxylated fatty acids or their salts, contained in the plant activator, contribute to an increase in sugar concentration in tomato leaves. In particular, they contribute to an increase in polysaccharides. This increase in sugar concentration is thought to be due in part to the activation of photosynthesis. Furthermore, the polyphenol content increaser and theanine content increaser of the present disclosure, as well as at least one compound selected from oxo fatty acids or their derivatives or their salts, and hydroxylated fatty acids or their derivatives or their salts, contained in the plant activator, contribute to an improvement in photosynthetic rate and stomatal conductance. Stomatal conductance, also known as stomatal conductance, is an index of the ease with which gas passes through stomata. Generally, a high measured value indicates that stomata are open and photosynthesis is active. Photosynthetic rate and stomatal conductance can be measured using a portable photosynthetic transpiration measurement system. Furthermore, in recent years, research on plant factories has been active, and cultivation methods have been attempted in which plant growth is promoted by increasing light intensity and carbon dioxide concentration within the factory. However, under conditions of increased light intensity and carbon dioxide concentration, plants, particularly leafy vegetables, can suffer from a physiological disorder in which the leaf margins and sepal tips of new leaves brown and die (so-called chip burn). The polyphenol content increaser, the theanine content increaser, and at least one compound selected from oxo fatty acids or derivatives thereof or salts thereof, and hydroxylated fatty acids or derivatives thereof or salts thereof contained in the plant activator of the present disclosure contribute to preventing or suppressing the chip burn phenomenon.

[0079] The present invention will be described based on examples, but the present invention is not limited to only the examples.

[0080] (Preparation of polyphenol content increaser) 580 g of 90% pure linoleic acid (manufactured by NOF Corporation) was used as a fatty acid-containing raw material, and 216 g of potassium carbonate (manufactured by FUJIFILM Wako Co., Ltd.), 280 g of dipotassium hydrogen phosphate (manufactured by FUJIFILM Wako Co., Ltd.), and 13,000 mL of distilled water were added to prepare a test solution. The pH of the test solution at this time was 9.0.

[0081] 40 mg of lipoxygenase (soybean-derived, manufactured by Nacalai Tesque) was added to the test solution, and the mixture was reacted for 3 hours at 15°C while being aerated with oxygen and stirred. The reaction mixture was then placed in a 90°C water bath for 90 minutes. The resulting reaction solution was designated Solution A. 35 mL of phosphoric acid (manufactured by Fujifilm Wako Co., Ltd.) was added to 6500 mL of Solution A to adjust the pH to 7.0. The resulting solution was reacted for 22 hours at 50°C while being aerated with oxygen and stirred. The reaction mixture was then placed in a 90°C water bath for 2 hours. The resulting reaction solution was designated Solution B.

[0082] The entire amount of Solution B obtained above was mixed with the entire amount of Solution A remaining without using it to prepare Solution B. The resulting mixture was used as a standard substance. 13-oxoODA (13-oxo-9,11-octadecadienoic acid) and 9-oxoODA (9-oxo-10,12-octadecadienoic acid) manufactured by Cayman Chemical Company, and 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid manufactured by Larodan Fine Chemicals were also used. Acid) and quantification was performed by liquid chromatography mass spectrometry (LC-MS) using MS2 spectral analysis.

[0083] Ketooctadecadienoic acid (13-oxoODA, 9-oxoODA) was quantified at a UV detection wavelength of 272 nm, and trihydroxyoctadecenoic acid was quantified at a UV detection wavelength of 210 nm using the absolute calibration curve method. The combined yield of 13-oxoODA and its isomers, including the (E,E) and (E,Z) isomers, was 3.7%. The yield of 9-oxoODA was 1.7%. The combined yield of 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid was 1.2% (peaks unseparable by LC-MS), and the recovery of linoleic acid was 84.1%.

[0084] A plant activation solution was prepared by diluting 0.01178 mL of the mixture (plant activator) of solutions A and B obtained above with ion-exchanged water to 2000 mL. The plant activation solution contained 13-oxoODA at a concentration of 0.00875 ppm, 9-oxoODA at a concentration of 0.0040 ppm, and 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid at a combined concentration of 0.0029 ppm.

[0085] (Example 1) (Plant Cultivation Test) At the time of the third bud sprouting of tea plants (Tea plant variety: Yabukita) that had been conventionally cultivated in the open field, 75 L of plant activation solution was poured into 250 ml ２ The plot was sprayed with a boom sprayer.

[0086] (Analysis Method) (Amount of Epigallocatechin Gallate and Caffeine) Approximately three months after spraying, ten plants were randomly selected, new leaves were collected, and the amounts of epigallocatechin gallate (EGCg) and caffeine contained were measured. The amounts of epigallocatechin gallate and caffeine were determined by freezing the samples at -80°C for one day, immersing them in a 10-fold volume of a 20:1:80 mixture of water:acetic acid:methanol, sonicating them for 30 minutes, and then allowing them to stand at 25°C for 24 hours, and analyzing the resulting extract. The epigallocatechin gallate and caffeine contents were calculated as the average values ​​for the ten plants.

[0087] Comparative Example 1 (Water Treatment) In the same tea field as in Example 1, water was sprayed instead of the plant activation solution over the same area, and the amounts of epigallocatechin gallate (EGCg) and caffeine contained in the new leaves were measured in the same manner as in Example 1.

[0088] Analysis was performed using an LC-MS / MS system (LC unit: DIONEX Ultimate 3000, MS / MS unit: Q Exactive Focus: manufactured by Thermo Fisher Scientific Co., Ltd.) under the following conditions: Column: Acclaim PR-MS 2.1 mmφ × 150 mm (manufactured by Thermo Fisher Scientific Co., Ltd.), Solvent: 15% methanol / aqueous acetic acid, Flow rate: 0.25 mL / min, Column temperature: 40°C, Detection UV: 280 nm, Injection: 2 μL of sample solution. Quantitation was performed using caffeine standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and (-)-epigallocatechin gallate standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as standards.

[0089] (Results) As can be seen from Figure 1, the catechin content in tea plant leaves is increased by applying an agent for increasing the polyphenol content in leaves of Theaceae plants containing 13-oxo-9,11-octadecadienoic acid, 9-oxo-10,12-octadecadienoic acid, 9,10,13-trihydroxy-11-octadecenoic acid, and 9,12,13-trihydroxy-10-octadecenoic acid. Furthermore, since no increase in caffeine content in tea plant leaves was confirmed, this suggests that the genes encoding enzymes in the catechin synthesis pathway are selectively activated.

[0090] (Preparation of theanine content increaser) 580 g of 90% pure linoleic acid (manufactured by NOF Corporation) was used as a fatty acid-containing raw material, and 216 g of potassium carbonate (manufactured by FUJIFILM Wako Co., Ltd.), 280 g of dipotassium hydrogen phosphate (manufactured by FUJIFILM Wako Co., Ltd.), and 13,000 mL of distilled water were added to prepare a test solution. The pH of the test solution at this time was 9.0.

[0091] 40 mg of lipoxygenase (soybean-derived, manufactured by Nacalai Tesque) was added to the test solution, and the mixture was reacted for 3 hours at 15°C while being aerated with oxygen and stirred. The reaction mixture was then placed in a 90°C water bath for 90 minutes. The resulting reaction solution was designated Solution A. 35 mL of phosphoric acid (manufactured by Fujifilm Wako Co., Ltd.) was added to 6500 mL of Solution A to adjust the pH to 7.0. The resulting solution was reacted for 22 hours at 50°C while being aerated with oxygen and stirred. The reaction mixture was then placed in a 90°C water bath for 2 hours. The resulting reaction solution was designated Solution B.

[0092] The entire amount of Solution B obtained above was mixed with the entire amount of Solution A remaining without using it to prepare Solution B. The resulting mixture was used as a standard substance. 13-oxoODA (13-oxo-9,11-octadecadienoic acid) and 9-oxoODA (9-oxo-10,12-octadecadienoic acid) manufactured by Cayman Chemical Company, and 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid manufactured by Larodan Fine Chemicals were also used. Acid) and quantification was performed by liquid chromatography mass spectrometry (LC-MS) using MS2 spectral analysis.

[0093] Ketooctadecadienoic acid (13-oxoODA, 9-oxoODA) was quantified at a UV detection wavelength of 272 nm, and trihydroxyoctadecenoic acid was quantified at a UV detection wavelength of 210 nm using the absolute calibration curve method. The combined yield of 13-oxoODA and its isomers, including the (E,E) and (E,Z) isomers, was 3.7%. The yield of 9-oxoODA was 1.7%. The combined yield of 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid was 1.2% (peaks unseparable by LC-MS), and the recovery of linoleic acid was 84.1%.

[0094] A 0.094 mL portion of the mixture (plant activator) of solutions A and B obtained above was diluted with ion-exchanged water to 2000 mL to prepare a plant activator solution. The plant activator solution contained 13-oxoODA at a concentration of 0.0642 ppm, 9-oxoODA at a concentration of 0.0295 ppm, and 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid at a combined concentration of 0.0208 ppm.

[0095] (Example 2) (Plant cultivation test) 19 days before the harvest of the first flush of tea plants (Tea Garden Tea, variety: Yabukita) that had been conventionally cultivated outdoors, 50 L of the plant activation solution was sprayed onto a 4a plot using a boom sprayer, and the plot was covered with cheesecloth (to block light) until harvest.

[0096] (Analysis Method) (Theanine Amount) When the first tea harvest was made, 10 plants were randomly selected, new leaves were collected, and the amount of theanine contained per weight was measured. The amount of theanine was determined by freezing the sample at -80°C for one day, immersing it in a 10-fold volume of a 20:1:80 mixture of water, acetic acid, and methanol, subjecting it to ultrasound for 30 minutes, and then allowing it to stand at 25°C for 24 hours, and analyzing the resulting extract. The theanine content was calculated as the average value for the 10 plants.

[0097] Comparative Example 2 (Water Treatment) In the same tea field as in Example 1, water was sprayed instead of the plant activation solution over the same area, and the tea was covered with cheesecloth (shading) until harvest. The amount of theanine contained in new leaves was measured in the same manner as in Example 2.

[0098] Analysis was performed using an LC-MS / MS system (LC unit: DIONEX Ultimate 3000, MS / MS unit: Q Exactive Focus: manufactured by Thermo Fisher Scientific Co., Ltd.) under the following conditions: Column: Acclaim PR-MS 2.1 mmφ x 150 mm (manufactured by Thermo Fisher Scientific Co., Ltd.), Solvent: 0% acetonitrile / acetic acid water → 30% acetonitrile / acetic acid water, Flow rate: 0.25 mL / min, Column temperature: 40°C, Detection: MS-(SIM), Injection: 2 μL of sample solution. Qualitative analysis was performed using L-theanine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a standard substance.

[0099] As can be seen from Figure 2, the theanine content in tea plant leaves increases when an agent for increasing the theanine content in the leaves of Theaceae plants containing 13-oxo-9,11-octadecadienoic acid, 9-oxo-10,12-octadecadienoic acid, 9,10,13-trihydroxy-11-octadecenoic acid, and 9,12,13-trihydroxy-10-octadecenoic acid is applied. This suggests that theanine synthesis is activated when the synthesis of catechins from theanine is suppressed by cover cultivation (shade cultivation).

[0100] As described above in Example 1, the catechin content in tea plant leaves is increased by applying a plant activator containing 13-oxo-9,11-octadecadienoic acid, 9-oxo-10,12-octadecadienoic acid, 9,10,13-trihydroxy-11-octadecenoic acid, and 9,12,13-trihydroxy-10-octadecenoic acid. Furthermore, as described in Example 2, the theanine content in tea plant leaves is increased by applying a plant activator containing 13-oxo-9,11-octadecadienoic acid, 9-oxo-10,12-octadecadienoic acid, 9,10,13-trihydroxy-11-octadecenoic acid, and 9,12,13-trihydroxy-10-octadecenoic acid. Therefore, a plant enhancer containing 13-oxo-9,11-octadecadienoic acid, 9-oxo-10,12-octadecadienoic acid, 9,10,13-trihydroxy-11-octadecenoic acid, and 9,12,13-trihydroxy-10-octadecenoic acid can be used as an agent for increasing the polyphenol and theanine content in the leaves of plants of the Theaceae family.

[0101] This application claims priority based on Japanese Patent Application No. 2024-005002 filed on January 17, 2024, and Japanese Patent Application No. 2024-035510 filed on March 8, 2024, the contents of which are incorporated herein by reference. The contents of International Publication No. 2020 / 054630, Japanese Patent Application Laid-Open No. 2006-56761, and Japanese Patent Application Laid-Open No. 2006-87323 are incorporated herein by reference.

Claims

1. An agent for increasing the content of polyphenols in the leaves of Camellia plants, comprising at least one compound selected from the group consisting of oxo fatty acids or salts thereof and hydroxylated fatty acids or salts thereof.

2. An agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1, comprising an oxo fatty acid or a salt thereof and a hydroxylated fatty acid or a salt thereof.

3. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1 or 2, wherein at least one compound selected from the group consisting of the oxo fatty acid or a salt thereof and the hydroxylated fatty acid or a salt thereof is an unsaturated fatty acid having 18 carbon atoms and no α-keto group structure.

4. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 3, wherein the oxo fatty acid is 13-oxo-9,11-octadecadienoic acid or 9-oxo-10,12-octadecadienoic acid.

5. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 3, wherein the hydroxylated fatty acid is 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid.

6. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1 or 2, which is used as a spraying agent or dipping agent to be brought into contact with the stems, leaves or roots of Camellia plants, or as a soil perfusion agent.

7. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1 or 2, wherein the polyphenol is catechins.

8. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1 or 2, wherein the concentration of the oxo fatty acid or a salt thereof and the concentration of the hydroxylated fatty acid or a salt thereof are each 0.0001 ppm or more and 1 ppm or less when sprayed as a plant activator containing the agent for increasing the content of polyphenols.

9. The agent for increasing the content of polyphenols in the leaves of Camellia plants according to claim 1 or 2, wherein the concentration of the oxo fatty acid or a salt thereof and the concentration of the hydroxylated fatty acid or a salt thereof are each 0.001 ppm or more and 0.1 ppm or less when sprayed as a plant activator containing the agent for increasing the content of polyphenols.

10. The weight ratio of the oxo fatty acid or its salt to the hydroxylated fatty acid or its salt is such that the hydroxylated fatty acid or its salt is 5 to 100 with respect to 100 of the oxo fatty acid or its salt. The polyphenol content increasing agent in the leaves of the Camellia family plants according to claim 2.

11. The agent contains 13-oxo-9,11-octadecadienoic acid and 9-oxo-10,12-octadecadienoic acid, and the ratio of the content of 9-oxo-10,12-octadecadienoic acid to 13-oxo-9,11-octadecadienoic acid is 0.1 to 10 by weight ratio. The polyphenol content increasing agent in the leaves of the Camellia family plants according to claim 4.

12. The ratio of the content of 9-oxo-10,12-octadecadienoic acid to 13-oxo-9,11-octadecadienoic acid is 0.3 to 2.5 by weight ratio. The polyphenol content increasing agent in the leaves of the Camellia family plants according to claim 11.

13. The catechins are epigallocatechin gallate. The polyphenol content increasing agent in the leaves of the Camellia family plants according to claim 7.

14. The Camellia family plant is Camellia nitidissima. The polyphenol content increasing agent in the leaves of the Camellia family plants according to claims 1 to 13.

15. A theanine content increasing agent in the leaves of Camellia family plants, comprising at least one compound selected from the group consisting of oxo fatty acids or their salts and hydroxylated fatty acids or their salts.

16. The theanine content increasing agent in the leaves of Camellia family plants according to claim 15, comprising an oxo fatty acid or its salt and a hydroxylated fatty acid or its salt.

17. At least one compound selected from the group consisting of the oxo fatty acid or its salt and the hydroxylated fatty acid or its salt is an unsaturated fatty acid having 18 carbon atoms and no α-keto structure. The theanine content increasing agent in the leaves of Camellia family plants according to claim 15 or 16.

18. The oxo fatty acid is 13-oxo-9,11-octadecadienoic acid or 9-oxo-10,12-octadecadienoic acid. The theanine content increasing agent in the leaves of Camellia family plants according to claim 17.

19. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 17, wherein the hydroxylated fatty acid is 9,10,13-trihydroxy-11-octadecenoic acid or 9,12,13-trihydroxy-10-octadecenoic acid.

20. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 15 or 16, which is used as a spraying agent or dipping agent to be contacted with the stems, leaves or roots of the Camellia family plants, or as a chemical agent for soil perfusion.

21. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 15 or 16, wherein the concentration of the oxo fatty acid or its salt and the concentration of the hydroxylated fatty acid or its salt are each 0.0001 ppm or more and 1 ppm or less when sprayed as a plant activator containing the theanine content increasing agent.

22. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 21, wherein the concentration of the oxo fatty acid or its salt and the concentration of the hydroxylated fatty acid or its salt are each 0.001 ppm or more and 0.1 ppm or less when sprayed as a plant activator containing the theanine content increasing agent.

23. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 16, wherein the weight ratio of the oxo fatty acid or its salt to the hydroxylated fatty acid or its salt is such that the hydroxylated fatty acid or its salt is 5 to 100 with respect to 100 of the oxo fatty acid or its salt.

24. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 18, which contains the 13-oxo-9,11-octadecadienoic acid and the 9-oxo-10,12-octadecadienoic acid, and the content ratio of the 9-oxo-10,12-octadecadienoic acid to the 13-oxo-9,11-octadecadienoic acid is 0.1 to 10 by weight ratio.

25. The theanine content increasing agent in the leaves of the Camellia family plants according to claim 24, wherein the content ratio of the 9-oxo-10,12-octadecadienoic acid to the 13-oxo-9,11-octadecadienoic acid is 0.3 to 2.5 by weight ratio.

26. The theanine content increasing agent in the leaves of the Camellia family plants according to claims 15 to 25, wherein the Camellia family plant is Camellia sasanqua.

27. The theanine content increasing agent according to claims 15 to 26, wherein the theanine content increasing agent is used in the covered cultivation of Camellia family plants.

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