Peach leaf essential oil and application thereof

Abstract

The invention relates to the technical field of essential oil, in particular to peach leaf essential oil and application thereof. According to the method, the peach leaf essential oil is extracted by adopting a water distillation method, the components of the peach leaf essential oil are identified, 40 volatile chemical components are identified by utilizing headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GCMS), 23 chemical components are identified by utilizing ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), and the content of the volatile chemical components in the peach leaf essential oil is greatly improved. Researches find that the peach leaf essential oil can effectively inhibit and kill escherichia coli, staphylococcus aureus, micrococcus luteus, pantoea, fusarium oxysporum and monilinia fusarium, and in addition, the invention also finds that the peach leaf essential oil has better oxidation resistance and free radical scavenging ability, so that the invention develops new application of the peach leaf essential oil.

Description

Technical Field

[0001] The invention relates to the technical field of essential oils, in particular to peach leaf essential oil and application thereof. Background Art

[0002] The peach (Prunus persica) is a member of the genus Prunus in the Rosaceae family, native to China. It has a cultivated history of over 4,000 years and is widely cultivated in Beijing, Hebei, Henan, Shandong, Shaanxi, Jiangsu, Zhejiang, and Hubei. The peach tree is a treasure trove. Besides its large, edible fruit, its leaves also possess significant medicinal value. For example, the Compendium of Materia Medica states that "peach leaves are bitter, mild, and non-toxic," and "treat colds, rheumatism, and headaches, and promote urination and defecation." The Bielu (Bielu) book states that "peach leaves are bitter, pungent, mild, and non-toxic," and that "peach leaves expel insects from sores." The Zaixin (Bencao Zaixin) book states that "peach leaves enter the spleen and kidney meridians," and that "peach leaves induce sweating, eliminate phlegm, dissipate dampness, and kill insects." The Bencao Huiyan (Compendium of Materia Medica) book states that "peach leaves dissolve blood clots and blood stasis in women." Peach leaves are also widely used as a folk remedy for ailments such as prickly heat.

[0003] However, in peach-producing areas, a large number of peach leaves are not fully utilized after harvest, falling naturally in autumn and winter. Therefore, exploring the bioactive components in peach leaves and studying their functions is a key technology for developing and utilizing the abundant peach leaf resources in peach-producing areas and increasing the profitability of the peach cultivation industry. Summary of the Invention

[0004] The present invention adopts water distillation to extract peach leaf essential oil, utilizes HS-SPME-GCMS technology to identify 40 kinds of volatile chemical components, utilizes UPLC-MS technology to identify 23 kinds of chemical components. The invention is creative and found that, thanks to the composite synergistic effect of various compounds in peach leaf essential oil, it has excellent antibacterial and bactericidal effects on Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Pantoea, and Fusarium oxysporum, and brown rot fungi. Only 5-10 μL peach leaf essential oil can completely inhibit the growth of Staphylococcus aureus, Micrococcus luteus, Pantoea, Fusarium oxysporum, and brown rot fungi, and can completely kill Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Pantoea, and Fusarium oxysporum, and brown rot fungi. At the same time, this experiment found that peach leaf essential oil has good antioxidant and free radical scavenging ability. Based on this, the following technical scheme is proposed.

[0005] Firstly, the invention provides a peach leaf essential oil, which is obtained by taking peach leaves as raw materials and adopting a water distillation method to extract.

[0006] Preferably, the extraction step of the water distillation method comprises: mixing peach leaves with water and distilling at 100-110° C. for more than 2.5 hours.

[0007] Preferably, the peach leaf essential oil includes 63 chemical components. Among them, HS-SPME-GCMS detected the following components by weight: 0.5-1 part of limonene, 0.01-0.08 part of trans-2-(2-pentyl)furan, 0.1-0.5 part of n-hexanol, 0.1-0.8 part of trans-3-hexen-1-ol, 0.01-0.8 part of cis-2-hexen-1-ol, 0.1-0.5 part of N-butyric acid (trans-2-hexenyl) ester, 65-90 parts of benzaldehyde, 1-2 parts of methyl benzoate, 0.01-1 part of cis-2-decenal, 0.05-0.5 part of safranal, 0.05-0.5 part of acetophenone, 0.05-0.5 part of benzoic acid 0.05-0.5 parts of ethyl ester, 0.01-0.1 parts of salicylaldehyde, 0.01-0.1 parts of 1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene, 0.01-0.1 parts of α-terpineol, 0.01-0.3 parts of 1,1,6-trimethyl-1,2-dihydronaphthalene, 0.01-0.3 parts of nerol, 0.05-0.3 parts of 1-phenyl-1,2-propanedione, 0.01-0.1 parts of β-damascenone, 0.1-0.5 parts of damascenone, 0.01-0.1 parts of guaiacol, 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane-6- 0.001~0.1 parts of alcohol, 0.1~1 parts of benzyl alcohol, 0.001~0.1 parts of 2,6-dimethylphenol, 0.01~0.1 parts of phenylethyl alcohol, 0.005~0.1 parts of β-ionone, 0.001~0.1 parts of 3,3-dimethyl-2,3-2H-coumarone-5-ol-2-one, 0.001~0.1 parts of 1,6,6-trimethyl-7-(3-oxo-1-ene)-3,8-dioxetane[5.1.0.0(2,4)]octane-5-one, 0.01~0.1 parts of 4-ethyl-2-methoxyphenol, 0.001~0.02 parts of trans-cinnamaldehyde 5-0.05 parts, hexyl benzoate 0.02-0.15 parts, trans-4-phenyl-3-butene-2-one 0.001-0.01 parts, cis-3-hexenol benzoate 0.05-0.5 parts, 1,5,5-trimethyl L-3-methylene-1-cyclohexene 0.002-0.02 parts, trans-2-hexene benzoate 0.1-0.5 parts, 2-ethyl-5-methylphenol 0.001-0.01 parts, eugenol 0.005-0.05 parts, 4-ethylphenol 0.02-0.1 parts, carvacrol 0.01-0.1 parts, benzoic acid 2-9 parts;

[0008] The following components were detected by UPLC-MS in positive ion mode: 0.1-0.5 parts of betaine, 1-5 parts of vanillin, 10-15 parts of cinnamaldehyde, 5-10 parts of L-carvone, 2-6 parts of methyl salicylate, 10-15 parts of pulegone, 2-8 parts of curcuminol, 2-8 parts of 9,12-octadecadiynoic acid, 12-18 parts of patchouli alcohol, 2-8 parts of theaspirane, 20-30 parts of linolenic acid, and 1-5 parts of N-benzylpalmitamide;

[0009] The following components in parts by weight were detected in UPLC-MS negative ion mode: 0.1-0.5 parts of hyperoside, 1-5 parts of isovanillin, 0.2-0.6 parts of astragaloside, 0.02-0.06 parts of rhubarb glycoside, 2-5 parts of salicylic acid, 0.1-0.5 parts of apigenin, 3-5 parts of capric acid, 15-20 parts of lauric acid, 2-8 parts of myristic acid, 40-50 parts of linoleic acid, and 20-30 parts of stearic acid.

[0010] The application of peach leaf essential oil in at least one of the following aspects:

[0011] (1) Bacteriostasis and / or bactericidal;

[0012] (2) preparing products;

[0013] (3) Antioxidant;

[0014] (4) Eliminate free radicals.

[0015] Preferably, the bacteria are bacteria or fungi.

[0016] More preferably, the bacteria is at least one of Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Pantoea eucrina; and the fungus is at least one of Fusarium oxysporum and Monilinia fructicola. Escherichia coli, a common foodborne pathogen, can cause severe diarrhea, urinary tract infections and even sepsis; Staphylococcus aureus is highly drug-resistant and can easily cause purulent skin infections, pneumonia and systemic sepsis; although Micrococcus luteus is a conditionally pathogenic bacterium, it can induce catheter-related infections and wound contamination in people with weakened immunity; Pantoea is a Gram-negative bacillus that can cause serious infections such as bacteremia and sepsis in immunocompromised individuals; Fusarium oxysporum, an important plant pathogenic fungus, not only causes major economic losses such as crop wilt, but its toxins also threaten food safety; brown rot fungi belong to the genus Streptozotocin, a quarantine harmful fungus that mainly infects stone fruits such as peaches and cherries, causing the fruits to brown and rot and develop a gray-brown mold layer, resulting in serious economic losses.

[0017] Preferably, the product is a product with antibacterial and / or bactericidal properties, an antioxidant product or a free radical scavenging product.

[0018] More preferably, the antibacterial product is a disinfectant or a bactericide.

[0019] More preferably, the antioxidant product or free radical scavenging product is a cosmetic or health product.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention adopts a water distillation method to extract peach leaf essential oil, and identifies the components of the peach leaf essential oil. 40 volatile chemical components are identified by using HS-SPME-GCMS technology, wherein most of the volatile chemical components are aldehydes, esters, and olefins small molecular compounds, and a small portion are phenolic alcohols, acids, and ketones small molecular compounds; and 23 chemical components are identified by using UPLC-MS technology, wherein most of the volatile chemical components are fatty acids and aldehydes, and a small portion are phenols and flavonoids.

[0022] Further research in the present invention found that the extracted peach leaf essential oil containing the above-mentioned compound substances can have excellent antibacterial and bactericidal effects on Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Pantoea, Fusarium oxysporum, and brown rot fungi.

[0023] In addition, the present invention also finds that the extracted peach leaf essential oil has good antioxidant and free radical scavenging capabilities and can be used to prepare cosmetics or health products.

[0024] In summary, the present invention has opened up new applications for peach leaf essential oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the colony growth status of Escherichia coli in Example 3.

[0026] Figure 2 This is the colony growth status of Staphylococcus aureus in Example 3.

[0027] Figure 3 This is the colony growth status of Micrococcus luteus in Example 3.

[0028] Figure 4 This is the colony growth condition of Fusarium oxysporum in Example 3.

[0029] Figure 5 This is the test result of the bactericidal effect of peach leaf essential oil on Escherichia coli in Example 3.

[0030] Figure 6 This is the test result of the bactericidal effect of peach leaf essential oil on Staphylococcus aureus in Example 3.

[0031] Figure 7 This is the test result of the bactericidal effect of peach leaf essential oil on Micrococcus luteus in Example 3.

[0032] Figure 8 This is the test result of the fungicidal effect of peach leaf essential oil on Fusarium oxysporum in Example 3.

[0033] Figure 9 This is the colony growth condition of Pantoea in Example 4.

[0034] Figure 10 This is the colony growth condition of the brown rot fungus in Example 4.

[0035] Figure 11 This is the test result of the bactericidal effect of peach leaf essential oil on Pantoea in Example 4.

[0036] Figure 12 This is the test result of the fungicidal effect of peach leaf essential oil on brown rot fungi in Example 4.

[0037] Figure 13 This is the colony growth condition of Pantoea in Comparative Example 1.

[0038] Figure 14 This is the colony growth status of the brown rot fungus in Comparative Example 1.

[0039] Figure 15 This is the standard curve for total antioxidant capacity determination. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those in the embodiments that do not specify specific techniques or conditions are all conventional methods or are carried out according to the techniques or conditions described in the literature in this field, or are carried out according to the product instructions. Those whose manufacturers are not specified for the reagents and instruments used are all conventional products that can be purchased through regular channels.

[0041] In the following examples, fresh peach leaves were collected from peach varieties in Pinggu District, Beijing. A headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GCMS) was purchased from Agilent Technologies.

[0042] Example 1 Extraction of peach leaf essential oil

[0043] Fresh peach leaves were collected from Pinggu District, Beijing, and essential oil was extracted by water distillation. The specific steps were as follows: 2 kg of fresh peach leaves were taken, distilled water was added at a material-liquid mass ratio of 1:4, the distillation temperature was set at 105°C, and the distillation was performed for 2.5 h. The extracted peach leaf essential oil was placed in a brown bottle and stored at 4°C away from light.

[0044] The relative density, refractive index, and optical rotation of the extracted peach leaf essential oil were determined according to GB / T 11540, GB / T 14454.4, and GB / T 14454.5. The physicochemical properties of peach leaf essential oil are as follows: It is a translucent, light yellow, oily liquid with a distinctive, rich bitter almond aroma. It is volatile, insoluble in water, and prone to crystallization when stored at low temperatures. The relative density of peach leaf essential oil measured in this experiment was 1.07 g / mL, the refractive index was 1.54, and the optical rotation was 0.02°, indicating good stability.

[0045] Example 2 Composition Analysis of Essential Oils

[0046] The chemical components of the peach leaf essential oil prepared in Example 1 were analyzed using HS-SPME-GCMS. Gas chromatography conditions included a DB-WAX UI analytical column (60 m × 0.25 mm × 0.25 μm); He carrier gas; a flow rate of 1 mL / min; an inlet temperature of 250°C; and splitless mode. Heating conditions included an initial temperature of 50°C for 3 min, followed by a temperature increase of 3°C / min to 220°C and a hold of 5 min. Mass spectrometry conditions included an EI ion source; an electron energy of 70 eV; and a mass scan range of 35–500 m / z.

[0047] Gas chromatography-mass spectrometry was used to analyze Example 1 to obtain a total ion current (TIC) of the peach leaf essential oil. The NIST 14 standard spectral library of the National Institute of Standards and Technology (NIST) was then used in combination with the peak area normalization method to perform qualitative analysis and calculate the relative content of each component in the essential oil. The volatile components and relative contents of the peach leaf essential oil are shown in Table 1.

[0048] Table 1 Analysis of volatile chemical components of peach leaf essential oil

[0049]

[0050]

[0051] Most of the volatile chemical components in peach leaf essential oil are aldehydes, esters, and olefin compounds, and a small part is phenolic alcohols, acids, and ketone compounds. The number of carbon atoms in these compounds does not exceed 15, so they are mainly small molecular compounds.

[0052] Furthermore, UPLC-MS was used to analyze the chemical components of the peach leaf essential oil prepared in Example 1.

[0053] The instrumentation used was a SCIEX ExionLC AD ultrahigh-pressure liquid chromatography system and a TripleTOF 5600+ mass spectrometer from SCIEX (USA). Chromatographic conditions included a Waters ACQUITY UPLC HSS T3 column (2.1×100 mm, 1.8 μm), mobile phase A consisting of water (0.05% formic acid) and mobile phase B consisting of acetonitrile (0.05% formic acid). The mobile phase gradient was as follows: 95% A from 0 to 0.5 min; 95% to 5% A from 0.5 to 13 min; 5% A from 13 to 16 min; 5% to 95% A from 16 to 16.1 min; and 95% A from 16.1 to 20 min. The injection volume was 5 μL, the column temperature was 40°C, and the flow rate was 0.3 mL / min. Mass spectrometry conditions included ionization parameters: ESI positive and ESI negative modes. Ion nebulizer voltage was 5500 V (positive ion mode) and -4500 V (negative ion mode); the ion source temperature was 500°C; the nebulizer gas (GS1) was 50 psi, the auxiliary heater gas (GS2) was 60 psi; the collision gas was set to medium; and the curtain gas was 30 psi. Data acquisition method: IDA method, primary TOF-MS and secondary TOF-MS / MS data were acquired simultaneously. The scan range of TOF-MS was m / z 100-1200 Da, and the scan range of TOF-MS / MS was 50-2000 Da. The declustering voltage was 60 V (positive ion) and -60 V (negative ion); the collision energy for the MS / MS experiment was set to 35 V (positive ion) and -35 V (negative ion), with a collision energy range of 15 V.

[0054] Liquid chromatography-mass spectrometry (LC-MS) was used to analyze Example 1 to obtain a total ion chromatogram and mass spectrum of the peach leaf essential oil. Compound identification was performed using accurate mass matching and secondary spectrum matching. Compound retrieval, qualitative analysis, and relative content calculation were performed using the TripleTOF system's Analytics TF software. Twelve compounds were obtained in positive ion mode, and the relative contents of each compound are shown in Table 2. Eleven compounds were obtained in negative ion mode, and the relative contents of each compound are shown in Table 3.

[0055] Table 2 Chemical composition analysis under positive ion mode

[0056] serial number Retention time (min) Compound name CAS Number Relative content (%) 1 0.86 Betaine 107-43-7 0.21 2 4.92 Vanillin 121-33-5 3.18 3 7.74 Cinnamaldehyde 104-55-2 12.30 4 8.14 L-Carvone 6485-40-1 7.72 5 8.41 Methyl salicylate 119-36-8 4.85 6 9.17 Pulegone 89-80-5 11.19 7 10.58 Curcumenol 19431-84-6 5.04 8 11.15 9,12-Octadecanediynoic acid 2012-14-8 6.38 9 12 Baiqiu Lichun 5986-55-0 15.73 10 12.73 Teaspirane 36431-72-8 5.15 11 12.74 Linolenic acid 463-40-1 26.47 12 14.39 N-Benzyl palmitamide 74058-71-2 1.80

[0057] Table 3 Chemical composition analysis under negative ion mode

[0058] serial number Retention time (min) Compound name CAS Number Relative content (%) 1 4.78 Hyperoside 482-36-0 0.11 2 4.95 Isovanillin 621-59-0 1.20 3 5.02 Astragaloside 480-10-4 0.45 4 5.05 Rhusin 17306-46-6 0.04 5 6.18 Salicylic acid 69-72-7 2.94 6 7.03 Apigenin 520-36-5 0.18 7 10.19 Decanoic acid 334-48-5 3.91 8 11.6 Lauric acid 143-07-7 17.02 9 12.89 Myristate 544-63-8 4.51 10 13.39 Linoleic acid 2197-37-7 45.06 11 14.96 stearic acid 57-11-4 24.58

[0059] Example 3 Determination of antibacterial and bactericidal activity of peach leaf essential oil against Escherichia coli, Staphylococcus aureus, Micrococcus luteus, and Fusarium oxysporum

[0060] The materials required for this experiment are as follows: LB medium (Beijing Coolaibo Technology Co., Ltd.); PDA medium (Beijing Luqiao Technology Co., Ltd.). Escherichia coli, Staphylococcus aureus, Micrococcus luteus, and Fusarium oxysporum were stored by the Beijing Academy of Agriculture and Forestry Sciences.

[0061] 1. Antibacterial effect on Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Fusarium oxysporum

[0062] Take the concentration as (1~9)×10 8 100 μL of bacterial solution with a CFU / mL was evenly spread on an antibiotic-free LB plate (90 mm diameter). A sterilized 6 mm filter paper was then added and placed in the center of the plate. Finally, 10 μL of the peach leaf essential oil from Example 1 was dripped onto the filter paper. A filter paper plate without essential oil was used as a control. After incubation at 37°C for 24 h, the diameter of the inhibition zone was measured to determine the antibacterial effect. Each treatment was repeated three times.

[0063] A 5 mm diameter Fusarium oxysporum cake was placed on a 90 mm diameter PDA plate. A small well was dug approximately 2 cm from each side of the plate. 5 μL of peach leaf essential oil was added to each well. A plate without essential oil was used as a control. The colony diameters were measured at 28°C for 72 hours, and the inhibition rate was calculated. Each treatment was replicated three times. Inhibition rate (%) = [(control colony diameter - treated colony diameter / (control colony diameter - cake diameter)] × 100.

[0064] The colony growth of Escherichia coli, Staphylococcus aureus and Micrococcus luteus in the peach leaf essential oil treatment group and the control group after being cultured at 37℃ for 24 hours was as follows: Figure 1 、 Figure 2 、 Figure 3 .

[0065] According to previous studies, when the diameter of the inhibition zone is greater than 20 mm, it is highly sensitive; between 14 and 20 mm, it is sensitive; between 8 and 14 mm, it is moderately sensitive; and less than 8 mm, it is insensitive. [1]. In this experiment, the diameters of the inhibition zones of peach leaf essential oil against Escherichia coli were 24.18mm, 24.98mm, and 28.13mm, respectively, with an average of 25.76mm±1.71mm. This shows that Escherichia coli is highly sensitive to peach leaf essential oil. At the same time, after treatment with peach leaf essential oil, no colony growth was found in Staphylococcus aureus and Micrococcus luteus, that is, the diameter of the inhibition zone was greater than 90mm. This shows that Staphylococcus aureus and Micrococcus luteus are also highly sensitive to peach leaf essential oil. According to the existing technology, the diameter of the inhibition zone of Rhododendron capitatum essential oil against Staphylococcus aureus and Micrococcus luteus obtained by Ji Ruowei et al. is only between 14 and 20 mm. [2] The diameter of the inhibition zone of grapefruit peel essential oil against Micrococcus luteus found by Lü Gan et al. is only between 8 and 14 mm. [3] .

[0066] After the Fusarium oxysporum was cultured at 28℃ for 72 hours, the colony growth was as follows: Figure 4 Peach leaf essential oil has a significant inhibitory effect on Fusarium oxysporum, and the colony does not spread, with an inhibition rate of 100%. Compared with the existing technology, the antibacterial activity of peach leaf essential oil against Fusarium oxysporum is stronger than that of bay leaf essential oil, lemongrass essential oil, palmarosa essential oil and thyme essential oil. [4] .

[0067] In summary, peach leaf essential oil has a strong inhibitory effect on the growth of Escherichia coli, Staphylococcus aureus, Micrococcus luteus, and Fusarium oxysporum, especially the antibacterial effect on Staphylococcus aureus, Micrococcus luteus, and Fusarium oxysporum, which far exceeds the existing technology.

[0068] 2. Bactericidal effect on Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Fusarium oxysporum

[0069] In order to further clarify the bactericidal effect of peach leaf essential oil, the inhibition zone areas or areas without colony growth of three types of bacteria and fungi were selected and transferred to new plate culture media to observe whether the bacteria and fungi were killed.

[0070] Take the inhibition zone culture medium from the Escherichia coli culture dish treated with peach leaf essential oil, streak culture on a new plate for 24 hours, and no colonies will grow (see Figure 5 A1-A3 in the middle); however, after taking culture medium from the non-inhibition zone and streaking it onto a new plate, the bacteria can grow normally and form colonies (see Figure 5 This experiment showed that the Escherichia coli in the inhibition zone of the peach leaf essential oil-treated group was killed.

[0071] Take the culture medium from the Staphylococcus aureus and Micrococcus luteus culture plates treated with peach leaf essential oil, streak culture on new plates, and no colonies will grow (see Figure 6-Figure 7A1-A3 in the control group). After streaking culture medium from the culture dish, both bacteria were able to grow normally and form colonies (see Figure 6-Figure 7 A4); This experiment showed that Staphylococcus aureus and Micrococcus luteus in the peach leaf essential oil treatment group were killed.

[0072] The culture medium around the Fusarium oxysporum culture plate treated with peach leaf essential oil was taken and cultured on a new plate. No colonies were grown (see Figure 8 A1-A3); however, the fungus could grow normally after the culture medium taken from the peach leaf essential oil control group was cultured in a new culture dish (see Figure 8 This experiment showed that the Fusarium oxysporum in the peach leaf essential oil treatment group was killed.

[0073] In summary, peach leaf essential oil has excellent growth inhibition effect on Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Fusarium oxysporum, and can also achieve complete killing of them, that is, it has both excellent antibacterial and bactericidal effects. In the existing technology, although most plant essential oils have certain antibacterial activity against some specific bacteria, they do not have strong bactericidal activity. For example, Zhang Shoumei et al. determined the effects of 6 kinds of plant essential oils on the growth of Fusarium oxysporum. The results showed that filter paper containing pepper essential oil, cinnamon essential oil, clove essential oil, lemon essential oil, oregano essential oil and wintergreen essential oil all had an inhibitory effect on the growth of Fusarium oxysporum, but did not completely kill Fusarium oxysporum. [5] .

[0074] Example 4 Determination of antibacterial and bactericidal activity of peach leaf essential oil against Pantoea and brown rot pathogens

[0075] The materials required for this experiment are as follows: LB medium (provided by Beijing Coolaibo Technology Co., Ltd.); PDA medium (provided by Beijing Luqiao Technology Co., Ltd.); Pantoea eucrina (Pantoea eucrina) was isolated from peach leaves infected with black spot disease, and Monilinia fructicola (Monilinia fructicola) was isolated from peach fruit infected with brown rot disease. They were identified using 16s rDNA and ITS molecular identification. Sweet orange and lavender essential oils were purchased from Organic Earth Biotechnology Co., Ltd.

[0076] 1. Antibacterial effect on Pantoea and brown rot fungi

[0077] Take the concentration as (1~9)×10 8100 μL of Pantoea solution (CFU / mL) was evenly spread on an antibiotic-free LB plate (90 mm diameter). A sterilized 6 mm filter paper was then placed in the center of the plate. Finally, 10 μL of essential oil (peach leaf essential oil, sweet orange essential oil, and lavender essential oil, respectively, were dropped onto the filter paper. A filter paper plate without essential oil was used as a control. After incubation at 28°C for 10 h, the diameter of the inhibition zone was measured to determine the antibacterial effect. Each treatment was repeated three times.

[0078] like Figure 9 As shown, after Pantoea was cultured on LB plates at 28°C for 10 hours, clear inhibition zones appeared on the plates containing 10 μL of sweet orange essential oil and 10 μL of lavender essential oil, measuring 35.85 mm ± 4.21 mm and 32.23 mm ± 0.27 mm, respectively. However, no colonies were observed on the plates containing 10 μL of peach leaf essential oil, indicating that peach leaf essential oil completely inhibited the growth of Pantoea.

[0079] A 5 mm diameter brown rot fungus cake was placed on a PDA plate medium (90 mm in diameter), a small hole was dug about 2 cm on both sides, and 10 μL of essential oil was added to each well (the essential oils were peach leaf essential oil, sweet orange essential oil, and lavender essential oil in Example 1, respectively). A well-plate medium without essential oil was used as a control and cultured at 28 ° C for 96 h.

[0080] like Figure 10 As shown in the figure, after 96 hours of incubation at 28°C on PDA plates, the brown rot fungus in the 10 μL sweet orange essential oil and 10 μL lavender essential oil groups did not spread, but brown circles appeared to varying degrees on the plates. This may be because the essential oil treatment inhibited the growth of brown rot mycelium, causing the fungus to produce pigment metabolites. In contrast, the group containing 10 μL peach leaf essential oil had its growth completely inhibited and no pigment metabolites were produced, indicating that peach leaf essential oil completely inhibited the growth of brown rot fungi.

[0081] 2. Bactericidal effect on Pantoea and brown rot pathogens

[0082] In order to further clarify the bactericidal effect of peach leaf essential oil on Pantoea and brown rot pathogens, the plates treated with peach leaf essential oil were selected and transferred to new plate culture medium to observe whether the bacteria were killed.

[0083] Depend on Figure 11 It can be seen that after 10 hours of culture on the new plate, no Pantoea colonies grew, indicating that the Pantoea in the peach leaf essential oil treatment group was killed.

[0084] Depend on Figure 12 It can be seen that after 96 hours of culture on the new plate, no brown rot fungus colonies grew, indicating that the brown rot fungus in the peach leaf essential oil treatment group was killed.

[0085] In summary, peach leaf essential oil has an excellent growth inhibition effect on Pantoea and brown rot fungi, and can also completely kill them, that is, it has both excellent antibacterial and bactericidal effects. Comparative Example 1 Determination of the antibacterial activity of other peach leaf extracts against Pantoea and brown rot fungi

[0086] The materials required for this experiment are as follows: LB medium: Beijing Coolaibo Technology Co., Ltd.; PDA medium: Beijing Luqiao Technology Co., Ltd.; Pantoea eucrina was isolated from peach leaves infected with black spot disease, and Monilinia fructicola was isolated from peach fruit infected with brown rot disease. They were identified using 16s rDNA and ITS molecular identification. Peach leaf aqueous extract was prepared by adding distilled water to 2 kg of fresh peach leaves at a material-to-liquid ratio of 1:4, soaking and boiling for 2 hours, and filtering the resulting filtrate. Peach leaf ethanol extract was prepared by drying and grinding the peach leaves, adding 80% ethanol aqueous solution at a mass ratio of 1:10, and extracting them with 300W ultrasonic waves for 2 hours. The filtrate was then cooled, filtered, and concentrated under reduced pressure to remove the ethanol.

[0087] Take the concentration as (1~9)×10 8 100 μL of Pantoea spp. culture solution (CFU / mL) was evenly spread on an antibiotic-free LB plate (90 mm in diameter). A sterilized 6 mm filter paper was then added and placed in the center of the plate. Finally, 10 μL of peach leaf extract (peach leaf aqueous extract, peach leaf alcohol extract, and the peach leaf essential oil of Example 1) was dripped onto the filter paper. A filter paper plate without essential oil was used as a control and cultured at 28°C for 10 h. Each treatment was repeated three times.

[0088] like Figure 13 As shown, after Pantoea was cultured in LB plates at 28°C for 10 h, no inhibition zone appeared in the plates containing 10 μL of peach leaf water extract and 10 μL of peach leaf alcohol extract, indicating that the growth of Pantoea was not significantly inhibited.

[0089] A brown rot fungus cake with a diameter of 5 mm was placed on a PDA flat plate culture medium (diameter 90 mm), and a small hole was dug at about 2 cm on both sides of it. 10 μL of peach leaf extract (peach leaf extracts were selected from peach leaf water extract, peach leaf alcohol extract and peach leaf essential oil in Example 1) was added to each well. A well-plate culture medium without essential oil was used as a control and cultured at 28°C for 96 h.

[0090] like Figure 14 As shown, after 96 hours of incubation at 28°C on PDA plates, the growth of brown rot fungi was not significantly inhibited in the plates containing 10 μL of peach leaf aqueous extract or 10 μL of peach leaf alcohol extract. These results indicate that peach leaf essential oil has much greater antibacterial activity against Pantoea and brown rot fungi than peach leaf aqueous extract or peach leaf alcohol extract.

[0091] Example 5 Free Radical Scavenging and Total Antioxidant Capacity Determination

[0092] Microplate reader: Swiss TECAN, model: SPARK; water bath: Shanghai Yiheng Scientific Instrument Co., Ltd., model: DK-8D; anhydrous ethanol (AR grade): Beijing Tongguang Fine Chemical Company; 96-well plate: Thermo Scientific Company; other chemical reagents used were from Shanghai MacLean Biochemical Technology Co., Ltd.

[0093] In this example, the free radical scavenging ability of the peach leaf essential oil prepared in Example 1 was measured, and the steps were as follows:

[0094] Mix 20 μL of essential oil with 380 μL of DPPH solution, react at room temperature in the dark for 20 min, take 200 μL and transfer to a 96-well plate. Use a microplate reader to measure the absorbance A1 at 515 nm. Replace the essential oil with 20 μL of anhydrous ethanol as a blank, measure the absorbance A2 at 515 nm, and calculate the DPPH free radical scavenging rate using the following formula: DPPH free radical scavenging rate (%) = (A2-A1) / A2×100%.

[0095] The results of the DPPH free radical scavenging test showed that the DPPH free radical scavenging rate of peach leaf essential oil was (79.44±1.39)%.

[0096] Furthermore, the total antioxidant capacity of peach leaf essential oil was determined as follows:

[0097] Mix 30 μL of essential oil with 264 μL of FRAP working solution, then place in a 37°C water bath for 30 minutes. Take 200 μL and transfer it to a 96-well plate. Measure the absorbance at 593 nm using a microplate reader. Dilute the ferrous standard solution to 0.1-2 mM with distilled water, measure the absorbance, and create a standard curve ( Figure 15 ). According to the absorbance of the sample, the corresponding ferrous ion concentration is found on the standard curve to obtain the total antioxidant capacity of the sample.

[0098] The FRAP total antioxidant capacity was determined by drawing a standard curve using FeSO4. It was found that the linear relationship was good between 0.10 and 2.00 mmol / L, and the regression equation was Y = 1.3272X + 0.1293 (R 2 =0.9982), and by measuring the absorbance of peach leaf essential oil, the FRAP value of the total antioxidant capacity of peach leaf essential oil was calculated to be (0.75±0.19) mM. Therefore, it can be seen that the antioxidant capacity of peach leaf essential oil is relatively strong.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

[0100] References:

[0101] [1] Yang Lihua, Xu Haihan, Li Deyan, et al. Antibacterial stability and antioxidant activity of lemongrass essential oil. J Food Industry Science, 2024: 1-13.

[0102] [2] Ji Ruowei, Yang Yang, Lin Pengcheng. Study on the essential oil components and antibacterial activity of Rhododendron capitatum leaves. Journal of Hubei Agricultural Sciences, 2021, 60(03): 120-124.

[0103] [3] Lü Gan, Chen Siting, Wu Guangheng, et al. Extraction of pomelo peel essential oil by enzyme-assisted steam distillation and its antibacterial activity. Journal of Guangdong Chemical Industry, 2019, 46(23): 17-19+33.

[0104] [4] Wang Dan, Zhang Jing, Zhai Hao, et al. Isolation and identification of blueberry postharvest decay fungi and study on their inhibitory effect of plant essential oils. J. Preservation & Processing, 2020, 20(02): 52-56.

[0105] [5] Zhang Shoumei, Zhang Nana, Wang Xingya, et al. Study on the inhibitory effect of plant essential oils on dominant fungi contaminating wheat during storage. Journal of Agricultural Product Quality and Safety, 2021(03):28-32+39.

Claims

1. A peach leaf essential oil, characterized in that It is extracted from peach leaves using water distillation.

2. A peach leaf essential oil according to claim 1, characterized in that, The extraction step of the water distillation method comprises: mixing peach leaves with water, and distilling at 100-110° C. for more than 2.5 hours.

3. A peach leaf essential oil according to claim 1 or 2, characterized in that, The invention comprises the following components in parts by weight: 0.5-1 part of limonene, 0.01-0.08 part of trans-2-(2-pentyl)furan, 0.1-0.5 part of n-hexanol, 0.1-0.8 part of trans-3-hexen-1-ol, 0.01-0.8 part of cis-2-hexen-1-ol, 0.1-0.5 part of N-butyric acid (trans-2-hexenyl) ester, 65-90 parts of benzaldehyde, 1-2 parts of methyl benzoate, 0.01-1 part of cis-2-decenal, 0.05-0.5 part of safranal, 0.05-0.5 part of acetophenone, 0.05-0.5 part of ethyl benzoate, 0.01-0.1 part of salicylaldehyde, 0.01-0.1 part of 1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene, and α-terpineol. 0.01~0.3 parts, 1,1,6-trimethyl-1,2-dihydronaphthalene 0.01~0.3 parts, nerol 0.01~0.3 parts, 1-phenyl-1,2-propanedione 0.05~0.3 parts, β-damascenone 0.01~0.1 parts, damascenone 0.1~0.5 parts, guaiacol 0.01~0.1 parts, 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-ol 0.001~0.1 parts, benzyl alcohol 0.1~1 parts, 2,6-dimethylphenol 0.001~0.1 parts, phenylethyl alcohol 0.01~0.1 parts, β-ionone 0.005~0.1 parts, 3,3-dimethyl-2,3-2H-coumarone-5-ol-2-one 0.001~0. 1 part, 1,6,6-trimethyl-7-(3-oxo-1-ene)-3,8-dioxetane[5.1.0.0(2,4)]octane-5-one 0.01~0.1 part, 4-ethyl-2-methoxyphenol 0.001~0.02 part, trans-cinnamaldehyde 0.005~0.05 part, hexyl benzoate 0.02~0.15 part, trans-4-phenyl-3-butene-2-one 0.001~0.01 part, cis-3-hexenol benzoate 0.05~0.5 part, 1,5,5-trimethyl L-3-methylene-1-cyclohexene 0.002~0.02 part, trans-2-hexene benzoate 0.1~0.5 part, 2-ethyl-5-methylphenol 0.001~0.01 part, Eugenol 0.005-0.05 parts, 4-ethylphenol 0.02-0.1 parts, carvacrol 0.01-0.1 parts, benzoic acid 2-9 parts, betaine 0.1-0.5 parts, vanillin 1-5 parts, cinnamaldehyde 10-15 parts, L-carvone 5-10 parts, methyl salicylate 2-6 parts, pulegone 10-15 parts, curcuminol 2-8 parts, 9,12-octadecadiynoic acid 2-8 parts, patchouli alcohol 12-18 parts, tea spirane 2-8 parts, linolenic acid 20-30 parts, N-benzyl palmitamide 1-5 parts, hyperoside 0.1-0.5 parts, isovanillin 1-5 parts, astragalin 0.2-0.6 parts, wild sumacin 0.02-0.06 parts, salicylic acid 2-5 parts, apigenin 0.1-0.5 parts, capric acid 3-5 parts, lauric acid 15-20 parts, myristic acid 2-8 parts, linoleic acid 40-50 parts and stearic acid 20-30 parts.

4. The use of peach leaf essential oil according to any one of claims 1 to 3 in at least one of the following aspects: (1) Bacteriostasis and / or bactericidal; (2) preparing products; (3) Antioxidant; (4) Eliminate free radicals.

5. The use according to claim 4, characterized in that The bacteria are bacteria or fungi.

6. The use according to claim 5, characterized in that The bacteria is at least one of Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Pantoea; the fungus is at least one of Fusarium oxysporum and brown rot fungus.

7. The use according to claim 4, characterized in that The product is a product with antibacterial and / or bactericidal properties, an antioxidant product or a free radical scavenging product.

8. The use according to claim 7, characterized in that The product having bacteriostatic and / or bactericidal properties is a disinfectant or bactericide.

9. The use according to claim 7, characterized in that The antioxidant product or free radical scavenging product is a cosmetic or health product.

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