A method for increasing the content of flavonoids and cyanidin in Phyllostachys edulis

Abstract

This invention discloses a method for increasing the content of flavonoids and cyanidin in *Phyllostachys edulis*, belonging to the field of plant cultivation technology. This invention uses continuous irradiation of *Phyllostachys edulis* with light of specific wavelengths and intensities; light with wavelengths of 354-478 nm is the main wavelength inducing culm discoloration; when the blue light intensity exceeds 8 μmol / m², the irradiation is further enhanced. 2 At a certain temperature, the color and anthocyanin content of bamboo increased significantly. After light treatment, the contents of six flavonoids, including vitexin, isohypericin, narcissin, hyperoside, luteolinin, and luteolin, increased by 9.02, 8.79, 2.34, 8.5, 9.4, and 1.9 times, respectively; the content of cyanidin-3-O-rutin increased by 7.41 times.

Description

Technical Field

[0001] This invention belongs to the field of plant cultivation technology, and more specifically, relates to a method for increasing the content of flavonoids and cyanidin in Phyllostachys edulis. Background Technology

[0002] The genus *Chimonobambusa* comprises small to medium-diameter bamboos, currently primarily used for their shoots, with few reports on other applications. Bamboo culm discoloration is a common phenomenon in *Chimonobambusa*, especially in late autumn, deep winter, and early spring. While discoloration in green plants is often related to changes in pigments within green tissue cells, there is a lack of existing research specifically on discoloration in *Chimonobambusa*. No studies have confirmed whether this discoloration is related to the high cold resistance of *Chimonobambusa* species, and the ecological and physiological significance of the discolored culms has not been reported.

[0003] Plant flavonoids are important components of traditional Chinese medicine, possessing functions such as regulating bodily functions, enhancing immunity, anti-oxidation, scavenging free radicals, anti-aging, lowering cholesterol, improving blood circulation, anti-inflammation, and anti-tumor effects. Flavonoids refer to a group of compounds formed by two phenolic hydroxyl groups (A and B rings) linked by a central three-carbon atom, with 2-phenylchromone as their basic nucleus. Based on the degree of oxidation of the central three-carbon chain, the position of the B-ring link (2- or 3-position), and whether the three-carbon chain forms a ring, natural flavonoids are classified into flavones, flavonols, flavonones, flavanonol, isoflavones, dihydroisoflavones, anthocyanidins, chalcones, aurones, flavanes, and biflavonoids. Currently, bamboo leaf flavonoids are generally considered to be mainly classified into five categories: red rutin and isorhodin, luteolin, vitexin, apigenin and other 4'-OH flavonoid glycosides. Among them, red rutin, isorhodin and vitexin are C-glycoside flavonoids, that is, the glycoside and phenolic ring are linked together by C-C bonds.

[0004] The Bamboo Research Institute of Nanjing Forestry University previously used a flavonoid-targeted metabolomics analysis method to analyze the green bamboo of *Chimonobambusa sichuanensis*, *Phyllostachys nigra*, *Phyllostachys edulis*, *Phyllostachys vivax 'Aureocaulis'*, *Chimonobambusa purpurea*, *Chimonobambusa quadrangularis*, and *Chimonobambusa marmorea*, as well as the yellow bamboo of *Chimonobambusa sichuanensis* and *Chimonobambusa jinfoshanensis*. Absolute quantitative analysis (AQUA) was performed on 204 detectable flavonoid compounds in the bamboo sheaths and shoots of *Phyllostachys utilis*. The results showed that the flavonoid content in the inner bamboo shoot was higher than that in the outer bamboo shoot. After blue light induction, the contents of three flavonoids—hyperoside, rutin, and isopropanol—in the purple inner bamboo shoot significantly increased, by 9.47 times, 8.79 times, and 4.29 times, respectively, compared to the green inner bamboo shoot. The most abundant anthocyanin in the inner bamboo shoot was cyanidin-3-O-rutin, followed by cyanidin-3-O-glucoside; the contents of these two pigments in the purple inner bamboo shoot were nearly 10 times higher than in the green inner bamboo shoot. A color comparison was made between standard solutions of hyperoside, isorhodin, rutin, shampooside, cyanidin-3-O-glucoside, and cyanidin-3-O-rutinoside and solutions of the above flavonoid compounds extracted from *Phyllostachys edulis* using methanol (0.1% HCl). The cyanidin-3-O-glucoside solution was deep red, while the cyanidin-3-O-rutinoside solution was light red, with a color difference discernible to the naked eye. The cyanidin-3-O-glucoside solution was similar in color to the purple *Phyllostachys edulis* extract, confirming that the purple portion of *Phyllostachys edulis* exhibits the color of cyanidin-type anthocyanins. Furthermore, since the *Phyllostachys edulis* also contains a high amount of chlorophyll, it exhibits a certain degree of deep purple. Summary of the Invention

[0005] In view of the above-mentioned problems in the existing technology, the technical problem to be solved by the present invention is to provide a method for increasing the content of flavonoids and cyanidin in bamboo, for the purpose of bamboo variety improvement.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for increasing the content of flavonoids and cyanidin in Phyllostachys edulis, using a wavelength of 354-478 nm and 100 μmol / m 2 Bamboo was continuously irradiated with light of intensity below / s.

[0008] The wavelength is 460nm.

[0009] The light intensity is 8 μmol / m 2 / s.

[0010] The continuous irradiation treatment refers to continuous irradiation for more than 15 days.

[0011] The flavonoids mentioned are vitexin, isohypericin, narcissin, hyperoside, luteolin, and luteolin.

[0012] The cyanidin mentioned is cyanidin-3-O-rutin.

[0013] The specific steps for increasing the content of flavonoids and cyanidin in *Phyllostachys edulis* include:

[0014] Install blue light lamps in the bamboo forest, at a quantity of 1-2 per 100m. 2 One bamboo leaf is required to receive a light intensity of 8 μmol / m², even if the leaf is furthest from the blue light source. 2 / s, with a blue light wavelength of 460nm, a photocycle of 16h supplemental light and 8h no supplemental light, and an irradiation time of 30 days, resulted in bamboo shoots with significantly increased levels of flavonoids and cyanidin in the body.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention uses light of specific wavelengths and intensities to continuously irradiate square bamboo. Light with wavelengths of 354-478 nm is the primary wavelength inducing discoloration of the bamboo culms; when the blue light intensity exceeds 8 μmol / m²... 2 At a certain temperature, the color and anthocyanin content of bamboo increased significantly. After light treatment, the contents of six flavonoids, including vitexin, isohypericin, narcissin, hyperoside, luteolinin, and luteolin, increased by 9.02, 8.79, 2.34, 8.5, 9.4, and 1.9 times, respectively; the content of cyanidin-3-O-rutin increased by 7.41 times. Attached Figure Description

[0017] Figure 1 This diagram illustrates the effect of different wavelengths of light on the discoloration of bamboo culms.

[0018] Figure 2 The effect of light of different intensities and durations on the color and anthocyanin content of bamboo is shown in the figure.

[0019] Figure 3 This image shows the color change of bamboo stalks after blue light treatment.

[0020] Figure 4 This image shows the anthocyanin content in different parts of bamboo after blue light treatment.

[0021] Figure 5 The graph shows the changes in the content of flavonoids in bamboo after blue light treatment.

[0022] Figure 6 This graph shows the changes in cyanidin content in bamboo after blue light treatment. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to specific embodiments. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art.

[0024] The bamboo forest of this invention grows in Yunnan at an altitude of 600-1800m, and the trial began in April 2021.

[0025] Example 1

[0026] Bamboo stalks were wrapped with films that transmit different wavelengths of light (purple, green, red, orange, blue, pink, yellow, and colorless films) and exposed to sunlight for 30 days, with a photocycle of 16 hours of daytime and 8 hours of nighttime.

[0027] The results are as follows Figure 1 As shown, light with wavelengths of 354-478nm is the main wavelength that induces discoloration in bamboo culms.

[0028] Example 2

[0029] Using 0, 8, 30, 50, 70 and 100 μmol / m respectively 2 Bamboo was irradiated with 460nm blue light for 30 days, with a photocycle of 16 hours of daytime and 8 hours of nighttime.

[0030] The results are as follows Figure 2 As shown, when the blue light intensity exceeds 8 μmol / m 2 At / s, the color and anthocyanin content of bamboo increased significantly.

[0031] Example 3

[0032] 1. Install blue lights in the bamboo forest, at a quantity of 1-2 per 100m². 2 One bamboo leaf is required to receive a light intensity of 8 μmol / m², even if the leaf is furthest from the blue light source. 2 / s, the wavelength of the blue light is 460nm, the photocycle is 16h supplemental lighting, 8h no supplemental lighting, the irradiation time is 30 days, and the discoloration of the bamboo culms is as follows. Figure 3 As shown in the figure. Anthocyanin content was determined by extracting the purple bamboo shoots, the transition zone, and the green bamboo shoots, respectively.

[0033] The results are as follows Figure 4As shown, the anthocyanin content in the discolored parts of bamboo is significantly higher than that in the non-discolored parts.

[0034] 2. Collect the same parts of bamboo samples that have been treated with light and those that have not been treated with light, freeze-dry them under vacuum, grind them into powder using a ball mill, and perform absolute quantitative analysis by LC-MS / MS using the internal standard method.

[0035] The results are as follows Figure 5 As shown, the contents of six flavonoids, namely vitexin (CAS 3681-93-4), isorhizin (CAS 4261-42-1), narcissin (CAS 604-80-8), hyperoside (CAS 482-36-0), luteolinin (CAS 5373-11-5), and luteolin (CAS 491-70-3), increased by 9.02, 8.79, 2.34, 8.5, 9.4, and 1.9 times, respectively.

[0036] The results are as follows Figure 6 As shown, the content of cyanidin-3-O-rutin increased by 7.41 times.

Claims

1. A method for increasing the content of flavonoids and cyanidin in *Phyllostachys edulis*, characterized in that, Install blue light lamps in the bamboo forest, at a quantity of 1-2 per 100m. 2 One bamboo leaf is required to receive a light intensity of 8 μmol / m², even if the leaf is furthest from the blue light source. 2 / s, the wavelength of the blue light lamp is 460nm, the photocycle is 16h supplementary light, 8h no supplementary light, the irradiation time is 30 days, and the content of flavonoids and cyanidin in the body of the bamboo is significantly increased. The flavonoids mentioned are vitexin, isohypericin, narcissin, hyperoside, luteolin, and luteolin; the cyanidin is cyanidin-3-O-rutin.

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