The effective living biomass contained in bamboo leaves is mainly flavonoids, which are highly polar and hydrophilic, so solvents such as hot water, methanol, ethanol, and acetone can be selected for extraction.
Bamboo leaves are rich in flavonoids, with an average content of about 2%. The functional factor of bamboo leaf flavonoids is flavone glycosides. Bamboo leaf flavone glycosides have two types: carbon glycosides and oxyglycosides. Carbon glycoside flavones refer to the sugar groups in which are connected to the flavone mother nucleus through C-C bonds, and oxyglycoside flavones are linked to flavones through O-C bonds. The mother nucleus is connected. Compared with oxyglycoside flavonoids, carbon glycoside flavones have the advantages of stable structure, can penetrate deep into the lesion site, and directly exert the curative effect, and have strong hydrophilicity, which is beneficial to the development of drugs, food, cosmetics, etc. The carbon glycoside flavonoids in bamboo leaves mainly include orientin, isoorientin, vitexin and isovitexin.
Bamboo leaf flavonoids have a strong antibacterial effect. Studies have shown that bamboo leaf flavonoids have strong inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The minimum inhibitory concentration of Sarcina luteus is only 4%, and the inhibitory effect on Escherichia coli and Bacillus subtilis is relatively weak, and the minimum inhibitory concentration is 10%; it has no obvious inhibitory effect on yeast and mold. It has a certain antibacterial effect on some molds such as Rhizopus and Penicillium, but has no antibacterial effect on Aspergillus niger and bread mold.
The optimal antibacterial effect of different bamboo species is different. The bamboo species with higher flavonoid content shows better antibacterial effect, while the one with lower flavonoid content has relatively poor antibacterial effect. The best antibacterial effect of each bamboo species There is a good correlation between the effect and the content of flavonoids. The longer the action time of the same concentration of flavonoids, the higher the inhibition rate.
Studies have shown that the purified product of bamboo leaf flavonoids is separated by silica gel column for the second time, and the part with the best antibacterial effect is obtained. Through HPLC and LC-MS analysis, it is judged that vitexin may be one of the main antibacterial components, and it may also be There is a small portion of isovitexin components.
Bamboo leaf flavonoids have good sun protection effect, and the average absorbance of bamboo leaf extract powder flavonoids skin cream with a mass fraction of 1.5% is 1.273 in the UV-B area, and 0.965 in the UV-A area, indicating that bamboo leaf flavonoids have the effect on ultraviolet radiation. Certain absorbency. bamboo leaf extract flavonoid skin cream also exhibited better moisturizing performance, which can improve the moisturizing performance to 72.6%, which is nearly 30% higher than that of the control sample. Bamboo leaf flavonoids can also be properly combined with other components commonly used in cosmetics, such as various vitamins, hyaluronic acid, amino acids, etc. to make products with different uses and more outstanding effects.
