The Research On Extracting Cosmetics Preservative From Bamboo Leaves

In this paper, the extract of Phyllostachys pubescens Mazel Ex H. De Lehaie Leaves from Longyou was studied. The research consisted of the optimization of extract technics, antibacterial activity evaluation and the stability test. The isolation and purification of effective part were also studied to find the effective components. Eventually, we gave the result of bamboo leaves extract's application in cosmetic.The ethanol-water extract and water extract were obtained by refluxing, concentrating and drying, successively. The process conditions were optimized by single factor experiment with orthogonal design test and response surface analysis methods, respectively. The optimum extraction conditions were as follows: the concentration of ethanol was 60 % and extract at 60°C for 2 h while the ratio of solvent and material was 20: 1(mL: g) while the water extract was obtained by extracting for 4.3 h at 83°C with the ratio was 24.6: 1(mL: g). The predicted value of water extract's maximal inhibition zone will be 9.43 mm. We found that the difference between ethanol-water and water extracts'antibacterial activity is not evident. Considering that most effective components in bamboo leaves are flavones in form of indican, so the method of water refluxing is advisable.Water extract was deposited with ethanol to remove the sample matrix and further extracted by four different polarity solvents i.e. petroleum ether, chloroform, ethyl acetate and n-butanol, successively. And then the four different parts both with the last water part were compared through testing their antibacterial activities, we found that the fractions extracted by petroleum ether, chloroform and ethyl acetate exhibited significant inhibitory effect on both kinds of bacteria, and the second fraction excelled the third part but inferior to the first part. The minimal inhibitory concentration(MIC)were tested by the method of cuvette-dilution with equimultiple. MIC value of the three active parts was 1.25 mg/mL, 2.50 mg/mL and 5.00 mg/mL, that was consistent with the result of inhibition zone. The result of stability test indicated that the extract was relative stable to temperature and the pH of buffer solution, but the activity was influenced a little by ultraviolet. The more the concentration of extract or the longer the action time was, the higher inhibition ratio was. The extract's inhibitory effect on microzyme was not as good as the effect on mildew or bacillus as mildew was the best.To track the antimicrobial components in extract of chloroform, the qualitative analysis of TLC is conducted. By colour reaction with AlCl₃ and iodine vapor, we suspected that flavonoids was the component. With Rutin as the standard sample, the regression equation was established to calculate the total flavonoids content. The extract was purified further by polyamide and silica gel column chromatography in two steps. The best antibacterial part was determined by HPLC and LC-MS analytical technique. The results proved that Vitexin was one of antibacterial components, also with a little Isoviextin, possibly.Eventually, we applied the extracts to the formulation of cosmetic and progressed the Nit-R-Co²⁺ system experiment, we found the extracts take on good antibacterial effect and antioxidant activity. Therefore, Bamboo Leaves extract can be more used in cosmetics.