Extraction And Analysis Of The Antimicrobial Ingredient Of Phyllostachys Pubescens Leaves

In this paper,extract of Phyllostachys pubescens leaves was tested for its antimicrobial actives, the extraction technology of active components from P. pubescens leaves and their antimicrobial actives was studied. The stability to universal factors of the extracts was studied. At the same time, the primary isolation and purification of the antimicrobial components of P. pubescens leaves were also studied.Using disc diffusion method, plate dilution method,photometric assay method investigate the antimicrobial actives of the extracts from P. pubescens leaves,with Staphylococcus aureus and Escherichia coli as indicative bacteria.The results showed that the extracts of P. pubescens leaves has the antimicrobial actives.The extraction technology was optimized with disc diffusion method,use the diameter of bacteriostatic circle as assessing index, S. aureus and E. coli as indicative bacteria. The optimum extraction conditions of every factor for leaching active substances determined by the single factor experiment method were as follows: extraction temperature 60 oC, 60 %(volume fraction)ethanol, liquid:solid ratio 20:1(mL:g), extraction time 2 h. To With the orthogonal design test, the results showed that the optimum extracting condition was: extraction temperature 60 oC, 60 %(volume fraction)ethanol, liquid:solid ratio 20:1(mL:g), extraction time 2 h.The extracts of P. pubescens leaves has wide Antibacterial spectrum.The MIC of the extracts from P. pubescens leaves was 3.125mg/mL against S. aureus, which was 6.25mg/mL against E. coli.The stability to temperature,ultraviolet and pH value of the extracts of P. pubescens leaves were also studied. The result showed the extract was very stable to temperature,ultraviolet and pH 6.5~7.5.All extracts obtained in different fractions by using different polarities of solvents such as petroleum ether, chloroform, ethyl acetate, normal butyl alcohol and water were compared through the testing of their antimicrobial activities.The results showed the extraction of ethyl acetate had a strong capacity on S. aureus and E. coli.The colour reaction of reduction,metallic salts complexing and under ultraviolet and visible light showed that the main actives of the extraction of ethyl acetate is flavonoids.With Rutin being taken as the standard sample,the regression equation of rutin standard working curve was established. Total flavonoids content was determined by Spectrophotometry.The treatment of the extracts from P. pubescens leaves with ethyl acetate and AB-8 macroporous adsorption resin made flavonoids content increased.The extracts of ethyl acetate of P. pubescens leaves was seperated by silica gel column chromatography,polyamide columnchromatography, AB-8 macroporous adsorption resin.Three components were obtained.But the results of RP-HPLC showed that the extrats of P. pubescens leaves is complex.The extract of P. pubescens leaves was applied in cosmetics. All the results confirmed that extract of P. pubescens leaves has the antimicrobial effect, the skin-lightening effect and the antioxidative effect. So it can be good used in the cosmetics.