Study On The Extraction And The Anti-microbial Activity Of Volatile Oils From The Leaves Of Phyllostachys Pubescens Mazei Ex H.de Lebaie

As the main bioactive components of bamboo leaves volatile oils have multiple important physiological effects including relieving cough and asthma, eliminating phlegm, reducing inflammation and fever, expelling intestinal worms, inhibiting tumor growth, promoting urination, controlling blood pressure and strengthening heart. The leaves of Phyllostachys pubescens Mazei ex H.de Lebaie collected from the Nan Ping City of Fu jian Province were chosen as the experimental materials to perform the following studies.1. Optimization of the extraction technique of volatile oil from leaves of Phyllostachys pubescens Mazei ex H.de Lebaie via response surface analysisBy using the modified volatile oil distillatory (VOD) the optimum conditions for the extraction of volatile oil from bamboo leaves have been determined through Box-Behken center-united experiment design and response surface analysis. The bamboo leaves power with 10 mesh average grain size were heated to reflux for 4.5h in water while the ratio of water to material was 35:1 (mL:g). The experimental value of volatile oil extraction rate was 0.32% and its predicated value was 0.35% under the optimum condition. Compared with traditional technique, the optimized extraction method was more convenient and efficient.2. Qualitative and quantitative studies on volatile oil of leaves of Phyllostachys pubescens Mazei ex H.de Lebaie collected from different seasonsThe volatile oils from leaves of Phyllostachys pubescens Mazei ex H.de Lebaie were extracted by the modified VOD and then analyzed by capillary GC and GC-MS techniques, which showed volatile constituents. The ketenes, alcohols, carboxylic acids and alkanet hydrocarbons were main compounds in the volatile oils and the contents of above ingredients were 52.25%,17.79%,9.41% and 7.68%, respectively by the internal standard quantitative method in GC. The study showed that the contents of the main compounds in volatile oils and the yield of volatile oils were significantly different in the bamboo leaves collected from different seasons and the maximum yield of volatile oils was 0.326%in autumn.3. Anti-microbial activities of volatile oils of leaves of Phyllostachys pubescens Mazei ex H.de LebaieOne strain of Gram-positive(Bacillus subtilis) bacteria, four strains of Gram-negative (Escherichia coli, Pseudomonas fluorescens SHL5,SHL7, Flavobacterium SHL45) bacteria and three stains of Saccharomyces cerevisiae(Ja64,Tokay,Y8) were selected as the tested strains to evaluate the anti-microbial activities of volatile oils. Then, the minimum inhibitory concentration (MIC) of volatile oils against Flavobacterium SHL45, Escherichia coli and Bacillus subtitles were tested. The results showed that the volatile oils from the leaves of Phyllostachys pubescens Mazei ex H.de Lebaie have significant anti-microbial activities. The MIC of volatile oils against Flavobacterium SHL45, Escherichia coli and Bacillus subtilis were 0.56mg/mL,4.50mg/mL and 1.12mg/mL, respectively.4. The analysis of anti-microbial mechanisms of volatile oils of leaves of Phyllostachys pubescens Mazei ex H.de LebaieOne strain of Gram-positive(Bacillus subtitles) bacteria, four strains of Gram-negative (Escherichia coli, Pseudomonas fluorescents SHL5,SHL7, Flavobacterium SHL45) bacteria and three stains of Saccharomyces cerevisiae(Ja64,Tokay,Y8) were selected as the tested strains to evaluate the anti-microbial activities of three main active ingredients, which were tricosane, cedrol and hexadecane acid, in volatile oils from Phyllostachys pubescens Mazei ex H.de Lebaie. leaves and study the anti-microbial mechanisms of volatile oils. The results showed that the different active ingredients and the same ingredient at different concentrations have different anti-microbial activities on tested bacteria. Furthermore, the combination of individual active ingredients could significantly enhance the anti-microbial effects, suggesting that the anti-microbial activities of the volatile oils was attributed to the synergy effects among all active compounds in Phyllostachys pubescens Mazei ex H.de Lebaie leaves.In conclusion, the present study proved that volatile oils from bamboo leaves contained large amounts of active compounds and exhibited good performances in anti-microbial activities. The contents of the main active compounds in volatile oils depended on the growing seasons. The above studies would be very useful in the following aspects:(a promotion of the fine processing of bamboo leaves in the field of food, drugs, and cosmetics; b) identification of the species of bamboo.