【作者】 陆志科；

【导师】 谢碧霞；

【作者基本信息】 中南林学院 ， 森林培育学， 2004， 博士

【摘要】 竹子(Bamboo)是禾本科(Poaceae)竹亚科(Bambuaoideae)多年生常绿植物,广泛分布于亚洲、拉丁美洲、非洲。世界竹类植物有70～80属1300多种,其中中国有39属500余种。竹叶中含有多种黄酮类化合物、香豆素内酯、活性多糖等丰富的生物活性成分,具有重要的生理功能和较高的保健价值,开发潜力巨大。 本试验以竹叶为原料,系统地研究了竹叶的抗菌防腐性能。以蒸馏水、乙醇、乙醚和石油醚作溶剂,研究了干燥方法、溶剂等因素对提取率及提取液抗菌活性的影响,通过单因素试验和正交试验考察了温度、液料比及时间对提取率的影响,确定了合适的浸提条件,并对竹叶不同竹种、不同生长期的抗菌活性进行了比较。以大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌及部分霉菌和酵母菌为对象菌,用滤纸片法和平板稀释法进一步证实并系统地研究了竹叶的抗菌活性;以革兰氏阳性菌中的金黄色葡萄球菌及革兰氏阴性菌中的大肠杆菌为代表菌种,首先对竹叶提取物分组分、分溶剂萃取段进行抗菌活性的初步研究,筛选出对所选细菌的生长具有明显抑制作用的抗菌活性部分:30%乙醇溶解物经石油醚、乙醚萃取后对两种细菌的抑菌活性最强。对其进一步精制,通过抗菌活性追踪,采用硅胶和聚酰胺柱层析、真空层析等方法,从中分离并纯化出4种具有抗菌活性的成分,用MS、UV等波谱技术,结合一定的化学方法以及有关文献数据对照,并分别进行初步鉴定。将纯化得到的抗菌性化合物与几种具类似结构的化合物进行抑菌效果比较,初步确立了黄酮类化合物结构与抗菌活性的关系。分离纯化得到的化合物与金属离子形成的配合物,提高了抑菌效果。并将竹叶防腐抑菌剂应用于卤肉、水豆腐和番茄片的保藏。 研究结果表明: 1.原料的干燥方法对竹叶抗菌活性成分的提取率及抑菌效果有显著影响(p<0.01)。其中,40℃热风干燥提取率最高,为7.36%,太阳晒后阴干次之,为7.08%,室温晾干较低,为6.97%,太阳晒干燥最低,为6.50%;40℃热风干燥抑菌力最强,对大肠杆菌的抑菌圈直径最大,为12.70mm,太阳晒后阴干次之,为11.27mm,室温晾干较弱,为11.13mm,太阳晒干燥最弱,为10.40mm。 2.蒸馏水和乙醇水溶液两种提取液对所试细菌、霉菌和酵母菌均有抑菌作用。60%乙醇提取液对细菌的抑制效果最好,抑菌圈直径达到10.02mm以上,对酵母菌的抑制效果次之,对霉菌的抑制效果最弱;蒸馏水提取液对所试微生物的抑制顺序同乙醇提取液,但对细菌、酵母菌和霉菌的抑制效果稍差于乙醇提取液。 3.液料比和温度对提取率的影响较大。乙醇为溶剂时的最佳提取工艺条件为:液料比12∶1、浸提温度80℃、时间1.5h。在此条件下的提取率为7.74%。更多还原

【Abstract】 Bamboo, widely distributed in Asia, Latin America and Africa, is one of the tall, treelike evergreen grasses comprising the Bambuaoideae Nees of the family Poaceae plant. 70~80 genera and more than 1,300 species of bamboo have been recorded in botanical literature all over the world, and in which about 39 genera and more than 500 species were located in China. Bamboo leaves consist of abundant bio-active constituents which make it a potential resource for advanced pharmaceutical utilization such as Baicalein, coumarin lactones and activity polysaccharide in Bamboo leaves. It has important physiological and health protective value that makes it significant in food industry and medicine field.In order to study the antimicrobal Bamboo systematically, its leaves were taken as materials with stilled water, alcohol, aether and petroleum ether as solvents, the effect of drying methods and solvents on extraction ratio and antimicrobial activity were reviewed. The effect on extraction ration of ratio between solvents and material, temperature and time were investigated by means of single factor and orthogonal experiments and the optimum extraction condition was determined, furthermore, the antimicrobial activity of different breed and the same organ gathered in different growing periods were compared. With Escherichia coil, Bacillus subtilis, Staphyloccocus arueus and some moulds and yeasts as experimented microbes, the characteristics of antimicrobial activity were studied by means of filter paper method and plate dilution method. Gram-positives Staphylococcus aureus and Gram-negative Escherichia coli were chosen for the antibacterial assays. Firstly, Extract of bamboo leaf (Ebl) were extracted by polar-different organic solvents respectively. The antibacterial activities of all the fractions obtained were studied and the active fractions were established: According to the antibacterial assay, 30% ethanol-soluble fraction of Ebl after leached by petroleum ether-solution and aether-solution is the most significant and attributed to it, it was used for further purification, and 4 compounds of antibacterial activity were obtained through tracing the activity and repetitive column chromatography on silica gel and poly-Hexanolactam. Their structures were identified on the basis of spectral technology (MS, UV) chemical methods and comparison with related reports of literatures. The structure-activityrelationships were established elementarily using compounds 1,2,3,4 and several synthetic products by comparison of their antibacterial activities. Extract was separated with Layer Chromatography and applied in the preservations of stewed meat, damped bean curd and tomato piece. The results indicated:1. Drying methods had significant effect on extraction ration and antimicrobial function and the difference was significant (p<0.01) .The raw material dried by 40 ℃ sirocco had the highest extraction ration with 7.36%, the second higher of 7.08% dry in the shade after shine upon, the third higher of 6.97% appeared in that dried by room temperature and the smallest was in that dried by insolation under sun, which was only 6.50%. The diameter of antimicrobial ring to Escherichia coli of raw material dried by microwave was 12.70mm, which was the most in four treatments , the second of 11.27mm was in that dried in the shade after shine up, the third of 11.13mm was in that dried by room temperature and the last one was in that dried by by insolation under sun ,which was 10.40mm.2. Stilled water and alcohol-water extracts had bacteriostasis to germs, moulds and yeast.The inhibition sequence to experimented microbes of stilled water and 60% alcohol extract was: to germs>to yeast>to moulds. But 60% alcohol extract had the best antimicrobial effect on germs, with the diameter of antimicrobial rings to Escherichia coli beyond 10.02mm and 60% alcohol extract had better inhibition to germs , to yeast and moulds than that of stilled water.3. The effect on extraction ration of ratio between solvents and raw material and temperature were greater than that of time. Alcohol as solvent, the optimum extraction condition was: ratio between solvents and raw material: 12:1, temperature: 80℃, time: 1.5 h. The extraction ration was 7.74% at this condition.4. The antimicrobial activity of different bamboo leaves and that of the same organ growed in different periods were different. The antimicrobial activity of Sinocalamus latiflorus McClure leaves was better than that of others. bamboo leaves gathered in the second part of July and November had better antimicrobial activity than others.5. Bamboo leaves alcohol extract had wide antimicrobial spectrum. Its minimal inhibitory. Concentration to germ was 0.156%, and that to moulds and yeast was 0.625% and 1.25%.更多还原