【作者】 耿晓玲；

【导师】 姚卫蓉；

【作者基本信息】 江南大学 ， 营养与食品卫生学， 2007， 硕士

【摘要】 杨梅（Myrica rubra Sieb.et Zucc）为杨梅科、杨梅属果树,我国历来有用杨梅的根、茎、果入药治疗肠炎、止血、止关节痛、腹痛等习俗。杨梅中含多种酚性化合物,具有显著的生理活性。本论文以无锡产荸荠种杨梅为原料,主要研究了杨梅醇提物对不同致病菌的抑制作用,并进一步探讨了其抑菌机理,旨在为杨梅的进一步开发提供理论依据,这对天然防腐抑菌剂的开发和杨梅综合价值的提高具有重要意义。本文以乙醇为溶剂,连续回流法提取杨梅果实中的酚类物质,确定最佳条件为提取温度50℃,液料比为5:2,提取时间24h,所得提取率可达到10.34%,并进一步通过液液萃取法、沉淀萃取法对其进行粗分离,得到杨梅黄酮和鞣质的粗分离物,采用琼脂扩散法、抑制曲线法、浊度分析法等研究了杨梅果实提取物对几种常见致病菌的抑菌活性,结果显示,杨梅果实提取物对志贺氏痢疾杆菌、伤寒沙门氏菌、溶血性链球菌和金黄色葡萄球菌具有良好的抑制作用,对大肠杆菌和黑曲霉几乎没有抑菌作用;通过琼脂扩散法检测发现杨梅中黄酮粗提物和鞣质粗提物对金黄色葡萄球菌等目标菌株具有良好的抑制作用;通过二倍稀释法测定了杨梅提取物对不同菌株的最低抑菌浓度分别为金黄色葡萄球菌1.29×10^-2 g/mL,志贺氏痢疾杆菌为5.17×10^-2 g/mL,伤寒沙门氏菌为5.17×10^-2 g/mL,溶血性链球菌为2.59×10^-2 g/mL。抑菌调控实验表明,杨梅果实提取物具有良好的热稳定性;蛋白酶、活性炭脱色预处理对杨梅提取物抑菌作用影响较小;作用时间和体系pH对抑菌结果影响显著,体系pH降低、作用时间延长有利于抑菌作用的提高;在含盐、糖的体系中杨梅提取物具有明显的抑菌作用;在模拟人工肠液体系中,抑菌效果与细菌培养基上测得的抑菌活性显著不同。本文以金黄色葡萄球菌为目标菌株,通过GC-MS、SEM /TEM等考察了杨梅提取物的抑菌机制,发现杨梅提取物的抑菌作用与改变金黄色葡萄球菌菌体脂肪酸、细胞的完整性和呼吸作用相关。更多还原

【Abstract】 Myrica rubra Sieb.ei Zucc belongs to the branch of Myrica, genus of Myrica. It is widely distributed in China. The root, stem,fruit of myrica nana Ceval has not only been used to cure enteritis, hemostasia, arthralgia, but also be used to cure scald, carbuncle and bellyache etc. The friut of Myrica rubra Sieb.et Zucc contains high content of phenolic compound, which has an important bioactive activity.In order to probe into the bioactive activity of the fruit, this paper focused on the ethanol extract from myrica rubra fruit and its antimicrobial properties,as well as the antimicrobial mechanism.The optimum extracting condition of phenolic from Myrica rubra flesh were stud- ied in this article. Under continuously refluxing treatment, ethanol was used to soak the myrica rubra flesh and distill the phenolic.The result showed that the optimal extraction condition is 5:2 of ethanol to douse the flesh 24h, keep the temperature of 50℃,The extraction rate was 10.34%. Different methods ,such as Agar diffusion assay ,turbidimetric assay and inhibition curves were used to investigate the antimicrobial activity, The results indicated that the ethanol extraction showed significant antimicrobial activity on Staphylococcus aureus,Salmonella typhi ,Streptococcus haemolyc, Shigella dysenteriae ,especially to Staphylococus aureus and Streptococcus haemolyc. But it was not effective to Escherichia coli and A. niger.The minimum inhibition concentration （MIC） was 1.29×10^-2 g/mL for Staphylococcus aureus, 5.17×10^-2 g/mL for Shigella dysenteriae,5.17×10^-2g/mL for Salmonella typhi, 2.59×10^-2g/mL for Streptococcus haemolyc, respectively.The influence of several factors was investigated, including temperature, pH , time ,sugar and salt ,enzyme and decoloration. The results indicated that the extraction has a very good temperature stability and it could be effective from pH 5～9. Added with salt or sugar at the same time ,the inhibitory rate was higher. The pretreatment of protease and decolorization with active carbon showed unconspicuous effect.The antimicrobial activity in artificial intestinal juice dramatically differed from in culture medium. The membrane fatty acid of G +（ Staphylococcus aureus） was also been effected by GC-MS.By SEM/TEM, the ethanol extraction could destroy the cell integrity and stabilization of Staphylococcus aureus.更多还原