关键词： 白及, 多糖, 正交法, 大肠杆菌, 金黄色葡萄球菌

Abstract: Bletilla striata polysaccharides were extracted by water extraction and alcohol precipitation,with different ratio of material to liquid,extraction temperature and extraction time as the research conditions and the extraction content as the index of orthogonal experiment,so as to determine the best extraction technology.Under the optimum conditions,the extracted polysaccharides were added to the ointment to make Bletilla striata ointment.The inhibitory effects of Bletilla striata polysaccharide and Bletilla striata ointment on the growth of Escherichia coli and Staphylococcus aureus were determined by filter paper diffusion method.The results showed that the optimum extraction conditions were as follows:the ratio of material to liquid was 1:35 (g:mL),the extraction temperature was 80 ℃ and the extraction time was 4.0 h.Under these extraction conditions,the yield of polysaccharide was 25.97%.When the mass concentration of Bletilla striata polysaccharide reached 0.33 g/mL,it had inhibitory effect on Escherichia coli and Staphylococcus aureus.When the mass concentration was increased to 0.66 g/mL,the bacteriostatic effect of polysaccharide extract was stronger,and the bacteriostatic effect on Escherichia coli was better than that of commercial Yifubaiying bacteriostatic paste.The performance of Bletilla striata ointment was stable and the bacteriostatic effect against Escherichia coli was stronger than Staphylococcus aureus.

Key words: Bletilla striata, polysaccharide, orthogonal method, escherichia coli, staphylococcus aureus