湄潭白茶多糖对金黄色葡萄球菌的抑菌活性及其稳定性

目的:研究湄潭白茶多糖对金黄色葡萄球菌的体外抑菌活性及其稳定性。方法:采用牛津杯法和微量肉汤稀释法测定湄潭白茶多糖对金黄色葡萄球菌的抑菌活性及最小抑菌浓度（Minimum inhibitory concentration，MIC），并进一步探讨温度、pH、紫外线照射和金属离子对其抑菌活性稳定性的影响。结果:湄潭白茶多糖对金黄色葡萄球菌具有抑菌活性，其MIC为8 mg/mL。对湄潭白茶多糖进行抑菌稳定性实验，以金黄色葡萄球菌的OD₆₀₀值为指标进行分析。结果表明，湄潭白茶多糖在20~60 ℃时抑菌活性保持稳定，但经高温度（80~100 ℃）处理后，抑菌活性略有下降，相比4 ℃实验组抑菌活性保留约45.8%；在pH4~10抑菌活性保持稳定；经30 W紫外线处理10～50 min后，抑菌活性无显著变化（P>0.05）；在0.1 mol/L Na+、K+处理下，抑菌活性稳定，但在0.1 mol/L Ca2+处理下，抑菌活性丧失。结论:湄潭白茶多糖对金黄色葡萄球菌具有稳定的体外抑菌活性，为其作为天然防腐剂的开发提供依据。

Antibacterial Activity and Stability of Polysaccharides from Meitan White Tea on Staphylococcus aureus

Objective: To study the antibacterial activity and stability of polysaccharides from Meitan White Tea against standard strains of Staphylococcus aureus in vitro. Method: The minimum inhibitory concentration (MIC) of polysaccharides from Meitan White Tea on Staphylococcus aureus was determined by oxford cup test and microdilution broth method. The effects of temperature, pH, ultraviolet and metal ion on the antibacterial activity of polysaccharides from Meitan White Tea were studied. Results: The polysaccharides from Meitan White Tea had significant antibacterial activity against Staphylococcus aureus, and the minimum inhibitory concentration was 8 mg/mL. The bacteriostatic stability experiment of MIC was carried out, and the OD₆₀₀ value of Staphylococcus aureus was used as an index. The results showed that the antibacterial activity of polysaccharides from Meitan White Tea was stable at 20~60 ℃, but it decreased slightly after being treated at high temperature (80~100 ℃), about 45.8% retained at high temperature compared with 4 ℃. The antibacterial activity remained stable at pH4~10. After 30 W ultraviolet treatment for 10~50 min, the antibacterial activity had no significant change (P>0.05). Under the treatment of 0.1 mol/L Na+ and K+, the antibacterial activity was stable, but under the treatment of 0.1 mol/L Ca2+, the antibacterial activity was lost. Conclusion: The polysaccharides from Meitan White Tea have stable inhibitory activity against Staphylococcus aureus in vitro, which provides a basis for its development as a natural preservative.