兴安杜鹃叶总生物碱提取及其生物活性

Extraction and Biological Activity of Alkaloids from Leaves of Rhododendron dauricum L.

以兴安杜鹃叶为原料,采用超声波提取、旋转蒸发、离心等方法结合提取总生物碱,以盐酸小檗碱为标准品,采用紫外-可见分光光度法测定兴安杜鹃叶提取物的总生物碱含量,采用抑菌圈法和二倍稀释法对总生物碱提取物抑菌活性以及最低抑菌浓度进行测试,并对总生物碱提取物进行抗氧化性能力测试。结果表明:兴安杜鹃叶中总生物碱的提取率为1.5mg·g^(-1),对大肠杆菌和金黄色葡萄球菌均有抑制作用,最低抑菌质量浓度均为0.63g·L^(-1);对羟基自由基、亚硝酸根离子和超氧阴离子均有清除能力,随着总生物碱提取物质量浓度的增大,清除能力逐渐增强,清除羟基自由基的IC50值为3.71mg·L^(-1),清除亚硝酸根离子的IC50值为4.58mg·L^(-1),清除超氧阴离子的IC50值为3.19mg·L^(-1),对超氧阴离子的清除效果优于对羟自由基和亚硝酸盐。

Alkaloid extraction from the leaves of Rhododendron dauricum L. was carried out by means of ultrasound, vacuum rotary evaporation, and centrifugation. Content of total alkaloids extracted was determined by UV spectroscopy with berberine as the standard. The biological activity of the extracted alkaloids was determined using the antibacterial, minimum antibacterial concentration, and antioxidant tests. The alkaloid yield from the extraction process was 1.5 mg · g^-1. The alkaloids obtained showed an inhibition effect on Escherichia coli and Staphylococcus aureus at a minimum antibacterial concentration of 0.63 g· L^-1 , and exhibited a scavenging action on hydroxyl, nitrite, and oxygen radicals that increased with increasing concentrations of the extract. The IC50 of the extract were 3. 71 mg· L^-1on hydroxyl radicals, 4.58 mg · L^-1 on nitrite radicals, and 3. 19 mg · L^-1 on oxygen radicals. The scavenging effect of the alkaloids on oxygen radicals was found to be greater than that on hydroxyl or nitrite radicals.