不同采收期牛至叶提取物体外抗氧化和降糖活性研究

In vitro anti-oxidant and hypoglycemic activity of acetonitrile-water extract of Origanum vulgare leaves harvested in different times

目的对比研究不同采收期牛至叶提取物的物质组成与体外抗氧化和降糖活性。方法采用乙腈-水(1∶1)提取制备牛至叶提取物,福林酚法测定其中总酚含量,AlCl_3比色法测定其中总黄酮含量,LC-Q-TOF-MS法分析主要成分。采用ABTS自由基清除和FRAP总抗氧化实验评价不同采收期牛至叶提取物的抗氧化活性,荧光葡萄糖摄取法和对α-葡萄糖苷酶的体外抑制实验评价不同采收期牛至叶提取物体外降糖活性。结果从牛至叶提取物中鉴定出6种主要成分,分别为牛至苷I、木犀草素7-O-葡萄糖醛酸苷、芹菜素7-O-葡萄糖醛酸苷、迷迭香酸、紫草酸、牛至苷I衍生物;提取物中总酚含量以开花期7月份采收的最高,总黄酮含量以成熟期9月份采收的最高。不同采收期牛至叶提取物均有较好的抗氧化和降糖作用,其中7月份采收的牛至叶提取物体外抗氧化活性最强,10月份采收的牛至叶提取物体外降血糖活性最强。结论牛至叶乙腈-水(1∶1)提取物具有潜在的抗氧化及降糖活性,其抗氧化及降糖活性强度受牛至叶采收时间的影响。

Objective By investigating the material composition, anti-oxidant and hypoglycemic activity of acetonitrile-water extracts of Origanum vulgare leaf（OL） in different harvest time, to acquire the scientific data for the utilization of OL. Methods OL was extracted with acetonitrile and water（1∶1）. The contents of total phenols and total flavonoid were measured by Foline-Phenol reagent method and AlCl3 colorimetry. The main compositional analysis was performed using LC-QTOF-MS technology. Meanwhile, the anti-oxidation of OL extracts in different harvest time was evaluated by total anti-oxidant capacity assay kit with ABTS method and ferric reducing anti-oxidant potential assay（FRAP）. The methods of 2-NBDG glucose uptake and α-glycosides inhibition were applied to evaluate hypoglycemic activity of OL extracts. Results The six main components in OL extract were identified to be origanoside I, luteolin 7-O-glucuronide, apigenin 7-O-glucuronide, rosmarinic acid, lithospermic acid and origanoside I derivative. The contents of total phenols and the total flavonoids were the highest in OL extracts harvested in July and September, respectively. There was good invitro anti-oxidant and hypoglycemic activity for OL extracts harvested in different times. Among them, the best anti-oxidant activity was observed in OL extracts harvested in July, while the best hypoglycemic activity was observed in OL extracts harvested in October. Conclusion OL has potential anti-oxidant and hypoglycemic activity, which is affected by the harvest time.