生地黄提取物的抗氧化活性研究

Antioxidant activities of Rehmannia glutinosa extracts

【目的】通过体外抗氧化试验,研究生地黄块根不同溶剂提取物的抗氧化活性,为生地黄的进一步开发利用提供理论依据。【方法】用体积分数70%的乙醇回流提取生地黄根粉末,减压浓缩得到乙醇浸膏,加蒸馏水制成悬浮液,依次用等体积的石油醚、氯仿、乙酸乙酯、正丁醇萃取,分别得到石油醚、氯仿、乙酸乙酯、正丁醇提取物;以2,6-二叔丁基对甲酚(BHT)为对照,分别采用DPPH法、Feton法、FRAP法和还原能力测定法,研究4种不同熔剂提取物的抗氧化活性。【结果】生地黄4种不同熔剂提取物均具有不同程度的抗氧化活性,且抗氧化活性与提取物质量浓度呈量效关系。生地黄乙酸乙酯提取物的1,1-二苯基-2-苦苯肼自由基(DPPH.)清除活性(IC50值为0.178mg/mL)、还原能力(IC50值为0.341 mg/mL)和总抗氧化活性均最高,其中乙酸乙酯提取物的DPPH.清除活性高于对照BHT(IC50值为0.456 mg/mL)。生地黄氯仿提取物的羟自由基(OH.)清除活性最强,IC50值为1.397 mg/mL。【结论】生地黄乙酸乙酯提取物具有较强的抗氧化活性,可作为一种新的自由基清除剂和天然抗氧化剂。

【Objective】 By antioxidant test in vitro,the antioxidant activities of the different polar solvents root extracts of Rehmannia glutinosa were studied to provide a basis for its further development and utilization.【Method】 The powdered roots of R.glutinosa were extracted with 70% ethanol refluxing extraction,ethanol condensate were obtained and evaporated to dryness under vacuum on a rotary evaporator.The dry condensate was dissolved in water,the made water pending liquid was obtained and extracted with a volume of solvents of increasing polarity such as petroleum ether,chloroform,ethyl acetate,n-butanol and were evaporated to dryness under vacuum on a rotary evaporator.The antioxidation activities of dried residues were detected and evaluated by four methods of DPPH,Feton,FRAP and reducing power with control for BHT.【Result】 The results indicated that four kinds of solvent extracts of R.glutinosa had a certain degree of antioxidant capacity in four determination systems.And it showed that the quality concentration of extracts was higher and the effect better.The ethyl acetate extraction had better effect on scavenging DPPH·radical（IC50=0.178 mg/mL）,reducing power（IC50=0.341 mg/mL） and total antioxidant activity,in which DPPH·radical scavenging activity of ethyl acetate extract was higher than BHT（IC50=0.456 mg/mL）.The chloroform extraction had better effect on scavenging hydroxyl radical,and the IC50 was 1.397 mg/mL.【Conclusion】 The ethyl acetate extraction of R.glutinosa has strong antioxidant activity,which can be used as a new free radical scavenging scavenger and natural antioxidants.