Sasikumar J M, Maheshu V, Aseervatham G Smilin Bell, Darsini D Teepica Priya
Department of Biotechnology, Karpagam University, Coimbatore 641 021, Tamil Nadu, India.
Indian J Biochem Biophys. 2010 Feb;47(1):49-52.
The methanolic extract of the aerial part of Hedyotis corymbosa (L.) Lam. (Rubiaceae) was screened for antioxidant activity using 1,1-diphenyl-2-picryl hydroxyl (DPPH) quenching assay, 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) cation decolorization test, ferric reducing power (FRP), scavenging capacity towards hydroxyl ion (OH*) radicals and nitric oxide (NO) radical inhibition activity using established assay procedures. Total phenolics and total flavonoid contents were, also determined. The plant yielded 210 mg gallic acid equivalent/100 g phenolic content and 55 mg quercetin equivalent/100 g flavonoid content. The extract exhibited high antiradical activity against DPPH, ABTS, nitric oxide and hydroxyl radicals with EC50 value of 82, 150, 130, and 170 microg/ml, respectively. The FRP increased with increasing concentration of the sample. The antioxidant activity of the extract was comparable with that of the standard butylated hydroxyl toluene (BHT). High correlation between total phenolic/flavonoid contents and scavenging potential of different reactive oxygen species (R2 = 0.785-0.998) indicated the polyphenols as the main antioxidants.
对伞房花耳草（茜草科）地上部分的甲醇提取物进行了抗氧化活性筛选，采用1,1-二苯基-2-苦基肼（DPPH）淬灭试验、2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）阳离子脱色试验、铁还原能力（FRP）、利用既定的试验程序测定对羟基离子（OH*）自由基的清除能力和一氧化氮（NO）自由基抑制活性。还测定了总酚含量和总黄酮含量。该植物的酚含量为210毫克没食子酸当量/100克，黄酮含量为55毫克槲皮素当量/100克。提取物对DPPH、ABTS、一氧化氮和羟基自由基表现出高抗自由基活性，其半数有效浓度（EC50）值分别为82、150、130和170微克/毫升。FRP随样品浓度的增加而增加。提取物的抗氧化活性与标准丁基羟基甲苯（BHT）相当。总酚/黄酮含量与不同活性氧清除能力之间的高度相关性（R2 = 0.785 - 0.998）表明多酚是主要的抗氧化剂。
