ABSTRACT
Aim: To evaluate the in vitro antioxidant potential and total phenolic contents of the methanolic extract of Swertia chirata. Place and Duration: Department of Botany, Dr. H. S. Gour University (HSGVV), Sagar, between February 2010 to July 2010. Methodology: The plant material (aerial part) was subjected to defatting with petroleum ether then successively extracted with methanol. Total phenolic contents of methanolic extract was determined using the Folin-Ciocalteau reagent method while in vitro antioxidant potential was evaluated by using DPPH, hydroxyl radical, nitric oxide radical scavenging as well as ferric reducing power assays. Results: The total phenolic content in 1 mg of methanolic extract of S. chirata was equivalent to 4.5 μg Catechol. The IC50 value of the DPPH method, hydroxyl radical and nitric oxide radical scavenging activity was 222.74±0.19, 307.93±0.10 and 870.55±0.20 μg/ml respectively. When these IC50 value compared with that of standard drug Butylated hydroxy anisole (BHA) the result obtained was as follows: FRSA-SCM>BHA (p=0.000246); HRSA-SCM<BHA (p=0.000507); NORA-SCM<BHA (p=2.22614). These results showed that the S. chirata methanolic extract exhibited significant free radical DPPH scavenging activity and Hydroxyl radical scavenging activity while it exhibited nonsignificant Nitric oxide radical scavenging activity. In ferric reducing power various concentrations (100, 250 and 500 μg/ml) of methanolic extract of S. chirata showed absorbance 0.013±0.31, 0.156±0.12 and 0.298±0.14. Phytochemical screening showed the presence of phenolic compounds such as flavonoids and tannins which may be responsible for the activity. Conclusion: Methanolic extract of Swertia chirata showed significant antioxidant activity which suggest the extract may act as a natural antioxidant agent offering effective protection from free radicals.
ABSTRACT
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 µg/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.