Determination of polyphenols and free radical scavenging activity of Tephrosia purpurea linn leaves (Leguminosae)

Background: Leaves of Tephrosia purpurea Linn. (sarpankh), belonging to the family Leguminaceae, are used for the treatment of jaundice and are also claimed to be effective in many other diseases. This research work was undertaken to investigate the in vitro antioxidant activity of aqueous and ethanolic extracts of the leaves. Method: The therapeutic effects of tannins and flavonoids can be largely attributed to their antioxidant properties. So, the quantitative determinations were undertaken. All the methods are based on UV-spectrophotometric determination. Result: The total phenolic content of aqueous and ethanolic extracts showed the content values of 9.44 0.22% w/w and 18.44 0.13% w/w, respectively, and total flavonoid estimation of aqueous and ethanolic extracts showed the content values of 0.91 0.08% w/w and 1.56 0.12%w/w, respectively, for quercetin and 1.85 0.08% w/w and 2.54 0.12% w/w, respectively, for rutin. Further investigations were carried out for in vitro antioxidant activity and radical scavenging activity by calculating its percentage inhibition by means of IC 50 values, all the extracts concentrations were adjusted to fall under the linearity range and here many reference standards like tannic acid, gallic acid, quercetin, ascorbic acid were taken for the method suitability. Conclusion: The results revealed that leaves of this plant have antioxidant potential. The results also show the ethanolic extract to be more potent than the aqueous decoction which is claimed traditionally. In conclusion, T. purpurea Linn. (Leguminosae) leaves possess the antioxidant substance which may be responsible for the treatment of jaundice and other oxidative stress-related diseases.