Comparative study of antioxidant properties of the extracts of Polygonum acre H.B.K.

Abstract

Aims: This study aimed to characterize and compare the antioxidative potential ofextracts obtained by infusion, decoction, tincture, aqueous extraction, and hydroethanolicmaceration from the aerial parts of Polygonum acre H.B.K., which hasbeen traditionally used in herbal preparations, for different purposes. The therapeuticbenefits are attributed to phenolic compounds and their antioxidant properties.Methods: All extracts were characterized considering their quantitative contentof the total phenolics, flavonoids, condensed and, hydrolysable tannins, by colorimetricmethods. EHW-PA was selected for HPLC analysis as it showed a higheryield (10.58 % w/m) and a phenolic content > 200 mg GAE/g dry extract. Thephenolic profile showed a chromatogram with 20 peaks, and the presence of gallicacid, rutin, and quercetin was verified by comparison with the retention times ofstandard compounds. The antioxidant activities were determined by ABTS capturetest, ferric reducing antioxidant power test (FRAP), and the superoxide anionscavenging test. Results: Tinctures showed a higher average content of phenoliccompounds, present mainly as flavonoid content. A significant correlation coefficientwas observed between the total phenolic content and its antioxidant activity,determining by ABTS and FRAP assays. Differently, a low to moderate correlationbetween the flavonoid content and antioxidant activity was verified. Conclusion:This study reinforces the ethnopharmacological relevance of the Polygonumgenus and could contribute to the scientific basis for the use of P. acre preparations.