In Vitro Antioxidant Activity and Total Phenolic Content of Root Extracts from Phragmanthera glaucocarpa (Peyr.) Balle

Africa has a rich diversity of plant species, which can be considered important sources of new chemical compounds that can be used in the development of novel therapeutic drugs.

The present study aimed at investigating the antioxidant activity and total phenolic content of extracts obtained from the roots of Phragmanthera glaucocarpa (Peyr.) Balle, a plant used in Angola folk medicine.

The prepared extracts were tested for their antioxidant activity using ABTS (2,2’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid), DPPH (1’,1’-diphenyl-2-picrylhydrazyl), and peroxide value methods. Total phenolics were evaluated by the Folin-Ciocalteu method.

For ABTS, the best EC50 result was obtained with the ethyl acetate fraction (1.06 ± 0.30 mg/mL). For the DPPH method, the methanol extract and aqueous fraction presented the best EC50 results, 0.10 ± 0.01 mg/mL and 0.10 ± 0.00 mg/mL, respectively. The ethyl acetate fraction had the highest phenolic content (280.42 ± 0.15 mg G.A.E. /g of dry extract). The best result for the peroxide reduction value on the eighth day of sunflower oil oxidation was obtained for the aqueous fraction, with 131.40 ± 1.05 meq O2/g of lipid sample.

The results of the present study demonstrate that the roots of the medicinal plant Phragmanthera glaucocarpa (Peyr.) Balle represent a promising source of natural phenolic compounds with antioxidant activity