Polyphenols quantification and antioxidant activity of methanolic and aqueous extracts from eight medicinal plants used to manage avian diseases in Burkina Faso

Abstract

The present study aimed to quantify the polyphenols and evaluate the antioxidant activity of methanolic and aqueous extracts from eight medicinal plants used by the poultry farmers to manage avian diseases in Burkina Faso. Total phenolics and total flavonoids were quantified using Folin-Ciocalteu and AlCl3 reagents, respectively. The antioxidant activity was evaluated using three methods: 1,1-dipheenyl-2-picrylhydrazyl (DPPH), 2’-2-azino-bis (3-eethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP). The results obtained showed that aqueous extracts contain more total phenolics than methanolic extracts in contrary to the total flavonoids where methanolic extracts presented the best contents. The evaluation of the antioxidant activity by the three methods showed that the extracts exhibited an interesting activity. The methanolic and the aqueous extracts of Parkia biglobosa, Sclerocarya birrea, and Detarium microcarpum, are distinguished by a good capacity to scavenge free DPPH radicals than those of the standards (trolox and quercetin). The methanolic extracts of all plant samples have shown their superiority in terms of their ability to scavenge the ABTS radical cations compared to aqueous extracts. Compared to other plant extracts and quercetin the methanolic and aqueous extracts of D. microcarpum bark presented the best reducing power with the values of 5360.23 and 4584.55 µmol EAA / g extract, respectively. These different results could justify the traditional uses of these plants in the treatment of avian pathologies. Key words: Medicinal plants, total phenolics, total flavonoids, antioxidant, poultry diseases.