Antioxidant compounds of dietary plants have been widely studied because of their bioactive properties. The objective of this research study was to analyse the health enhancing attributes of 31 cowpeas varieties from Burkina Faso. Significant variations were observed in the phenolic content as well as the antioxidant and anti-lipid peroxidation activities amongst the cowpea varieties. Pearson correlation coefficient analysis showed that the ferric reducing ability (r = 0.954) and anti-lipid peroxidation (r = 0.616) were positively correlated with the total phenolic content. A significant relationship between cowpea ferric reducing ability and anti-lipid peroxidation (r = 0.64) was also revealed. However, nitric oxide scavenging potential was found not to be related to its total phenolic and total flavonoid content. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals scavenging potentials were not correlated with the total flavonoid content. The pigmented seeds of cowpea varieties possess higher total phenolic, total flavonoid content, ferric reduction ability, and anti-lipid peroxidation activities than the colourless ones. The results obtained from this study suggest that Burkina Faso cowpea cultivars are rich in phenolic compounds and have significant antioxidant and anti-lipid peroxidation activities. Consumption of the cowpea, particularly of coloured cowpea seed varieties, should be beneficial for chronic human diseases prevention.

To evaluate antioxidant activities of seven medicinal plant species and their fractions, and to identify their phenolic compounds. Two extractions were processed and further fractionated by column chromatography to evaluate the concentration that inhibit 50% of 2,2'-azinobis (3-ethylbenzothiazoline-6-suslfonic acid, 1,1-diphenyl-2-picryl-hydrazyl radicals, and their ferric reducing antioxidant power. The identification of the fractions of phenolic compounds was done by ultra performance liquid chromatography. The aqueous-acetone extracts of Feretia apodanthera and Ozoroa insignis exhibited the highest antioxidant potentials comparable to those of the standard quercetin. Their subsequently silica gel column fractionation showed three most active fractions from which the major constituents quercetin, myricetin, kampferol, rutin and isoquercetin were identified. These plant species have potent antioxidant profiles and polyphenol compounds that may help to manage with radical related disease and aging.

Different extracts were obtained from Scoparia dulcis L. (Scrophulariaceae) by successive extraction with hexane, chloroform, and methanol. These extracts exhibited significant antioxidant capacity in various antioxidant models mediated (xantine oxidase and lipoxygenase) or not mediated (2,2-diphenyl-picrylhydrazyl, ferric-reducing antioxidant power, β-carotene bleaching, lipid peroxidation) by enzymes. The antioxidant activity of the extracts was related to their phytochemical composition in terms of polyphenol and carotenoid contents. The chloroform extract was richest in phytochemicals and had the highest antioxidant activity in the different antioxidant systems. All the extracts exhibited less than 50% inhibition on xanthine oxidase but more than 50% inhibition on lipid peroxidation and lipoxygenase. The extracts strongly inhibited lipid peroxidation mediated by lipoxygenase.

Seven medicinal plants used in folk medicine to relieve various diseases including diabetes, were investigated for antihyperglycemic activities. Two types of extracts for each plant were processed by decoction and by soaking in an aqueous-acetone mixture. The inhibitory activities were tested on α-amylase and α-glucosidase along with chelating activity. The aqueous-acetone extracts of Feretia apodanthera and Ozoroa insignis exerted strong inhibition on α-glucosidase (96.51±0.14 and 96.44±0.68 %, respectively) but lower inhibition on α-amylase (21.60±1.69 and 93.85±6.58 %, respectively) and displayed a weak chelating activity as compared to the respective standards acarbose and ethylenediaminetetraacetic acid. Subsequent column fractionation resulted in selectively strong inhibition of α-glucosidase. The inhibitory activities of α-amylase and α-glucosidase were weakly correlated (R=0,389) and both were inversely correlated with metal chelating activity (R=-0.731 and R=-0.809, respectively). Volatile compounds, 1-nonadecene and 1-heptadecene identified by GC-MS were related to the inhibitory activities of α-amylase and α-glucosidase enzymes. This potent inhibition of sugar degrading enzymes may help to manage the hyperglycemia occurring in type 2 diabetes.