Protective effect of the fruit of Dialum guineense Willd (Fabaceae) against oxidative stress
Background: Plants with adequate antioxidant potential can be useful in combating cellular damage and diseases. Objectives: The aim of the study is to determine the antioxidant capacity of the different parts (fruit coat, pulp and seed) of Dialium guineenses (Willd) (Fabaceae) fruit. Methods: The extracts were screened for scavenging activity against 1,1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, nitric oxide radicals, reducing power and metal chelating capacity. Protective effect of the seed extract was evaluated in ethanol-induced oxidative stress in rats at the dose of 50,100 and 150 mg/kg and the levels of antioxidant markers; Lipid peroxidation (MDA) and catalase (CAT) were assayed using standard methods. The total polyphenolic content and GC-MS analysis of the seed extract were also done. Results: The seed extract exhibited significant and higher antioxidant activity than the fruit coat and pulp extracts in three of the in vitro assays. The extract dose-dependently reduced lipid peroxidation and increased the activity of catalase at all the doses tested compared with the control. The total phenolics, flavonoids and proanthocyanidin content of the seed extract were 32.71 mg gallic acid equivalent/g, 2.41 mg quercetin equivalent /g and 130.21 mg catechin equivalent/g of the extract respectively. The major component in the seed oil was 10,13-0ctadecadienoic acid methyl ester (52.38%) following GC-MS analysis. Our findings suggest that D. guineense seed showed high antioxidant potential with considerable content of total proanthocyanidins. Conclusion: The seeds of D. guineense which are generally discarded as wastes may serve as viable functional food ingredients with protective antioxidant potential.