In vivo and in vitro antioxidant fffects of Icacina trichantha tuber extract
The phytochemical and antioxidant properties of the methanol extract of Icacina trichantha tuber were evaluated using standard assays. The antioxidant potential was studied with both in vitro and in vivo models. The in vitro procedures involved the use of 2, 2-diphenyl-1-picrylhydrazyl free radical (DPPH) and ferric reducing/antioxidant power (FRAP) spectrophotometrically. The in vivo models quantified the gradation in the levels of malondialdehyde (MDA), serum superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) activities in rats that were fed on graded doses of the extract incorporated in feed for 12 weeks. DPPH assay revealed that the crude extract possessed a high antioxidant capacity of 67.3% compared to 80.3% with ascorbic acid at 400 μg/ml. The findings from the FRAP test buttressed the fact that the extract displayed a remarkably high and dose-dependent antioxidant effect with a maximal value of 6.7 μM at 800 μg/ml. The extract also exhibited potent in vivo antioxidant effects when the plasma MDA levels became depressed while the serum SOD, CAT and GSH values of test rats that received the medium and high dose (0.5 and 1.0 g/kg feed) of the extract were significantly (p<0.05) elevated from days 60-90 compared to values in the control and low dose (0.25 g/kg feed) of the extract. Phytochemical analysis revealed the presence of alkaloids, flavonoids, tannins, saponins, carbohydrates, reducing sugars, sterols and terpenes in the crude methanol extract of I. trichantha tuber. The results of the study demonstrated that I. trichantha tuber extract possessed high in vitro and in vivo antioxidant activities. The extract could be a potential source for the isolation of novel plant-derived antioxidant agents.
Key words: Antioxidant, Icacina trichantha, Free radicals, Bioassay.