Phytochemical screening and evaluation of antioxidant capacities of Allium cepa, Allium sativum, and Monodora myristica using in vitro and in vivo models

Abstract

Background: Allium cepa, Allium sativum, and Monodora myristica are commonly sourced food condiments in every household in Nigeria. In the present study, we investigated the phytochemical compositions, in vitro and in vivo antioxidant activity of these plants. Methods: The aqueous extracts from the A. cepa, A. sativum, and M. myristica were evaluated for phytochemical composition using standard protocols while the antioxidant activities were evaluated using the reducing power assay. Forty-five (45) Male Wistar rats (weighing 185±10 g) were divided into five groups (n=9) and were orally administered with 100 mg/kg BW each of A. sativum, M. myristica, A. cepa, and ascorbic acid while the control group received 0.5 mL/kg BW distilled water alone. Animals (n=3) from each group were sacrificed after the 20th, 25th, and 30th days of oral administration. The blood and tissue samples were collected for the analysis of biochemical parameters. Result: Our results revealed the presence of flavonoids, alkaloids, tannins, saponins, and terpenes in the plant extracts. A. sativum had the highest reducing power capacity followed by M. myristica and then A. cepa. The in vitro antioxidants activities demonstrated by the plant extracts were higher than that of ascorbic acid but less than butylated hydroxytoluene. In vivo antioxidant studies showed a marked increase (p<0.05) in the level of catalase with a concurrent decrease (p<0.05) in the levels of MDA and H2O2 in the liver and kidney of rats administered with aqueous extracts of the condiments compared to the normal control and ascorbic acid in the following order control < ascorbic acid < A. cepa < M. myristica < A. sativum. Conclusion: Based on these findings, we infer that the aqueous extracts of A. cepa, A. sativum, and M. myristica are rich in antioxidants and as a result could serve as promising novel functional foods and nutraceuticals