COMPARATIVE ASSESSMENT OF PHYTOCHEMICALS, ANTIOXIDANT ACTIVITY AND ANTIMICROBIAL ACTIVITY OF Cola acuminata, Garcinia kola and Vernonia amygdalina

Abstract

Folin Ciocalteu’ s method was employed to screen Vernonia amygdalina leaf and the seeds of Garcinia kola and Cola accuminata for total polyphenols. The in vitro antioxidant activities of the extracts were evaluated by 1, 1 -diphenyl-2-picryl-hydrazyl (DPPH) assay. The result of the total polyphenol content indicated 3211.6, 1826.2 and 892.8mg (GAE)/100g dry weight of sample and the antioxidant activity ranged from 50.80, 46.00 to 36.32 for C. acuminata, G. kola and V amygdalia respectively. A high level of correlation (r2 = 0.927) was observed for total polyphenols and antioxidant activity. The methanol, chloroform and ethyl acetate extracts were also assessed for antimicrobial activity using agar well diffusion method. Screening for major classes of phytochemicals was done using standard chemical tests. The preliminary phytochemical test revealed the presence of flavonoids, tannins, saponins, phenols, alkaloids and steroids as the major chemical groups in these plant extracts. The plant extracts showed antibacterial activity against the test organisms. However, the highest spectrum of activity was indicated by Garcinia Kola as it was active against B. subtilis and S. mutans at a low concentration of 1.25mg/mi (l4 & l2mm). The results obtained in the present investigation showed that the use of these plants as nutraceuticals may reduce the risk of microbial infections and diseases associated with oxidative stress.