Abstract

This study evaluated the antioxidant and antimicrobial properties of Piper guineense, Ocimum gratissimum, Murraya koenigii and Gongronema latifolium leave extracts using ethanol, petroleum-ether and aqueous media. The scavenging activities of the extracts was measured with free radical 2, 2-diphenyl-1-picrylhydrazyl, flavonoid and phenolic contents were assessed by spectrophotometry while, gas chromatographic flame ionization detector was used for phytochemical screening of the extracts. The micro-broth dilution and agar diffusion methods were used to assess Minimum inhibitory and bactericidal concentrations of the extracts respectively. The different leaves extracts differed significantly (P<0.05) at 25, 50, 75 and 100µg/ml of radical scavenging activities, with the lowest and highest values recorded at 25 and 100µg/ml respectively. The aqueous extract of G. latifolium had the highest value (67.60 ± 0.12mg GAE/100g DW) while, petroleum ether extract of P. guineense had the lowest value (30.65 ± 0.06mg GAE/100g DW) of total phenolic content. The highest and lowest flavonoid contents were found in petroleum ether extract of P. guineense (80.75 ± 0.37mg Rutin/g DW) and in aqueous extract of M. koenigii (36.27 ± 0.62mg Rutin/g DW).  Phytochemicals screening indicated that the extracts were rich in steroids, terpenoids, tannins, saponins, phlobatannins, cardiac glycosides and alkaloids. The petroleum ether, ethanol and aqueous extracts were active against the growth of S. epidermidis, P. aeruginosa, K. pneumonia, E. coli, S. aureus, and S. typhimurium.  This study proved that all crude extracts showed robust antioxidant and antimicrobial potentials which, could be harnessed for both their health and nutritional benefits in fisheries.

Key Words: Antimicrobial, antioxidant; P. guineense, O. gratissimum, M. koenigii, G. latifolium

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