Effect of fertilizer treatment on the antimicrobial activity of the leaves of Ocimum gratissimum (L.) and Gongronema latifolium (Benth)

Abstract

The effect of fertilizer treatment on the antimicrobial activity of the leaves of Ocimum gratissimum (L.) and Gongronema latifolium (Benth) was investigated. Cultivated O. gratissimum (L) and G. latifolium were applied with NPK (15:15:15) fertilizer at 100, 200, 300, 400 and 500 kg/ha treatment levels in planting buckets derived using the furrow slice method two months after seedling emergence. No fertilizer treatment served as control. Leaves were harvested one month after treatment. The ethanolic extracts of the harvested leaves were used to determine the sensitivity of the extracts on Klebsiella pneumonia, Escherichia coli, Staphylococcus aurues, Pseudomonas aeruginosa, Salmonella typhi,
Streptococcus faecalis, Candida albicans and Aspergillus niger. The result obtained showed that the antimicrobial activity of the leaves of O. gratissimum and G. latifolium was significantly (P < 0.05) increased by fertilizer treatment. The inhibition zone increased with increase in the level of fertilizer treatment. The ethanolic extracts of both plants whether treated or not had no antimicrobial effect on A. niger. This research revealed that fertilizer treatment might have increased the phytochemical content of the leaves of the plants which in turn enhanced their antimicrobial potential.

Keywords: Pathogens, NPK fertilizer, ethanolic extracts, inhibition zone