An investigation of the antimicrobial activity of the aqueous, dichloromethane, ethanol and methanol extract of the seeds and whole plant of Ipomoea nil

Abstract

Ipomoea nil (Linn) Roth, (morning glory / kaladanah; Convolvulaceae), is frequently grown in gardens and lawns for its ornamental flowers and often runs wild in hedges and wastelands. Plant is documented to possess beneficial effect in erectile dysfunction, impotence and also have antispasmodic, bronchodilator, blood purifier, diuretics, astringent, anti-inflammatory and hepato-protective etc. In this study, disc diffusion method was adopted to evaluate and compare the antimicrobial activity of the aqueous and organic (DCM, ethanol, methanol) extracts of the seeds and whole plant (leaves, flower and bark) of Ipomoea nil, in order to know the best extract and plant part having the beneficial activity against pathogenic bacteria species of both G +ve strains, i.e., Staphylococcus aureus, Bacillus pumilus, Streptococcus pneumoniae, G -ve strains, i.e., Escherichia coli, Citrobacter freundii and Klebsiella pneumoniae and two species of fungi (Candida albicans, Aspergillus niger). Methanolic and ethanolic extract of the seeds of the Ipomoea nil showed significant antibacterial activity against Staphylococcus aureus (G +ve) having the relative percentage of inhibition of 89.88 % and 85.67 % respectively, while methanolic extract of the whole plant also have relative percentage of inhibition of 83.96%, whereas ethanolic extract of the whole plant have good antibacterial activity. Aqueous and DCM extract of seeds and whole plant showed weak inhibitory response. Modified agar well diffusion method was adopted to measure the minimum inhibitory concentration (MIC) and MIC values for G +ve, lies within the range of 30 to 60 ?g /ml (seeds), 60 to 90 ?g /ml (whole plant) and for the Gram –ve, it lies within the range of 90 to 250 ?g /ml (seeds), 180 to 500 ?g /ml (whole plant)  and for the fungi, it varies from 500  to 2000 ?g /ml. Present study clearly indicate that the antimicrobial activity varies from part to part and the plant material used and it also indicate that the methanolic extract of Ipomoea nil is a potentially good candidate for the therapy of antibacterial-resistant bacteria and would therefore require further study.