Assessment of antibacterial activity of <i>Moringa oleifera</i> leaf extract against bacteria isolated from some drinking water sources in Katsina metropolis

Abstract

Continuous consumption of sachet and tap water in Nigeria is of public health significance as the potential bacterial water contaminants could develop resistance to commonly used antimicrobials. This study was carried out to assess the bacteriological quality and TLC-Bio autographic profile of water samples using M. oleifera leaf extract. One hundred samples comprising 50 sachets and 50 tap water were collected from five different locations in Katsina metropolis. Most probable number (MPN) was used to identify indicator bacteria and characterized using biochemical tests followed by 16S rRNA gene sequencing identification. The results showed that the pH and temperature level of all the samples were significantly different. Turbidity (0.2-0.47NTU), dissolved oxygen (1.34-2.03mg/L and 0.85-2.45mg/L) and biological oxygen demand (0.49-1.09mg/L and 0.19-.59mg/L) were below the minimum permissible limits set by WHO and NAFDAC (≤5). Total coliform counts exceeded limits of 2 MPN/100ml and Escherichia coli was detected from tap water of Kofar Marusa, Kofar Durbi and Kofar Kaura as well as the sachet water of Kofar Marusa and Kofar Keke. However, there was no statistically significant difference (P≤0.05) between the total coliform counts of both sachet and tap water. The 16S rRNA gene identification showed the presence of Escherichia marmotae and Enterobacter kobei in both sachet and tap water. The GC-MS demonstrated that M. oleifera leaf extract contained 9,12,15-Octadecatrienoic acid, ethyl ester, Octadec-9-enoic acid and Hexadecanoic acid, The TLC-bioautography result indicate antibacterial activity, with inhibition zones ranging from 15±0.00 to 19.5±4.95mm (E. coli) to 23.5±6.36mm (E. faecalis) and 20±0.00 to 22±1.41mm (E. faecium). Waterborne faecal bacterial contaminants were found associated with the sachet and tap water analyzed. M. oleifera leaf has bioactive principles with nobility to be used as candidate for drug development.