28. Assessment of antibacterial potential of methanol, n-hexane, ethyl acetate and chloroform Moringa oliefera leaf extracts

Abstract

Bacterial infections and their increasing resistance to common antibiotics is posing serious threat to global public health.  To this end, finding new alternatives and evaluating their antibacterial efficacy is always desirable. Therefore, in the present study we used methanol (MeOH), n-hexane (n-Hex), ethyl acetate (ETAC) and chloroform (CHCl₃) to prepared four different types of extracts from Moringa oleifera (M. oliefera) leaves aiming to inhibit five selected bacteria. Initially, agar well diffusion methods was used, and zones of inhibition were measured as an indicator of bacterial susceptibility. MeOH, n-Hex, ETAC and CHCl₃ leaf extracts showed highest zone of inhibition against E. coli, B. cereus, S. pyogenes, S. aureus and S. enterica, respectively. Moreover, highest zones of inhibition were observed at lowest incubation (24hr) and lowest zones were observed at highest incubation period (72hr) for all tested concentrations. Later, macrodilution method was used to access the antibacterial susceptibility in liquid medium. Results confirmed the susceptibility of all test bacteria with different level of IC₅₀ values ranging from 7.07 ± 0.44 to10.91 ± 0.10 mg/ml for MeOH extract, 1.66 ± 0.08 to 2.11 ± 0.11 mg/ml for n-Hex extract, 2.58 ± 0.13 to 3.84 ± 0.21 mg/ml for ETAC extract and 3.73 ± 0.75 to 8.36 ± 0.20 mg/ml for CHCl₃ extract. Interestingly, none of the tested bacteria showed resistance against any of the tested extract in well diffusion or macrodilution method expressing the M. oliefera leaves extracts as potent candidates to kill bacteria in semisolid or in liquid medium to fulfill medical needs in future.

Keywords: Bacteria; M. oleifera; Macrodilution method; Zones of inhibition

http://dx.doi.org/10.19045/bspab.2020.90207