ANTIBACTERIAL EFFICACY OF ETHANOLIC EXTRACTS FROM RHIZOME BARK AND TUBER OF Colocasia esculenta (L) Schott, Cranberry variety (ARROWROOT), PHYTOCHEMICAL ANALYSIS AND MINIMUM INHIBITORY CONCENTRATION DETERMINATION AGAINST Salmonella typhi, Klebsiella pneumoniae and Acinetobacter baumanii

Abstract

Colocasia esculenta (L) Schott is a widely grown plant with edible corms and medicinal properties. While the leaves of this plant have been studied for their potential medicinal uses, research on the tuber and bark has limited exploration of the synergistic effects of specific phytochemicals present in the ethanolic extracts of Colocasia esculenta (L) Schott Cranberry variety and how these interactions contribute to the antibacterial efficacy. Additionally, more comprehensive studies on minimum inhibitory concentration across a broader spectrum of bacterial strains to assess the generalizability of the plant extracts antibacterial properties need research. This study explores the antibacterial efficacy of ethanolic extracts derived from the rhizome bark and tubers of Colocasia esculenta (L) Schott Cranberry variety. The research involved phytochemical analysis and determination of minimum inhibitory concentration against three pathogenic bacteria: Acinetobacter baumanii, Klebsiella pneumoniae and Salmonella typhi that are a WHO priority, and are commonly associated with respiratory infections in Kenya.n. Experimental research design was adopted. Twenty pieces of Colocasia esculenta were obtained from Kaimosi Friends University to prepare rhizome bark and tuber extracts, in triplicates, using ethanol at concentrations of 25%, 50%, 75% and 100%, with sterile distilled water as the negative control and ciprofloxacin as the positive control in botany laboratory of Maseno University. Three bacterial strains were obtained from KEMRI and were cultured using Mueller- Hinton Agar. Standard techniques were used in phytochemical screening and in antibacterial experiments. Minimum inhibitory concentration was determined by the broth dilution method. Statistical analysis was performed using Statistical Analysis System version 9. 1. Descriptive data analysis was used to determine presence of phytochemicals. One way analysis of variance was done to assess significant differences in activity between the ethanol extracts and the bacteria, and to determine means of diameters of zones of inhibition at a confidence interval of 95%, with p-values obtained to give significant differences between the means. Predictive data analysis was performed to determine the minimum inhibitory concentration. Results showed presence of saponins, steroids, tannins, alkaloids, glycosides and phenolic compounds. Ethanolic extracts from the rhizome bark and rhizome tuber exhibited antimicrobial activity against all three bacteria. A concentration of 25% of the bark extract was most effective against Salmonella typhi and Klebsiella pneumoniae, 75% of the bark extract was most effective against Acinetobacter baumannii, 50% of the tuber extract was most effective against Salmonella typhi and Klebsiella pneumoniae while 100% of the tuber extract was most effective against Acinetobacter baumannii. Extracts from the bark were more effective than those from the tuber. The minimum inhibitory concentrations for the bark extract ranged from 100µg/ml to 160µg/ml, while those for the tuber extract ranged from 150µg/ml to 250µg/ml. Results from this study contribute valuable insights into potential natural sources for antibacterial agents and their effectiveness against clinically relevant pathogens. Beneficiaries for this study are Pharmaceutical companies developing new antimicrobial agents, microbiologists, communities affected by bacteria used in the study, and healthcare professionals seeking for alternative treatment of bacterial infections.