Antimicrobial Activities of Palm Kernel Oil (Elaeis guineensis Jacq.) and Castor Oil (Ricinus communis Linn.) on Uropathogens
Rita Ngozi Nweke *
Department of Microbiology, University of Nigeria Nsukka, Enugu State, Nigeria.
Bernard Uzoma Nweke
General Hospital Ekwulobia, Aguata Local Government Area, Anambra State, Nigeria.
Precious Chidimma Onyeka
Department of Microbiology, University of Nigeria Nsukka, Enugu State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: This study investigates the antimicrobial activities of castor bean oil and palm kernel oil against uropathogens, focusing on their potential as alternatives for treating urinary tract infections.
Study Design: This study is a cross sectional research.
Place and Duration of Study: Urine samples were collected from urinary tract infection (UTI) suspected patients at University of Nigeria Nsukka, Medical Centre. Fresh Castor bean (Ricinus communis) and palm kernel (Elaeis guineensis) were bought from Orba main market in Orba, Udenu Local Government of Enugu state. The plant products were transported to the Herbarium and authenticated by a plant taxonomist from the Department of Plant Science and Biotechnology, University of Nigeria, Nsukka, Enugu state. The plant materials were transported to Microbiology laboratory, University of Nigeria, Nsukka for oil extraction and analysis from January to May, 2024.
Materials and Methods: The urine samples were cultured on Eosin methylene blue agar, Mannitol agar and potatoes dextrose agar. The isolates were identified by morphological growth characteristics, biochemical tests and by Gram staining reaction. Castor bean oil and palm kernel oil extraction was done by semi-thermal process at a low temperature. The antimicrobial activities of the extracted oils against the isolates were carried out using the agar well diffusion method.
Results: The presence of terpenoid, flavonoids and glycosides were observed in both PKO and CBO among others. The isolated uropathogens were identified as Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial testing indicated that PKO was fully effective against S. aureus at all concentrations, 50% sensitivity against E. coli at 100mg/ml and 50 mg/ml; whereas C. albicans had 50% sensitivity at 100 mg/ml and 50mg/ml, but completely resistant at 25 mg/ml and 12.5mg/ml. PKO showed inhibition zone diameter (IZD) against S. aureus (16.5 mm) at 100 mg/m, 11 mm against C. albicans at 100 mg/ml and 50 mg/ml whereas 0 mm was observed at 25 mg/ml and 12.5 mg/ml. CBO had lower antimicrobial activities than PKO. The maximum IZD for CBO was against S. aureus (14 mm) and E. coli (11 mm) at 100 mg/ml concentration, while 0 mm IZD was observed against C. albicans. However, the combination of the 2 oils had no synergistic effect.
Conclusion: The sensitivity of mostly S. aureus, then, E. coli to these oil extracts particularly PKO highlights a viable alternative in treating UTIs. The poor antimicrobial effects of the oils especially the CBO on the uropathogens could be attributed to the dissolution strength of the solvent, DMSO used in this study.
Keywords: Uropathogens, castor bean oil, palm kernel oil, phytochemicals, antimicrobial activities and inhibition zone diameter