PHYTOCHEMICAL SCREENING AND IN VITRO ANTIMICOBIAL ACTIVITIES OF (Plectranthus amboinicus (Lour)) OF LEAF AND STEM EXTRACTS

Abstract

Plectranthus amboinicus is knowns us traditional plant medicine in dif erent rural and urban community. However, production and usage of this traditional medicines require a scientific techniques and supports for the appropriate development of antibacterial drugs. The current study was intended to investigate phytochemical screening and antibacterial activities of Plectranthus amboinicus crude extracts, against pathogenic bacteria using the disc dif usion method. The minimum inhibitory concentrations of the extracts were assessed using broth dilution method. Amoxicillin and sterilized distilled water were used as positive and negative controls, respectively in the determination of antimicrobial activities. The results of qualitative analysis of the crude extracts revealed the presence of alkaloids, tannins, saponins, anthraquinones, flavonoids, terpenoids, and steroids. Phlobatannin has been found absent in both stem and leaf examined. With regard to the antibacterial activities of the crude extracts, ethanol crude extracts of leaf and stem showed better antibacterial activities than the crude extracts obtained using water solvents. The ethanol leaf extract showed 15.62, 15.21, 14.36 and 14.21mm of the zone of inhibitions against S. aureus, S. pyogenes, S. Typhi and E. coli, respectively, at a concentration of 150 mg/ml. The result shows four tested bacterial species S. aureus and E. coli were the most and least susceptible, respectively. Data was analysed by SPSS, version 27. The inhibitory ef ects of the crude extracts were significantly dif erent at p<0.05. The MIC of the crude extracts was generally in the range of 25.00 to 100.00mg /ml against the four tested bacterial species However, the minimum bactericidal concentrations values ranged from 50 to 125mg/ml against the four tested bacterial species. In general, the present investigation shown that the leaf and stem extracts of P. amboinicus have antimicrobial potential for selected pathogen. However, further research is needed for isolation and quantification of the specific bioactive compounds to authenticate the most important chemical componen