ANTIMICROBIAL AND PHYTOCHEMICAL SCREENING OF Heliotropium indicum LEAF EXTRACTS

Abstract

Fresh leaves of Heliotropium indicum were harvested from FUTA Campus. The antimicrobial activities of methanol, water and petroleum ether extracts of the leaf were examined against clinical and non-clinical bacterial isolates namely, Staphylococcus aureus, Klebsiella pneumoniae, pseudomonas aeruginosa, Escherichia coli, Shigella dysentariae, Salmonella typhi, Bacillus substilis, Staphylococcus aueus (ATCC 25923), Klebsiella pneumoniae (ATCC 34089), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 35218), Bacillus substilis (ATCC 21332), Shigella dysentariae (ATCC 24162), Salmonella typhi (ATCC 22648) and five fungal isolates; Aspergillus flavus, Aspergillus niger, Candida albicans, Aspergillus fumigatus and Candida albicans (ATCC 10231) using agar well diffusion method. The antifungal assay was also determined using agar well diffusion method. The methanol extract had the highest antimicrobial effect on the test organisms. However, for fungal the isolates, the highest zone of inhibition of 8.0mm was observed on Aspergillus fumigatus by the water extract while the lowest was 4.00mm against Candida albicans (ATTC 10231) by the petroleum ether extract. Purification of the extracts was determined using Column Chromatographic techniques and the antimicrobial potency of the purified fractions was investigated against the test organisms. The minimum inhibitory concentration (MIC) of extracts was determined using tube dilution method with values that ranged from 3.125 to 25mg/ml; while the death rate of organisms exposed to the extracts over a period of 24hours revealed a continuous decrease in the microbial load. The functional groups present in the bioactive compounds of the extract revealed structures of alkyne , alkenyl, carbonyl, and amine groups while phytochemical analysis revealed the presence of tannin, saponin, alkaloids, steroid and anthraquinone. Findings from this research indicated that the leaf extracts of Heliotropium indicum possess antimicrobial potency.