PHYTOCHEMICAL SCREENING, ANTIMICROBIAL PROPERTIES AND ESSENTIAL OIL CONSTITUENTS OF COMBRETUM SORDIDUM EXELL

Plants in Combretaceae family are traditionally reputed to be anthelmintics and antimicrobial agents. Dried aerial parts of Combretum sordidum (Exell) were ground to fine powder and extracted using ethanol. Ethanol extract was partitioned to obtain hexane and ethylacetate extracts successively. These extracts were screened for secondary metabolites using standard methods and evaluated for their antimicrobial potentials against two Gram positive bacteria; Bacillus subtilis (ATCC 14579) and Bacillus cereus (ATCC 33923); two Gram negative bacteria; Proteus mirabilis (ATCC 21784), Salmonella typhi (ATCC 25179) and a fungus; Candida albicans (NCTC 227) by tube dilution method. Essential oil from its leaves was obtained by hydrodistillation method and analyzed by GC and GC-MS. Preliminary phytochemical screening revealed the presence of alkaloids, saponins, tannins, flavonoids, cardiac glycosides, steroids and anthraquinones in the ethylacetate and ethanol extracts. Both extracts displayed broad spectrum activities against the organisms used with minium inhibitory concentration (MIC) at 400µg/mL. Five compounds comprising 99.99% of the total peak area were identified from the volatile oil. The most abundant constituent was 7- octadecenoic acid methyl ester (51.26%) and others were dodecanoic acid (21.12%), hexadecanoic acid (11.58%), tetradecanoic acid (8.94%) and octadecanoic acid (7.09%) methyl esters. These secondary metabolites might be responsible for the antimicrobial activities of C. sordidum. The result obtained from this study further justifies the use of this plant as antimicrobial agent by the traditional healers.