ANTIBACTERIAL ACTIVITY OF THREE PLANT EXTRACTS USED IN NIGERIA FOLKLORIC MEDICINE AGAINST HOSPITAL ISOLATES OF METHICILLIN- RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) AND METHICILLIN-SENSITIVE STAPHYLOCOCCUS AUREUS (MSSA)

Abstract

Staphylococcus aureus is a species of bacterium commonly found on the skin and/or in the noses of healthy people. Although it is usually harmless at these sites, it may occasionally get into the body (eg through breaks in the skin such as abrasions, cuts, wounds, surgical incisions or indwelling catheters) and cause infections. These infections may be mild (eg pimples or boils) or serious (eg infection of the bloodstream, bones or joints). It is one of the important bacteria as a potential pathogen specifically for nosocomial infections. Interest in plants with antimicrobial properties has revived as a result of current problems associated with the use of antibiotics.Hexane, ethylacetate, methanol and water extracts from 3 different plant species, Jatropha curcas, Piliostigma thonningii and Hyptis suaveolens used in Nigeria as popular medicine for the treatment of several ailments of microbial and non-microbial origin were evaluated for potential antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) using agar dilution method. Results revealed that there were no significant differences in the % susceptibility to MRSA and MSSA between the standard drugs and the different plant extracts using different extracting solvents (P>0.05). All the extracts of the 3 plants were effective on MRSA except water extract of Jatropha curcas and Piliostigma thonningii. Hexane extract from P. thonningii was inhibitory to 100% of both MRSA and MSSA isolates followed by ethyl acetate extract of J. curcas 61% of MSSA, ethyl acetate extract of P. thonningii on 38% of MRSA, methanol extract of J. curcas on 33% of both MSSA and MRSA and the least activity was with water extract of H. suaveolens on 17% of both MSSA and MRSA; no activity was observed with water extract of J. curcas. Hexane extract of P.thonningii was the only extract found in this study to inhibit the growth of both MRSA and MSSA. The phytochemical screening of crude extracts revealed the presence of tannins, phenols, sterol, and saponin in J curcas; saponin, tannin, flavonoid, phenols and alkaloid was observed in H. suaveolens, while P. thonningii extracts consist of flavonoid, phenol, sterol, tannin, saponin and cardiac glycosides. The presence of these bioactive components in the present study may be responsible for inhibition of the isolates. The results provide a scientific basis for the centuries-old usage of these medicinal plants. This study may help to suggest an alternative possible leading compounds for development of new antimicrobial agents against MRSA and MSSA resistant S. aureus