|Authors: ||K.S. Khoo, P.S. Gwee, V. Beh, T.C. Chung, L.Y. Tan , N.W. Sit, H.C. Ong|
|Keywords: ||bacteriostatic, bactericidal, fungistatic, fungicidal, broth microdilution |
The increase of opportunistic fungal infections and the escalation of bacterial resistance, particularly multi-drug resistance, has seriously impacted the efficacy of chemotherapeutic agents available, thus necessitating the search for new anti-microbial agents from natural sources such as medicinal plants.
In this study, parts of three local plants, Diodia sarmentosa (tropical buttonweed; whole plant except roots), Hydrocotyle sibthorpioides (lawn marshpennywort; whole plant) and Muehlenbeckia platyclada (centipede plant; stem) were selected and sequentially extracted using hexane, chloroform, ethyl acetate, ethanol, methanol and water.
The extracts were then evaluated, in triplicate, against 12 medically important micro-organisms for microbiostatic and microbiocidal activities using colorimetric broth microdilution methods.
One hundred and eight of the bioassays for antifungal property most exhibited fungistatic and fungicidal activity, respectively.
The lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration was exhibited by the hexane extract of D. sarmentosa against Cryptococcus neoformans, and hexane extract of H. sibthorpioides against C. neoformans and Issatchenkia orientalis. The lowest MIC and minimum bactericidal concentration was obtained in the hexane extract of H. sibthorpioides against K. pneumonia. Yeasts were found to be more susceptible to the plant extracts than molds.
However, for bacteria, the susceptibility was species-dependent.
The results corroborate the efficacy of H. sibthorpioides in traditional medicine for treating abscesses, sore throat and skin ailments caused by microorganisms.
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