Antifungal and antibacterial activities of six different extracts of Harungana madagascariensis stem bark

Ethnoveterinary usefulness of Harungana madagascariensis Choisy Poir (Clusiaceae) has been documented in Africa and in Europe for the treatment of animals with anaemia and various infections [1]. Most of these studies were on the aqueous extract of the leaves. We have found out in our laboratory that aqueous extract of plant material does not show prominent antimicrobial activity. Therefore in this study, hexane (H), dichloromethane (D), chloroform (C), ethyl acetate (E), acetone (A) and methanol (M) extracts were subjected to antimicrobial activity in-vitro testing against fungi (M. canis, C. albicans, C. neoformans, S. schenckii, and A. fumigatus) and bacteria (E. faecalis, E. coli, P. aeruginosa, and S. aureus) using the TLC fingerprint and bioautography [2]. The % yield of extractants indicated for M (11.1%), A (10.5%), C (5.8%), D (5.2%), E (5.1%) and H (2.4%). TLC fingerprint and bioautography were best eluted in benzene: ethanol: ammonia (BEA) (18: 2: 0.2) and showed at least 8 different compounds that are active against the different strains of fungi and bacteria used. These compounds are common to D, C, E, A and M, but were not present in H extract. The MIC values of the six extracts showed inhibition of the fungi and bacteria organisms in various degrees. D and H extracts exhibited the lowest (6.3–104.1µg/ml) and the highest (27.9–500.0µg/ml) MIC on fungi pathogens respectively as compared to Amphotericin B which gave (0.62µg/ml). Likewise, the same D and H extracts also gave the lowest (3.6–7.8µg/ml) and the highest (13.0–26.0µg/ml) MIC values respectively on bacteria pathogens as compared to Gentamycin which gave 0.36µg/ml. The study therefore showed that antimicrobial compounds also reside in the stem bark like in the leaves [3, 4] with the highest activities found in the D extract.

References: [1] Committee for Veterinary Medical Product (1999): Harungana madagascariensis. The European Agency for the Evaluation of Medicinal Products. http://www.eudra.org/emea.html. [2] Eloff. J.N. (1998) J. Ethnopharmacol. 60 1–8. [3] Moulari, B. et al. (2006) J. Ethnopharmacol. 106 272–278. [4] Okoli A.S. et al. (2002) Phytother Res/16:/174–179.