Research: ZOFOU and COLLEAGUES,

Listed in Issue 205

Abstract

ZOFOU and COLLEAGUES, Biotechnology Unit, University of Buea, P.O. Box 63 Buea, South West Region, Cameroon evaluated the anti-malarial potential and the safety of the methanol extract of the Hypericum lanceolatum stem bark.

Background

Malaria is a major public health threat in Africa, and traditional medicine continues to play a key role in its control especially in rural areas. A bioassay-guided fractionation was carried out in order to evaluate the anti-malarial potential and the safety of the methanol extract of the Hypericum lanceolatum stem bark.

Methodology

The anti-plasmodial activity was assayed by the lactate dehydrogenase method (pLDH) against the multidrug-resistant W2mef laboratory strain, and a field isolate (SHF4) of Plasmodium falciparum. Cytotoxicity tests were carried out using the LLC-MK2 monkey kidney epithelial cells.

Results

Five compounds were isolated from the most active and least cytotoxic ethylacetate sub-extract: betulinic acid (HLT1), 2,2',5,6'-tetrahydroxybenzophenone (HLT2), 5-hydroxy-3-methoxyxanthone (HLT3), 3-hydroxy-5-methoxyxanthone (HLT4) and HLT0 (yet to be identified). Three of the tested compounds presented significant anti-plasmodial activities (with 50% inhibitory concentration, IC50 < 5 muM), with 5-hydroxy-3-methoxyxanthone exerting the highest activity, followed by HLT0 and betulinic acid. All the compounds with significant anti-plasmodial activity were non-cytotoxic, except betulinic acid which showed a 50% cytotoxic concentration, CC50 of 25 mug/mL.

Conclusion

These findings justify the use of H. lanceolatum stem bark as anti-malarial by traditional healers of Western Cameroon, and could constitute a good basis for further studies towards development of new drug candidates or phytomedicines for malaria.

References

Zofou D, Kowa TK, Wabo HK, Ngemenya MN, Tane P and Titanji VP. Hypericum lanceolatum (Hypericaceae) as a potential source of new anti-malarial agents: a bioassay-guided fractionation of the stem bark. Source Malaria Journal. 10:167, 2011. Other ID Source: NLM. PMC3131257. 2011.

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