Antileishmanial Activity of Selected Turkish Medicinal Plants

Purpose: To determine the in vitro and in vivo anti-leishmanial activities of extracts obtained from Centaurea calolepis, Phlomis lycia, Eryngium thorifolium, Origanum sipyleum and Galium incanum ssp. centrale. Methods: To estimate the cytotoxicity of plant extracts, WST-1 assay was used. Parasite inhibition in the presence of plant extracts (25 - 500 mu g/ml) in comparision with control group and reference group (glucantime, 25 mu g/ml) at 12 - 72 h were determined in vitro on L. tropica promastigotes. The in vivo leishmanicidal activity of the extracts was evaluated against L. tropica-infected mice with glucantime as reference drug. Results: The chloroform extract of Galium incanum ssp. centrale showed the highest cytotoxicity with IC50 value of 0.0316 +/- 0.005 mu g/ml. In vitro parasite inhibition by the plant extracts ranged between 16.7 +/- 0.01 % and 100 +/- 0.00 % at 25 mu g/ml concentration. The methanol extract of Eryngium thorifolium possessed the highest activity on promastigotes of L. tropica with 100 % inhibition at 25 mu g/ml. The water and chloroform extracts of C. calolepis and water and methanol extracts of E. thorifolium at a dose of 100 mg/kg reduced parasitaemia in L. tropica infected mice. Conclusion: Parasite viability results suggest that the methanol extract of Eryngium thorifolium, regarded as non-cytotoxic, is a promising candidate drug for treating L. tropica infection.