Evaluation of selected tropical seaweeds for in vitro anti-trichomonal activity

Ethnopharmacological relevance: Human parasitic infections are a serious problem in tropical and subtropical developing countries. Trichomoniasis, responsible for the annual infection of 180 million people, is a common sexually transmitted disease caused by the protozoan Trichomonas vaginalis. Traditionally seaweeds have been used in folk medicine by coastal people in Asia and the Caribbean to treat parasitic infections and are a valuable source of novel anti-trichomonals. Aim of the study: In our search for therapeutical alternatives to anti-protozoal chemotherapy, we collected a selection of 25 tropical seaweeds (12 Rhodophyta, 5 Phaeophyta and 8 Chlorophyta) from the coast of Yucatan (Mexico) in order to undertake ethnopharmacological and chemotaxonomic investigations. Materials and methods: Organic algal extracts were tested for their anti-trichomonal properties on the growth inhibition of Trichomonas vaginalis. The cytotoxicity of seaweed extracts on mammal cell lines was also assessed. Results: The results indicated that 44% of the seaweeds studied had high to moderate anti-trichomonal activity. Lobophora variegata and Udotea conglutinata showed the maximal anti-trichomonal activity with IC50 values of 1.39 and 1.66 mu g/ml, respectively, with good selectivity. Conclusions: Lobophora variegata and Udotea conglutinata demonstrated promising anti-trichomonal potential and have been selected for further bio-guided fractionation and isolation of active anti-trichomonal compounds. (C) 2008 Elsevier Ireland Ltd. All rights reserved.