Anti-Toxoplasma gondii activity of GAS in vitro

Ethnopharmacological relevance: The sarcotesta of Ginkgo biloba is a Chinese herbal medicine used for treating toxoplasmosis, a serious disease requiring treatment with antibiotics that can have serious side effects. Aim of the study: To investigate the anti-Toxoplasma gondii activity of ginkgolic acids (GAs) isolated from the Ginkgo biloba sarcotesta in Toxoplasma gondii-infected human foreskin fibroblast (HFF) cells in vitro. Materials and methods: The safe concentration of GAs for HFF cells was determined by methyl thiazolyl tetrazolium (MTT) cell proliferation assay. The presence of Toxoplasma gondii was measured by [H-3]-thymine deoxyriboside([H-3]-TdR) and [H-3]-leucine ([H-3]-Leu) incorporation, as well as Giemsa staining. The positive control was the commonly used and highly effective antibiotic azithromycin. Results: Light microscopy revealed that most HFF cells were infected after 4h of exposure to Toxoplasma gondii. After 48 h of exposure to either GAs or azithromycin, Toxoplasma gondii DNA and protein synthesis were minimal, there were no visible parasites in HFF cells, and the HFF cells had no significant morphological changes. Conclusions: These results demonstrate that GAs have significant anti-Toxoplasma activity with low toxicity to HFF cells, suggesting that GAs could be an alternative treatment for toxoplasmosis. (c) 2008 Elsevier Ireland Ltd. All rights reserved.