Anti-Toxoplasma gondii activity of GAS in vitro.

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. To investigate the anti-Toxoplasmagondii activity of ginkgolic acids (GAs) isolated from the Ginkgo biloba sarcotesta in Toxoplasmagondii-infected human foreskin fibroblast (HFF) cells in vitro. The safe concentration of GAs for HFF cells was determined by methyl thiazolyl tetrazolium (MTT) cell proliferation assay. The presence of Toxoplasmagondii was measured by [3H]-thymine deoxyriboside ([3H]-TdR) and [3H]-leucine ([3H]-Leu) incorporation, as well as Giemsa staining. The positive control was the commonly used and highly effective antibiotic azithromycin. Light microscopy revealed that most HFF cells were infected after 4h of exposure to Toxoplasmagondii. After 48 h of exposure to either GAs or azithromycin, Toxoplasmagondii DNA and protein synthesis were minimal, there were no visible parasites in HFF cells, and the HFF cells had no significant morphological changes. 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.