The Thai Journal of Pharmaceutical Sciences


Introduction: Geophila obvallata (Rubiaceae) is a medicinal herb used for the treatment of diseases associated with oxidative damage. Objective: The study investigated the toxic effects of acute and sub-acute oral doses of methanol extracts of G. obvallata (GOE) in rats. Materials and Methods: In acute toxicity study, extract doses of 1600, 2900, and 5000 mg/kg were orally administered. The rats were observed for signs of toxicity for 2 weeks. In sub-acute toxicity study, the extract was administered to rats at doses of 100, 500, and 1000 mg/kg for 28 days, while control rats received only water. At the end of 28 days, rats were sacrificed. Organ weights, biochemical and histological parameters were determined using standard procedures. Results: In acute toxicity studies, the extract did not induce death after single dose administration. Hence, the lethal dose 50 was above 5000 mg/kg. The results of sub-acute toxicity study showed no significant changes in body weights, organ weights, kidney function, and histology. In contrast, there were significant changes in hematology and biochemical indices at higher extract doses of 500 and 1000 mg/kg. Conclusion: These results suggest that GOE is non-toxic at a dose of 100 mg/kg and can be used for therapeutic applications at an equivalent dose in humans.


Faculty of Pharmaceutical Sciences, Chulalongkorn University

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