Acute oral toxicity evaluation of -standardized first true leaf ethanolic extract.

is widely used in traditional herbal medicines for the treatment of common cold, fever and diarrhea, in many regions of Scandinavia and Asia, including Thailand. The pharmacological activities of are mainly attributed to active diterpenoids including 14-deoxyandrographolide, which is uniquely high in first true leaf ethanolic extract (FTLEE) of . In this study, the acute toxicity of the standardized FTLEE of was examined according to the OECD test guideline No. 420. Mice were divided into four groups of each sex and orally received the standardized FTLEE of (0, 300, 2000, or 5000 mg/kg BW). Post-treatment, body weight, signs of toxicity, and/or mortality were observed for 14 days. At Day 15, animals were euthanized, internal organs were observed grossly, and blood samples collected were subjected to hematology and clinical biochemistry analyses. The results showed that all treated animals survived and no apparent adverse effects were observed during the duration of the study. Gross necropsy observation revealed no lesion in any organ of all the standardized FTLEE-treated mice. Although significant alterations in BUN, lymphocytes, neutrophils, hematocrit and hemoglobin were observed, these alterations were not treatment-related toxic effects. Therefore, we concluded that a single oral administration of the standardized FTLEE of with an upper fixed dose of 5000 mg/kg BW has no significant acute toxicological effects.