Assessment of acute and sub-chronic toxicity of Camellia hakodae Ninh leaves aqueous extracts in experimental animals

Camellia hakodae Ninh (CHN) is an ornamental plant of Vietnam, whose extracts is used as a potential phytotherapeutic beverage due to its good improvement in the immune system, reduction of inflammation and assisting the treatment of some chronic diseases. CHN production may be useful for health during this coronavirus epidemic period. This study aimed to evaluate the safety, acute and sub-chronic toxicity of aqueous extracts of CHN leaf in mice. In the acute toxicity study, CHN leaf at doses from 24.0 to 120.0 g/kg/day was given to 5 groups of Swiss mice by oral administration (equivalent in humans is 0.2 to 10 g/kg/day). Mice were observed for general behavioral changes, adverse effects and mortality up to 7 days post-treatment to find the highest dose that did not kill mice (the dose of death 0% (LD0)), the lowest dose that completely killed the mice (the dose of death 100% (LD100)) and the intermediate doses (LD50). In sub-chronic toxicity studies, CHN was given orally to 2 groups of Wistar rats at doses of 2.8 and 14 g CHN/kg/day (equivalent in humans is 0.4 and 2 g/kg) for 28 days taking CHN daily. After 28 days of taking CHN, mice were operated to observe the whole organ for histopathology. The microscopic structure of the liver, spleen, and kidney of at least 30% of mice in each group was randomly checked. The acute toxicity study in all the doses used did not cause any significant change as no LD50 was found. In addition, the sub-chronic toxicity study did not show any treatment-related abnormalities with regard to hematological and biochemical parameters. These results demonstrated that the CHN leaf aqueous extract is safe and does not appear to exert toxicity. Key words: Camellia hakodae Ninh, golden tea, acute and sub-chronic administration, Vietnamese tea.