Study on the Toxicology and Safety of Ethanol Extracts from Branches and Leaves of Tectona grandis

PurposeTo study the toxicology and safety of ethanol extracts from the branches and leaves of Tectona grandis (EBLTG), a Dai medicine, providing scientific references for its further development and utilization.

MethodsAccording to the result of maximum tolerance test, the SPF SD rats aged 5-7 weeks were given high (2 500 mg/kg), medium (1 250 mg/kg) and low (625 mg/kg) dose of EBTLG for 28 days, biochemical and hematological indexes were determined. After euthanasia, general anatomy observation, organ extraction and weighing, and histopathological examination were performed.

ResultsThe median lethal dose (LD₅₀) of EBLTG to Kunming mice was over 5.0 g/kg. According to the WHO classification standard of acute toxicity of exogenous chemicals, EBLTG was actually non-toxic. Compared with the control group, the body weight, food consumption and food utilization rate of the SD rats in each group didn’t show significant differences in the 28-day oral toxicity test (P>0.05). The serum biochemical and coagulation indexes, blood routine and electrolyte indexes showed no toxicological significance, although some indexes were higher or lower than those of the control group. Most of these differences did not appear in male and female rats at the same time, and all the indexes were within the normal range in our laboratory. No abnormality was observed in gross anatomy, and no histopathological changes and specific lesions associated with EBLTG.

ConclusionEBLTG has no dose-dependent effect on blood physiological and biochemical indexes and organ tissue pathology, no toxic effect on SD rats at all doses used in this study, and the no observed adverse effect level in SD rats is 2.5 g/kg.