Acute and sub-acute toxicity studies of roselle leaves

Abstract

Roselle leaves are widely used in traditional medicine but have not previously been studied for their safety through standard in vivo toxicity studies. This study aimed to evaluate the safety of roselle leaves extract through acute and sub-acute oral toxicity studies in Sprague Dawley (SD) rats. An acute toxicity study was carried out using a single high dose of roselle leaves extract at 3000 mg/kg and toxic signs were observed within 14 days. While sub-acute toxicological study was carried out using 28-days repeated doses of 0 mg/kg (control), 1000 mg/kg, 2000 mg/kg, and 5000 mg/kg of roselle leaves extract. Bodyweight changes were recorded throughout the experimental period. On day 29, blood was withdrawn and analysed for haematology and clinical biochemistry values. During the 14-day acute toxicity study, there were no significant changes in body weight increment, adverse clinical signs and mortality. In the sub-acute toxicity study, there were also no toxicology significant changes in haematology and clinical biochemistry except a slight decrease in triglyceride (TG) and glucose level (p < 0.05) which is attributed to roselle leaves aqueous extract administration. However, the results were within the normal reference range of SD rats. Therefore, the acute and sub-acute toxicity studies in SD rats showed that roselle leaves aqueous extract is non-toxic and could be classified as a no-observed-adverse-effect level (NOAEL).