In-vivo toxicity studies of a mixture of Hibiscus sabdariffa L., Clinacanthus nutans L. and Stevia leaves in Sprague Dawley rats

Natural products from medicinal plants are widely used worldwide as they are claimed to generate new alternative medicines. Following its proven medicinal properties, a mixture of Hibiscus sabdariffa L., Clinacanthus nutans L., Stevia rebaudiana in the ratio of 1:1:0.5 (HS:CN:Stevia; w/w/w) was shown to be effective therapy as diuretic and in chemoprevention. However, no study has been conducted to assess the toxic effect or the LD50 of this mixture. Therefore, a standard in-vivo toxicological assessment was carried out in a 28-day oral administration study. The doses tested were 1,000 mg/kg, 2,000 mg/kg and 5,000 mg/kg of body weight in Sprague Dawley rats. No mortality, adverse clinical signs and abnormal changes in body weight. Toxicologically significant changes were only seen in relative liver weight, red blood cell count, haematocrit, haemoglobin and total protein. However, the difference was toxicologically insignificant since the values were within normal physiological ranges. These observations suggest that the mixture is practically nontoxic in Sprague Dawley rats and the no-observed-adverse-effect level (NOAEL) is greater than 5,000 mg/kg.