Safety evaluation of aqueous root extract of Hermannia geniculata EckL. & Zeyh. (Streculiaceae) in Wistar rats

Introduction: Hermannia geniculata is a medicinal plant used by the Basotho tribe (South Africa) for the management of diarrhoea and sugar-related disorders either individually or in synergy with orthodox antidiabetic drugs. Methods: Aqueous root extract of Hermannia geniculata was evaluated for its safety and or toxicity in Wistar rats. A preliminary evaluation in rats observed signs of toxicity over a 14 day period after a single oral dose of 5000 mg/kg body weight of H. geniculata extract. Detailed experiments were then conducted by orally administering graded doses (75, 150 and 300 mg/kg) of H. geniculata extract to rats daily for 28 days. Behavioural changes as well as haematological, biochemical and histological parameters were then evaluated. Results: The extract significantly reduced (p < 0.05) white blood cells and other haematological parameters. The levels of conjugated bilirubin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and calcium ion were also significantly affected (p < 0.05) by the administration of H. geniculata extracts. Histopathological study on the lungs, liver, kidney and heart of the animals after treatment with H. geniculata extract, showed that the organs were not structurally different compared to that of the control. Conclusions: Results suggest that at these doses the administration of aqueous root extract of H. geniculata to Wistar rats did not produce any deleterious effect on the livers, kidneys, lungs or hearts of the animals. However, caution is needed as continuous usage could lead to reduction of systemic immunity. (C) 2015 Elsevier GmbH. All rights reserved.