Antidiabetic and Toxicological Potentials of the Ethanol Leaf Extract of Annona muricata (L.) (Annonaceae)

Abstract

Drug resistance and adverse effects plague conventional diabetic treatments.  Annona muricata L. (Annonaceae) leaves have been reported to be relatively safe and possess antidiabetic activities amongst other medicinal uses. This study was aimed at confirming the antidiabetic activity of the leaf of A. muricata and evaluating its toxicological profile. Doses of the ethanol extract ranging from 100 – 500 mg/kg were evaluated in normoglycaemic rats. Wistar rats were induced with diabetes by a single intraperitoneal injection of freshly prepared streptozotocin (55 mg/kg body weight). The dose of 500 mg/kg of ethanol extract was administered to the diabetic rats with glibenclamide (1.25 mg/kg) as the reference standard. Acute toxicity of the extract (1-5 g/kg) was tested in Swiss albino mice. Animals were monitored for 10 min after 6 h and for 10 min every day for the next two days. Wistar rats were administered with 5 ml/kg of normal saline (vehicle) and 250 mg/kg of the ethanol extract, respectively for 30 consecutive days. The effects of the extract on the livers, kidneys, hearts, and testes were examined. Various doses of the extract produced a significant (p < 0.05) reduction in blood glucose levels in normoglycaemic and Streptozotocin-induced diabetic rats. The LD50 in mice was above 5 g/kg body weight. Sub-acute evaluation in rats showed that the extract induced a mild chronic inflammation in the testes and epididymis, while in the tissues of the liver, kidney, and heart, the extract provoked a mild chronic inflammatory response, in addition to vascular reactions leading to rupture of the blood vessels and haemorrhage. It was concluded that A. muricata leaves have antidiabetic properties. The inflammatory and immune responses evoked in the sub-acute toxicological evaluation could be a protective response.