Acute and Subacute Toxicity of Methanol Extract of Syzygium guineense Leaves on the Histology of the Liver and Kidney and Biochemical Compositions of Blood in Rats

Plant medicine is the oldest form of health care known to mankind. Syzygium guineense is one of the many species of Ethiopian medicinal plants which has a long history of use as remedies for various ailments such as dysentery, diarrhea, and hypertension. In many countries, herbal medicines and related products are introduced into the market without safety or toxicological evaluation. The aim of this study was to investigate the histopathological effect of 80% methanol extract of S. guineense on liver and kidney and blood parameters of rats. For acute toxicity study, rats were randomly divided into three groups (n=4). The control group received distilled water, while the experimental groups received a single dose of 2000 mg/kg and 5000 mg/kg 80% methanolic extract of S. guineense leaves per oral. For subacute toxicity study, the rats were randomly divided into three groups (n=6). The control group received distilled water, while the experimental groups received 500 mg/kg and 1500 mg/kg 80% methanol extract of S. guineense leaves orally for 28 days. At the end of the experiment, blood samples were collected for hematology and clinical chemistry evaluations. Gross pathology and histopathology of liver and kidneys were assessed. In the acute toxicity study, rats treated with 2000 mg/kg and 5000 mg/kg showed no toxicological signs observed on behavior, gross pathology, and body weight of rats. In the subacute toxicity study rats have showed no significant changes on behavior, gross pathology, body weight, and hematological and biochemical parameters, whereas both experimental groups had a lower blood glucose level compared with the control group (p < 0.05). There were no significant differences in the gross and histopathology of the liver and kidneys of experimental animals in extract exposed groups and their counterpart control. The 80% methanol extract of S. guineense does not produce adverse effects in rats after acute and subacute treatment. Before marketing a S. guineense leaf based remedy, subchronic and chronic toxicity evaluations need to be done.