Phytochemical Screening and Acute Exposure of Methanolic Bark Extract of Pterocarpus Tinctorius in Wistar Rats

Abstract

The bark extract of Pterocarpus tinctorius (Fabaceae) is traditionally used to treat diseases such as diabetes, gonorrhoea, hypertension, stomachache and bacterial gastroenteritis. However, little is known about toxicity and phytochemicals found in the bark of Pterocarpus tinctorius. Therefore, this study aimed at phytochemical screening and investigating acute oral toxicity of the stem bark of Pterocarpus tinctorius in Wistar rats. Wistar rats (N=3 per group) were randomly assigned to four groups: negative control, 50, 300, and 2000 mg/ kg methanolic sub-extract. A single dose was administered and female Wistar rats were observed for 14 days according to the Organisation for Economic Co- operation and Development guidelines for acute toxicity testing in rats. After dosing, rats were individually observed for their physical and behavioural changes throughout the study. The body weight of Wistar rats were monitored weekly and gross pathological changes of rat organs were observed. In addition, the biochemical markers and organ- body weight ratios of the kidneys and the liver were measured. Qualitative phytochemical tests were carried out to determine the types of phytochemicals present in the bark of Pterocarpus tinctorius. There were no signs of toxicity observed in all treatment groups and no abnormalities were observed on organs of rats. There was no significant difference in body weight, organ- body weight and biochemical markers with p>0.05, for the Wistar rats in all treatment groups compared to the negative control. Phytochemical tests showed the presence of alkaloids, phenolics, flavonoids, tannins, steroids, terpenoids, anthocyanins and saponins in the stem bark of Pterocarpus tinctorius as compounds that could be responsible to treat diseases in traditional medicine. This study demonstrated that Pterocarpus tinctorius methanolic bark sub-extract is not acutely toxic to the liver and kidneys up to the dose of 2000 mg/kg body weight. It is highly recommended that toxicity studies on other organs of rats such as the heart, brain, pancreas and intestines are carried out.