Sub-chronic toxicological evaluation of Strophanthus hispidus DC (Apocynaceae) aqueous root extract

Strophanthus hispidus DC (Apocynaceae) has gained wide and extensive applications in herbal medicine in Africa for the treatment of quite a lot of diseases. Owing to the extensive application and the propensity of persistent consumption of this shrub, this research investigates the sub-chronic toxicological effect of aqueous root extract of S. hispidus (SHP) in laboratory animals (rats).

The rats were allotted into four groups of eight rats each (n=8) and orally treated daily for ninety (90) days with SHP extract at 100, 500 and 1,000 mg/kg and the control group received distilled water (10 mL/kg). The rats were weighed at 15 days interval. After 90 days daily oral administration of SHP extract, blood samples were collected from the rats into lithium heparin and EDTA bottles for biochemical and haematological analysis respectively. Vital organs were weighed and histological examination was performed on the liver and kidney.

The SHP extract displayed no significant (p>0.05) alterations in body weight of treated compared to control rats. At doses of 500 and 1,000 mg/kg, SHP-treated rats showed significant (p<0.05) increase in white blood cell (WBC), without significant difference in other haematological parameters. Non-significant (p>0.05) decrease in urea and non-significant (p>0.05) increase Na⁺, K⁺ and blood urea nitrogen (BUN) were observed. Significant (p<0.05) decrease in liver weight was observed without any alteration in the architecture of the liver and other organs investigated.

Aqueous root extract of S. hispidus demonstrated a good safety profile in rats. Therefore, S. hispidus is harmless and safe following sub-chronic oral administration.