Toxicological evaluation of hydro-alcohol root extract of Rauwolfia vomitoria Afzel (Apocynaceae)

Purpose: To investigate the phytochemical content and toxicity profile of Rauwolfia vomitoria Afze (Apocynaceae). Method: Qualitative phytochemical screening of hydro-alcohol extract (HAE) of R. vomitoria roots was carried out followed by acute toxicity evaluation in nine Swiss albino Wistar rats using two phases of Lorke's method. In the 14 days subacute study, thirty-two Swiss albino rats were randomly divided into 4 groups of 8 rats each. Group A received 0.5 mL Tween 80 daily and served as control, while groups B, C and D was administered 125, 250 and 500 mg/kg/day of HAE respectively. All the rats were monitored daily for signs of toxicity. Selected haematological and biochemical parameters were assessed at the termination of experiment. Results: Alkaloids, cardiac glycosides, flavonoids and saponins were present in HAE. The estimated oral median lethal dose (LD50) was greater than 5000 mg/kg. Daily administration of HAE for 14 days resulted in 15.63 % mortality of animals across the groups by day 14 with significant loss in total body weight in group D animals on day 8 (p < 0.05), and in group C animals on day 11 (p < 0.05) and day 15 (p < 0.001). The dose of 500 mg/kg/day significantly (p < 0.05) increased haemoglobin concentration but reduced (p < 0.05) white blood cell count, while the dose of 250 mg/kg/day significantly (p < 0.05) reduced alkaline phosphatase levels but increased serum albumin levels (p < 0.05). Conclusion: Rauwolfia vomitoria may be safe on acute basis but repeated administration of high doses over many days needs to be done with caution.