Full Length Research Paper

Evaluation of acute and subchronic toxicity of Stachytarpheta angustifolia (Mill) Vahl (Fam. Verbanaceae) extract in animals

Steve O. Ogbonnia¹*, Florence E. Nkemehule¹ and Emmanuel N. Anyika²

¹Department of Pharmacognosy, Faculty of Pharmacy, College of Medicine Campus, University of Lagos, Idi-Araba, PMB 12003, Lagos.

²Clinical Pharmacy and Biopharmacy, Faculty of Pharmacy, College of Medicine Campus, University of Lagos, PMB 12003,Idi-Araba, Lagos.

*Corresponding author. E-mail: steveogbonnia@hotmail.com,  steve_ogbonnia@yahoo.com.  Tel: 234 806 207 3970.

Accepted 16 February, 2009

Stachytarpheta angustifolia is an important and a highly valued medicinal plant ethnobotanically used in the treatment of various diseases. The present study was carried out to evaluate acute and subchronic toxicity in animals and also evaluate the phytochemical profiles of hydroethanolic extract of S. angustifolia (Mill) Vahl plant. S. angustifolia attracted the attention of the researchers because of its uses as an anti-infective, antidiabetic in folkloric medicine and also as soap by local farmers. The aqueous ethanol (80%) extract of the powdered dried plant was obtained by maceration. Evaluation of acute and subchronic toxicity and phytochemical profiles of the plant extract was performed using standard procedures. The median acute toxicity value (LD₅₀) of the extract of S. angustifolia was determined to be 8.721g/kg body weight. The extract lowered blood plasma glucose and low density lipoprotein (LDL-cholesterol) levels but raised high density lipoprotein (HDL-cholesterol) level. The protein, creatinine, and phosphorous levels were significantly affected only by the highest dose of the extract while calcium level was not affected by all the doses used. The extract contained triterpenoid saponins as the major bioactive constituent. The LD₅₀ value indicated the drug as being slightly toxic. The extract did not produce any toxic effect in the animals’ tissues at low and moderate doses but could cause kidney damage in higher doses. Lowering of plasma glucose level and the positive effects of the extract on the cardiovascular risk factors were an indicator that the extract could have some good antidiabetic activity.

Key words: Stachytarpheta angustifolia, acute, subchronic, toxicity, phytochemical profile.