The Bioscientist (May 2013)
Evaluation of the pharmacological activity of ethanol leaf extract of Acalypha torta (Muell)
Abstract
The effects of ethanol extract of the leaves of Acalypha torta on spontaneous contraction of isolated rabbit gut, rat blood platelet aggregation and other haematological indices were investigated. The height of contraction of the isolated rabbit gut was 0.80 ± 0.03 cm on stabilization. Following the introduction of A.torta extract (2.5 mg), the height increased to 1.7 ± 0.4(i.e 112.5% increase). Higher concentrations of the extract ( 5.0, 7.5 and 10.0 mg) did not alter the size of response . Histamine and acetylcholine standards produced opposite effects on the isolated rabbit gut. While histamine (0.002µg) abolished contraction, acetylcholine(0.002µg) enhanced contraction. Administration of the extract (10.0 mg) after incubation with acetylcholine reversed the effect of acetylcholine suggesting that the extract antagonizes the actions of acetylcholine and may possess antidiarrhoeal potential. Extract (5.0 mg/ml) also inhibited CaCl2 – induced platelet aggregation by 81.72% (i.e from 87.95 ± 0.16 to 16.08 ± 0.08 % aggregation). Administration of 15.0 mg/ml the extract completely inhibited the aggregatory effect of CaCl2. This indicates antithrombotic or thrombolytic activity of the extract. A significant (p < 0.05) increase in haemoglobin concentration (from 12.85 ± 0.1 to 14.43 ± 0.33 g/dl) was observed at 50.0 mg/kg body wt. of extract. Decreased white blood cell numbers were recorded.
