Pharmacognosy and hypotensive evaluation of Ficus exasperata Vahl (Moraceae) leaf.

There is already a literature report on the anti-ulcer effect of water extract of Ficus exasperata. Some communities in Edo and Delta States of Nigeria use the decoction of the leaf as hypotensive crude drug. Verification of this claim and also the microscopy and other pharmacognostic parameters which can be used to establish the identity of the leaf were carried out. The microscopy of the leaf powder revealed the presence of straight walled epidermal cells, cone or nail shaped trichomes or epidermal hairs, clustered or prismatic calcium oxalate crystals of varying dimensions. The percentage weight loss on drying was 9.84 +/- 0.08 whereas water and alcohol extractive values were 5.29 +/- 0.07 and 2.21 +/- 0.11, respectively. The ash value was 30.68 +/- 0.44 whereas the acid insoluble ash and water soluble ash values were 17.87 +/- 0.37 and 16.73 +/- 0.13, respectively. Preliminary phytochemistry of leaf showed that it contains tannins, flavonoids and saponins with no traces of alkaloids or anthraquinones. The water extract showed a dose related reduction in mean arterial blood pressure. At 10 mg/kg, a reduction of 16.6 +/- 1.1 mmHg was observed, whereas at 30 mg/kg, a fall in mean arterial pressure of 38.3 +/- 0.6 mmHg was obtained. The hypotensive effect of the extract was significantly reduced with a prior administration of 2.5 mg of either atropine or chlorpheniramine. This suggests the probable stimulation of muscarinic receptors in the heart or release of histamine into the circulatory system thereby causing the initial fall in blood pressure.