Effects of Leaf Extracts of Piliostigma thonningii Schum on Aortic Ring Contractility and Bleeding Time in Rats

Abstract

The leaves of Piliostigma thonningii Schum have been used in herbal medicine to treat inflammations, bacterial infections, and worm infestations and to arrest bleeding. In an investigation of the possible scientific basis for the use of P. thonningii as a hemostatic agent, the contractility of isolated rat aortic rings and wound bleeding times were measured after exposure of the tissues to aqueous and ethanol extracts of P. thonningii leaves. The extracts produced responses on the isolated aortic rings. The maximum contractile response produced by 32 mg mL−1 of the aqueous extract was 30.8% ± 1.6% of the contractile response produced by 1 μM phenylephrine. The ethanol extract was much less potent with 64 mg mL−1 producing only 12.3% ± 0.9% of the contractile response produced with the phenylephrine. In addition, the aqueous extract, but not the ethanol extract, significantly reduced bleeding time as compared with saline solution (p < .05) but was significantly less than the reduction produced with 0.1% epinephrine solution. The constriction of blood vessels may be the basis for P. thonningii's use as a hemostatic agent in traditional herbal medicine.