Some aspects of the pharmacology of the methanolic extract of Prosopis Africana (Fruit) (Guill and Peer) Taub

Abstract

Some pharmacological effects of the methanolic extract of Prosopis africana fruits (MEPAF) were investigated. MEPAF was prepared by cold maceration using 80% methanol at room temperature with intermittent shaking at 2 hours intervals for 48 hours to obtain a yield of 4.2% w/w dry extract. It was golden brown in colour, sticky with aromatic odour and dissolved in distilled water with foaming. It did not demonstrate any acute toxicity effect in mice at the dose range (250-2000 mg/kg, i.p) tested. The highest dose of 2000 mg/kg, i.p was tolerated with signs of transient dullness which lasted for 3 hours only. Intradermal administration of the extract showed desensitization of the guinea pig skin with a potency which is comparable to that of 2% lignocaine hydrochloride. The MEPAF did not show any measurable effect on the ocular reflexes and isolated frog rectus abdominis muscles but showed both concentration and time-dependent inhibitions of the intrinsic peristaltic contractions of the rabbit jejunum. It also induced concentration-dependent inhibitions of the contractions induced by acetylcholine (2.5 μg/ml) on isolated rabbit jejunum. These inhibitions are thought to be anti-muscarinic or atropine-like, since the contractions of the jejunal segment is believed to be through muscarinic receptors and could be blocked by atropine and related compounds. Phytochemical spot tests of MEPAF revealed the presence of alkaloids, carbohydrates, saponins, tannins, sterol, terpenes, flavonoids, polyuronoids and reducing sugar. These findings give credence to the folkloric use of Propsopis africana in the treatment of body pain, toothache and dysentery.

Keywords: Propsopis africana, Methanolic Extracts, Local Anaesthetics, Antimuscarinic, Inhibitions.