PHARMACOGNOSTIC AND ANTIULCER EVALUATION OF THE STEM BARK OF PROSOPIS AFRICANA (GUILL. & PERR.) TAUB. (MIMOSACEAE)

PHARMACOGNOSTIC AND ANTIULCER EVALUATION OF THE STEM BARK OF PROSOPIS AFRICANA (GUILL. & PERR.) TAUB. (MIMOSACEAE)

Abstract:

Prosopis africana (Guill. & Perr.) Taub. (Mimosaceae) is the only known species of its genus found in Africa. Pharmacognostic standardization was carried out on the stem bark powder and its anatomical sections, to determine the micro-morphological characters, along with its quantitative and qualitative profiles. Identified microscopic features in the bark powder include radial bands of rectangular, tangentially elongated, thin-walled cork cells in rows; Secondary phloem composed of phloem fibres in small patches with thin walled parenchyma in between and few druse type of calcium oxalate crystals with unequal axes. Identified also are elongated fibres cells with blunt end and thick walls. Sclerids are isodiametric in shape. Histochemical evaluation revealed the presence of lignin, tannin and hydroxyanthraquinnones. After repeated evaluations, the bark powder was found to have an average of 5.27% Moisture Content, 3.93% Total Ash Value, 1.61% Acid Insoluble Ash Value, 0.33% Water Soluble Ash Value, 22% Water Extractive Value (Hot Maceration).These parameters serve as reference data for the identification and quality control of P. africana crude drug. The stem bark was extracted by Soxhlet extraction method using ethylacetate as the solvent. The acute toxicity evaluation of the crude extract shows that it is safe, up to a dose of 3000 mg/kg administered orally in rats. Antiulcer activity of the crude extract was evaluated using ethanol and indomethacin induced gastric ulcer models in rats. Using the ethanol model, doses of the extract at 300, 600 and 900 mg/kg produced significant (p<0.05) protective effect in rats with preventive index of 19, 71 and 81% respectively as against 15% with omeprazole (20 mg/kg) and 0% with distilled water. Using the indomethacin model, the extract at 300, 600, and 900 mg/kg produced significant (p<0.05) gastroprotective effects of 22, 43 and 56% respectively as against 28% with omeprazole (20 mg/kg) and Page | x 0% with distilled water. Prosopis africana stem bark extract was found to be significantly (P<0.05) protective against ethanol and indomethacin-induced gastric ulcers in the experimental rats. The crude ethylacetate extract was fractionated with petroleum ether, chloroform and methanol to obtain their respective fractions. Friedelin, a pentacyclic triterpenoid was isolated by column chromatography from the chloroform fraction. The structure of the compound was assigned on the basis of spectroscopic data. Friedelin is being reported for the first time as a chemical constituent of P. africana

PHARMACOGNOSTIC AND ANTIULCER EVALUATION OF THE STEM BARK OF PROSOPIS AFRICANA (GUILL. & PERR.) TAUB. (MIMOSACEAE)

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