Gastro-Protective Properties of the Leaf Extracts of Ocimum gratissimum L. Against Experimental Ulcers in Rat
Methanol leaf extract of Ocimum gratissimum L. (Lamiaceae) was investigated for gastroprotective properties. The anti-ulcer effect was evaluated in three experimental ulcer models induced by ethanol, indomethacin and hypothermic-restraint stress in rats. Anti-ulcer related properties of the extract such as gastrointestinal transit and the activity on isolated gut tissue preparations of guinea pig and rabbit were also determined. The extract (ME) administered orally at doses of 200, 400 and 800 mg kg-1 significantly (p<0.05) reduced the ulcer indices in a dose-related manner. The extract showed higher gastroprotection against indomethacin and ethanol-induced ulcers than the stress-induced ulcer. Gastrointestinal motility was significantly (p<0.05) reduced by the extract in mice. On the rabbit jejunum, ME produced a concentration-dependent relaxation and inhibited ACh contractile responses. The extract, ME had no effect on guinea-pig ileum but inhibited the contractions produced by histamine. At doses above 3 g kg-1 (p.o.), ME caused no signs of acute toxicity or deaths in mice. Flavonoids, tannins, saponins, carbohydrate, steroids, alkaloids, terpenes and volatile oils were found present in the methanol extract of O. gratissimum leaf. The results show that the methanol leaf extract of O. gratissimum offers protection against ulcers induced by different ulcerogens and could justify the folk use of the plant in peptic ulcer diseases. Cyto-protection and antispasmodic activities may be the likely mechanisms for the anti-ulcer property of this plant.
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