A NTIDIARRHEAL ACTIVITY OF CASHEW TREE BARK AND LEAF EXTRACTS FORTIFIED WITH ZINC IN RATS

Abstract

This study investigated the antidiarrheal activity of aqueous extracts of cashew bark and leaf fortified with zinc in rats. Diarrhea was induced in rats by the administration of 2 ml of castor oil with control group receiving normal saline. The aqueous extracts (100, 250, and 500 mg/kg) and zinc (15, 30 and 45 mg/kg) was administered orally to different groups of rats in order to evaluate their antidiarrheal effect. The diarrheal stool and concentration of colonal nitric oxide (NO), mg/100ml was determined. At oral doses of 15 mg/kg zinc, 500 mg/kg bark and 500 mg/kg leaf extracts, diarrheal stool was significantly (p<0.01) reduced by 44% (6.67± 1.53), 56% (5.33±2.08) and 42% (7.00±1.00) respectively against castor oil control group 100% (12.0 ±1.73). Also, there was a corresponding reduction in colonal nitric oxide concentration (1.29±0.07, 1.42±0.14 and 1.40±0.05)mg/100ml respectively for 15 mg/kg zinc, 500 mg/kg bark and 500mg/kg of leaf extracts compared to the castor oil control group (1.62±1.73)mg/100ml. Though, 500 mg/kg of both cashew extracts showed a significant (p<0.01) decrease in diarrheal stool with values of (5.33±2.08) 56% and (7.00 ±1.00) 42% for cashew bark and leaf extracts respectively, the zinc fortified 500 mg/kg aqueous extracts of bark 70% (3.67±1.53) and leaf extracts 64% (4.33±1.53) showed a better significant (p<0.01) reduction in diarrheal stool output. These results suggested that the extracts of bark 7 and leaf fortified with zinc showed a higher antidiarrheal activity than unfortified extracts. Furthermore, the effect of zinc-fortified loperamide(a standard antidiarrheal drug) with a value of 75% (3.00±0.70) showed a better antidiarrheal effect than non fortified loperamide with a value of 66%(4.00±2.65). This was possibly as a result of the ability of the extracts to stimulate the re-absorption of water from the intestinal lumen. Also, the reduction in colonal nitric oxide concentration suggests that zinc or the extracts might have an inhibitory effect on the activity of nitric oxide synthase enzyme. The LD5O was evaluated. Animals treated with 2900 and 5000mg/kg died within 48 and 24 hours after treatment, respectively. Also, serum ALT and AST levels in extract-treated rats at 1.44 and 2.87g/kg doses were significantly different from those of the control and may indicate hepatotoxicity. But the serum levels of ALP, TB and TP in treated animals were statistically same with those of the control