Effects of piperine on gastric acid secretion in albino rats

Piperine, the pungent principle in Piper nigrum and Piper guinensis was studied for its effect on gastric acid secretion in white albino rats. Increasing the dose from 20 mg kg(-1) weight to 142 mg kg(-1) body weight produced dose dependent increases in gastric acid secretion. When compared with control basal acid secretion, these increases were significant (P<0.05). 20 mg kg(-1) produced a 22.2% (n=7) increase, while the highest dose employed in this study (142 mg kg(-1)) produced 334.6% (n=7) increase in the gastric acid secretion. Piperine was however about 40 times less effective than histamine in increasing gastric acid secretion. The effect of piperine was significantly antagonized by cimetidine (1 mg kg(-1), n=6) but not by atropine (1 mg kg(-1), n=6). Any involvement of cholinergic receptors in the observed piperine-induced increase in gastric acid secretion is thus excluded. There is however an indication that stimulation of histamine H2 receptors by piperine is likely to be involved in the increased acidity induced by piperine.