Evaluation of Angiotensin converting enzyme inhibition and anti-oxidant activity of Piper longum L.

The present. study was aimed to investigate the Angiotensin Converting Enzyme (ACE) inhibition and antioxidant activity of the standardized hydro alcoholic extract of Piper longum L. fruits, its fractions and isolated piperine. Extract and its fractions were standardized with reference to marker piperine by HPLC method. ACE inhibition activity was estimated using hippuryl-L-histidyl-L-leucine (HHL) as substrate. Antioxidant activity was determined by DPPH radical scavenging method. Among all the fractions tested, ethyl acetate and butanol fractions showed the maximum ACE inhibitory activity in a concentration-dependent manner with IC50 value of 1.40 +/- 0.07 mg/ml and 1.75 +/- 0.43 mg/ml respectively. Potential DPPH radical scavenging effect was elicited by the extract and ethyl acetate fraction with IC50 value of 193.12 +/- 0.43 mu g/ml and 247.78 +/- 0.20 mu g/ml, respectively. Though piperine showed ACE inhibition and scavenging of DPPH radical but not significant compared to the ethyl acetate fraction. P. longum can be explored further as a functional food to be useful as antihypertensive. The present experiment justifies its traditional claim as antihypertensive agent.