Angiotensin-converting enzyme inhibitory activity of some Vietnamese medicinal plants

Abstract

This study investigated the angiotensin 1-converting enzyme (ACE) inhibitory activity of certain medicinal plants that have been traditionally used as an anti-hypertensive, diuretic, or related diseases treatment in Vietnam. Ten different medicinal plants were selected and screened for in vitro ACE inhibitory activity. A spectrophotometric assay was developed for the determination of ACE activity in the presence of ACE inhibitors using hippuryl-L-histidvl-L-leucine as the ACE-specific substrate. When the in vitro activities of ACE were assessed in the presence and absence of aqueous or ethanol extracts from each medicinal plant, 2 out of the 22 medicinal plant extracts inhibited the ACE activity by more than 90% at a concentration of 50 µg/ml. The estimated IC₅₀ value of the L. rubra and U. sessilifructus were 1.31±0.44 and 12.86 µg/ml, respectively. These results suggest that the L. rubra rhizome and U. sessilifructus extract are potential antihypertensive drug-like candidates with ACE inhibitory activity.