Abstract
The methanolic extracts of 20 medicinal plants from the island Soqotra/Yemen were screened with respect to their inhibitory potency against angiotensin converting enzyme (ACE), neutral endopeptidase (NEP) and aminopeptidase N (APN). Eight extracts did not show significant inhibitory activity against the enzymes tested, only Kalanchoe farinacea, Boswellia elongata and Cissus hamaderohensis inhibited all three enzymes. The most active extract was prepared from Kalanchoe farinacea characterized by low IC50 values especially for NEP and APN.