A study of the cardio-depressant actions of harman alkaloids isolated from the seeds of Peganum harmala

Introduction: The plant Peganum harmala is a shrub native to the arid parts of the world including India. It’s therapeutic value is attributed to the presence of alkaloids harmala and harmine in the dried ripe seeds. In traditional medicine these seeds are considered to have anti-spasmodic, hypnotic, anodyne, emetic, emmenogogue, stimulant, aphrodisiac, lactogogue and antihelminthic actions. Objectives: The present study was undertaken to find out the effects of the active principle extracted from the seeds of Peganum harmala on isolated cardiac muscle and skeletal muscle preparations and the probable mechanism of action Materials & Methods: The harman alkaloid isolated from Peganum harmala seeds was used for experiments on isolated preparations of frog heart and frog rectus abdominis muscles and the responses were recorded on a rotating smoked drum on a kymograph. Results: The Harman alkaloids were shown to inhibit the normal contractions and also the inotropic actions of Adrenaline, 5HT and calcium on isolated frog heart. These have not shown any effect on the frog rectus abdominus muscle either on their own or on the contractions induced by Acetylcholine. Conclusion: Harman alkaloids have cardio-depressant activity, it is unlikely that these alkaloids have a specific receptor antagonistic activity. Also these have found to inhibit the cardiac muscle contractions but not the skeletal muscle contractions. The cardio-depressant action may be due to calcium channel blockade