Deserpidine hydrochloride (Harmonyl hydrochloride) is an antihypertensive compound that competitively inhibits the activity of angiotensin converting enzyme (ACE). Deserpidine hydrochloride competes with angiotensin I for ACE, preventing the conversion of angiotensin I to angiotensin II, thereby lowering blood pressure. Deserpidine hydrochloride can also reduce angiotensin II-induced aldosterone secretion from the adrenal cortex.