Estudo químico de rizomas de Alpinia zerumbet: inibidores da enzima de conversão da angiotensina, com potencial antioxidante e de inibição da acetilcolinesterase

Abstract

Hypertension is one of the most common diseases in the world, is a chronic disease in which high blood pressure can affect health. The angiotensin I converting enzyme (ACE) can increase blood pressure through the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II. Thus, inhibition of ACE activity is considered a useful therapeutic approach to combat hypertension. Alpinia zerumbet, a herb abundant in northeastern Brazil, is commonly used in folk medicine due to its diuretic and hypotensive properties. Moreover, several studies reported for this species antihypertensive activity. Thus, Alpinia zerumbet can be an important source of ACE inhibitors. Knowing this, we decided to investigate the extracts of the rhizomes of this species in the search for compounds ACE inhibitors. Prospecting chemical hexane extract of the rhizome allowed the isolation of five substances: A stilbene, named (E) -3,5-dimethoxystilbene, unprecedented in the species in this study, a labdane diterpene skeleton called (E) -15.16-bisnorlabda- 8,11-diene-13-one; one chalcone called 2’,4’-dihydroxy-6’-methoxy-3’-(3’’-methyl-6’’- methyl - ethyl -2’’-cyclohexenyl) chalcone; a steroid called β-sitosterol, commonly found in plants, and an aromatic hydrocarbon class kavapirone, called 5,6- dehidrokawain. In the structural determination of individual compounds, spectrometric techniques were employed dimensional analysis [nuclear magnetic resonance (NMR) 1H and 13C and two dimensional techniques (1H-1H COSY, HSQC, HMBC, NOESY). Inhibition angiotensin converting enzyme, antioxidant potential, inhibition of acetilcolinestarase and larvicidal tests of ethanol and hexane extracts of the rhizomes of Alpinia zerumbet were tested. The two extracts showed potential for inhibition of angiotensin converting enzyme and antioxidant potential. Only the hexane extract showed larvicidal activity with LC50 823.1 ppm. None of the extracts studied showed potential inhibition of the enzyme acetylcholinesterase.