Química de Acosmium dasycarpum: identificação de alcalóides quinolizidínicos por CG-EM

Abstract

This work reports the identification of quinolizidíne alkaloids (QA) and other non-alkaloidal secondary metabolites found in plants, and a discussion on the likely biosynthetic pathway of quinolizidine alkaloids. Phytochemical study of A. dasycarpum resulted in the isolation of 26 substances, 9 of them quinolizidine alkaloids: homo-6-epipodopetaline, acosmine, acosminine, dasycarpumine, bowdechine, panascomine, a mixture of lupanine and lupanocosmine and 24-methyl-homo-6-epipodopetaline, the later reported for the first time in the literature; two styryl α-pyrones: 12-O-desmethylyangonine and 12-O-βDglucopyranosyldesmethylyangonine; two triterpenes: lupenone and lupeol, the later in large amounts; a mixture of steroids: sistosterol, campesterol and stigmasterol, and a chlorogenic acid: 5-O-cafeoilquinic acid. It was also isolated 2,3-dihidrobenzofuran derivatives: bowdenol and a mixture containing eight fatty acid esters of bowdenol, bowdenyl myristate, pentadecanoate, palmitoleate, palmitate, margarate, linoleate, oleate and stearate esters . The investigation of the methanol extract from the of roots of Acosmium dasycarpum using GC-MS, led to detect 30 quinolizidine alkaloids: α-isosparteine, β-sparteine, 5,6 dehydrosparteine, sparteine, ammodendrine, 4-hydroxysparteine, N- methyl angustifoline, lupanine, aphylline, multiflorine, homo-6-epipodopetaline, 18-epipiptanthine, piptanthine, podopetaline, ormosanine, homosweetinine, homoormosanine, homo-18-epiamazonine, homopiptanthine, homo-18-epipiptanthine, homopodopetaline, lupanocosmine, dasycarpumine, dasycosmine, acosmine, panascosmine and acosminine, santanine, isodasinine, dasinine and dasycosmine, the last four are compounds are reported here for the first time. It has been suggested a possible biogenesis for the quinolizidine alkaloids with lupine, acosmine and diazo-adamantane skeleta.