Análisis de los ácidos kaurénicos presentes en Espeletiopsis angustifolia Cuatrec. de los Andes venezolanos

Analysis of kaurenic acids present in Espeletiopsis angustifolia Cuatrec. from the Venezuelan Andes. Leaves of Espeletiopsis angustifolia were collected at paramo of San José de Acequias (Mérida State) at 2870 m.a.s.l. The dried leaves were minced and extracted with hexane-diethyl ether (3:1). This extract was shaken with 0.5 N NaOH to separate the acid fraction which was purified by flash chromatography. An aliquote of it was methylated with diazomethane and analyzed by GC-MS which permitted to identify ent-kaurenic acid (18.6%), ent-15α-O-isovaleroxy-kaur-16-en-19-oic acid (16.2%), ent-15α-hidroxy-kaur-16-en-19-oic acid (grandiflorolic acid, 9.2%), ent-kauranic acid (4.9%), ent-kaur-9(11),16-diene-19-oic acid (grandiflorenic acid, 4.5%) and ent-15α-O-acetoxy-kaur-16-en-19-oic acid (3.4%). The neutral fraction yielded ent-kaur-16-en-19-ol (kaurenol, 32.7%) and several long-chain wax n-alkanes with predominance of odd carbon number alkanes: heptacosane (38.3%), nonacosane (21.0%) and entriacontane (4.6%)