Estudio químico de los compuestos bioactivos de hojas senescentes de Croton funckianus (Euphorbiaceae) / Chemical analysis of bioactive compounds from senescent leaves of Croton funckianus (Euphorbiaceae)

El extracto etanolico de hojas senescentes frescas de Croton funckianus se sometio a particion liquido-liquido con disolventes de diferente polaridad. Los ensayos de actividad larvicida frente a larvas de tercer estadio de Culex quinquefasciatus, mostraron que las fracciones separadas en eter de petroleo (F2), acetato de isopropilo (F5) y butanol (F7) presentan actividad promisoria. El fraccionamiento, guiado por el bioensayo de actividad larvicida de la fraccion en butanol, condujo a la obtencion de quercetina, el cual presento bioactividad (CE50= 47 µg/mL). De la fraccion (F5) se obtuvieron dos mezclas de flavonoides glicosidados, cuyos componentes mayoritarios se aislaron por metodos cromatograficos y se identificaron por tecnicas espectroscopicas. El componente mayoritario de la mezcla 1 fue identificado como quercitrina. De la fraccion (F2) bioactiva, se detectaron por analisis de CGAR-EM, hexadecanoato de etilo (1,2%), acetato de fitol (4.1%), tetracosa-2,6,10,14,18,22-hexa-eno (16,1%) y vitamina E (64,5%); de este fraccion se aislo e identifico el heneicosan-1-ol (C21H44O), del cual se presenta por primera vez la asignacion completa de las senales de 1H- RMN y de 13C-RMN, el cual no presento actividad larvicida. De esta fraccion se separo e identifico el alcohol diterpenico denominado cassipourol, con base en el analisis espectroscopico (IR, RMN 1H y 13C de 1D y 2D) el cual presento actividad larvicida (CE50= 18 µg/mL), es cual es nuevo en el genero Croton y en la especie en estudio. / Abstract. Alcoholic extract of fresh senescent leaves of Croton funckianus, by liquid-liquid partition with solvents of different polarity, was separated. These samples, with larvicidal activity assay against third instar of Culex quinquefasciatus (LAB-Cq) were evaluated and the following fractions F2 (ether petroleum), F5 (isopropyl acetate) and F7 (n-butylic alcohol) have indicated promising activity. Bioassay guided fractionation of F7, conducted to the identification of the flavonol named quercetin, that have had presented bioactivity (EC50= 47 µg/mL). From F5 two mixtures of glycoside flavonoids, were obtained, that by chromatographic methods were isolated and by spectroscopic techniques were elucidated; major component of this fractions as quercitrin was identified. By GCAR-MS from fractions F2 several compounds were detected included ethyl hexadecanoate (1.2%), phytol acetate (4.1%), tetracosa-2,6,10,14,18,22-hexa-eno (16.1%) and vitamin E (64.5%) among others. From this fraction, heneicosanol (C21H44O), was identificated and this work by first time report the complete assignation of of 1H-NMR and 13C-NMR signals; this compound was inactive. From this fraction, the diterpenoid alcohol named cassipourol, by spectroscopic analysis (IR, 1H and 13C NMR 1D, 2D)) was identified. By first time this bioactive compound, in the specie Croton funckianus was reported and at the best of our knowledge it is new in the genus.