Identification de deux phytostérols biologiquement actifs de l’extrait cyclohexanique des feuilles de Ficus sur (Moraceae)

Ficus sur est une plante alimentaire couramment utilisee en medecine traditionnelle au Togo. Elle a cependant fait l’objet de tres peu d’etudes phytochimiques. Le present travail a pour but de valoriser cette espece a travers l’identification continue de ses metabolites. Ainsi, l’extraction cyclohexanique au Soxhlet a ete realisee sur les feuilles de Ficus sur . Cet extrait cyclohexanique obtenu a ete ensuite fractionne puis purifie par chromatographie sur colonne de gel de silice. L’identification des composes a ete realisee par GC-MS, precedee quelquefois d’une etape de derivatisation. Treize fractions (A1 a A13) ont ete obtenues du fractionnement de cet extrait. Apres deux purifications successives de la fraction A5, deux sous-fractions A5.1 et A5.2 ont ete obtenues. Le spectre de masse d’un compose de A2 presente un pic moleculaire a m/z 426 et des pics fragments [M-69] + , [M-154] + , [M-169] + , [M-197] + , [M-208] + et [M-219] + caracteristique du taraxasterol. Pour A5.2 derivatisee, un compose presente un spectre de masse de pic moleculaire a m/z 486 et des pics fragments [M-90] + , [M-129] + et [M-357] + propres au β -sitosterol trimethylsilyl ether derive du β - sitosterol. La presence de ces deux phytosterols bioactifs serait un atout majeur dans l’usage therapeutique de cette plante. © 2017 International Formulae Group. All rights reserved. Mots cles: Ficus sur , GC-MS, taraxasterol, β -sitosterol English Title: Identification of two bioactive phytosterols of the cyclohexane extract of Ficus sur (moraceae) leaves English Abstract Ficus sur is a food plant commonly used in traditional medicine in Togo. However, few phytochemical studies of this species are available. This work aims at contributing to the enhancement of this approach through an identification of its metabolites. The leaves of Ficus sur were then extracted with cyclohexane using soxhlet. The obtained cyclohexane extract was fractionated and purified by chromatography on silica gel column. Identification of the compounds was carried out by GC-MS, sometimes preceded by a derivatization step. Thirteen fractions (A1 to A13) were obtained from the fractionation of this extract. After two successive purifications of the fraction A5, two subfractions A5.1 and A5.2 were obtained. The mass spectrum of a compound of A2 has a molecular peak at m/z 426 and peaks [M-69] + , [M-154] + , [M-169] + , [M-197] + , [M-208] + and [M-219] + characteristic of taraxasterol. For the derivatized fraction A5.2, a compound has a mass spectrum of molecular peak at m/z 486 and peaks [M-90] ++ and [M-357] + characteristic of β -sitosterol trimethylsilyl ether derived from β -sitosterol. The presence of these two bioactive phytosterols would be a major asset in the therapeutic use of this plant. © 2017 International Formulae Group. All rights reserved. Keywords: Ficus sur , GC-MS, taraxasterol, β- sitosterol