Fraksionasi dan identifikasi golongan senyawa toksik dari fraksi etil asetat ekstrak buah sirsak hutan (Annona glabra)

Abstract

Fraksi etil asetat buah sirsak hutan (Annona glabra) telah dilaporkan menunjukkan sitotoksisitas tertinggi dibandingkan dengan fraksi etanol dan air. Dalam penelitian ini, fraksi etil asetat difraksionasi lebih lanjut dengan metode kromatografi lapis tipis preparatif dan dihasilkan 5 noda (rentang Rf 0.27–0.95) di bawah sinar ultraviolet 254 nm. Fraksi dengan Rf = 0.66 mengandung kristal berbentuk jarum dan berwarna putih. Spektrum ultraviolet fraksi tersebut menunjukkan puncak serapan pada 206 nm. Kenampakan fisis, panjang gelombang serapan ultraviolet serta spektrum inframerah yang memperlihatkan serapan khas, yaitu gugus OH (3396 cm-1), C=O (1737 cm-1), C=C (1561 cm-1), dan C–O (1384 cm-1) menunjukkan ciri khas golongan senyawa asetogenin. Serapan C=O dan C–O diduga sebagai penciri keberadaan cincin lakton yang lazim ditemukan dalam struktur asetogenin. Sitotoksisitas asetogenin telah dilaporkan berhubungan dengan adanya lakton tersebut, gugus OH, dan rantai karbon takjenuhnya. Kata kunci: asetogenin, inframerah, kromatografi, sirsak hutan.

Ethyl acetate fraction of pond apple has been reported as the most cytotoxic fraction compared with ethanol and water fractions. In this study the ethyl acetate fraction was further fractionated using preparative thin layer chromatography and the resulted five fractions showed Rf range from 0.27 to 0.95 under ultraviolet irradiation at 254 nm. Fraction having Rf = 0.66 was a white needle shape crystal. The ultraviolet spectrum of this fraction showed absorption peak at 206 nm. The physical appearance, absorption wavelengh and infrared spectrum, including OH group (3396 cm-1), C=O (1737 cm-1), C=C (1561 cm-1), and C-O (1383 cm-1) was further showed characteristic absorptions of acetogenin compound, The lactone ring which is common in acetogenin structures was predicted from the C=O and C–O absorptions. The cytotoxicity of acetogenins has been reported as related with this lactone, as well as the OH groups and the unsaturated hydrocarbon. Key words: acetogenin, infrared, chromatography, pond apple