PRENYLATED DIHYDROSTILBENES FROM Macaranga heynei (EUPHORBIACEAE)

Abstract

Macaranga is the largest genus in Euphorbiaceae which consists of approximately 300 species and are widely distributed in New Guinea, Borneo and from West Africa to the south Pacific islands. Phytochemical study on the leaves of Macaranga heynei has been conducted. The powder of the leaves of M. heynei was macerated in methanol at room temperature for 24 hours and repeated three times. The crude extract obtained was dissolved in aqueous methanol (80:20) and partitioned with hexane and ethyl acetate. The ethyl acetate crude extract was fractionated by vacuum liquid chromatography (VLC) with hexane:ethyl acetate in increasing polarity to give seven combined fractions (MH 1-7). Fraction MH 2 (1000 mg) was further purified by radial chromatography (RC) with hexane:ethyl acetate in increasing polarity to give six combined subfractions . Fraction MH 23 (693.7 mg) was further purified by the same chromatographic technique but with different eluent which was chloroform:ethyl acetate in increasing polarity to afford two pure compounds (1) (10 mg) and (2) (12 mg). Based on spectroscopy analysis, the pure compounds were characterized as laevifolins A (1) and B (2). Keywords: Laevifolin A, laevifolin B, leaves, Macaranga heynei AbstrakMacaranga merupakan genus terbesar dalam famili Euphorbiaceae yang mengandungi kira-kira 300 spesies dan taburannya meliputi New Guinea, Borneo dan dari Afrika Selatan ke utara kepulauan Pasifik. Kajian fitokimia ke atas daun Macaranga heynei telah dijalankan. Serbuk daun M. heynei direndam dalam metanol pada suhu bilik selama 24 jam dan pengesktrakan diulang sebanyak tiga kali. Ekstrak mentah yang diperolehi telah dilarutkan dalam larutan metanol (80:20) dan dipisahkan dengan heksana dan etil asetat. Etil asetat mentah difraksinasi menggunakan kromatografi cecair vakum (KCV) dengan heksana:etil asetat mengikut peningkatan kekutuban menghasilkan tujuh fraksi gabungan (MH 1-7). Fraksi MH 2 (1000 mg) selanjutnya ditulenkan dengan menggunakan kromatografi radial (RC) dengan heksana:etil asetat mengikut peningkatan kekutuban menghasilkan enam subfraksi gabungan . Fraksi MH 23 (693.7 mg) seterusnya ditulenkan dengan menggunakan teknik kromatografi yang sama tetapi menggunakan eluen yang berbeza iaitu kloroform:etil asetat mengikut peningkatan kekutuban menghasilkan dua sebatian tulen (1) (10 mg) dan (2) (12 mg). Berdasarkan analisis spektroskopi, sebatian tulen tersebut dicirikan sebagai laevifolin A (1) dan B (2). Kata kunci: Laevifolin A, laevifolin B, daun, Macaranga heynei