Antioksidan adalah suatu senyawa yang dapat menangkap radikal bebas. Salah satu sumber anti oksidan alami adalah dari tumbuh-tumbuhan. Dalam usaha pencarian antioksidan baru, telah dilakukan identifikasi senyawa antioksidan dari ekstrak n-heksana kulit batang Garcinia bancana Miq dengan metode 1,1-difenil-2-pikrilhidrazil (DPPH). Metode isolasi dilakukan dengan cara kombinasi kromatografi (Kromatografi kolom vacum, kromatografi kolom gravitasi, kromatografi lapis tipis sentrifugal dan kromatografi lempeng tipis) Penentuan struktur molekul berdasarkan analisis data spektroskopi UV-VIS, IR, LC-MS, NMR proton dan karbon. Dari hasil isolasi didapatkan suatu senyawa isoprenil bezofenon dengan bobot molekul 466,22 dan rumus molekul C28H34O6 dengan nama IUPAC 3-(3,4-dihidroksibenzoil)-4-hidroksi-8-8-dimetil-1,7-bis(3-metilbut-2enil) bisiklo (3.3.1) non-3-ene-2,9-dione atau disebut bacanone yang diduga senyawa baru. Dari proses isolasi juga ditemukan senyawa atsiri b- caryophyllene, α-humulene dan b-cadinene serta stigmasterol. Hasil uji aktivitas antioksidan ekstrak n-heksana dan hasil isolat murni menunjukkan IC50 berturut-turut 17,78 ppm dan 12,79 ppm dimana pembanding kuersetin adalah 9,90 ppm.Kata kunci: Garcinia bancana, antioksidan, DPPH, 3-(3,4-dihidroksibenzoil)-4-hidroksi-8-8-dimetil-1,7-bis(3-metilbut-2enil)bisiklo(3.3.1)no-3-ene-2,9-dione, bacanone. Antioxidants are compounds that can capture free radicals. One source of natural antioxidant is from plants. On searching for new antioxidant, identification of antioxidant compound of the n-hexane extract of the stem bark of Garciniabancana Miq was done by 1.1-diphenyl-2-pikrilhidrazil (DPPH) method. Isolation active compound were done by combination of chromatographic methods (Flash column chromatography, gravitation column chromatography, cetrifugal thin layer chromatography and thin layer chromatography) .Determination of molecular structure by analysis spectroscopic data of UV-VIS, IR, LC-MS, NMR proton and carbon.Isolation results were isophrenyl bezophenon with molecular weight 466.22 and the molecular formula is C28H34O6 IUPAC name 3 - (3,4-dihydroxybenzoil)-4-hydroxy-8-8-dimethyl-1,7-bis (3-methylbut-2enyl) bicyclo (3.3.1) non-3-ene-2,9-dione or named bacanone wich is suspected as a new compound. From the isolation were also found of known volatile compounds b - caryophyllene, α-humulene and b-cadinene and stigmasterol. The test results of antioxidant activity of n-hexane extract and pure compound showed IC50 respectively 17.78 ppm and 12.79 ppm which comparison with quercetin is 9.90 ppm. Key words : Garcinia bancana Miq., antioxidant, DPPH, 3-(3,4-dihydroxybenzoil)-4-hidroxy-8-8-dimethyl-1,7-bis (3-methylbut-2enil)bisiklo(3.3.1)no-3-ene-2,9-dione, bacanone.
Changes in fatty acid composition during preparative thin-layer chromatography
