J. Siallagan et al. Proceeding of The International Seminar on Chemistry 2008 (pp. 225-228) Jatinangor, 30-31 October 2008 225 Secondary metabolites kurzichalcolactone A and B from Cryptocarya lucida Blume (Lauraceae) Johnson Siallagan, Euis H. Hakim, Yana M. Syah, Lia D. Juliawaty, Sjamsul A. Achmad, Lukman Makmur, Didin Mujahidin Natural Products Research Group, Department of Chemistry, Institut Teknologi Bandung, Jalan Ganeca 10 Bandung 40132, Indonesia Abstract Plants of Cryptocarya (Lauraceae) are known to contain 6-substituted 5,6-dihydro-2-pyrones, flavanoids, alkaloids, and terpenoids. One of endemic plants of Kalimantan forest, C. lucida Blume, has been selected for phytochemical study on its phenolic constituents. Fractionation of the methanol extract of the stem bark of this plant, followed by purification of the phenolic fractions, afforded two chalcone derivatives, named kurzichalcolactones A and B. The structures of both compounds were determined by spectroscopic methods, including UV, IR, 1 H-NMR, 13 C-NMR data, as well as by comparison with those reported data. Cytotoxic evaluation of both compounds against murine leukemia P388 cells showed that their IC 50 to be 6.3 and 17.9 g/mL, respectively. Keywords: Kurzichalcolactone A and B, chalcone derivatives, Cryptocarya lucida Blume, cytotoxic Introduction The genus Cryptocarya belongs to the pantropical family Lauraceae and most of the species grow in the Pacific-Asian tropical rainforests (Dumontet, 2001). Many of these species have been examined for their chemical constituents and revealed to contain flavonoids, 6-alkyl- or 6-aryl-α-pyrones (Davies- Coleman and Rivett, 1989; Collet et al., 1998), lignans, terpenoids, and alkaloids (Juliawaty, 2000a,b). In continuation of our on going search for cytotoxic compounds from Indonesia plants, we investigated C. lucida Blume (Lauraceae), an endemic plant collected at Bukit Bengkirai forest, East Kalimantan Province, Indonesia. In this communication, we report the isolation and structural elucidation, as well as cytotoxicity against murine leukemia P388 cells, of two chalcone derivatives, kurzichalcolactones A (1) and B (2). Materials and Methods The following instruments were used: melting points were determined by ‘micro melting point apparatus’. Optical rotations, Perkin-Elmer 341 polarimeters in MeOH. UV spectra, Cary Varian 100 Conc and IR spectra, Perkin-Elmer Spectrum One FT- IR spectrophotometers. 1 H and 13 C NMR spectra, JEOL ECP500 spectrophotometers, 500 MHz ( 1 H) and 125 MHz ( 13 C). The following adsorbents were used for purification : Vacuum liquid chromatogaphy (VLC), Si-gel 60 GF 254 (Merck), Flash column chromatography (FCC), Si-gel G60 (230-400 mesh) (Merck), Radial chromatography (RC), Si-gel 60 PF 254 (Merck), and TLC plates, Kieselgel 60 F 254 0.25 mm (Merck) thick were used. All solvents distilled technical qualities. Plant material. Samples of the stem bark of C. lucida was collected in Oktober 2005 from the Bukit Bengkirai forest, Balikpapan, East Kalimantan, Borneo island, Indonesia. A herbarium specimen has been deposited at the Herbarium Bogorienses, Center of Biological Research and Development, National Institute of Science, Bogor, Indonesia. Extraction and isolation. The milled stem bark of C. lucida (3.1 kg) was extracted successively with with methanol (3 x 24h x 6L) at room temperature. The residue give the crude extract (120 g) which was then partitioned by use of n-hexane to produce extract (3.7 g) and than EtOAc extract (61.5 g). Next, the EtOAc extract was subject to chromatography on silica gel and eluted successively with n-hexane, n- hexane/acetone, acetone, and MeOH in the order of increasing polarity. Extract EtOAc was subjected to VLC with column ∅ 10 cm (3 x 20g), adsorbent Si- gel (200 g) and eluted with mixture hexane-acetone (9:1; 8:2; 7.5:2.5; 6:4; 1:1), acetone 100 %, and MeOH (100 %), to give 7 fraction (A-G) were 1.6 g, 4.1 g, 5.1 g, 5.4 g, 16.2 g, 11.4 g, and 5.8 g, respectively. The major component of fraction E. Compound 1 (40 mg) and 2 (35 mg) were obtained by purification of E (293 mg) using radial chromatography (Si-gel, hexane:acetone = 6.5:3.5 and hexane:acetone = 6:4). These compounds were all determined by spectral methods and compare with corresponding data reported in the literature. Kurzichalcolactone A (1), yellow powder : [α] 20 D - 47 0 (c= 0.1 Me-OH) UV absorption λ maks (nm) MeOH) (log ) 206 (2.34), 239 (1.20), 355 (1.12) nm, showed bathochromic shift (MeOH + NaOH). ISBN 978-979-18962-0-7