Chem. Pharm. Bull. 53(1) 137—139 (2005)

and inflammatory responses, once activated they result in pro-inflammatory cytokines, oxygen, and nitrogen species, which recruit activated immune and inflammatory cells to the site of lesion, thereby amplifying and perpetuating the inflammatory state. The inorganic free radical nitric oxide (NO) has been implicated in physiological and pathological processes such as vasodilation, nonspecific host defense, ischemia reperfusion injury, and chronic or acute inflammation. NO is produced by the oxidation of L-arginine catalyzed by NO synthase (NOS). In the NOS family, inducible NOS (iNOS) in particular is involved in pathological overproduction of NO, and can be expressed in response to pro-inflammatory agents such as lipopolysaccharide (LPS) in various cell types including macrophages, endothelial cells, and smooth muscle cells. In inflammatory disease such as rheumatoid arthritis, excessive NO production by activated macrophages has been observed. Therefore, inhibition of iNOS activation and NO production may be of therapeutic benefit in various types of inflammation. Wikstroemia indica (Thymelaeceae) is distributed in the southeast of China. It has long been used as a traditional crude drugs for the treatment of pneumonia, rheumatism, and bronchitis in China. Previous investigations of E. lanulata have yielded some flavonoids, lignans, and coumarins. However, no report on the isolation and characterization of anti-allergic constituents from this plant has been made. The roots of Wikstroemia indica were extracted with 80% MeOH. The extract was then partitioned with hexane, ethyl acetate, n-butanol, and water, successively. The ethyl acetate fractions showed strong NO production inhibitory activity. Further bioassay-directed fractionation of this fraction led to the isolation of one new guaiane type sesquiterpene, Indicanone (1), and two known biflavonoids, sikokianin B (2), and sikokianin C (3). Here, we describe the isolation, structure elucidation and biological evaluation of these compounds. 1 was isolated as a colorless oil and assigned to possess a molecular formula of C15H20O2 by HR-EI-MS ([M] , m/z 232.1464). Hydroxyl (3410 cm ) and unsaturated ketone (1665 cm ) absorptions were observed in the IR spectrum. The UV spectrum displayed an absorption maximum at 257 nm. The C-NMR spectrum showed 15 carbon atoms which were classified as two methyls, six methylens, one methine, and six quaternary carbon atoms using distortionless enhancement by polarization transfer (DEPT) C-NMR analysis. Furthermore, the C-NMR chemical shifts suggested the presence of one carbonyl, one exo-methylene, two double bonds, one oxygen-bearing methylene. The detailed analysis of 1 using H–H correlation spectroscopy (H–H COSY) and heteronuclear multiplequantum coherence (HMQC) disclosed two partial structural units with correlated protons: CH3–C CH2– (A) and –CH2–CH–CH2–CH2– (B) (Table 1). In the heteronuclear multiplebond connectivity (HMBC) spectrum, the methyl proton signal at dH 1.79 (13Me) was correlated with the carbon signals at dC 44.0 (C-7), 150.7 (C-11), and 109.8 (C-12) and the methine proton signal at dH 2.53 (7-H) with the carbon signals at dC 150.7 (C11) (Table 1). These facts clearly indicated the combination of the partial structures A and B. Detailed analysis of 1 using HMBC spectrum showed twoand three-bond correlations between H-8 and C-10; between H-9 and C-1, 10, 14. In the NOESY spectrum, 1 showed significant NOE correlations between the oxygen-bearing methylene signal at dH 4.12 (H14) and dH 2.92 (H-2). From these facts, the assignment at C1, 2, 10, and 14 was confirmed. By the same way, HMBC correlations between H-6 and C-1, 4, and 5, between Me-15 and H-4 and H-5, and NOE correlations between Me-15 and January 2005 Notes Chem. Pharm. Bull. 53(1) 137—139 (2005) 137