Chemical constituents from the stems of Machilus philippinensis

Abstract

Machilus philippinensis Merr. (Lauraceae) is a medium-sized evergreen tree distributed at an altitude of 500 to 1600 m in Taiwan and the Philippines [1]. In continuation of some studies of chemotaxonomy and biologically active metabolites from Formosan Lauraceous plants [2–10], a methanol extraction of the stems of M. philippinensis afforded 10 known compounds, including three lignans: cinnamophilin (1) [11], erythro-austrobailignan (2) [12], (+)-syringaresinol (3) [13]; one amide: cinnaretamine (4) [4]; four benzenoids: p-hydroxybenzoic acid (5) [14], p-hydroxybenzadehyde (6) [14], vanillic acid (7) [14], p-anisaldehyde (8) [15]; and two steroids: -sitosterol (9) [16] and -sitostenone (10) [16]. In addition to cinnamophilin [11], all of these compounds were found for the first time from this plant. The stems of M. philippinensis were collected from Taiwan County in May 2008. Plant material was identified by Dr. Yen-Ray Hsui (Chungpu Research Center, Taiwan Forestry Research Institute). A voucher specimen has been deposited at the Department of Medical Technology, School of Medical and Health Sciences, Fooyin University, Kaohsiung, Taiwan. The stems (6.14 kg) of M. philippinensis were extracted repeatedly with MeOH at room temperature for 24–48 h. The MeOH extract was dried and evaporated to leave a viscous residue (425.8 g). The residue was placed on a silica gel column and eluted with CH2Cl2 gradually enriched with MeOH to afford 9 fractions. Part of fraction 1 (13.7 g) was subjected to silica gel chromatography by eluting with n-hexane–acetone (40:1) and enriched gradually with acetone to furnish three fractions (1-1–1-3). Fraction 1-1 (4.3 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain -sitostenone (10, 12 mg). Fraction 1-2 (4.3 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain -sitosterol (9, 10 mg) and p-hydroxybenzaldehyde (6, 5 mg). Fraction 1-3 (3.2 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain erythro-austrobailignan (2, 13 mg). Part of fraction 4 (8.8 g) was subjected to silica gel chromatography by eluting with n-hexane–acetone (20:1) and enriched with acetone to furnish two further fractions (4-1–4-2). Fraction 4-1 (6.3 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain cinnamophilin (1, 30 mg). Part of fraction 4-2 (2.3 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain p-hydroxybenzoic acid (5, 4 mg). Part of fraction 7 (12.4 g) was subjected to silica gel chromatography by eluting with n-hexane–acetone (10:1) and enriched with acetone to furnish two further fractions (7-1–7-2). Fraction 7-1 (6.4 g) was further purified on a silica gel column using n-hexane–acetone mixtures to obtain vanillic acid (7, 18 mg). Part of fraction 8 (24.6 g) was subjected to silica gel chromatography by eluting with CH2Cl2–MeOH (100:1) and enriched with MeOH to furnish three fractions (8-1–8-3). Fraction 8-2 (10.3 g) was further purified on a silica gel column using CHCl3–MeOH mixtures to obtain (+)-syringaresinol (3, 10 mg). Fraction 8-3 (7.3 g), eluted with CHCl3–MeOH (60:1), was further separated using silica gel column chromatography and preparative TLC (CHCl3–MeOH 100:1) and gave cinnaretamine (4, 5 mg). Fraction 9 (6.4 g) eluted with CHCl3–MeOH (50:1) was further separated using silica gel column chromatography and preparative TLC (CHCl3–MeOH 15:1) to give p-anisaldehyde (8, 22 mg).