A New Germacrane-Type Sesquiterpenoid Isolated from Salvia cavaleriei var. simplicifolia
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A NEW GERMACRANE-TYPE SESQUITERPENOID ISOLATED FROM Salvia cavaleriei var. simplicifolia
Zhenghong Guo, Xiaoyan Tao, Ye Hu, Guoyong Luo, Xiang Yu, Yan Zhang, and Wude Yang*
Salvia cavaleriei var. simplicifolia Stib., a common Chinese herbal medicine, is prescribed to treat dysentery, hemoptysis, boils, and fall injuries. Previous phytochemical investigations have resulted in the isolation of terpenoids, steroids, and phenolic compounds. In this paper, a new germacrane-type sesquiterpenoid named 8,14-O-ditigloyl-9,12-O-diacetyl-6R,7R,8R,9R,12,14-pentahydroxygermacra-1(10)E,4(5)Z-diene was isolated. The chemical structure was established by HR-ESI-MS, 1H, 13C, 2D NMR, and X-Ray. Keywords: Salvia cavaleriei var. simplicifolia Stib., sesquiterpenoid, germacrane. Salvia, including about 200 species, is the largest genus of the family Lamiaceae, which accounts for 20% of the plants. The genus Salvia is distributed in tropical and temperate regions of the world. In China, there are about 83 species, 25 varieties, and nine variants, and about 30 species (including varieties and variants) have been cultivated for use in herbal medicine [1]. Natural products, such as terpenoids, steroids, and phenolic compounds, have been isolated from Salvia species, and these compounds have been proven to have cardioactive, antiviral, antibacterial, and cytotoxic properties [2, 3]. Salvia cavaleriei var. simplicifolia Stib., an endemic species in China, is a common Chinese herbal folk medicine and is distributed in Guizhou, Sichuan, Guangdong, and Guangxi. It has been used to treat dysentery, hemoptysis, boils, and fall injuries [4, 1]. Chemical composition studies have shown that Salvia contains long-chain alkanes, phenylpropanoids, flavonoids, terpenoids (diterpenoids and triterpenoids), and steroids [5]. During our investigation of the biologically active components of S. cavaleriei var. simplicifolia Stib, a new sesquiterpenoid named 8,14-O-ditigloyl-9,12-O-diacetyl-6R,7R,8R,9R,12,14pentahydroxygermacra-1(10)E,4(5)Z-diene, which contains the germacrane skeleton, was isolated. In this paper, we report its isolation and structural identification by NMR and X-ray. Compound 1 was isolated as colorless crystals. Its molecular formula, C29H42O9, was established by HR-ESI-MS m/z 557.2721 [M + Na]+, calcd for C29H42O9Na, 557.2727, implying nine unsaturation degrees. The 1H NMR spectrum (Table 1) of 1 showed resonances for four double bond signals [δH 5.52 (1H, d, J = 8.0 Hz), 6.88 (1H, q, J = 6.0 Hz), 6.87 (1H, q, J = 6.0 Hz), 5.40 (1H, m)]. Seven signals [δH 5.26 (1H, dd, J = 10.8, 2.4 Hz), 4.91 (1H, d, J = 10.8 Hz), 4.59 (1H, br.d, J = 8.0 Hz), 4.49 (1H, d, J = 12.6 Hz), 4.44 (1H, d, J = 12.6 Hz), 4.36 (1H, dd, J = 10.8, 3.6 Hz), 4.05 (1H, dd, J = 10.8, 3.6 Hz)] were assigned to protons attached to oxygen-bearing carbons. The spectrum also showed eight methyl groups [δH 1.78 (3H, s), 1.08 (3H, d, J = 6.6 Hz), 2.07 (3H, s), 1.93 (3H, s), 1.82 (3H, d, J = 6.0 Hz), 1.80 (3H, s), 1.80 (3H, s), 1.82 (3H, d, J = 6.0 Hz)]. The 13 C NMR spectrum (
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