Chemical constiuents of Euonymus acanthocarpus

Abstract

The genus Euonymus belongs to the Celastraceae family and comprises ca. 220 species widely scattered in subtropical and temperate zones, of which about 111 species are extensively distributed in southern China [1]. Euonymus acanthocarpus is used as folk medicine to treat rheumatic arthralgia, hydrops, and traumatic injuries [2], while the chemical constituents and bioactivities of this plant have not been studied before. Our current research on this plant resulted in the isolation of four terpenes, seven flavones, four aryl glycosides, and twenty other aromatic compounds, of which compounds 3–4, 8, 13–14, 17, and 19–35 were isolated from Celastraceae family for the first time. The stems and leaves of Euonymus acanthocarpus were gathered in Xishuangbanna, Yunnan Province, P. R. China, in August of 2010, and were authenticated by Assoc. Prof. Xielishan, Kunming Institute of Botany, Chinese Academy of Sciences. A voucher specimen (No. 2009EAC1) is deposited at the School of Pharmacy, Shanghai Jiao Tong University. The dried stems and leaves of E. acanthocarpus (10.0 kg) were powered and extracted with 95% ethanol for six times at room temperature and evaporated under reduced pressure to give 560.8 g of extract, which was resuspended with H2O (2.5 L) and successively partitioned with petroleum ether (PE, 12.0 L), dichloromethane (DCM, 20.0 L), ethyl acetate (EtOAc, 20.0 L), and n-butanol (12.0 L) to give four fractions. The PE fraction (107.3 g) was subjected to silica gel (100–200 mesh, 1.3 kg) column chromatography (CC, 10 100 cm) and eluted with a PE–EtOAc gradient system (v/v = 100:0, 100:1, 50:1, 20:1, 10:1, 5:1) to give subfractions PE1–PE4. PE2 (9.3282 g) was isolated by silica gel (200–300 mesh) and recrystallization (MeOH–Me2CO) to give 1 (25.8 mg), 5 (20.0 mg), and 6 (10.0 mg); PE3 (6.1696 g) was further purified over silica gel column and preparative HPLC (MeOH–H2O system, 8 mL/min) to yield 16 (8.1 mg, 50% MeOH), 17 (1.0 mg, 80% MeOH), 18 (3.7 mg, 55% MeOH), 19 (15.0 mg, 55% MeOH), and 35 (9.2 mg, 55% MeOH). Compounds 2 (3.2 mg) and 15 (2.0 mg) were obtained by a similar process using PE4 (8.2 g).