| Dregea sinensis var. corrugata belongs to the genus Dregea in the familyAsclepiadaceae. Dregea sinensis var. corrugata is distributed in Shanxi, Gansu, Jiangsu, Zhejiang, Hubei, Guangxi, Yunnan, Guizhou Provinces, and Southwest in China. Ithas been used for expelling wind to relieve spasm, eliminating sputum and stoppingcoughing, detoxicating and promoting blood flow in China. The result of bioassaydisplayed that the EtOAc and n-BuOH parts of 95% alcohol extract of Dregea sinensisvar. corrugata exhibited inhibition activities against MAO. Meanwhile, the petrol ether, EtOAc and H2O parts of Dregea sinensis var. corrugata showed anti-hyperspasmiaactivity, respectively. In our investigation, 44 compounds were obtained, in which thestructures of 42 compounds were elucidated, including 17 new C-21 pregnane-typeglycosides, together with 16 known compounds were isolated from the EtOAc extractof the stems of Dregea sinensis var. corrugata for the first time.On basis of spectroscopic analysis and chemical methods, the structures of the 42compounds were established as 12-O-cinnamoyl-20-O-nicotinoyl-dihydrosarcostin3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaro-pyranoside (1), 12-O-benzyl-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-digitoxopyranosyl-(1→4)-O-β-D-cymaro-pyranoside (2), 12-O-nicotinoyl-20-O-cinnamoyl-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside(3), 12-O-benzyl-20-O-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-digitoxopyranosyl-(1→4)-O-β-D-cymaropyranoside (4), 12-O-cinnamoyl-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-digitoxopyranosyl-(1→4)-O-β-D-cymaropyranoside (5), 12-O-cinnamoyl-tayloron 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-digitoxopyranosyl-(1→4)-O-β-D-cymaropyranoside (6), 12-O-cinnamoyl-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranosyl-(1→4)-O-β-D-cymaropyrano side (7), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihyrosarcostin3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside (8), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihydrosarcostin3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside (9), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihydrosarcostin3-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside (10), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihydrosarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-theveto-pyranosyl-(1→4)-β-O-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranosyl-(1→4)-O-β-D-cymaropyranoside (11), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihydrosarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyran-osyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranosyl-(1→4)-O-β-D-cymaropyranoside (12), 12-O-acetyl-20-O-benzyl-(14, 17, 18-orthoacetate)-dihydrosarcostin 3-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranosyl-(1→4)-O-β-D-cymaropyranoside (13), 12-O-acetyl-20-O-benzyl-(14, 17, 18-orthoacetate)-dihydrosarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside (14), 12-O-acetyl-20-O-benzyl-(14, 17, 18-ortho-acetate)-dihydrosarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranosyl-(1→4)-O-β-D-cymaropyranoside (15), 12-O-acetyl-20-O-benzyl-(8, 14, 18-orthoacetate)-dihydro-sarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside(16), 12-O-acetyl-20-O-benzyl-(14, 17, 18-orthoacetate)-dihydrosarcostin 3-O-β-D-glycopyranosyl-(1→4)-O-β-D-glycopyranosyl-(1→4)-O-β-D-thevetopyranosyl-(1→4)-O-β-D-oleandropyranosyl-(1→4)-O-β-D-cymaropyranoside (17), dresigenin A(18), dihydrosarcostin (19), syringaresinol (20), 5-methoxyl- pinoresinol (21), pinoresinol(22), syringaresinol-O-β-D-glycopyranoside (23), 3, 4'-dimethoxyl-4, 9, 9'-trihydroxyl-benzofuranneolignan-7'-ene (24), 3, 4'- dimethoxyl-4, 9-dihydroxyl-4, 9-dihydroxyl-9'-hydroethyl-benzofuranneolignan-7'-ene (25), 3-(4-hydoxyl-3-methoxyl-phenyl)-propenal (26), 3-(4-hydroxy-3, 5-dimethoxyphenyl)-propenal (27), 4-hydoxy-3, 5-dimthoxy-benzaldehyde (28), 5-(3-hydroxypropenyl)-2-methoxy-phenol (29), 3-hydoxy-1- (4-hydroxy-3-methoxyphenyl)-propan-1-one (30), 4-hydroxymethyl-2, 6-dimethoxy- phenol (31), usrane (32), oleanic acid (33), 3-acetyl-dammane (34), trihydroxyeudesm-4-ene (35),β-sitosterol (36), daucosterol(37), sucrose (35), cymarose (39), digitoxose (40), thevetose (41), oleanose(42)。To determine the absolute configurations of the deoxysugars in compounds 1-17, we performed hydrolysis experiment on the crude glycosides of Dregea sinensis var.corrugata, and obtained D-digitose, D-cymmarose, D-oleanose, and D-thevetose(39-42). The absolute configurations of the four deoxysugars are all D-types, according to optical rotation data and NMR methods.To illuminate the mass spectroscopy characteristics of C21 steroidal glycosides, theESI-MS fragmentation behaviors of C21 steroidal glycosides isolated from Dregeasinensis var. corrugata were investigated. The characteristic fragmentation patterns ofthe aglycones and the sugar residues were discussed in detail to give some valuableconclusions, which provided more rapid and accurate methods for identifying knowncompounds with similar structures, determining structures of new compounds, detecting trace constituents of crude extracts and analyzing active ingredients. On thebasis of them, 2 fractions containing steroidal glycosides were investigated by use ofHPLC-MS/MSn. As a result, the possible structures of 21 trace C-(21) steroidalglycosides were deduced, in which 11 ones have been obtained previously in ourinvestigation, while the other 10 compounds were new ones.
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