A new bibenzyl derivative from stems of Dendrobium officinale / 中国中药杂志

Eleven compounds were isolated from the 95% ethanol extract of the stems of Dendrobium officinale after water extraction by various modern chromatographic techniques, such as silica gel column chromatography(CC), octadecyl-silica(ODS) CC, Sephadex LH-20 CC, preparative thin layer chromatography(PTLC) and preparative high performance liquid chromatography(PHPLC). According to spectroscopic analyses(MS, 1D-NMR, 2D-NMR) combined with optical rotation data and calculated electronic circular dichroism(ECD), their structures were identified as dendrocandin Y(1), 4,4'-dihydroxybibenzyl(2), 3-hydroxy-4',5-dimethoxybibenzyl(3), 3,3'-dihydroxy-5-methoxybibenzyl(4), 3-hydroxy-3',4',5-trimethoxybibenzyl(5), crepidatin(6), alternariol(7), 4-hydroxy-3-methoxypropiophenone(8), 3-hydroxy-4,5-dimethoxypropiophenone(9), auriculatum A(10) and hyperalcohol(11). Among them, compound 1 was a new bibenzyl derivative; compounds 2 and 7-11 have not been previously reported from Dendrobium plants; compound 6 was reported from D.officinale for the first time. Compounds 3-6 exhibited potent antioxidant activity with IC_(50) values of 3.11-9.05 μmol·L~(-1) in ABTS radical scavenging assay. Compound 4 showed significant inhibitory effect on α-glucosidase, with IC_(50) value of 17.42 μmol·L~(-1), indicating that it boasted hypoglycemic activity.

Heterocyclic compounds and phenolic glycosides from flowers of Dendrobium officinale / 中国中药杂志

Eight heterocyclic compounds and twelve phenolic glycosides were separated from the water extract of Dendrobium officinale flowers through chromatographic techniques, such as Diaion HP-20 macroporous adsorption resin column chromatography(CC), silica gel CC, ODS CC, Sephadex LH-20 CC, and preparative high performance liquid chromatography(PHPLC). According to the spectroscopic analyses(MS, ~1H-NMR, and ~(13)C-NMR) and optical rotation data, the compounds were identified as dendrofurfural A(1), 2'-deoxyadenosine(2), 4-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl] butanoic acid(3), 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl] butanoic acid(4), 1-(2-hydroxyethyl)-5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde(5), 5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde(6), methyl 5-(hydroxymethyl)-furan-2-carboxylate(7),(S)-5-hydroxymethyl-5H-furan-2-one(8), 2-methoxyphenyl-1-O-β-D-glucopyranoside(9), arbutin(10), isotachioside(11), 2,6-dimethoxy-4-hydroxyphenol-1-O-β-D-glucopyranoside(12), orcinol glucoside(13), tachioside(14), gastrodin(15), 4-O-β-D-glucopyranosylvanillyl alcohol(16), 2,6-dimethoxy-4-hydroxymethylphenol-1-O-β-D-glucopyranoside(17), icariside D_2(18), 4-formylphenyl-β-D-glucopyranoside(19), and vanillin-4-O-β-D-glucopyranoside(20). Among them, compound 1 is a new furfural benzyl alcohol condensate, with the skeleton first found in Dendrobium. Compounds 2-9, 11, 13, and 19 are reported from Dendrobium for the first time, and compounds 14 and 18 are reported for the first time from D. officinale. Compounds 11 and 14 showed moderate DPPH radical scavenging capacity, and compounds 11-14 demonstrated potent ABTS radical scavenging capacity, possessing antioxidant activity.