Chemical constituents from Dendrobium chrysanthum and their chemotaxonomic significance

Nineteen known compounds were isolated from the 75% alcohol extract of the stems of Dendrobium chrysanthum, including four phenols (1–4), three alkaloids (5–7), six phenanthrenes (8–13), three monoterpenes (14–16), and three lignans (17–19). This is the first report on compounds 3 (trans-3,4,5-trimethoxylcinnamyl alcohol), 5 (1-(6-hydroxy-[3]pyridyl)-propan-1-one), 16 ((+)-(1S,5R)-verbenon-10-oic acid) and 18 (cinnacassin F) isolated from the family Orchidaceae, compounds 2 (3-hydroxy-4,5-dimethoxypropiophenone) and 7 (1H-Indole-3-carbaldehyde) from the genus Dendrobium, and compounds 1 (syringaldehyde), 4 (apocynin), 8 (confusarin), 9 (nudol), 10 (orchinol), 11 (ephemeranthol-A), 12 (5,7-dimethoxyphenanthrene-2,6-diol), 13 (moscatilin), 15 (loliolide), 17 (3,3′-bis(3,4-dihydro-4-hydroxy-6-methoxy-2H-1-benzopyran) and 19 ((+)-syringaresinol) from D. chrysanthum. It is worth mentioning that compounds 6 (carbofuran) and 14 ((6R,7aR)-7a-hydroxy-3,6-dimethyl-5,6,7,7a-tetrahydrobenzofuran-2(4H)-one) have not been previously reported from any plant. Their structures were elucidated on the basis of NMR spectroscopic data. Moreover, the chemotaxonomic significance of the isolated compounds is discussed.