[Study on chemical constituents from stem of Dendrobium aphyllum].

Objective: To study the active constituents of Dendrobium aphyllum.
Method: Various chromatographic techniques were used to isolate and purify the constituents, their physico-chemical properties and spectral data are determinated to elucidate the structure.
Result: Eight compounds were isolated and identified as: 4'-methoxyl-tricin (1), tricin (2), 7, 3', 5'-tri-O-methyl-tricetin (3), syringic acid (4), ( + )-syring-aresinol (5), D-allitol (6), sucrose (7), icariside D2 (8).
Conclusion: Compounds 1-3, 6-8 were isolated from genus Dendrobium for the first time, additionally, the others were obtained firstly from the plant.