Two new chemical constituents from Chishui Dendrobium nobile

The phytochemical investigation of the ethyl acetate fraction of 95% ethanol extract of Dendrobium nobile led to the isolation of two previously unreported compounds by various column chromatography methods, including silica gel, MCI, Toyopearl HW-40C combined with the semi-preparative HPLC. Their structures were determined by HRESIMS, NMR, IR, and UV, and identified as neodendronbibisline A (1), neodendronside A (2). Furthermore, compound 1 is a new phenanthrene with a benzofuran structural unit, and compound 2 is a new phenylpropanin glycoside.