Two new phenolic compounds from the stems of Ephedra sinica Stapf.

Seventeen phenolic compounds were isolated from the aqueous extract of the stems of Ephedra sinica using various column chromatographic techniques, including silica gel and Sephadex LH-20, combined with semi-preparative HPLC. Their structures were elucidated by modern spectroscopic methods such as NMR, UV, IR, and MS. Compounds 1 and 2 were identified as new phenols, and compounds 3-17 were isolated from this plant for the first time. The proliferation inhibitory activities of all the compounds on human non-small cell lung cancer cells (A549) was screened. The results showed that compounds 1-17 exhibited no proliferation inhibitory activity on A549 cells at a concentration of 10 μmol·L^-1.