Five new compounds from the stems of Ephedra equisetina.

Five new compounds were identified from the stems of Ephedra equisetina Bunge. Their structures were elucidated by spectroscopic methods, involving UV, IR, NMR spectrum and HRESIMS analyses. The absolute configuration of compound 2 was proved by comparing their experimental and calculated ECD spectrum. The vitro bioactive assay of all compounds suggested that compound 1, 3, 4, 5 and 6 may have potential anti-asthmatic activities.