Chemical constituents from the stems of Ephedra equisetina

Five new compounds, including two naphthalenes (1, 2), a phenolic derivative (3) and two glycosides (4, 5) were isolated from the stems of Ephedra equisetina Bunge. Their chemical structures were identified by spectroscopic analyses (IR, UV, HRESIMS NMR and ECD). An in vitro bioassay suggested that compound 5 possesses potential anti-asthmatic activities.