Biflavonoids from Lonicera japonica

Two biflavorioids, 3'-O-methyl loniflavone [5,5,7,7-tetrahydroxy 3'-methoxy 4',4'-biflavonyl ether (1)] and loniflavone [5,5,7,7,3-pentahydroxy 4',4'-biflavonyl ether (2)] along with luteolin (3) and chrysin (4) were isolated from the leaves of Lonicera japonica. The structures were established on the basis of UV/vis, 1D, 2D NMR (HMQC and HMBC) and ESI-QTOF-MS/MS spectroscopic methods and chemical evidences. (c) 2005 Elsevier Ltd. All rights reserved.