Chakyunglupulins A and B, two novel 4,8,8-trimethylcyclooct-2-enone derivatives from Barleria lupulina

Two novel 4,8,8-trimethylcyclooct-2-enone derivatives, chakyunglupulins A and B, together with six known lignans were isolated from the aerial part of Barleria lupulina. The structures of new compounds were established by extensive spectroscopic data and HR-MS, and their absolute configurations were determined by a combination of NOE experiment and application of the modified Mosher's method.