Sterically hindered carotenoids with 3Z, 5Z configuration from the seeds of oriental bitter sweet, Celastrus orbiculatus

Sterically hindered cis-carotenoids 1 and 2 were isolated from seeds of the oriental bitter sweet, Celastrus orbiculatus. The structures of 1 and 2 were determined to be (3'Z,5'Z)-celaxanthin and (3'Z,5'Z)-torulene, respectively, on the basis of spectroscopic data and iodine-catalyzed stereomutation. This is the first report on carotenoids with a 3Z,5Z configuration.