Carotenoid composition and its chemotaxonomic significance in leaves of ten species of the genus Ceratozamia (Cycads)

The characteristic red-brown transitory coloration shown by the newly formed leaflets during the first stages of development is due to this latter keto mixture. It is constituted of three very rare keto-carotenoids, which were, in our case, identified for the first time from the photosynthetic tissues (semi-β-carotenone, triphasiaxanthin, and β-carotenone). It is also constituted of four others, which are completely novel (ceratoxanthin, ceratozamiaxanthin, kuesteriaxanthin, and ceratoxanthone). Some hypotheses about their presence and function are presented.