Coumarins and psoralens from sicilian lemon oil (Citrus limon (L.) Burm. f.)

The coumarin fraction of cold-pressed Sicilian lemon oils (Citrus limon (L.) Burm. f.) was investigated by HPLC, MS, GC-MS and NMR. Twenty-nine structurally different compounds were identified. Eleven of these were previously unknown as constituents of lemon oil. 5-(2′,3′-Dihydroxy-3′-methylbutyloxy)-7-methoxycoumarin, 5-(2′,3′-epoxy-3′-methylbutyloxy)-7-methoxycoumarin, 8-(7′,8′-epoxygeranyloxy)psoralen as well as 5-(3′-methylbut-2′-enyloxy)-8-(2′,3′-dihydroxy-3′-methylbutyloxy)psoralen are hitherto unknown natural products. Moreover, a new derivatization method for the investigation of allyloxycoumarins, based on mild hydrogenation, is presented.