Coumarins and psoralens from sicilian lemon oil (<i>Citrus limon</i> (L.) Burm. f.)

Abstract

Abstract 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.