Naturally Occurring Plant Coumarins

Shikimic Acid Pathway

“…Coumarins absorb ultraviolet light at~320 nm (log ε~4) [5][6][7][8][9] due to the α,-β-unsaturated-δ-lactonic carbonyl. All coumarins exhibit strong absorption in the UV region.…”

“…However, its structure, not known at that time, was elaborated to be 8-hydroxy-7-0-β-D-glucosylcoumarin [5][6][7][8][9] in 1930. Coumarins are widely distributed in plants and are prevalent in the plants belonging to Rutaceae, Umbelliferae (Apiaceae), Compositae (Asteraceae), Leguminosae, and Moraceae families.…”

“…Quite often a C 5 -unit is locked in the form of a ring. C 10 -, C 15 -Terpenoid chains as such or their modified units are also known to be present as side chain or as a part of a ring [5][6][7][8][9]. A few examples are shown in Fig.…”

“…The interesting part of coumarin substitution is the occurrence of one or more C 5 -units arising out of γ,γ-dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP). These two C 5 -units amazingly undergo all possible structural modifications that one can chemically conceive of [5][6][7][8][9] (Fig. 13.21).…”

“…Coumarins are widely distributed in plants and are prevalent in the plants belonging to Rutaceae, Umbelliferae (Apiaceae), Compositae (Asteraceae), Leguminosae, and Moraceae families. A number of review articles and a book on natural plant coumarins have appeared [5][6][7][8][9]. Plants elaborate mono-to polyoxygenated coumarins, of which the most common one is umbelliferone (¼7-hydroxycoumarin).…”