ABSTRACT
References ............................................................................................................. 397
All coumarins are benzo-a-pyrone derivatives. They are also classified under phenylopropane derivatives because of biogenetic origin and basic skeleton C6-C3, which represents lactone system. Biologically, coumarins are derived from phenylopropane and through shickimig acid cycle they lead to trans-cinnamic acid. Transcinnamic acid passes to o-coumaric acid, its glycoside, and coumarin. In the similar cycle, p-coumaric acid passes to umbelliferone. The active isoprene is attached to the simple coumarin molecule and forms furano-and pyranocoumarins by the cyclization [1].
