Umbelliferone is a widespread natural product of the coumarin family. It absorbs ultraviolet light strongly at several wavelengths. Despite several indications that this chemical is photomutagenic, it is used in sunscreens. Umbelliferone has been reported to have antioxidant properties. It is a yellowish-white crystalline solid that has a slight solubility in hot water, but high solubility in ethanol. Umbelliferone is a phenylpropanoid and as such is synthesized from L-phenylalanine, which in turn is produced via the shikimate pathway. Phenylalanine is lysated into cinnamic acid, followed by hydroxylation by cinnamate 4-hydroxylase to yield 4-coumaric acid. The 4-coumaric acid is again hydroxylated by cinnamate/coumarate 2-hydroxylase to yield 2,4-dihydroxy-cinnamic acid (umbellic acid) followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group.
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