Muriolide, a novel antioxidant lactone from Ranunculus muricatus.

Muriolide (1), a new aromatic lactone, has been isolated from the ethyl acetate fraction of Ranunculus muricatus. The compound was structurally characterized with the help of UV, IR, mass, 1D- and 2D-NMR data. It was tested in vitro for antioxidant and lipoxygenase inhibitory potential. Compound 1 showed good DPPH radical scavenging activity (IC₅₀=56.9 μM), however it was moderately active against lipoxygenase enzyme (IC₅₀=68.3 μM).