Repenins A-D, four new antioxidative coumarinolignoids from Duranta repens Linn

Phytochemical investigations on the CHCl(3)-soluble fraction of the whole plant of Duranta repens Linn. led to the isolation of four new coumarinolignoids, Repenins A-D (1-4), along with the known coumarinolignoids, cleomiscosin A (5) and durantin A (6). Their structures were determined by modern spectroscopic analysis including 1D and 2D NMR techniques and chemical studies. The compounds (1-6) showed potent antioxidative scavenging activity against DPPH radicals, with IC(50) values in the range 0.420-0.625mM. Repenin B (2) displayed the strongest scavenging potential with IC(50) values of (0.420mM).