Antioxidants and a new germacrane sesquiteroene from Carissa spinarum.

A new germacrane derivative, care none (1) was isolated from the stems of a well-known medicinal plant, Carissa spinarum L. together with a new ester, 3'-(4''-methoxyphenyl)-3-oxo-ropionyl hexadecanoate (2). Their structures were established using 1D, 2D NMR spectroscopic and synthetic methods. The chloroform extract of the plant displayed strong antioxidant (DPPH) activity. Several other known compounds were also isolated for the first time from this active extract. The antioxidant activity of major lignans was studied.