Regardless of the applications: therapeutic vehicle or membrane model to mimic complex biological systems; it is of a great importance to develop easy, reproducible and rapid model assays allowing for a relevant assessment of the liposomal membrane oxidation and therefore antioxidant activity of selected molecules or extracts. Here, we describe a new and high-throughput assay that we called “Vesicle Conjugated Autoxidizable Triene (VesiCAT)”. It is based on specific UV absorbance spectral properties of a new phospholipid probe, synthesized with natural conjugated eleostearic acid extracted from Tung oil. The VesiCAT assay has been developed with two different radical generators (2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN), producing a constant flux of oxidant species, either in membrane or in aqueous phase. This method appears very efficient in evaluating the effect of various pure antioxidant molecules or extracts in their ability to preserve liposomes from oxidative degradation. In addition, the AAPH- and AMVN-induced oxidations offer the possibility of extracting different but complementary information with respect to the antioxidants efficacy.