Interaction between α-Tocopherol, Tocotrienols and Astaxanthin in Liposomes, Subjected to Lipid Peroxidation

We studied the cooperative interaction between α-tocopherol, tocotrienols and astaxanthin, incorporated in soybean phosphatidylcholine (PC) multilamellar vesicles (MLV) against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), 2,2′-azobis (2,4-dimethyl-valeronitrile) (AMVN), or 1,3-morpholinosydnonimine hydrochloride (SIN-1) induced lipid peroxidation. Tocotrienols spared α-tocopherol consumption in hydrophilic or lipophylic radicals initiated oxidation. The combination of tocotrienols and astaxanthin had the greatest protective effect on α-tocopherol consumption in MLV, oxidized by the hydrophilic radical initiator. α-Tocopherol and tocotrienols protected astaxanthin against AAPH-, AMVN-, and SIN-1-induced oxidations. In the three oxidations α-tocotrienol was consumed first, followed by α-tocopherol and the tocotrienols in the sequence: β > γ > δ. Astaxanthin was consumed as fast as γ-tocotrienol in AAPH oxidation, as fast as α-tocopherol in AMVN oxidation, and before δ-tocotrienol in SIN-1 oxidation. In conclusion, α-tocopherol, tocotrienols, and astaxanthin cooperated in protecting against MLV lipid peroxidation. α-Tocotrienol was the most effective antioxidant among them. Astaxanthin was as effective as the chain-breaking antioxidants against lipid peroxidation.