Tocotrienols are one of two major subgroups of the vitamin E family (the other being the tocopherols). Each subgroup contains four structurally and chemically diverse molecules: alpha beta gamma and delta. While both subgroups possess powerful antioxidant properties tocotrienols are more flexible due to their structure and they provide benefits other than protection from oxidation. In addition delta- and gamma-tocotrienols were shown to be most potent for various applications since their smaller size allows easier access to cell membranes to attack free radicals.
Tocotrienols particularly the gamma isomer have been shown to possess cytotoxic effects associated with the induction of apoptosis in various cancers. Individual tocotrienol isomers are believed to bring about diverse apoptotic mechanisms in different types of cancer. In a new study in BMC Complementary and Alternative Medicine researchers compared the cytotoxic potency of alpha- gamma- and delta-tocotrienols and explored their apoptotic mechanisms in human lung adenocarcinoma A549 and glioblastoma U87MG cells.
The study demonstrated that all tocotrienols inhibited the growth of A549 and U87MG cancer cells. The tocotrienols induced only double strand DNA breaks (DSBs) and no single strand DNA breaks (SSBs) in both types of treated cancer cells. In addition it was shown that delta-tocotrienol possessed a higher efficacy and effectiveness of apoptosis in both A549 and U87MG cancer cells as compared to alpha- and gamma-tocotrienols. Thus tocotrienols notably the delta isomer can be an alternative chemotherapeutic agent in the fight against lung and brain cancers.
Tocotrienols role in cancer has been demonstrated through various mechanisms such as enhanced apoptosis reduced angiogenesis inhibition of proliferation enhanced immune function reduced risk of initial cancer occurrence and reduced inflammation.
Source: Lim SW Loh HS Ting KN Bradshaw TD Zeenathul NA. Cytotoxicity and apoptotic activities of alpha- gamma- and delta-tocotrienol isomers on human cancer cells. BMC Complement Altern Med. 2014 Dec 6;14(1):469