Effects of new combinative antioxidant FeAOX-6 and alpha-tocotrienol on macrophage atherogenesis-related functions.

Pivotal role in atherogenesis is played by macrophages, which are early site for lipid accumulation and mediate the inflammatory and immune response in the intima. Epidemiological evidence indicates that natural antioxidants reduce the risk of heart disease, but, so far, supplementation studies have failed to confirm any protective effects of these compounds against cardiovascular disease. This study evaluated the effects of the natural antioxidant alpha-tocotrienol and of the newly designed compound, FeAOX-6, which combines antioxidant structural features of both tocopherols and carotenoids into a single molecule, on macrophage functions involved in foam cell formation. FeAOX-6 or alpha-tocotrienol induce a strong dose-dependent reduction of cholesterol and reduce cholesterol accumulation in human macrophages. The extent of the reduction found with alpha-tocotrienol was greater than that induced by FeAOX-6 and did not correlate with their respective antioxidant capacities. Treatment of HMDM with alpha-tocotrienol or FeAOX-6 enhanced also tumor necrosis factor-alpha secretion. These results are consistent with a reduction in scavenger receptor activity, but we found that antioxidant treatment did not affect cholesterol uptake from modified LDL. The effects on release on pro-inflammatory prostanoid precursors, PGE(2) and cytokine suggest a variety of metabolic responses that are both dependent on antioxidant compounds and macrophages activation status.

Comparative antioxidant activity of tocotrienols and the novel chromanyl-polyisoprenyl molecule FeAox-6 in isolated membranes and intact cells.

Oxidative stress plays a pivotal role in the pathogenesis of several chronic diseases and antioxidants may represent potential tools for the prevention of these diseases. Here, we investigated the antioxidant efficiency of different tocotrienol isoforms (alpha-, delta-, gamma-tocotrienols), and that of FeAox-6, a novel synthetic compound which combines, by a stable covalent bond, the chroman head of vitamin E and a polyisoprenyl sequence of four conjugated double bonds into a single molecule. The antioxidant efficiency was evaluated as the ability of the compounds to inhibit lipid peroxidation, reactive oxygen species (ROS) production, heat shock protein (hsp) expression in rat liver microsomal membranes as well as in RAT-1 immortalized fibroblasts challenged with different free radical sources, including 2,2'-azobis(2-amidinopropane) (AAPH), tert-butyl hydroperoxide (tert-BOOH) and H2O2. Our results show that individual tocotrienols display different antioxidant potencies. Irrespective of the prooxidant used, the order of effectiveness was:delta-tocotrienol > gamma-tocotrienol = alpha-tocotrienol in both isolated membranes and intact cells. This is presumably due to the decreased methylation of delta-tocotrienol chromane ring, which allows the molecule to be more easily incorporated into cell membranes. Moreover, we found that FeAox-6 showed an antioxidant potency greater than that of delta-tocotrienol. Such an efficiency seems to depend on the concomitant presence of a chromane ring and a phytyl chain in the molecule, which because of four conjugated double bonds, may induce a greater mobility and a more uniform distribution within cell membrane. In view of these results, FeAox-6 represents a new potential preventive agent in chronic diseases in which oxidative stress plays a pathogenic role.

In vitro neuroprotection by novel antioxidants in guinea-pig urinary bladder subjected to anoxia-glucopenia/reperfusion damage.

In a previous study, the neuroprotection provided by some hindered phenols of synthetic nature and alpha-tocopherol in guinea-pig detrusor strips subjected to ischaemia/reperfusion-like conditions was shown to be related directly to the antioxidant activity. The aim of the present study was to estimate the capability of three novel chimeric molecules derived by assembling known antioxidant moieties, namely FeAOX-6, comprising a chromanyl head and the polyisoprenyl sequence characteristic for lycopene, FeCD-52, derived from the conjugation of ascorbic acid and a polyphenol moiety (FeRS-4) and FeDG-17, derived from the combination of ascorbic acid and a chromanyl head, to confer neuroprotection in an in vitro model of guinea-pig whole urinary bladder subjected to anoxia-glucopenia/reperfusion injury. The antioxidant potential of these compounds was determined by oxygen radical absorbance capacity (ORAC) and phochemiluminescence (PCL) assays to test their peroxyl and anion superoxide (O2(*-)) radical trapping activity, respectively. FeAOX-6, FeCD-52 and FeDG-17 exerted both strong neuroprotective and antioxidant activity, significantly higher than those exerted by the individual component moieties. The antioxidant activity of FeCD-52 was 37-fold higher than that of the reference compound trolox. FeAOX-6 exerted remarkable neuroprotective activity, superior to that of FeCD-52 or FeDG-17, in spite of its lower antioxidant activity. These findings indicate that assembling antioxidant moieties yields neuroprotective agents, the effectiveness of which, however, is not related to the antioxidant activity. It is possible that a different partitioning in cell compartments critically involved in the oxidative damage pathway plays a role in neuroprotection exerted by these compounds.

Design, synthesis, and antioxidant activity of FeAOX-6, a novel agent deriving from a molecular combination of the chromanyl and polyisoprenyl moieties.

Several lines of evidence suggest potential benefits by a combination of carotenoids and tocopherols in chronic diseases. Therefore, we have designed FeAOX-6, a novel antioxidant that combines into a single molecule the chroman head of tocopherols and a fragment of lycopene, consisting of a polyisoprenyl sequence of four conjugated double bonds. The ability of FeAOX-6 in inhibiting lipid peroxidation and reactive oxygen species (ROS) production induced by different sources of free radicals (t-BOOH, AAPH, and H2O2) in arachidonic acid solution and in isolated thymocytes was investigated. Its antioxidant efficiency was also compared with that of alpha-tocopherol, lycopene, and a mixture of the two antioxidants. The results strongly suggest that FeAOX-6 can act as a potent antioxidant in our models, by inhibiting malondialdehyde production and ROS generation in a dose- and a time-dependent manner. In the cell model, the compound also provides a higher antioxidant capacity than alpha-tocopherol and lycopene, alone or in combination, suggesting the possibility of an oxidative intramolecular cooperation.