THE SCAVENGING CAPACITY OF COMBINATIONS OF LYCOPENE, β-CAROTENE, VITAMIN E, AND VITAMIN C ON THE FREE RADICAL 2,2-DIPHENYL-1-PICRYLHYDRAZYL (DPPH)

Apolar Radical Initiated Conjugated Autoxidizable Triene (ApoCAT) Assay: Effects of Oxidant Locations on Antioxidant Capacities and Interactions

Development of an antioxidant assay explaining antioxidant behaviors in complex food systems has been a challenging topic for food scientists. This research aimed to investigate antioxidant capacities and interactions of selected synthetic antioxidants and commercial natural antioxidant extracts using the CAT assay and a newly developed ApoCAT assay, which used water- and lipid-soluble azo radical initiators, respectively. Results suggested that the higher the hydrophobicity of an antioxidant, the higher the antioxidant capacity of an antioxidant observed in the ApoCAT assay. The relationship between the two different assays was explained by the ratio between the ApoCAT and the CAT values. Interestingly, all lipophilic derivatives of the antioxidants exhibited higher ApoCAT/CAT ratios than their hydrophilic derivatives. In the case of the commercial food-grade antioxidants, green tea extract and mixed tocopherols showed a higher antioxidant capacity in the ApoCAT assay than in the CAT assay, while grape seed and rosemary extracts did not show significantly different changes in behaviors in both assays. The study on antioxidant interactions revealed that additive, synergistic, and antagonistic effects between hydrophilic antioxidants and natural extracts, and mixed tocopherols could be observed in both the CAT and the ApoCAT assays, depending on the combined ratios. In most cases, at a particular ratio, the synergistic effect reached the maximum level before suddenly dropping to additive and antagonistic effects in both assays.

Interactions between α-tocopherol and rosmarinic acid and its alkyl esters in emulsions: synergistic, additive, or antagonistic effect?

Many antioxidants can interact to produce synergistic interactions that can more effectively inhibit lipid oxidation in foods. Esterification of rosmarinic acid produces a variety of compounds with different antioxidant activity due to differences in polarity and thus differences in partitioning in oil, water, and interfacial regions of oil-in-water emulsions (O/W). Therefore, rosmarinic acid and rosmarinate esters provide an interesting tool to study the ability of antioxidant to interact in O/W emulsions. In O/W emulsions, rosmarinic acid (R0) exhibited the strongest synergistic interaction with α-tocopherol while butyl (R4) and dodecyl (R12) rosmarinate esters exhibited small synergistic interaction and eicosyl rosmarinate esters (R20) exhibited slightly antagonistic interaction. Fluorescence quenching and electron paramagnetic resonance (EPR) studies showed that water-soluble rosmarinic acid (R0) exhibited more interactions with α-tocopherol than any of the tested esters (R4, R12, R20). This was also confirmed in O/W emulsions where R0 altered the formation of α-tocopherol quinone and α-tocopherol increased the formation of caffeic acid from R0. This formation of caffeic acid was proposed to be responsible for the synergistic activity of R0 and α-tocopherol since the formation of an additional antioxidant could further increase the oxidative stability of the emulsion.

Alzheimer's disease: biological aspects, therapeutic perspectives and diagnostic tools

Alzheimer's disease (AD) is the most common form of dementia among older people. Dementia is an irreversible brain disorder that seriously affects a person's ability to carry out daily activities. It is characterized by loss of cognitive functioning and behavioral abilities, to such an extent that it interferes with the daily life and activities of the affected patients. Although it is still unknown how the disease process begins, it seems that brain damage starts a decade or more before problems become evident. Scientific data seem to indicate that changes in the generation or the degradation of the amyloid-b peptide (Aβ) lead to the formation of aggregated structures that are the triggering molecular events in the pathogenic cascade of AD. This review summarizes some characteristic features of Aβ misfolding and aggregation and how cell damage and death mechanisms are induced by these supramolecular and toxic structures. Further, some interventions for the early diagnosis of AD are described and in the last part the potential therapeutic strategies adoptable to slow down, or better block, the progression of the pathology are reported.

The role of polyphenolic antioxidants in health, disease, and aging

Polyphenolic antioxidants from dietary sources are frequently a topic of interest due to widespread scientific agreement that they may help lower the incidence of certain cancers, cardiovascular and neurodegenerative diseases, and DNA damage and even may have antiaging properties. On the other hand, questions still remain as to whether some antioxidants could be potentially harmful to health, because an increase in glycation-mediated protein damage (carbonyl stress) has been reported in some cases. Nevertheless, the quest for healthy aging has led to the extensive use of phytochemically derived antioxidants to disrupt age-associated deterioration in physiological function and to prevent many age-related diseases. Although a diet rich in the polyphenolic forms of antioxidants does seem to offer hope in delaying the onset of age-related disorders, it is still too early to define their exact clinical benefit for treating age-related disease. This review critically examines polyphenolic antioxidants, such as flavonoids, curcumene, and resveratrol in health, disease, and aging with the hope that a better understanding of the many mechanisms involved with these diverse compounds may lead to better health and novel treatment approaches for age-related diseases.