RESUMO
The ultimate health benefits of peanuts and tree nuts partially depend on the effective gastrointestinal delivery of their phytochemicals. The chemical composition and in vitro bioaccessibility of tocopherols, tocotrienols and phenolic compounds from peanuts and seven tree nuts were evaluated by analytical and chemometric methods. Total fat and dietary fiber (g 100 g-1) ranged from 34.2 (Emory oak acorn) to 72.5 (pink pine nut; PPN) and from 1.2 (PPN) to 22.5 (pistachio). Samples were rich in oleic and linoleic acids (56-87 g 100 g-1 oil). Tocopherols and tocotrienols (mg·kg-1) ranged from 48.1 (peanut) to 156.3 (almond) and 0 (almond, pecan) to 22.1 (PPN) and hydrophilic phenolics from 533 (PPN) to 12,896 (Emory oak acorn); flavonoids and condensed tannins (mg CE.100 g-1) ranged from 142 (white pine nut) to 1833 (Emory oak acorn) and 14 (PPN) to 460 (Emory oak acorn). Three principal components explained 90% of the variance associated with the diversity of antioxidant phytochemicals in samples. In vitro bioaccessibility of tocopherols, tocotrienols, hydrophilic phenolics, flavonoids, and condensed tannins ranged from 11-51%, 16-79%, 25-55%, 0-100%, and 0-94%, respectively. Multiple regression analyses revealed a potential influence of dietary fiber, fats and/or unsaturated fatty acids on phytochemical bioaccessibility, in a structure-specific manner.
Assuntos
Antioxidantes/farmacocinética , Nozes/química , Compostos Fitoquímicos/farmacocinética , Disponibilidade Biológica , Flavonoides/farmacocinética , Humanos , Hidroxibenzoatos/farmacocinética , Análise de Componente Principal , Proantocianidinas/farmacocinética , Análise de Regressão , Tocoferóis/farmacocinética , Tocotrienóis/farmacocinéticaRESUMO
There has been much recent interest from both applied and basic scientists in the broad series of benefits that animals reap from acquiring high concentrations of dietary antioxidants, such as carotenoids and vitamins (e.g., vitamin E, or tocopherol). Most attention has been paid to separate effects of these compounds on, for example, coloration, health state, development, and vision, but because of possible interactions between these lipid-soluble molecules, we are in need of more studies that co-manipulate these substances and examine their possible synergistic impacts on animal physiology and phenotype. We capitalized on a model avian system (the house finch, Haemorhous mexicanus), where extensive information is available on the fitness roles of carotenoids, to test how variation in carotenoid and/or vitamin E concentrations in the diet impacts body accumulation of these compounds, factors related to oxidative damage (e.g., breast muscle and plasma oxidative-stress susceptibility, plasma nitric-oxide levels), and plumage color development. As in a previous study of ours on carotenoids and health in finches, we employed a 2×2 factorial experimental design on birds in both molting and non-molting conditions, to understand how seasonal shifts in carotenoid use (i.e., pigment incorporation into plumage) might alter the accumulation and roles of carotenoids and vitamins. As expected, lutein supplementation increased the level of circulating carotenoids in both experiments and the color of newly molted plumage. By contrast, vitamin E provisioning did not significantly affect plasma carotenoid levels or plumage coloration in either experiment. Interestingly, carotenoid provisioning decreased circulating vitamin E levels during molt, which suggests either molecular competition between carotenoids and tocopherol at the absorption/transport stages or that vitamin E serves as an antioxidant to offset harmful actions that carotenoids may have at very high concentrations. Finally, in both experiments, we found a reduction in breast-muscle oxidative damage for tocopherol-supplemented birds, which constitutes the first demonstration of a protective effect of vitamin E against oxidative stress in wild birds. Taken together, these findings provide an interesting contrast with our earlier work on season-specific physiological benefits of carotenoids in finches and point to complex associations between indicators of antioxidant and oxidative state in wild-caught animals.