494 resultados para Carotenoids


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The market for cosmeceuticals continues with significant annual growth, but today consumers are more aware of nutritional products that contribute to both skin health and disease prevention. In the last 10 years, pharmacists, chemists, nutritionists, and physicians have been working together to develop new nutritional applications to satisfy peoples needs and demands. As a recent result of convergence phenomenon between cosmetics and food industries, nutricosmetics is a blurry area unfamiliar to many consumers and sometimes even to foods and cosmetics experts. Characterized by oral supplementation of nutrients, nutricosmetics are also known as beauty pills,beauty from within, and even oral cosmetics. The major claim is the antiaging effect, reducing wrinkles by fighting free radicals generated by solar radiation. Among the ingredients used in nutricosmetics, antioxidants represent the most crucial. The best-known antioxidants are carotenoids (beta-carotene, lycopene, lutein, zeaxanthin, and astaxanthin) and polyphenols (anthocyanidins, catechins, flavonoids, tannins, and procyanidins). This study presents an overview about the concept of nutricosmetics and gives us information about the difference between nutricosmetics, nutraceuticals, and cosmeceuticals. The article also discusses about carotenoids and polyphenols, two classes of ingredients often employed in such products.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Watanabe et al. (1991 a,b) state that, vitamin E and carotenoids perform an essential role on the quality of egg spawning. Vitamin E is one of the main nutrients for the reproduction of fish (Izquierdo et al., 2001), and it has been proved that its inclusion in diets for broodstocks favors the quality of egg spawning in several species of fish (Watanabe and Takashima,1977; Takeuchi et al., 1981; Watanabe et al., 1985, 1991 a,b; Sutjaritvongsanon, 1987; Watanabe, 1990; Schimittou, 1993; Mushiake et al., 1993; Dube, 1996; Shiranee and Natarajan, 1996; Izquierdo et al., 2001; Morehead et al., 2001; Fernández- Palacios et al., 2005). On the other hand, the carotenoids which also perform an antioxidizing function (including the protection of lipids from oxidation), have been involved in the reproductive processes of marine organisms: crustaceans (Liñan-Cabello et al., 2002), marine fish (Watanabe y Kiron, 1995; Verakunpiriya et al., 1997 a,b; Vassallo-Agius et al., 2001 a,b,c, 2002; Watanabe and Vassallo-Agius 2003) and fresh water fish (Ahmadi et al., 2006). The results of this study suggest that the recommended levels of n-3 HUFA in diets for gilthead sea bream broodstocks could be increased up to 3,5 % when supplemented jointly with carotenoids from paprika oleoresin and vitamin E, thus favoring the quality of spawning.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. Egg yolks contain carotenoids that protect biological molecules against free-radical damage and promote maturation of the immune system. Availability of carotenoids to birds is often limited. Trade-offs can thus arise in the allocation of carotenoids to different physiological functions, and mothers may influence the immunocompetence of nestlings by modulating the transfer of carotenoid to the yolk.;2. In the great tit Parus major, we experimentally manipulated the dietary supply of carotenoid to mothers, and partially cross-fostered hatchlings to investigate the effect of an increased availability of carotenoids during egg laying on immunocompetence of nestlings.;3. In addition, we infested half of the nests with hen fleas Ceratophyllus gallinae to investigate the relationship between carotenoid availability, resistance to ectoparasites and immunocompetence.;4. We found that the procedure of cross-fostering can reduce the immune response of nestlings, but this effect can be compensated by the maternally transferred carotenoids. Cross-fostered nestlings of carotenoid-supplemented females show a similar immune response to non-cross-fostered nestlings, while cross-fostered nestlings of control females mounted a weaker cell-mediated immune response. This suggests that yolk carotenoids may help nestlings to cope with stress, for example the one generated by cross-fostering and/or they may enhance nestling competitiveness.;5. There was no statistically significant interaction between parasite and carotenoid treatments, as would be expected if carotenoids helped nestlings to fight parasites. Under parasite pressure, however, lighter nestlings raised a lower immune response, while the immune response was only weakly correlated with body mass in uninfested nests.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Theory suggests that carotenoid-based signals are used in animal communication because they contain specific information about parasite resistance or immunocompetence. This implies that honesty of carotenoid-based signals is maintained by a trade-off between pigmentation and immune function for carotenoids, assuming that the carotenoids used for coloration are also immunoenhancing. We tested this hypothesis by altering the diets of nestling great tits (Paris major) with supplementary beadlets containing the carotenoids that are naturally ingested with food or beadlets containing the carotenoids that are incorporated into the feathers; a control group received beadlets containing no carotenoids. We simultaneously immune challenged half of the nestlings of each supplementation group, using a two-factorial design. Activatior of the immune system led to reduced color expression. However, only nestlings fed with the naturally ingested carotenoids and not with the carotenoids deposited in the feathers showed an increased cellular immune response. This shows that the carotenoids used for ornamentation do not promote the immune function, which conflicts with the trade-off hypothesis. Our results indicate that honesty of carotenoid-based signals is maintained by an individual's physiological limitation to absorb and/or transport carotenoids and by access to carotenoids, indicating that preferences for carotenoid-based traits in sexual selection or parent-offspring interactions select for competitive individuals, rather than specifically for immune function.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A population-based case-comparison study of histologically confirmed lung cancer among white male and female residents of six Texas coastal counties was conducted from 1979-1982. Dietary information as well as information concerning smoking, alcohol consumption, occupational and residential exposures, and family history of cancer was obtained from 149 living cases and 359 comparison subjects.^ These data support the findings of previous studies that reported a protective association of total carotene intake with lung cancer (OR = 4.07, CI = 3.36-4.78), and no association for total Vitamin A or retinol. Of six specific carotenoids examined, these data reveal a statistically significant protective effect for alpha carotene (OR = 3.58, CI = 2.85-4.31), and an elevated, although non-significant effect for beta carotene (OR = 1.46, CI = 0.61-2.31). No consistent significant effect was found for cryptoxanthin, other xanthins, lutein or lycopene.^ Similar results were found for both males and females, and for both squamous cell and adenocarcinoma subtypes, although loss of power resulting from stratification may have rendered the celltype specific results more imprecise. These results should be considered with caution until confirmed by other studies, however, they suggest the importance of evaluating specific carotenoids in future diet-lung cancer investigations. ^

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background and Aims: Anthropogenic depletion of stratospheric ozone in Arctic latitudes has resulted in an increase of ultraviolet-B radiation (UV-B) reaching the biosphere. UV-B exposure is known to reduce aboveground biomass and plant height, to increase DNA damage and cause accumulation of UV-absorbing compounds in polar plants. However, many studies on Arctic mosses tended to be inconclusive. The importance of different water availability in influencing UV-B impacts on lower plants in the Arctic has been poorly explored and might partially explain the observed wide variation of responses, given the importance of water in controlling bryophyte physiology. This study aimed to assess the long-term responses of three common sub-Arctic bryophytes to enhanced UV-B radiation (+UV-B) and to elucidate the influence of water supply on those responses. Results: Responses were species specific: H. splendens responded most to +UV-B, with reduction in both annual growth (-22%) and sporophyte production (-44%), together with increased b-carotene, violaxanthin, total chlorophyll and NPQ, and decreased zeaxanthin and de-epoxidation of the xanthophyll cycle pool (DES). Barbilophozia lycopodioides responded less to +UV-B, showing increased b-carotene and sclerophylly and decreased UV-absorbing compounds. Polytrichum commune only showed small morphogenetic changes. No effect of UV-B on bryophyte cover was observed. Water availability had profound effects on bryophyte ecophysiology, and plants showed, in general, lower growth and ETR, together with a higher photoprotection in the drier site. Water availability also influenced bryophyte responses to +UV-B and, in particular, responses were less detectable in the drier site. Conclusions: Impacts of UV-B exposure on Arctic bryophytes were significant, in contrast to modest or absent UV-B effects measured in previous studies. The impacts were more easily detectable in species with high plasticity such as H. splendens and less obvious, or more subtle, under drier conditions. Species biology and water supply greatly influences the impact of UV-B on at least some Arctic bryophytes and could contribute to the wide variation of responses observed previously.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Carotenoids are important biomolecules that are ubiquitous in nature and find widespread application in medicine. In photosynthesis, they have a large role in light harvesting (LH) and photoprotection. They exert their LH function by donating their excited singlet state to nearby (bacterio)chlorophyll molecules. In photosynthetic bacteria, the efficiency of this energy transfer process can be as low as 30%. Here, we present evidence that an unusual pathway of excited state relaxation in carotenoids underlies this poor LH function, by which carotenoid triplet states are generated directly from carotenoid singlet states. This pathway, operative on a femtosecond and picosecond timescale, involves an intermediate state, which we identify as a new, hitherto uncharacterized carotenoid singlet excited state. In LH complex-bound carotenoids, this state is the precursor on the reaction pathway to the triplet state, whereas in extracted carotenoids in solution, this state returns to the singlet ground state without forming any triplets. We discuss the possible identity of this excited state and argue that fission of the singlet state into a pair of triplet states on individual carotenoid molecules constitutes the mechanism by which the triplets are generated. This is, to our knowledge, the first ever direct observation of a singlet-to-triplet conversion process on an ultrafast timescale in a photosynthetic antenna.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Carotenoids in the photosynthetic membranes of plants typically contain two β-rings (e.g., β-carotene and zeaxanthin) or one ɛ- and one β-ring (e.g., lutein). Carotenoids with two ɛ-rings are uncommon. We reported earlier that the Arabidopsis thaliana lycopene ɛ-cyclase (LCYe) adds one ɛ-ring to the symmetrical linear substrate lycopene, whereas the structurally related lycopene β-cyclase (LCYb) adds two β-rings. Here we describe a cDNA encoding LCYe in romaine lettuce (Lactuca sativa var. romaine), one of the few plant species known to accumulate substantial quantities of a carotenoid with two ɛ-rings: lactucaxanthin. The product of the lettuce cDNA, similar in sequence to the Arabidopsis LCYe (77% amino acid identity), efficiently converted lycopene into the bicyclic ɛ-carotene in a heterologous Escherichia coli system. Regions of the lettuce and Arabidopsis ɛ-cyclases involved in the determination of ring number were mapped by analysis of chimeric ɛ-cyclases constructed by using an inverse PCR approach. A single amino acid was found to act as a molecular switch: lettuce LCYe mutant H457L added only one ɛ-ring to lycopene, whereas the complementary Arabidopsis LCYe mutant, L448H, added two ɛ-rings. An R residue in this position also yields a bi-ɛ-cyclase for both the lettuce and Arabidopsis enzymes. Construction and analysis of chimera of related enzymes with differing catalytic activities provide an informative approach that may be of particular utility for studying membrane-associated enzymes that cannot easily be crystallized or modeled to existing crystal structures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The production of pigments by halophilic archaea has been analysed during the last half a century. The main reasons that sustains this research are: (i) many haloarchaeal species possess high carotenoids production availability; (ii) downstream processes related to carotenoid isolation from haloarchaea is relatively quick, easy and cheap; (iii) carotenoids production by haloarchaea can be improved by genetic modification or even by modifying several cultivation aspects such as nutrition, growth pH, temperature, etc.; (iv) carotenoids are needed to support plant and animal life and human well-being; and (v) carotenoids are compounds highly demanded by pharmaceutical, cosmetic and food markets. Several studies about carotenoid production by haloarchaea have been reported so far, most of them focused on pigments isolation or carotenoids production under different culture conditions. However, the understanding of carotenoid metabolism, regulation, and roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. The uses of those haloarchaeal pigments have also been poorly explored. This work summarises what has been described so far about carotenoids production by haloarchaea and their potential uses in biotechnology and biomedicine. In particular, new scientific evidence of improved carotenoid production by one of the better known haloarchaeon (Haloferax mediterranei) is also discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Literature cited: p. 23-33.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Few Micronesian foods have been analyzed for nutrient content. Information is needed on locally grown, culturally acceptable foods that could be promoted to alleviate, vitamin A deficiency in the Federated States of Micronesia. Using an ethnographic approach that included key informant interviews and observation, Micronesian cultivars with potential for high-carotenoid content according to their coloration were identified. These cultivars of banana, giant swamp taro, breadfruit and other foods were analyzed for alpha- and beta-carotene using high-performance liquid chromatography (HPLC) and for nine minerals using inductively coupled plasma (ICP). A wide range of provitamin A carotenoid levels was found in banana, taro, and breadfruit cultivars, some containing very high levels (beta-carotene content from 515 to 6360 mug/100 g in banana, 260 to 1651 mug/100 g in taro, and 295 to 868 mug/100 g in breadfruit, edible portion). Other cultivars contained moderate levels, but as they can be eaten in large quantities, they may contribute significantly to vitamin A status. The taro samples contained very high levels of zinc (mean 5.9 mg/100 g) and significant levels of other minerals (mean content of calcium was 120 mg/100 g). These staples with cultural acceptability and high availability potentially could play a role in vitamin A, micronutrient, and chronic disease programs in the Pacific. (C) 2003 Elsevier Science Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Commonly recommended plant sources of provitamin A, such as dark green leafy vegetables, are not acceptable in many population groups. The objective of this study was to identify other indigenous foods that may be effectively promoted to alleviate vitamin A deficiency (VAD) and to gather information relevant to identification, production, acquisition, and consumption of foods relevant to a food-based VAD prevention strategy in the Federated States of Micronesia. An ethnographic study on edible pandanus cultivars, involving key informant interviews and observation was carried out. Analyses revealed a great range in carotenoid content. Several orange-coloured pandanus cultivars, all highly acceptable, contained high levels of carotenoid, almost meeting daily requirements in usual consumption patterns, whereas light yellow-coloured cultivars contained low levels. Availability has decreased substantially in recent years due to increased consumption of imported foods and general neglect of indigenous foods. High-carotenoid pandanus should be promoted for general enjoyment and health benefits.