Carotenoids beneficial effects

The known beneficial effects of retinoids on malignancies are assumed to relate to retinoid receptor-mediated antipromoting and anti-initiating effects. The latter appeals to be influenced by interference of several xenobiotics with different steps of the retinoid metabolism in the target cell. Of the carotenoids, (3-carotene is the most potent retinol precursor, yet being... 

Similarly to carotenoids, flavonoids also show considerable biological activity. Their beneficial effect in cancer and heart diseases has been proven many times [86-89], It has further been established that flavonoids improve cardiovascular remodelling and vascular function in NO-deficient hypertension [90], Moreover, flavonoid intake reduces the risk of chronic diseases [91], and beneficially influences inflammations [92], and ulcer formation [93,94],... 

Carotenoids have beneficial effects in cancer chemoprevention (Astrog, 1997). Fucoxanthin, one of the the major carotenoids in brown algae, is known to exhibit antitumor activity against human neuroblastoma GOTO cells (Okuzumi et al., 1990). Inhibitory effects on mouse duodenum and on skin carcinogenesis have also been reported (Okuzumi et al., 1993 Satomi et al., 1996). 

Coenzyme QIO is a powerful antioxidant naturally occurring in the mitochondria of myocardium, and it is an electron carrier in the mitochondrial synthesis of ATP. Patients with heart failure have lower myocardial levels of coenzyme QIO, but supplementation has been demonstrated to have variable benefits in randomized controlled trials. One meta-analysis on the use in congestive heart failure showed improvements in stroke volume, ejection fraction, cardiac output, cardiac index, and end diastolic volume index. " Another antioxidant associated with beneficial effects in cardiac patients is lycopene, a natural constituent of tomatoes. Lycopene is the major carotenoid found in human serum, and epidemiological studies have indicated an effect of dietary supplementation in reducing heart disease. Few dietary interventions have been reported one study showed a mild but significant hypocholesterolemic effect, and another showed a significant reduction in LDL oxidation. " Animal studies show an antiatherogenic effect of DHEA, and a review of the clinical trials and studies on DHEA in males with coronary heart disease reported a favorable or neutral effect. Plasma levels of DHEA are decreased in patients with chronic heart failure in proportion to its severity. ... 

Niunerous chnical studies testing for the beneficial effects of carotenoids have been performed. A detailed description of these is beyond the scope of this chapter. However, the results of these studies performed with various carotenoid supplements are remarkably different. Results includes beneficial effects, no effects, and even adverse effects leading to trial interruption. Therefore, no conclusive evidence for the antioxidative or overall beneficial effects of carotenoids in certain situations can be given today. 

The ability of lycopene to act as an antioxidant and scavenger of free radicals is frequently cited as the most likely mechanism that could account for the hypothesized beneficial effects on human health.Supporting this theory, protection against oxidative stress has been shown in parallel with a preferential destraction of lycopene relative to P-carotene in a study of human skin irradiated with ultraviolet (UV) light. Further, the ability of carotenoids to act as antioxidants has been hypothesized as the mechanism underlying the protection of the human retina from photooxidation, a process that over time can result in the pathologies of age-related macular degeneration (AMD) and cataracts. ... 

Brown sea algae contain the characteristic carotenoid fucoxanthin. Dietary fucoxanthin has been shown to exhibit various beneficial effects. Das et ah (2010) reported that fucoxanthin from edible brown algae significantly suppressed the differentiation of RAW 264.7 cells at 2.5 pM, without any cytotoxic effects. They concluded that fucoxanthin is helpful for the prevention of diseases associated with abnormal bone metabolism, as fucoxanthin induced apoptotic cell death in osteoclast-like cells at a concentration that was nontoxic to osteoblast-like cells. Using the same bioassay system, om research group found ttrat the methanol extract of Sargassum fusiforme (SME) suppressed osteoclast differentiation and accelerated osteoblast differentiation. Osteoclast differentiation was estimated by TRAP-(-l-) multinucleated cell formation in osteoblastic cell/ bone marrow cell coculture. Osteoclast formation was induced by the presence of l,25(OH)2D3 in the coculture. As shown in Fig. 34.3, SME... 

Chemical synthesis has a major part to play in the sophisticated interdisciplinary studies that are now needed to study the biological functions and actions of carotenoids, and the interactions of carotenoids with other molecules such as proteins. Essential roles in photosynthesis have been discovered for several different carotenoids, including specific geometrical isomers. Synthesis is able to provide the pure and, when appropriate, isotopically labelled carotenoids that are required for reconstitution studies, investigation of photochemistry, etc. In the field of medicine it is now clear that the provitamin A activity of p,p-carotene (3) may not be the only beneficial effect of carotenoids. Several carotenoids found in the human diet, especially lycopene (31), lutein (133) and zeaxanthin (119), could also be important in giving protection against serious disorders such as cancer, heart disease, and degenerative eye diseases. Characterization of these effects and elucidation of the mechanisms involved require substantial quantities (g to kg) of pure carotenoids these materials can only be produced by chemical synthesis. 

Ribeiro and Schieber (2010) published a review about the bioactive compounds of mango. The authors explored this fruit as an important source of health-promoting bioactive compounds, including ascorbic and dehydroascorbic acids, carotenoids, phenolics compoimds, fiber, terpenoids, among others. They also describe a number of studies on the biological properties of compounds found in all parts of the mango plant, suggesting their beneficial effects on human health, particularly as antioxidants. 

Although food manufacturers have the freedom to innovate, they must also avoid marketing products with questionable effects. One common problem is that the biologically active ingredients in functional foods are often present in insufficient doses to give the desired beneficial effects. The raw materials are often costly, and this means that only small amounts are generally used in functional foods (Ernst, 2001). Food manufacturers must clearly demonstrate that new carotenoid-rich food products are safe for their intended use - and also that any health claims are substantiated by well-documented scientific evidence. 

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