Carotenoids, phenolic

As mentioned earlier, physiological concentrations of carotenoids in vivo are in the micromolar range, mainly because of limited bioavailabiUty. Also, the antioxidant efficiencies of carotenoids after absorption are probably limited. Concentrations before absorption are much higher and can justify possible antioxidant actions in vivo. To test this hypothesis, Vulcain et al. developed an in vitro system of lipid peroxidation in which the oxidative stress is of dietary origin (metmyoglobin from meat) and different types of antioxidants (carotenoids, phenols) are tested. 

Carmen Socaciu was bom in Cluj-Napoca, Romania and earned a BSc in chemistry in 1976, an MSc in 1977, and a PhD in 1986 from the University Babes-Bolyai in Cluj-Napoca, an important academic centre located in the Transylvania region. Dr. Socaciu worked as a researcher in medical and cellular biochemistry for more than 10 years, and became a lecturer in 1990 and full professor in 1998 in the Department of Chemistry and Biochemistry of the University of Agricultural Sciences and Veterinary Medicine (USAMV) in Cluj-Napoca. She extended her academic background in pure chemistry (synthesis and instrumental analysis) to the life sciences (agrifood chemistry and cellular biochemistry). Her fields of competence are directed especially toward natural bioactive phytochemicals (carotenoids, phenolics, flavonoids), looking to advanced methods of extraction and analysis and to their in vitro actions on cellular metabolism, their effects as functional food ingredients, and their impacts on health. 

Antioxidants from Cereais, Oiiseeds, and Rotated Sources Seeds rich in oils are also abundant sources of various types of antioxidative compounds. Among these carotenoids, phenolic acids, and their derivatives, flavonoids, phytic acid, lignans, and tocopherols are predominantly found depending on the plant genera and species. Reviews by Wanasundara et al. (110) and Shukla et al. (111) discuss antioxidants of oilseeds and their products in detail. 

Toxicological risks may develop when the daily doses of a compound rise above a certain threshhold limit therefore, toxicity is a matter of dose as well. Natural antioxidants, especially carotenoids, phenolic acids, flavonoids, and sterols, may also exert in vivo pro-oxidative activity. Rietjens et al. (166) have provided an elaborate discussion on the pro-oxidative chemistry and toxicity of well-known natural antioxidants, including ascorbic acid, tocopherols, carotenoids, and flavonoids. 

Certain bacteria are able to rearrange the normal carbon skeleton to give aromatic carotenoids. Phenolic examples were isolated from Streptomyces mediolani. As well as the hydrocarbon isorenieratene (43), 3-hydroxy- (44), and 3,3 -dihydroxy-isorenieratene (45) were present and their structures confirmed by synthesis. In Thiothece gelatinosa the major carotenoid was okenone... 

Researchers interested in the properties and occurrence of natural antioxidants concentrate on vitamins E and C, carotenoids, phenolic acids, flavonoids, sesame lignins, phytosterols, extracts from the leaves of the plants belonging to the Lami-aceae family, oryzanols, tea leaf extracts, phosphatides, olive oil phenols, squalene, and propolis. Barrera-AreUano et al. (1999), Boskou (1999), Blekas and Boskou... 

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. 

Zeaxanthin (135) was synthesized from the salt (133) and the dialdehyde (134) in 1,2-epoxybutane, a reagent superior to ethylene oxide particularly for polyenedialdehydes. The same salt was also used to prepare /3-cryptoxanthin and zeinoxanthin. Phenolic carotenoids from Strep-tomyces mediolani and 1,2-dihydro- and l,2,r,2 -tetrahydro-lycopene have also been obtained by conventional olefin synthesis. 

Results obtained in in vivo and ex vivo experiments are of various types. Some studies have found positive effects of the consumption of carotenoids or foods containing carotenoids on the markers of in vivo oxidative stress, even in smokers. Other studies demonstrated no effects of carotenoid ingestion on oxidative stress biomarkers of lipid peroxidation. " It should be noted that for studies using food, the activity observed may also be partly due to other antioxidant molecules in the food (phenols, antioxidant vitamins) or to the combination of actions of all the antioxidants in the food. 

Long, M. et al.. Metabolite profiling of carotenoid and phenolic pathways in mntant and transgenic lines of tomato identification of a high antioxidant fmit line. Phytochemistry, 67, 1750, 2006. 

Phytochemicals present in fruits and vegetables are very diverse, such as ascorbic acid, carotenoids, and phenolic compounds (Liu 2004 Percival and others 2006 Syngletary and others 2005 Yahia and others 2001a, 2001b). Plant polyphenols are ubiquitous in the diet, with rich sources being tea, wine, fruits, and vegetables they demonstrate considerable antioxidative activity in vitro, which can have important implications for health (Duthie and others 2000). 

Fresh peppers are excellent sources of vitamins A and C, as well as neutral and acidic phenolic compounds (Howard and others 2000). Levels of these can vary by genotype and maturity and are influenced by growing conditions and processing (Mejia and others 1988 Howard and others 1994 Lee and others 1995 Daood and others 1996 Simmone and others 1997 Osuna-Garcia and others 1998 Markus and others 1999 Howard and others 2000). Peppers have been reported to be rich in the provitamin A carotenoids (3-carotene, a-carotene, and (3-cryptoxanthin (Minguez-Mosquera and Hornero-Mendez 1994 Markus and others 1999), as well as xanthophylls (Davies and others 1970 Markus and others 1999). Bell peppers have been shown to exert low antioxidant activity (Al-Saikhan and others 1995 Cao and others 1996 Vinson and others 1998) or may even act as pro-oxidants (Gazzani and others 1998). 

Liu RH, Liu J and Chen B. 2005. Apples prevent mammary tumors in rats. J Agric Food Chem 53 2341-2343. Long M, Millar DJ, Kimura Y, Donovan G, Rees J, Fraser PD, Bramley PM and Bolwell GP. 2006. Metabolite profiling of carotenoid and phenolic pathways in mutant and transgenic lines of tomato identification of a high antioxidant fruit line. Phytochemistry 67 1750-1757. 

Rivera-PastarnaD, YahiaEM and Gonzalez-Aguilar G. 2009. Identification and quantification of carotenoids and phenolic compounds in papaya using mass spectroscopy. In preparation. 

Finally, it should also be considered that flavonoid-rich foods contain a great diversity of compounds with bioactive properties (for e.g., carotenoids, other phenolics, fiber, and minerals), and multiple interactions occur among all of them. There is also great diversity in the ingestion, absorption, and metabolism of these compounds in different populations, and all of these circumstances could camouflage any effect of flavonoids on disease prevention or treatment. 

Carrillo-Lopez A and Yahia EM. 2009. Qualitative and quantitative changes in carotenoids and phenolic compounds in tomato fruit during ripening. In preparation. 

Lima VLAG, Melo EA, Maciel MIS, Prazeres FG, Musser RS and Lima DES. 2005. Total phenolic and carotenoid contents in acerola genotypes harvested at three ripening stages. Food Chem 90 565-568. 

Odriozola-Serrano I, Soliva-Fortuny R, Hernandez-Jover T and Martfn-Belloso O. 2009. Carotenoid and phenolic profile of tomato juices processed by high intensity pulsed electric fields compared with conventional thermal treatments. Food Chem 112 258-266. 

This chapter reviews recent findings about the health benefits of phytochemicals present in fruits, vegetables, nuts, seeds, and herbs, including phenolics, carotenoids, sterols, and alkaloids. These phytochemicals are extracted using emerging technologies such as supercritical carbon dioxide (SC-CO2) extraction, PEF, MWE, HPP, UE, and OH. The impact of important parameters related to sample preparation (particle size and moisture content) and extraction process (temperature, pressure, solvent flow rate, extraction time, and the use of a cosolvent) on the efficiency of extraction and on the characteristics of the extracted products is evaluated based on an extensive review of recent literature. The future of extraction of phytochemicals is certainly bright with the... 

A large variety of phytochemicals are found within agricultural commodities. This chapter focuses on four main groups phenolics, carotenoids, sterols, and alkaloids. In addition, recent research related to the health benefits of these phytochemicals will be briefly reviewed. Table 9.1 summarizes the main chemical structure and solubility in organic solvents of phytochemicals such as phenolics (flavonoids), carotenoids, sterols, and alkaloids. 

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