Bioactivity of carotenoids

Bioactivities of Carotenoids other than Direct Antioxidants.335... 

BIOACTIVITIES OF CAROTENOIDS OTHER THAN DIRECT ANTIOXIDANTS... 

As this paper is prepared for a special volume on bioactive natural products, a brief overview on bioactivity of carotenoids is included, divided into known functions of carotenoids and to their actions on biological systems. Charged carotenoid species are involved in the function of carotenoids in photosynthesis and may turn out to be relevant unstable intermediates in other biological contexts, including antioxidant action. 

In plant plastids, GGPP is formed from products of glycolysis and is eight enzymatic steps away from central glucose metabolism. The MEP pathway (reviewed in recent literature - ) operates in plastids in plants and is a preferred source (non-mevalonate) of phosphate-activated prenyl units (IPPs) for plastid iso-prenoid accumulation, such as the phytol tail of chlorophyll, the backbones of carotenoids, and the cores of monoterpenes such as menthol, hnalool, and iridoids, diterpenes such as taxadiene, and the side chains of bioactive prenylated terpenophe-nolics such as humulone, lupulone, and xanthohumol. The mevalonic pathway to IPP that operates in the cytoplasm is the source of the carbon chains in isoprenes such as the polyisoprene, rubber, and the sesquiterpenes such as caryophyllene. 

Algae can be cultivated easily and quickly when compared to plants. They produce very high quantities of carotenoids compared to other sources (3.0 to 5.0% w/w on a dry weight basis). They contain both cis and trans isomers of carotenoids for high bioavailability and bioefflcacy, and also contain oxygenated carotenoids (xantho-phylls), which have greater bioactivity and better anticancer properties. The proteins from Dunaliella biomass can be utilized for bread and other products and whole cells can be utilized for animal, poultry, and fish foods because they are safe. ... 

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. 

Structurally, vitamin A (retinol) is essentially one half of the molecule of (3-carotene. Thus, (3-carotene is a potent provitamin A to which 100% activity is assigned. An unsubstituted (3 ring with a Cn polyene chain is the minimum requirement for vitamin A activity, y -Carotene, a-carotene, (3-cryptoxanthin, a-cryptoxanthin, and (3-carotene 5,6-epoxide, all having one unsubstituted ring, have about half the bioactivity of (3-carotene (Table7.4) On the other hand, the acyclic carotenoids, devoid of (3-rings, and the xanthophylls, in which the (3-rings have hydroxy, epoxy, and carbonyl substituents, are not provitamin A-active for humans. 

It may be concluded that PEF, HHP, and IR are adequate techniques for the retention of bioactive compounds in fruit and vegetable products and may even enhance bioactivity of juices, purees, and fresh-cut produce. A greater degradation of ascorbic acid in comparison with phenolics and carotenoids is usually observed. 

Ru complex and (CH3)3COK [(S, R)-34B] is also an excellent catalyst for hydrogenation of the cyclic enone [111]. The allylic alcohol product is a useful intermediate for the synthesis of carotenoid-derived odorants and other bioactive ter-penes. Hydrogenation of 2-cyclohexenone in the presence of the (S,S)-DIOP-Ir catalyst gives (R)-2-cyclohexenol in 25% ee (Fig. 32.43) [137]. 

Hydrogenation of 2,4,4-trimethyl-2-cyclohexenone with rrans-RuCl2(tolbinap)(dpen) and (CH3)3COK under 8 atm of hydrogen gives 2,4,4-trimethyl-2-cyclohexenol quantitatively with 96% ee (Scheme 1.70) [256,275,276]. In this case, unlike in the reaction of aromatic ketones, the combination of the R diphosphine and S,S diamine most effectively discriminates the enantiofaces. The chiral allylic alcohol is a versatile intermediate in the synthesis of carotenoid-derived odorants and other bioactive terpens such as a-damascone and dihydroactinidiolide [277]. 

The principle problem of algae as sources of lipids is their high water (70-90%) and low lipid content. Despite their lipid content (-7%), the fatty acids of marine algae have aroused considerable interest among researchers for their nutritional value to other marine organisms, occurrence of bioactive conjugated fatty acids, and potential medical applications. The annual production of carotenoids from seaweeds is estimated to be approximately 100 million tons, of which fucoxanthin, the main carotenoids from brown seaweed, contributes more than 10% (Matsuno, 2001). 

Many bioactive phytochemicals were systematically studied after their fractionation and characterization from many vegetables and fruits. New biological effects such as the differentiation-inducing activity of carotenoids— particularly vitamin A—were described in the 1930s. In addition, several experimental results suggested that various carotenoids might serve as dietary chemopreventive agents [6] because of their ability to quench excited molecules and excess radicals. 

Liau B-C, Shen C-T, Liang F-P, Hong S-E, Hsu S-L, JongT-T, et al. Supercritical fluids extraction and anti-solvent purification of carotenoids from microalgae and associated bioactivity. J Supercrit Fluids 2010 55 169. 

In all groups of terpenes, it is possible to find compounds with bioactive functions, and for this reasmi, they have been used since ancient times for their pharmacological properties. Terpenes also give plants their characteristic tastes and flavors and have been used as food additives or cosmeceuticals, and more recently, properties such as the antioxidant activity of carotenoids have given these... 

Bioactivity of Lycopene-Rich Carotenoid Concentrate Extracted from Tomatoes... 

Owing to the multiple forms of vitamin A in most diets and the lower efficiency of utilization of carotenoids compared to preformed vitamin A, the total amount of vitamin A (bioactivity) in foods or in the total diet must be expressed in equivalents. Over the years, several equivalency units and conversion factors have been adopted. Most recently, the retinol activity equivalent was adopted by the Institute of Medicine (lOM) in 2001 to replace older units of bioactivity because new information indicated that the conversion of carotenoids is less... 

In the natural world, carotenoid oxidation products are important mediators presenting different properties. Volatile carotenoid-derived compounds such as noriso-prenoids are well known for their aroma properties. Examples include the cyclic norisoprenoid P-ionone and the non-cyclic pseudoionone or Neral. Carotenoid oxidation products are also important bioactive mediators for plant development, the best-known example being abscisic acid. Apo-carotenoids act as visual and volatile signals to attract pollination and seed dispersal agents in the same way as carotenoids do, but they are also plant defense factors and signaling molecules for the regulation of plant architecture. 

Carotenoid-rich extracts can be used for coloring purposes and serve as good sources of bioactive compounds. Breeding or genetic manipulation can substantially increase the carotenoid contents of plants, resulting in carotenoid-rich foods that can be applied either as direct sonrces of nutrients or as raw materials for extracting natnral yellow to red colorants. 

Transferosomes represent another system of encapsulation using ultradeformable vesicle carriers for bioactive molecules, applied until now for direct transdermal drug delivery. They are built from polar lipids and have high flexibility, and are rich in unsaturated fatty acids and carotenoid pigments." ... 

Chen, F. et al.. Isolation and purification of the bioactive carotenoid zeaxanthin from the microalga Microcystis aeruginosa by high-speed counter-current chromatography, J. Chromatogr, 1064, 183, 2005. 

Hix LM, Lockwood SF, and Bertram JS. 2004. Bioactive carotenoids Potent antioxidants and regulators of gene expression. Redox Report 9 181-191. 

Bioactive compounds, such as carotenoids have strong antioxidative properties and are used as efficient radical scavengers. In some natural sources several carotenoid isomers can be found, which differ in their biochemical activities such as bioavailability or antioxidation potency. Knowing the structure and concentration of each stereoisomer is crucial for an understanding of the effectiveness... 

Stahl, W and Sies, H, 2005. Bioactivity and protective effects of natural carotenoids. Biochim Biophys Acta-Mol Basis Dis 1740, 101-107. 

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