Carotenoids discovery

Singh, G. Chemistry of terpenoids and carotenoids. Discovery Publishing House, 2007 Vol. 3. 

Animals cannot synthesize vitamin A-active compounds and necessary quantities are obtained by ingestion of vitamin A or by consumption of appropriate provitamin A compounds such as P-carotene. Carotenoids are manufactured exclusively by plants and photosynthetic bacteria. Until the discovery of vitamin A in the purple bacterium Halobacterium halobium in the 1970s, vitamin A was thought to be confined to only the animal kingdom (56). Table 4 Hsts RDA and U.S. RDA for vitamin A (67). 

Absorption and Raman analysis of LHCII complexes from xanthophyll biosynthesis mutants and plants containing unusual carotenoids (e.g., lactucoxanthin and lutein-epoxide) should also be interesting, since the role of these pigments and their binding properties are unknown. Understanding the specificity of binding can help to understand the reasons for xanthophyll variety in photosynthetic antennae and aid in the discovery of yet unknown functions for these molecules. 

Since its discovery in 1953, the reaction has been extensively studied with respect to structural variation in the phosphonium ylide, in the range of functionalised aldehydes and ketones, in the nature of the bases and the polarity of the solvents that may be used, and in the mechanism of the reaction and the factors which influence the ( /Z) ratio. Many thousands of simple and complex syntheses have been effected and the method is widely exploited in research laboratories and in the industrial processes for syntheses in the steroid and carotenoid field. 

Research on carotenoids and cardiovascular disease (CVD) stems from the discovery that the etiology of this disease involves oxidative processes that may be slowed by exogenous antioxidants. One of the best understood processes contributing to development of CVD is the oxidation of low-density lipoprotein (LDL). When LDL becomes oxidized, it is readily taken up by foam cells in the vascular endothelium where it contributes to the development of atherosclerotic lesion. Enhancement of the oxidative stability of LDL may also prevent other oxidative steps involved in clinical expression of coronary disease (e.g., myocardial infarction) and possibly steps not related to LDL oxidation. There is optimism about the potential role of P-carotene in prevention of CVD... 

Brazil has been associated with the use of bioproducts since its discovery. One example is the exportation of brazilwood, which started in the sixteenth century and continues to this day. This wood is valued for its resistance, but it also produces a pigment that has been used by craftsmen for many years as an important source of a variety of colors (Figure 1). Through acid treatment with vinegar or yeast, the craftsmen could obtain different shades of red and, when made alkaline with ash, other colors such as purple could be obtained. Pigments from plants have also been used by the native Indians, a good example of which is the red carotenoid pigment known as urucum. 

This chapter presents a personal historical perspective of the role of carotenoids in photosynthesis. It leads the reader into the early literature on the carotenoids and photosynthesis that are related to the discoveries on the excitation energy transfer and, to a lesser extent, on photoprotection. Excitation energy transfer from the carotenoid fucoxanthin to chlorophyll (Chi) a was shown first in the diatoms by H. Dutton, W. M. Manning and... 

Since the discovery of CPTA, research on onium compounds has generated a substantial amount of information relative to the structure-activity relationships for bioregulation of carotenoid pigments in higher plants and microorganisms. Both the trans-and cis-biosynthetic pathways can be regulated. The carotenoid pattern observed is determined essentially by the nature of the onium compounds employed. 

Studies of structure-activity relationships of compounds that affect carotenogenesis led to the discovery of a new class of bioregulators that cause the accumulation of poly-cis-carotenoids (25, 26). The natural occurrence of cis and poly-cis-carotenoids has been observed, but is not very common (27-32). 

Despite the tremendous potential impact of his discovery, chromatography was not revived until 1931, under the stimulus of widespread research on the separation of carotenoids from several natural sources by adsorption analysis on fibrous alumina [4]. Since the cited work was published, chromatography application has been extended over practically all areas of chemistry. In polymer science, chromatography was used for the first time by Moore in 1963 to determine the MWD of polymers [5]. 

A great deal of evidence for the Porter-Lincoln pathway of phytoene desaturation came with the advent of inhibitors of various steps of carotenoid biosynthesis, the discovery of carotenoid mutants in various organisms, and in vitro biosynthesis... 

Mentionings in the Carotenoids Handbook (Britton et al. 2004) which indicate discovery in the corresponding species or suitable source for isolation... 

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