Free Carotenoids Research Articles

Epicuticular and intracellular lipids ofHippophae rhamnoides leaves

It has been established that the bulk of the epicuticular lipids of common sea buckthorn leaves is represented by the class of higher aliphatic esters, while higher fatty acids, other acids of the aliphatic series, and cyclic acids of triterpene nature have also been detected. The intracellular lipids consist mainly of esters of various alcohols with higher fatty acids, while the same alcohols are found in the form of acetates and in the free state. In addition, the composition of the intracellular lipids includes hydrocarbons, triacylglycerols, free fatty acids, carotenoids, aldehydes, and acids of triterpene nature.

Carotenoid catabolism during leaf senescence and its control by light

Reviews on the biosynthesis, distribution and function of carotenoids in chloroplasts of higher plants and algae are available. However, the data, although limited, on degradation of the pigment during leaf senescence are not integrated. This review is an attempt to summarise the data available so far, generalise them, and address a few unanswered questions in the field. Both Chl and carotenoids degrade during leaf senescence; the latter process, however, is demonstrated in many plant systems to remain relatively stable. Senescence brings about changes in carotenoid composition and causes formation of xanthophyll esters and epoxides in some cases. The esters and free carotenoids are predominantly located in plastoglobuli formed during the process. In the context of compositional changes, the possibility of the operation of the xanthophyll cycle during senescence is discussed. The existing experimental findings suggest the involvement of enzymes for degradation of the pigment. Light is shown to stimulate carotenoid degradation in the background of dark treatment during aging of isolated chloroplasts and plants treated with herbicides. The mechanism of stimulation is mostly explained through the participation of free radicals. In contrast, photoinduced retardation of the pigment loss during leaf senescence is attributed to the action of phytochrome.

A molecular and carbon isotopic study towards the origin and diagenetic fate of diaromatic carotenoids

Pyrolysates of high-molecular-weigth sedimentary fractions of the Duvernay Formation (Western Canada Basin) are dominated by 1,2,3,4- and 1,2,3,5-tetramethylbenzene, which, generated via β-cleavage, indicate the presence of diaromatic carotenoids in the macromolecular aggregates. This was substantiated by desulphurization of sulphur-rich aggregates of the polar fraction, which released (partly) hydrogenated carotenoids. Furthermore, these components were important constituents of the aromatic hydrocarbon fractions and related oils. Apart from renieratane and isorenieratane, 1H NMR analysis established the aromatic substitution pattern of the most abundant component present, which was identified as a diaromatic compound with an unprecedented 2,3,6-/3,4,5-trimethyl aromatic substitution pattern. Molecular and isotopic analyses of both soluble and insoluble fractions of organic matter revealed relationships between diagenetically-derived carotenoids found in bitumen and related oils and their precursors incorporated into high-molecular-weight fractions. Aryl isoprenoids, important components in extracts and oils, were apparently derived from thermal cracking of bound diaromatic carotenoids rather than cleavage of free carotenoids as previously suggested. Furthermore, products derived from diaromatic carotenoids were substantially enriched in 13C relative to n-alkanes of algal origin. Together with the characteristic carotenoids, this isotopic enrichment provides evidence of significant contributions from photosynthetic green sulphur bacteria (Chlorobiaceae), which fix carbon via the reversed tricarboxylic acid (TCA) cycle. In spite of the prominence of these molecular signals, the overall isotopic composition of the organic matter indicated that only a very small portion of the preserved organic carbon was derived from the biomass of photosynthetic green sulphur bacteria.

Adsorption isotherms of sesame oil in a concentrated miscella system

The adsorption of peroxides, unsaturated carbonyls, free fatty acids and carotenoids from unrefined sesame oil on vegetable carbon (5%, w/w) in a miscella system was studied. Three different solvent conditions (hexane/ethanol, 100:0, 95:5 and 75:25, vol/vol), combined in a factorial design with five levels of solvent (0, 10, 20, 30 and 40%, w/w), were used to develop the miscella. Equilibrium adsorption was not achieved during the 100 min of adsorption, mainly because the oil components were involved in oxidation reactions during the adsorption process. However, for a given solvent concentration, adsorption of the oil components showed a significant linear regression on their respective initial concentration in the miscella (Ci). Peroxides and carbonyls showed, at all solvent levels investigated, an affinity for the carbon more independent of their Ci than free fatty acids and carotenoids. In general, at the same Ci, a higher adsorption was achieved as solvent concentration increased. The results indicated that free fatty acid adsorption may depend on competitive adsorption based on molecule hydrophobicity. However, in spite of the higher hydrophobicity of carotenoids, compared with free fatty acids, they might not be competing for the same adsorbing sites. Ethanol showed a prooxidant effect that increased peroxide production during adsorption but did not affect the reaction involved in carbonyl production.

The eyespot of euglena gracilis: a microspectrophotometric study

The eyespots in cells of streptomycin-bleached strains and of dark-grown cultures of Euglena gracilis, were examined by means of fluorescence microscopy and microspectrophotometry. When viewed with light in the region of 380–500 nm, the stigma appeared as a dark spot. Adjacent to this was a second spot, not seen with white light, but which was seen to fluoresce when excited with radiation at 370 ± 20nm. This fluorescence proved to be polarized in contrast to other fluorescing bodies in the cell. The absorption curves, obtained by microspectrophotometry of individual eyespots, were found to consist of two spectral maxima, an A-band in the blue and a B-band in the green. Unlike the A-band, the B-band provided evidence of originating from an anisotropic structure. Relating these data to literature findings, we conclude that the B-band is the absorbance of a pigment in the quasi-crystalline paraflagellar body and the A-band perhaps a pigment in the orange-red stigma. The spectrum of the B-band does not appear to be that of a flavoprotein or of a free carotenoid but its resemblance to the spectrum of rhodopsin is significant in relation to published data for the Chlamydomonas eyespot that suggests the presence of a rhodopsin-like pigment as the photosensitive system responsible for phototaxis in this alga.

One hour in 1 ATA oxygen enhances rat alveolar macrophage chemiluminescence and fungal cytotoxicity

The purpose of this study was to determine if 100% O2 would enhance rat pulmonary alveolar macrophage (PAM) oxidative killing of conidia of the fungus Neurospora crassa. First, we found that incubation in 100% O2 had no effect on conidia viability in the absence of PAM. We obtained resident PAM from nonpretreated anesthetized male Sprague-Dawley rats by bronchoalveolar lavage. Compared with similar air exposures we found that 1 h in vitro exposure of PAM to 100% O2 (1.0 atmosphere absolute) increased their killing of opsonized phagocytized conidia by 52%, without altering phagocytosis. A reactive oxygen killing mechanism is suggested because 1) 100% O2 increased PAM chemiluminescence (CL) by 60% both at rest and during 1 h of phagocytosis, and 2) PAM in 100% O2 killed albino conidia (lacking free radical-quenching carotenoids) 2.9 times more readily than they killed wild-type conidia. Compared with air, 100% O2 delayed the PAM respiratory burst time to peak by 18% but did not alter the burst maximal acceleration. The latter and the similar 60% increase in PAM CL in 100% O2 both at rest and during 1 h of phagocytosis suggests a nonenzymatic O2 enhancement of the respiratory burst. Changed timing of burst events in 100% O2 suggests early O2 toxicity. We conclude that 1 h in 100% O2 increases PAM free radical production and fungicidal activity.

Ecological implications of cultured mussel biodeposition for a short food web under winter conditions in the mediterranean sea

ln order to investigate trophic relationships in a simplified food chain including mussel biodeposition, in situ experiments were performed in an estuarine mussel-rope cultivation (Gulf of Fos). Cylindrical enclosures were placed at a depth of 2 m for one month during winter (sea temperature 10°C). Shrimps, Palaemon serratus, were kept in the cylinders, with and without mussel biodeposits as food supply. A control group was fed on mussel flesh. A comparison between the different biochemical components in both food and feeders was undertaken at three trophic levels; phytoplankton, mussels and shrimps. Under oligotrophic water conditions, shrimps could feed on mussel biodeposits. There were no noticeable differences between shrimps fed on mussel tissue or shrimps fed on mussel biodeposits, either in lipid and protein content, or in free amino acid, fatty acid or carotenoid pigment content. On the other hand, fasted shrimps exhibited significant modifications. The ecological significance of such anenergy flow pathway in intensive shellfish cultivation zones is discussed.

Resonance Raman study of reconstituted carotenoproteins incorporating astaxanthin and 15,15′-didehydroastaxanthin

Two reconstituted carotenoproteins have been studied by resonance Raman spectroscopy. They were prepared from the apoprotein of the Asterias rubens carotenoprotein, asteriarubin and either astaxanthin or 15,15′-didehydroastaxanthin. Spectral properties of dehydrocarotenoids are first discussed. The spectral properties of the complexes are compared to those of the free carotenoids and of other carotenoproteins containing astaxanthin, and posssible protein-carotenoid interactions are discussed. Greater delocalisation of the Π-electron system in the central part of the polyene chain, and the role of lateral methyl groups in binding is emphasised.

Simultaneous high-performance liquid chromatographic analysis of free carotenoids and carotenoid esters

High-performance liquid chromatography using a non-aqueous reversed phase with gradient elution on C 18 columns is a powerful tool for investigating the carotenoid composition of natural samples, e.g., flower petals, and for the simultaneous detection of carotenoids of the widest possible polarity range (xanthophylls, diones, hydrocarbons and carotenoid esters). The comparison of sample extracts submitted or not to saponification allows the presence of carotenoid esters to be revealed through the appearance of the corresponding free hydroxycarotenoids. The gas chromatographic analysis of the fatty acids after alkaline hydrolysis of esters provides further confirmation. In most cases, peaks of various carotenoids were identified by comparison with standards. The wavelengths of the visible absorbance maxima of the chromatographed carotenoids as obtained on-line by the stop-flow method in the eluent system and off-line in carbon disulphide are reported. The esters appear to constitute the main carotenoid fraction in flower petals.

The circular dichroism of ovoverdin and other carotenoproteins from the lobster Homarus americanus.

The circular dichroic (CD) spectra of the alpha-, beta'-, and gamma-crustacyanins, ovoverdin, and the yellow lobster-shell protein were measured in the region 200-750 nm, for comparison with the CD spectrum of the free carotenoid astaxanthin. The two carotenoid chromophores of ovoverdin gave a CD spectrum with a series of bands of alternating sign and ellipticities up to 1.9 X 10(5) degree X cm2 X dmol-1, comparable to the low temperature CD spectrum of astaxanthin in the UV region. The visible region of ovoverdin also contained strong CD bands where astaxanthin itself has very weak ones. The blue (640 nm) chromophore of ovoverdin gave a broad negative CD feature quite different from the blue chromophores of the three crustacyanins. The crustacyanins have a broad positive feature between 400 and 610 nm with ellipticities up to 2 X 10(5) degree X cm2 X dmol-1, followed at higher wavelengths by a negative band with an ellipticity up to 1 X 10(5) degree X cm2 X dmol-1. Gaussian curve-fitting procedures showed the positive features to consist of a minimum of two or three CD bands. In addition to the exciton bands at the main visible absorption, the yellow lobster-shell protein had a pair of CD bands of equal but opposite ellipticity associated with an absorption band between 250 and 340 nm. The UV regions of the CD spectra of the five carotenoproteins have bands from both carotenoid and protein chromophores, and possible assignments of these bands to one or the other of the two types of chromophore are proposed.

Carotenoids in ripe green and in autumn senescing leaves of apple tree: II - Seasonal changes of free carotenoids and xanthophyll esters and relationship between their content and senescing stage

Abstract Carotenoids (two carotenes, five free xanthophylls and seven xanthophyll esters previously isolated and identified, Cardini 1982) were measured in apple leaves from the early spring to autumn senescence; a detailed quantitative investigation on different senescence stages was also carried out. The xanthophyll esters were determinated by extinction coefficients (E1 cm 1%) experimentally obtained in this laboratory. α-carotene shows a clear character of « summer carotene », moreover for its sudden decrease in late summer it could perhaps be considered a biological indicator of early autumn. Violaxanthin shows a unique seasonal behaviour: a minimum during the summer maturity, a very marked biosynthesis in spring and a very intense esterification in autumn. In spring and in the first summer, violaxanthin shows a slight negative correlation with zeaxanthin in relationship with the « violaxanthin cycle », and also a negative correlation with neoxanthin; these correlations and the possible role of viola...

Carotenoids in ripe green and in autumn senescing leaves of apple tree: I - Qualitative composition of free carotenoids, xanthophyll esters and fatty acids of esters

Abstract By different chemical, spectral and chromatographic procedures seven carotenoids, two carotenes (α- and β-carotene) and five free xanthophylls (violaxanthin, lutein, antheraxanthin, zeaxanthin and neoxanthin) have been isolated and identified in green apple leaves. In autumn senescing leaves, besides the above seven carotenoids, the occurrence of at least seven xanthophyll esters has also been proved. Four esters, violaxanthin mono- and diester and lutein mono- and diester, (≥90% of total esters) and a minor component, neoxanthin triester, have been identified. Another minor component is most probably a monoester of antheraxanthin; the seventh, present in traces, has not been identified. The fatty acids combined with the above xanthophyll esters have been analysed by gas-chromatography. The unusual presence of low molecular weight fatty acids, C7-C11, has been registered (1,5-8% of the total); caprilic and capric acids have been identified. Lauric acid with three minor homologous (2-7% and myrist...

Analysis of light-controlled accumulation of carotenoids in mustard (Sinapis alba L.) seedlings

Carotenoid accumulation in the cotyledons of the mustard seedling (Sinapis alba L.) is controlled by light. Besides the stimulatory function of phytochrome in carotenogenesis the experiments reveal the significance of chlorophyll accumulation for the accumulation of larger amounts of acrotenoids. A specific blue light effect was not found. The data suggest that light exerts its control over carotenoid biogenesis through two separate mechanisms: A phytochrome regulation of enzyme levels before a postulated pool of free carotenoids, and a regulation by chlorophyll draining the pool by complex-formation.

Spectroscopic properties and related functions of the stigma measured in living cells of Euglena gracilis.

The spectroscopic properties of stigma inside green and dark-grown cells and of isolated stigma globules have been studied by means of a microspectrophotometer build in the Laboratory. On the base of these results and of the analysis of the absorption spectra of a stigma suspension, cell suspension and the cell methanolic extracts, it can be inferred that pigments localized in the stigma are free carotenoids which are not closely packed and do not show an ordered arrangement. Furthermore, the efficiency of the stigma as shading device is duscussed.

The polar carotenoid fraction from sarcina flava.

SUMMARY The polar carotenoid fraction from Sarcina flava does not not appear to be a free carotenoid, but a carotenoid associated with glucose and a peptide. The glucose seems to be glycosidically bound to the carotenoid through its reducing group. Presumably the peptide is linked to the glucose through either the primary or one of the secondary hydroxyl groups on the carbohydrate molecule. A model of the in vivo state of the carotenoid complex in the bacterial membrane has been proposed.

Chemical embryology of the crustacea.

Summary1. The dry weight of a neonate crustacean is sometimes lower than the initial dry weight of the egg, owing to utilization of respiratory substrates, as in Daphnia, where the dry weight decreases by 16–25 %. In Artemia any loss is compensated by an uptake of salts so that there is no change in dry weight during the course of embryonic development. The embryos of Ligia receive nutrients secreted into the maternal brood pouch, and the dry weight of the neonate is greater than the initial dry weight of the egg.2. Early embryos of Simocephalus, Artemia and Balanus consume less oxygen per unit dry weight than older embryos. The increase in oxygen consumption from early to late embryos is approximately six to eightfold.3. Oxygen consumption decreases when the rate of embryonic development of Artemia is reduced by increasing osmotic pressures in the external medium.4. Glycogen is formed rather than utilized in the embryos of Simocephalus and Artemia. In the latter the main carbohydrate reserve is trehalose, which is transformed to glycogen and glycerol. The relative formation of these two substances is influenced by external osmotic pressures. At high external osmotic pressures more glycerol is formed, and this aids osmotic rupture of the tough outer shell of the egg.5. Trehalose seems to be important in relation to the dormant state of Artemia embryos. The embryos which develop rapidly in the maternal brood pouch contain much less trehalose than those which become encysted and dormant.6. The proportion of the initial lipid content of a crustacean egg that is utilized during development is very variable. In Homarus 60% disappears by time the neonate emerges, in Ligia 32%, and in Artemia the decrease is very slight, or there may even be a slight increase.7. Haemoglobin in the eggs of Cladocera does not appear to act as a respiratory pigment, but does serve to accelerate development in poorly aerated water. It is suggested that the main function is to act as a supply of stable protein.8. The haemochromogen found in the gut of late embryos of Daphnia appears to be formed in part at least from haemoglobin, which diminishes in concentration as development proceeds.9. Breakdown of haemoglobin during embryonic development of Daphnia is not accompanied by formation of bile pigments.10. Biliverdin is synthesized in the embryonic eyes of Polyphemus but not elsewhere in the embryo.11. The carotenoproteins in the eggs of many different crustaceans break down towards the end of embryonic development, liberating free carotenoid. It is suggested that these proteins are stabilized and held in reserve by linkage to a carotenoid until a particular stage of embryonic development has been reached.12. Metabolic pathways in the formation of astaxanthin from β‐carotene may involve monoketo and diketo carotenes, or by an alternative route monohydroxy and dihydroxy carotenes.

United States government specification for automobile soap

The fruit of Lycium barbarum Linnaeus, a traditional Chinese herb containing functional components such as carotenoids, flavonoids and polysaccharides, has been widely used in the health food industry because of its possible role in the prevention of chronic disease like age-related macular degeneration. The objectives of this study were to develop a high performance liquid chromatography–photo diode array detection–mass spectrometry (HPLC–DAD–MS) method with atmospheric pressure chemical ionization (APCI) mode for qualitative and quantitative analyses of carotenoids in fruits of L. barbarum. Dried samples of L. barbarum were subjected to extraction without saponification or extraction followed by saponification. A C30 column with a gradient mobile phase of methylene chloride (100%) and methanol–acetonitrile–water (81:14:5, v/v/v) was used to separate carotenoids, with a total of 11 free carotenoids and 7 carotenoid esters being resolved from unsaponified and saponified L. barbarum extracts within 51 and 41 min, respectively. The fatty acid composition of carotenoid esters was confirmed by gas chromatography. Zeaxanthin dipalmitate (1143.7 μg/g) was present in the largest amount, followed by β-cryptoxanthin monopalmitate and its two isomers (32.9–68.5 μg/g), zeaxanthin monopalmitate and its two isomers (11.3–62.8 μg/g), all-trans-β-carotene (23.7 μg/g) and all-trans-zeaxanthin (1.4 μg/g).