Class Of Pigments Research Articles

Two Classes of Pigments, Carotenoids and C-Phycocyanin, in Spirulina Powder and Their Antioxidant Activities.

Arthrospira platensis is the widely available source of spirulina that contains distinctive natural pigments, including carotenoids and C-phycocyanin (C-PC). In this study, the major carotenoid and C-PC contents were determined in seven commercially available spirulina powder products and laboratory-prepared A. platensis trichomes (AP-1) by an LC-DAD method and UV-Visible spectrometry, respectively. The correlation of these two pigment content levels with Hunter color coordinates and antioxidant activity was also evaluated. The L* value failed to show a significant correlation with pigment content, but a positive correlation was observed between a* values and the contents of total carotenoid and C-PC. As b* values decreased, the chlorophyll a and C-PC contents increased. AP-1 exhibited the highest content of total carotenoids, chlorophyll a and C-PC, and antioxidant activities among the samples. This observation could be related to degradation of these pigments during the mass production process. The carotenoid profiles suggested that the commercial spirulina powders originated from two different sources, A. platensis and A. maxima. Total carotenoid and C-PC content exhibited positive significant correlations with antioxidant activities measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. These results provide a strong scientific foundation for the establishment of standards for the commercial distribution of quality spirulina products.

Comparative Test of Color Stability between Betalain Pigments of Red Dragon Fruits and Anthocyanin Pigments from Tamarillo Fruit at Various pH

Betalains and anthocyanins are classes of natural and water soluble pigments. Now days, these pigments have been developed as a replacement colouring agents. One of betalain resource is dragon fruit and anthocyanin resource is tamarillo. These pigments are relative unstable in some condition, one of them is pH. This research aim is to determine stability of betalain and anthocyanin pigments by pH parameter. These pigments can be isolated by macerated methods, technically processed by chopping the fruit and than soaking in ethanol for ± 24 h. These extracts were condensed by rotary evaporator. These extracts were analysed by ultraviolet-visible spectrophotometer at wavelength (λ) 200-800 nm. The absorption spectrum showed two major absorption peaks at 269 nm and 536 nm for betalain and 531 nm for anthocyanins. The result showed the optimal pH for betalain stability was at pH 5 and pH 3 for anthocyanin

Obtaining Multiple Coproducts from Red Grape Pomace via Anthocyanin Extraction and Biogas Production.

Redgrape pomace (RGP), a byproduct of redwine production, is an abundant foodprocessingwaste stream in California, rich in both anthocyanins, a class of red-blue pigments, and lignocellulose. Extraction of anthocyanins and biofuel production from RGP have been investigated independently, but no research has examined employing both strategies together for maximal valorization. In this study, anthocyanins were most effectively extracted from RGP at 80 °C. Convection- and vacuum-oven drying of the pomace were found to decrease anthocyanin yield, whereas lyophilization did not significantly affect yield. Fermentable sugars were successfully separated from the crude extract via solid-phase extraction. Ionicliquid pretreatment of RGP was determined to be a nonviable option for application to anaerobic digestion. Extraction reduced biomethane output, but supplementation with the aqueous fraction of the extract mitigated much of this difference, indicating sequential extraction and fractionation of anthocyanins from RGP can minimize the impact on biofuel yields.

Historical azo pigments: Synthesis and characterization

Abstract Synthetic organic pigments have been used in works of art for well over 130 years. During this time, many have been introduced and some have been removed from production. Historical pigments are synthetic organic pigments that are no longer commercially produced. Because of their limited range of time of commercial availability, they are of particular interest to art historians and conservators because, if identified in a painting, they can provide valuable information about artist materials and methods. In addition, once the pigment has been identified, conservators will be better informed in treatment and display conditions of the works of art. A number of azo-pigments are historical, and many of these have not been characterized by modern analytical techniques. We synthesized a series of azopigments, specifically members of the pigment classes: arylide (Hansa) yellow, diarylide yellow and oranges,as well as the red Naphthol AS. The pigments were characterized by Raman spectroscopy and Laser Desorption Ionization Mass Spectrometry (LDI-MS). The pigments synthesized and characterize include: PR7, PR11, PR18, PR19, PY49, PY203, PY113, PY124, PO14and PO15.

Chemical Mapping by Macroscopic X-ray Powder Diffraction (MA-XRPD) of Van Gogh's Sunflowers: Identification of Areas with Higher Degradation Risk.

The discoloration rate of chrome yellow (CY), a class of synthetic inorganic pigments (PbCr1-x Sx O4 ) frequently used by Van Gogh and his contemporaries, strongly depends on its sulfate content and on its crystalline structure (either monoclinic or orthorhombic). Macroscopic X-Ray powder diffraction imaging of selected areas on Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam) revealed the presence of two subtypes of CY: the light-fast monoclinic PbCrO4 (LF-CY) and the light-sensitive monoclinic PbCr1-x Sx O4 (x≈0.5; LS-CY). The latter was encountered in large parts of the painting (e.g., in the pale-yellow background and the bright-yellow petals, but also in the green stems and flower hearts), thus indicating their higher risk for past or future darkening. Overall, it is present in more than 50 % of the CY regions. Preferred orientation of LS-CY allows observation of a significant ordering of the elongated crystallites along the direction of Van Gogh's brush strokes.

Chemical Mapping by Macroscopic X‐ray Powder Diffraction (MA‐XRPD) of Van Gogh's Sunflowers: Identification of Areas with Higher Degradation Risk

AbstractThe discoloration rate of chrome yellow (CY), a class of synthetic inorganic pigments (PbCr1−xSxO4) frequently used by Van Gogh and his contemporaries, strongly depends on its sulfate content and on its crystalline structure (either monoclinic or orthorhombic). Macroscopic X‐Ray powder diffraction imaging of selected areas on Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam) revealed the presence of two subtypes of CY: the light‐fast monoclinic PbCrO4 (LF‐CY) and the light‐sensitive monoclinic PbCr1−xSxO4 (x≈0.5; LS‐CY). The latter was encountered in large parts of the painting (e.g., in the pale‐yellow background and the bright‐yellow petals, but also in the green stems and flower hearts), thus indicating their higher risk for past or future darkening. Overall, it is present in more than 50 % of the CY regions. Preferred orientation of LS‐CY allows observation of a significant ordering of the elongated crystallites along the direction of Van Gogh's brush strokes.

Visual pigment genes and absorbance spectra in the Japanese sardine Sardinops melanostictus (Teleostei: Clupeiformes).

The spectral absorbance of photoreceptor visual pigments and the opsin gene class of the visual pigments was investigated in Sardinops melanostictus. Microspectrophotometric (MSP) measurements showed that the rod photoreceptors had peak absorbance spectra (λmax) at 502 nm. The spectral sensitivity of single cones was centered at 393 nm. Double cones had a λmax of 493/522 nm, but a few displayed a red-shifted absorbance of the long-wave member at 542 nm. The mRNAs of six different opsins were isolated from the retina, retrotranscribed, cloned, and sequenced. Three genes encoded opsins in the green-sensitive class (RH2), and three genes encoded opsins in the red-sensitive class (LWS), the ultraviolet (UV)-sensitive (SWS1) class, and the rod class (RH1). A Southern blot analysis showed that the blue-sensitive (SWS2) opsin gene is absent from this species, hence it was concluded that the λmax of 393 nm was generated from the SWS1 opsin. Phylogenetic analyses of S. melanostictus RH1, LWS, and SWS1 sequences placed them with orthologs from other species (e.g., the cyprinids Danio rerio and Carrasius auratus) in Otomorpha. However, unexpectedly, the RH2 sequences were more similar to orthologs in members of the Euteleosteomorpha (e.g., Oryzias latipes and Takifugu rubripes) than to cyprinid RH2 opsins.

Chemistry Inspired by the Colors of Fruits, Flowers and Wine.

An overview is provided of the status of research at the frontiers of investigation of the chemistry and photochemistry of two classes of natural plant pigments, the anthocyanins and the betalains, as well as of the pyranoanthocyanin pigments formed from anthocyanins during the maturation of red wine. Together, anthocyanins and betalains are responsible for almost all of the red, purple and blue colors of fruits and flowers and anthocyanins and pyranoanthocyanins are major contributors to the color of red wines. All three types of pigments are cationic below about pH 3, highly colored, non-toxic, reasonably soluble in water or alcohol and fairly stable to light. They exhibit good antioxidant or antiradical activity and, as part of our diet, confer a number of important health benefits. Systematic studies of model compounds containing the basic chromophoric groups of these three types of pigments are providing a deeper understanding of the often complex chemistry and photochemistry of these pigments and their relationship to the roles in vivo of these pigments in plants. These natural pigments are currently being exploited as starting materials for the preparation of novel semi-synthetic dyes, pigments and fluorescence probes.

Engineering Pichia pastoris for the Production of Carotenoids.

Carotenoids are one of the most diverse and widely distributed classes of pigments in the biosphere and exhibit a variety of functions in the nature. Their importance and biotechnological applications are higher and higher, but their sources are not increasing in the same exponential way. Here we describe the process of bioengineering the yeast Pichia pastoris by sequential transformation to get an astaxanthin producer.

The push and pull of plant specialized metabolism underlies a long-standing, colorful mystery.

This article is a Commentary on Lopez‐Nieves et al., 217: 896–908.

Red colourants from filamentous fungi: Are they ready for the food industry?

Food components of microbial-origin have a long history in food science and the food industry. Thickening and gelling agents, flavour enhancers, polyunsaturated fatty acids, flavour compounds, vitamins, essential amino acids, and acidulants are some examples of such ingredients. This paper will provide an update on the current worldwide situation for four different fungal reds: (i) carotenoid lycopene (simple compound, complex current status); (ii) molecular biology on Monascus to avoid mycotoxin and cholesterol-lowering substance in pigmented extracts; (iii) newcomers with azaphilone-producing fungi such as Talaromyces atroroseus, Penicillium purpurogenum, and Talaromyces albobiverticillius; and (iv) anthraquinones as a possible alternative to the insect-sourced carmine. The future of Monascus in Europe and the USA is just around the corner, and markets will appear as soon as the citrinin issue has been solved, with the help of the current better knowledge of full genomes from industrial strains. Fungi bring a new class of pigments to the food industry, as azaphilones are not present in plants. These azaphilone-producing strains should now be thoroughly studied through liquid fermentation of Penicillium/Talaromyces strains, with optimized scale-up. A fungal alternative to carmine insect anthraquinone is further away from the market, however, due to the particular stability of this vibrant red in foods; research efforts should be intensified.

Admixture mapping in a hybrid zone reveals loci associated with avian feather coloration.

Identifying the genetic bases for colour patterns has provided important insights into the control and expression of pigmentation and how these characteristics influence fitness. However, much more is known about the genetic bases for traits based on melanin pigments than for traits based on another major class of pigments, carotenoids. Here, we use natural admixture in a hybrid zone between Audubon's and myrtle warblers (Setophaga coronata auduboni/S. c. coronata) to identify genomic regions associated with both types of pigmentation. Warblers are known for rapid speciation and dramatic differences in plumage. For each of five plumage coloration traits, we found highly significant associations with multiple single-nucleotide polymorphisms (SNPs) across the genome and these were clustered in discrete regions. Regions near significantly associated SNPs were enriched for genes associated with keratin filaments, fibrils that make up feathers. A carotenoid-based trait that differs between the taxa-throat colour-had more than a dozen genomic regions of association. One cluster of SNPs for this trait overlaps the Scavenger Receptor Class F Member 2 (SCARF2) gene. Other scavenger receptors are presumed to be expressed at target tissues and involved in the selective movement of carotenoids into the target cells, making SCARF2 a plausible new candidate for carotenoid processing. In addition, two melanin-based plumage traits-colours of the eye line and eye spot-show very strong associations with a single genomic region mapping to chromosome 20 in the zebra finch. These findings indicate that only a subset of the genomic regions differentiated between these two warblers are associated with the plumage differences between them and demonstrate the utility of reduced-representation genomic scans in hybrid zones.

Desert camouflage and what wildlife see

Desert, desert-scrub, savanna and sandy beach, and lakeshore environments can be particularly tricky in terms of camouflage selection due to their low vegetative density. Therefore many companies focus on the development of paint color schemes that match the vegetation and the desert soils/sands. However another factor in the consideration of which camouflage to purchase may lie in what the animal can see. White-tailed deer and similar large mammals have been shown to have three classes of photo pigments that are sensitive to the range of blue to yellow-green during day light hours and blue to blue-green at night. Six commercially-available camouflage patterns were investigated to determine if the reflectance characteristics measured in the laboratory and under field conditions were elevated in the blue range and perhaps more likely to be seen by wildlife. The camouflage patterns were evaluated against standard vegetation indices including normalized difference vegetation index, soil adjusted vegetation index, enhanced vegetation index, and simple ratio. Only two of the patterns (S4 and S5) possessed a reflectance more like vegetation. Patterns S4, S6, S3, and S2 all showed only slight elevations in the blue wavelength range which could only have been detected by near infrared measurements instead of visual observation by the human eye.

Rational Engineering of Bioinspired Anthocyanidin Fluorophores with Excellent Two-Photon Properties for Sensing and Imaging.

Fluorescent materials are widely employed in biological analysis owing to their biorthogonal chemistries for imaging and sensing purposes. However, it is always a challenge to design fluorophores with desired photophysical and biological properties, due to their complicated molecular and optical nature. Inspired by anthocyanidin, a class of flower pigments, we designed a new fluorescent molecular framework, AC-Fluor. The new fluorescent materials can be rationally engineered to produce a broad range of fluorescent scaffolds with flexibly tunable emission spectra covering the whole visible light range, from 467 to 707 nm. Furthermore, they exhibit unprecedented environment-insensitive two-photon properties with a substantial cross section as large as 1100 GM in aqueous solution. AC-Fluors demonstrate their biological values through two-photon deep tissue imaging, with penetration depths as much as 300 μm, while exhibiting minimal cytotoxicity. These features engender a rational engineering strategy for the design and optimization of new fluorescent materials for biological imaging.

Synthesis and anticorrosive performance evaluation of zinc vanadate pigment

Exclusion of chromate and lead based pigments and effective replacements of phosphate and molybdate are emergent demands in coating industry nowadays. In the present study zinc vanadate, the newest class of pigments, synthesized, characterized and evaluated for anticorrosive performance in coatings. The submicron size zinc vanadate pigment was synthesized by controlled coprecipitation reaction using zinc acetate as precursor and sodium metavanadate as the precipitant in presence of Polysorbate 80 (Tween-80) surfactant. The functional group, crystal structure and morphology of zinc vanadate were analyzed by FTIR, XRD, and FESEM respectively. Additionally, anticorrosive pigmentary properties of the synthesized pigment were evaluated using epoxy resin as a binder and polyamine as a curing agent as per ASTM and subsequently tested in artificial seawater (3.5 wt. % of NaCl). Superior performance in terms of anticorrosive protection with high tinting strength was exhibited by zinc vandate over their phosphate counterparts.

Compositions of Lipids and Fatty Acids from Various Parts of the Brown Alga Undaria pinnatifida

The contents of total and separate classes of lipids and photosynthetic pigments from various anatomical parts of the brown alga U. pinnatifida were determined. Differences were found in the contents of separate lipid constituents. The maximum amount of free lipids was found in stipe (0.012% of moist mass); of bound lipids, in sporophylls (0.98% of moist mass). Polar lipids constituted a large part of the bound lipids with glyceroglycolipids and neutral lipids dominating. A total of 20 fatty acids with 5 unsaturated, 4 monounsaturated, and 11 polyunsaturated were determined. The last were greatest in thallus, stipe, and rhizoids; unsaturated acids, in sporophylls.

A review of the effects of colour and light on non‐image function in humans

This paper reviews current knowledge on non‐image‐forming aspects of vision. Developments in the last 20 years have included the discovery of a fifth class of human visual pigment (melanopsin), in addition to the three classes of photopsin to be found in the cones and rhodopsin in the rods in the human retina. Melanopsin is found in a small number of retinal ganglion cells which then, in addition to receiving input from rods and cones, are intrinsically photosensitive. These retinal ganglion cells send their input primarily to the hypothalamus, where they help to regulate the circadian system (daily rhythms of sleep patterns, body temperature, heart rate, etc.). The discovery of the anatomical basis of non‐image‐forming vision has led to a great deal of research into the effects of light on sleep, depression and mood, retinal photodamage and well‐being, amongst other factors. Given that recent technological innovations in LED lighting now give us greater control over environmental lighting, it is timely to review the non‐visual effects of light in humans in order to inform lighting design in the future.

Compositional analysis of endogenous porphyrins from Helicobacter pylori

Bacteria able to accumulate porphyrins can be inactivated by visible light irradiation thanks to the photosensitizing properties of this class of aromatic pigments (photodynamic therapy, PDT). Since the bacterial resistance to antibiotic is growing, PDT is becoming a valid alternative. In this context, the pathogen Helicobacter pylori (Hp) is a suitable target for PDT since it spontaneously produces and accumulates porphyrins. It is then important to understand the spectroscopic behavior of these endogenous species to exploit them as photosensitizers, thus improving the results given by the application of PDT in the treatment of Hp infections. In this work we extracted porphyrins from both a laboratory-adapted and a virulent strain of Hp, and we performed spectroscopic and chromatographic experiments to collect information about the composition and the spectrophotometric features of the extracts. The main components of the porphyrin mixtures were identified and their relative contribution to the global red fluorescence was examined.

Thin Layer Chromatographic Characterization of Carotenoid Isolates in Sugar Date Palm (Phoenix sylvestris) Fruit Epicarp and Inflorescence Axis

Plant carotenoids are one of the most important classes of plant pigments and play a crucial role in defining the quality parameter of fruits and vegetables. They possess a large numbers of important biological activities such as antioxidant properties, anti – carcinogenic, precursor of vitamin A and preventive in a large number of chronic diseases. The objective of the present study was to characterize the carotenoids present in Phoenix sylvestris fruits and their inflorescence axis which are orange red in colour. So, in this study we isolated carotenoids from both the epicarp and the extensively large inflorescence axis by preparative TLC and also characterized some of the major components like β- carotene and lutein using HPTLC analytical techniques. The present findings suggest that the consumption of β-carotene and lutein from this fruit crop can be helpful in providing potential targets for combating vitamin A deficiency in countries where vitamin A deficiency is a public health problem

The Genetic and Evolutionary Drives behind Primate Color Vision

Primate color vision is based on two to three cone types in the retina, each expressing a different class of visual pigment, making them the only mammals that possess trichromacy. These pigment classes are the short wavelength-sensitive (SWS1) pigment and the long wavelength-sensitive (LWS) pigment, orthologues of the same pigments found in many other vertebrates, as well as the middle wavelength-sensitive (MWS) pigment, a paralogue to the LWS pigment. Trichromacy was achieved differently in Old World and New World primates. In Old World primates, a duplication of the LWS opsin gene occurred giving rise to a “red-sensitive” or L pigment and a “green-sensitive” or M pigment. Their corresponding L and M genes are adjacent on the X chromosome which, together with their high sequence homology, is the underlying cause for the high frequency of red-green color blindness seen in humans. In New World primates and prosimians, however, the mechanism leading to trichromacy, with one exception, is based on a single polymorphic LWS gene, from which different allelic variants encode pigments with differing spectral peaks. X chromosome inactivation limits expression to just one gene per photoreceptor meaning that trichromacy is only seen in females; while all male are red-green color blind. Despite several leading hypothesis, the reasons for the different evolutionary paths taken by Old and New World primates for trichromacy are still unclear and remain to be confirmed.