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Anthocyanins are polyphenol compounds that render various hues of pink, red, purple, and blue in flowers, vegetables, and fruits. Anthocyanins also play significant roles in plant propagation, ecophysiology, and plant defense mechanisms. Structurally, anthocyanins are anthocyanidins modified by sugars and acyl acids. Anthocyanin colors are susceptible to pH, light, temperatures, and metal ions. The stability of anthocyanins is controlled by various factors, including inter and intramolecular complexations. Chromatographic and spectrometric methods have been extensively used for the extraction, isolation, and identification of anthocyanins. Anthocyanins play a major role in the pharmaceutical; nutraceutical; and food coloring, flavoring, and preserving industries. Research in these areas has not satisfied the urge for natural and sustainable colors and supplemental products. The lability of anthocyanins under various formulated conditions is the primary reason for this delay. New gene editing technologies to modify anthocyanin structures in vivo and the structural modification of anthocyanin via semi-synthetic methods offer new opportunities in this area. This review focusses on the biogenetics of anthocyanins; their colors, structural modifications, and stability; their various applications in human health and welfare; and advances in the field.

Microalgae productive chains are gaining importance as sustainable alternatives to obtain natural pigments. This work presents a review on the most promising pigments and microalgal sources by gathering trends from a 10-year bibliometric survey, a patents search, and an industrial and market analysis built from available market reports, projects and companies’ webpages. The performed analysis pointed out chlorophylls, phycocyanin, astaxanthin, and β-carotene as the most relevant pigments, and Chlorella vulgaris, Spirulina platensis, Haematococcus pluvialis, and Dunaliella salina, respectively, as the most studied sources. Haematococcus is referred in the highest number of patents, corroborating a high technological interest in this microalga. The biorefinery concept, investment in projects and companies related to microalgae cultivation and/or pigment extraction is increasingly growing, particularly, for phycocyanin from Spirulina platensis. These pieces of evidence are a step forward to consolidate the microalgal pigments market, which is expected to grow in the coming years, increasing the prospects of replacing synthetic pigments by natural counterparts.

Many chameleons, and panther chameleons in particular, have the remarkable ability to exhibit complex and rapid colour changes during social interactions such as male contests or courtship. It is generally interpreted that these changes are due to dispersion/aggregation of pigment-containing organelles within dermal chromatophores. Here, combining microscopy, photometric videography and photonic band-gap modelling, we show that chameleons shift colour through active tuning of a lattice of guanine nanocrystals within a superficial thick layer of dermal iridophores. In addition, we show that a deeper population of iridophores with larger crystals reflects a substantial proportion of sunlight especially in the near-infrared range. The organization of iridophores into two superposed layers constitutes an evolutionary novelty for chameleons, which allows some species to combine efficient camouflage with spectacular display, while potentially providing passive thermal protection. Colour change in many vertebrates originates from pigment dispersion or aggregation. Here, Teyssier et al . show that chameleons rapidly shift colour through a physical mechanism involving a lattice of nanocrystals in dermal iridophores, a second and deeper iridophore layer strongly reflects near-infrared light.

Summary Pigments, as coloured secondary metabolites, endow the world with a rich palette of colours. They primarily originate from plants and microorganisms and play crucial roles in their survival and adaptation processes. In this article, we categorize pigments based on their chemical structure into flavonoids, carotenoids, pyrroles, quinones, azaphilones, melanins, betalains, flavins, and others. We further meticulously describe the colours, sources, and biosynthetic pathways, including key enzymatic steps and regulatory networks that control pigment production, in both plants and microorganisms. In particular, we highlight the role of transport proteins and transcription factors in fine‐tuning these pathways. Finally, we introduce the use of pigments in practical production and research, aiming to provide new insights and directions for the application of coloured compounds in diverse fields, such as agriculture, industry, and medicine.

The genus Monascus, comprising nine species, can reproduce either vegetatively with filaments and conidia or sexually by the formation of ascospores. The most well-known species of genus Monascus, namely, M. purpureus, M. ruber and M. pilosus, are often used for rice fermentation to produce red yeast rice, a special product used either for food coloring or as a food supplement with positive effects on human health. The colored appearance (red, orange or yellow) of Monascus-fermented substrates is produced by a mixture of oligoketide pigments that are synthesized by a combination of polyketide and fatty acid synthases. The major pigments consist of pairs of yellow (ankaflavin and monascin), orange (rubropunctatin and monascorubrin) and red (rubropunctamine and monascorubramine) compounds; however, more than 20 other colored products have recently been isolated from fermented rice or culture media. In addition to pigments, a group of monacolin substances and the mycotoxin citrinin can be produced by Monascus. Various non-specific biological activities (antimicrobial, antitumor, immunomodulative and others) of these pigmented compounds are, at least partly, ascribed to their reaction with amino group-containing compounds, i.e. amino acids, proteins or nucleic acids. Monacolins, in the form of β-hydroxy acids, inhibit hydroxymethylglutaryl-coenzyme A reductase, a key enzyme in cholesterol biosynthesis in animals and humans.

Anthocyanins are key pigments of plants, providing color to flowers, fruit, and foliage and helping to counter the harmful effects of environmental stresses. It is generally assumed that anthocyanin biosynthesis arose during the evolutionary transition of plants from aquatic to land environments. Liverworts, which may be the closest living relatives to the first land plants, have been reported to produce red cell wall-bound riccionidin pigments in response to stresses such as UV-B light, drought, and nutrient deprivation, and these have been proposed to correspond to the first anthocyanidins present in early land plant ancestors. Taking advantage of the liverwort model species Marchantia polymorpha, we show that the red pigments of Marchantia are formed by a phenylpropanoid biosynthetic branch distinct from that leading to anthocyanins. They constitute a previously unreported flavonoid class, for which we propose the name “auronidin,” with similar colors as anthocyanin but different chemistry, including strong fluorescence. Auronidins might contribute to the remarkable ability of liverworts to survive in extreme environments on land, and their discovery calls into question the possible pigment status of the first land plants.

Marine microalgae and cyanobacteria are sources of diverse bioactive compounds with potential biotechnological applications in food, feed, nutraceutical, pharmaceutical, cosmetic and biofuel industries. In this study, five microalgae, Nitzschia sp. S5, Nanofrustulum shiloi D1, Picochlorum sp. D3, Tetraselmis sp. Z3 and Tetraselmis sp. C6, and the cyanobacterium Euhalothece sp. C1 were isolated from the Adriatic Sea and characterized regarding their growth kinetics, biomass composition and specific products content (fatty acids, pigments, antioxidants, neutral and polar lipids). The strain Picochlorum sp. D3, showing the highest specific growth rate (0.009 h−1), had biomass productivity of 33.98 ± 0.02 mg L−1 day−1. Proteins were the most abundant macromolecule in the biomass (32.83–57.94%, g g−1). Nanofrustulum shiloi D1 contained significant amounts of neutral lipids (68.36%), while the biomass of Picochlorum sp. D3, Tetraselmis sp. Z3, Tetraselmis sp. C6 and Euhalothece sp. C1 was rich in glycolipids and phospholipids (75%). The lipids of all studied microalgae predominantly contained unsaturated fatty acids. Carotenoids were the most abundant pigments with the highest content of lutein and neoxanthin in representatives of Chlorophyta and fucoxanthin in strains belonging to the Bacillariophyta. All microalgal extracts showed antioxidant activity and antimicrobial activity against Gram-negative E. coli and S. typhimurium and Gram-positive S. aureus.

Chromatophore organs in cephalopod skin are known to produce ultra-fast changes in appearance for camouflage and communication. Light-scattering pigment granules within chromatocytes have been presumed to be the sole source of coloration in these complex organs. We report the discovery of structural coloration emanating in precise register with expanded pigmented chromatocytes. Concurrently, using an annotated squid chromatophore proteome together with microscopy, we identify a likely biochemical component of this reflective coloration as reflectin proteins distributed in sheath cells that envelop each chromatocyte. Additionally, within the chromatocytes, where the pigment resides in nanostructured granules, we find the lens protein Ω- crystallin interfacing tightly with pigment molecules. These findings offer fresh perspectives on the intricate biophotonic interplay between pigmentary and structural coloration elements tightly co-located within the same dynamic flexible organ - a feature that may help inspire the development of new classes of engineered materials that change color and pattern. Chromatophores in cephalopod skin are known for fast changes in coloration due to light-scattering pigment granules. Here, authors demonstrate structural coloration facilitated by reflectin in sheath cells and offer insights into the interplay between structural and pigmentary coloration elements.

Amaranth has two morphological types described as red and green morphs. Previous studies have extensively characterised red morph amaranth regarding both morphological and chemical properties including antioxidant activity, antioxidant phytochemical profile, mineral content and proximate composition. However, there is scarce information concerning green morph amaranth. Hence, the present study evaluated 12 green morph genotypes for proximate composition, antioxidant activity, antioxidant pigments, minerals, and phytochemicals. Green morph amaranth was found to contain abundant carbohydrates, dietary fiber and protein. We found notable levels of inorganic minerals including potassium, calcium, magnesium, iron, manganese, copper and zinc. Antioxidant capacity quantified as free radical quenching capacity varied between 27 and 48 μg g −1 Trolox equivalents. We additionally quantified antioxidants, including total phenolics, total flavonoid equivalents and vitamin C, as well as the antioxidant pigments carotenoids, chlorophylls and betalains. These data indicated that four green morph genotypes could be considered as enriched in their antioxidant profiles. Green morph amaranth could be a potential source of nutritional components and antioxidant phytochemicals in the human diet providing opportunities to address mineral nutrient deficiencies and provide an antioxidant rich food

Monascus pigments (MPs) as natural food colorants have been widely utilized in food industries in the world, especially in China and Japan. Moreover, MPs possess a range of biological activities, such as anti-mutagenic and anticancer properties, antimicrobial activities, potential anti-obesity activities, and so on. So, in the past two decades, more and more attention has been paid to MPs. Up to now, more than 50 MPs have been identified and studied. However, there have been some reviews about red fermented rice and the secondary metabolites produced by Monascus, but no monograph or review of MPs has been published. This review covers the categories and structures, biosynthetic pathway, production, properties, detection methods, functions, and molecular biology of MPs.