Seaweeds as Source of Bioactive Pigments with Neuroprotective and/or Anti-Neurodegenerative Activities: Astaxanthin and Fucoxanthin.

The marine kingdom is an important source of a huge variety of scaffolds inspiring the design of new drugs. The complex molecules found in the oceans present a great challenge to organic and medicinal chemists. However, the wide variety of biological activities they can display is worth the effort. In this article, we present an overview of different seaweeds as potential sources of bioactive pigments with activity against neurodegenerative diseases, especially due to their neuroprotective effects. Along with a broad introduction to seaweed as a source of bioactive pigments, this review is especially focused on astaxanthin and fucoxanthin as potential neuroprotective and/or anti-neurodegenerative agents. PubMed and SciFinder were used as the main sources to search and select the most relevant scientific articles within the field.

Naturally Occurring Partially Reduced Perylenequinones from Fungi.

This Review provides a critical analysis of the literature covering the naturally occurring partially reduced perylenequinones (PQs) from fungi without carbon substituents (which can be named class A perylenequinones) and discusses their structures, stereochemistry, biosynthesis, and biological activities as appropriate. Perylenequinones are natural pigments with a perylene skeleton produced by certain fungi, aphids, some plants, and animal species. These compounds display several biological activities, e.g., antimicrobial, anti-HIV, photosensitizers, cytotoxic, and phytotoxic. It describes 36 fungal PQs and cites 81 references, covering from 1956 to August 2022.

Production and antiproliferative effect of violacein, a purple pigment produced by an Antarctic bacterial isolate.

We studied the production and the potential use of a purple-pigment produced by an Antarctic bacterial isolate. This pigment was identified as violacein, a metabolite produced by many bacterial strains and reported that it has antiproliferative activity in many cell lines. We analyzed the effect of temperature and the composition of the growth medium on pigment production, achieving the highest yield at 20 °C in Tryptic Soy Broth medium supplemented with 3.6 g/L glucose. We doubled the yield of the pigment production when the process was scaled up in a 5 L bioreactor (77 mg/L of crude pigment). The pigment was purified and identified by mass spectrometry (DI-EI-MS) and Nuclear Magnetic Resonance (NMR) spectroscopy as violacein. We performed survival assays that showed that the pure pigment has antiproliferative activity and sensitize HeLa cells (cervix cell carcinoma) to cisplatin. Besides, the pigment did not show genotoxic activity in HeLa cells as found performing micronucleus assays. These results suggest that this pigment may be used as anticancer or sensitizer to cisplatin drug in cervix cancer.

Photoelectric performance evaluation of DSSCs using the dye extracted from different color petals of Leucanthemum vulgare flowers as novel sensitizers.

In this work, the natural flower extracted dyes containing luteolin were prepared using three different specimens from daisy flowers family (Leucanthemum vulgare), namely yellow daisy, purple daisy and wine daisy, according to the color of its petals. Moreover, DSSCs were fabricated using nanosized titanium dioxide (TiO2) as an anode; for the photocathodes, two different specimens were used: i) graphite electrode and ii) platinum electrode. To recognize the light absorption behavior, the existence of anchoring groups and coloring components of the extracted dyes were determined using absorption spectroscopy. The surface roughness of the photoanodes and cathodes were examined using atomic force microscope (AFM). The photovoltaic performance and efficiency of assembled DSSCs were evaluated to realize the influence of TiO2 photoanodes on interaction of the Leucanthemum vulgare extracted dye molecules with graphite or platinum photocathodes. DSSCs fabricated with platinum cathode show higher conversion efficiency (η) of 0.6%, 0.4% and 0.8% for the yellow daisy, wine daisy and purple daisy, respectively. DSSCs sensitized with daisy wine dye showed highest open-circuit voltage (Voc) of 520 mV and efficiency of 0.79% and 0.88%, for the graphite and platinum cathodes, respectively. These results showed that the DSSCs, using daisy flowers extracts as efficient photosensitizers, are suitable for the fabrication of environmentally safe, inexpensive, clean and renewable energy.

Prospective Study of Microbial Colorants under the Focus of Patent Documents.

BACKGROUND: Colorant-producing microorganisms are quite common in nature. These biomolecules present many biological activities such as antitumoral, antimicrobial and antioxidant, in addition to the various nuances of color, making them of special technological importance to the industrial sectors. OBJECTIVE: This study aims to conduct a technological mapping in the patent, at European patent Office (EPO), in order to evaluate the global panorama of the use of microbial colorants. METHODS: The experimental design was acquired by the keyword-driven approach through the advanced search in the Espacenet database European Patent Office (EPO). The keywords selected were bacteria or fungi* or yeast or algae or microorganism* but not plant* and pigment* or color* or colorant* or dye* and the International Patent Classification code, C09B61, for prospecting of interest. RESULTS: There has been a linear increase in patents developed in the last 20 years, with Japan as the largest depositor in the area. The companies Dainippon Ink and Chemicals and Ajinomoto, both being Japanese, are the largest depositors with 20% of all patents. Among the microorganisms, the filamentous fungi appeared in the first place with 32% of documents and the fungi of the genus Monascus were the most frequently used. CONCLUSION: The use of microbial colorants has been growing among industries, mainly in food sectors, due to the growing demand for products of natural origin. Thus, the increase in research and technological development in the area of microbial colorants can become an economically viable and promising strategy for the various industrial sectors.

Nor-guanacastepene pigments from the Chilean mushroom Cortinarius pyromyxa.

For the first time, the pigment composition of basidiocarps from the Chilean mushroom Cortinarius pyromyxa was studied under various aspects like phylogeny, chemistry and antibiotic activity. A molecular biological study supports the monotypic position of C. pyromyxa in subgenus Myxacium, genus Cortinarius. Four undescribed diterpenoids, named pyromyxones A-D, were isolated from fruiting bodies of C. pyromyxa. Their chemical structures were elucidated based on comprehensive one- and two-dimensional NMR spectroscopic analysis, ESI-HRMS measurements, as well as X-ray crystallography. In addition, the absolute configurations of pyromyxones A-D were established with the aid of JH,H, NOESY spectra and quantum chemical CD calculation. The pyromyxones A-D possess the undescribed nor-guanacastane skeleton. Tested pyromyxones A, B, and D exhibit only weak activity against gram-positive Bacillus subtilis and gram-negative Aliivibrio fischeri as well as the phytopathogenic fungi Botrytis cinerea, Septoria tritici and Phytophthora infestans.

Chemical Characterization and Biotechnological Applicability of Pigments Isolated from Antarctic Bacteria.

Considering the global trend in the search for alternative natural compounds with antioxidant and sun protection factor (SPF) boosting properties, bacterial carotenoids represent an opportunity for exploring pigments of natural origin which possess high antioxidant activity, lower toxicity, no residues, and no environmental risk and are readily decomposable. In this work, three pigmented bacteria from the Antarctic continent, named Arthrobacter agilis 50cyt, Zobellia laminarie 465, and Arthrobacter psychrochitiniphilus 366, were able to withstand UV-B and UV-C radiation. The pigments were extracted and tested for UV absorption, antioxidant capacity, photostability, and phototoxicity profile in murine fibroblasts (3T3 NRU PT-OECD TG 432) to evaluate their further potential use as UV filters. Furthermore, the pigments were identified by ultra-high-performance liquid chromatography-photodiode array detector-mass spectrometry (UPLC-PDA-MS/MS). The results showed that all pigments presented a very high antioxidant activity and good stability under exposure to UV light. However, except for a fraction of the A. agilis 50cyt pigment, they were shown to be phototoxic. A total of 18 different carotenoids were identified from 23 that were separated on a C18 column. The C50 carotenes bacterioruberin and decaprenoxanthin (including its variations) were confirmed for A. agilis 50cyt and A. psychrochitiniphilus 366, respectively. All-trans-bacterioruberin was identified as the pigment that did not express phototoxic activity in the 3T3 NRU PT assay (MPE < 0.1). Zeaxanthin, ß-cryptoxanthin, ß-carotene, and phytoene were detected in Z. laminarie 465. In conclusion, carotenoids identified in this work from Antarctic bacteria open perspectives for their further biotechnological application towards a more sustainable and environmentally friendly way of pigment exploitation.

Pigments in an iridescent bacterium, Cellulophaga fucicola, isolated from Antarctica.

An iridescent yellow pigmented bacterium isolated from the Antarctic continent, named Cellulophaga fucicola strain 416, was found to be able to tolerate UV-B radiation. Its crude pigment extract was tested for antioxidant capacity, UV light stability and phototoxicity profile against murine fibroblast lines. The pigments were further isolated and chemically identified by ultra-high-performance liquid chromatography with photodiode array and mass spectrometry detectors. The results showed that the pigment extract presented weak stability under exposure to UV light, a phototoxic profile in the 3t3 Neutral Red Uptake test and a very high antioxidant activity, suggesting that it could be used as food and feed colourants. Zeaxanthin and two isomers of zeaxanthin, ß-cryptoxanthin and ß-carotene, were identified using a C18 column. These five carotenoids were the major pigments isolated from C. fucicola 416. In conclusion, the identification of pigments produced by the bacterial strain under study may help us understand how bacteria thrive in high UV and cold environments, and opens avenues for further biotechnological application towards a more sustainable and environmentally friendly way of pigment exploitation.

Purification and characterization of indochrome type blue pigment produced by Pseudarthrobacter sp. 34LCH1 isolated from Atacama desert.

The interest in and demand for natural dyes has increased significantly in recent years; however, very few natural blue dyes are commercially available, because blue colored compounds in nature are relatively rare. In this study, a blue pigment-producing bacteria from Lake Chungará (Atacama Desert, Chile) was isolated, and its blue pigment was purified and chemically characterized. The pigment-producing strain was identified as Pseudarthrobacter sp. by 16S rRNA gene sequencing. The pigment was separated from the filtered culture medium by column chromatography/solid-phase extraction using different resins (ionic exchange, C-18, size exclusion). The strain produced up to 2.5 g L-1 of blue pigment, which was very soluble in water, partially soluble in methanol and insoluble in other organic solvents. The pigment was analyzed and characterized by analytical HPLC, UV-Vis, FT-IR, and H-NMR, and purified by semi-preparative HPLC. The pigment was non-toxic to brine shrimp (LD50 > 2.3 g L-1) and was stable at pH 6-10 at temperatures below 60 °C. HPLC analysis shows that the pigment is composed of four major blue fractions. The physicochemical properties and structural analysis demonstrate that this pigment belongs to the indochrome isomers, whose properties have yet to have been characterized. The high solubility in water, good stability in neutral and basic pH, and negligible toxicity of the blue pigment make it a good candidate suitable for several industrial and possibly some food applications.

Inclusion complexes of yellow bell pepper pigments with ß-cyclodextrin: preparation, characterisation and application as food natural colorant.

BACKGROUND: This work aimed to prepare inclusion complexes using yellow bell pepper pigments and ß-cyclodextrin by two different procedures (method A, ultrasonic homogenisation; method B, kneading), to characterise them and evaluate their colour stability in an isotonic beverage model. The extract/ß-cyclodextrin ratio was 1:2 for both inclusion methodologies evaluated. The formed extract-ß-cyclodextrin complexes and a physical mixture of extract and ß-cyclodextrin were evaluated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). RESULTS: Both methodologies resulted in good complex yield and inclusion efficiency. The colour indices L* (lightness), a* (green/red) and b* (blue/yellow) of isotonic drinks added with the complexes were measured during storage under irradiance (1400 lx) and in the absence of light at temperatures between 25 and 31 °C for 21 days. CONCLUSION: The complex obtained by inclusion method B promoted better colour protection for the beverage compared with the use of the crude extract, showing that the molecular inclusion of yellow bell pepper carotenoids can provide good results for that purpose. © 2017 Society of Chemical Industry.

Natural colorants from filamentous fungi.

In the last years, there is a trend towards the replacement of synthetic colorants by natural ones, mainly due to the increase of consumer demand for natural products. The natural colorants are used to enhance the appearance of pharmaceutical products, food, and different materials, making them preferable or attractive. This review intends to provide and describe a comprehensive overview of the history of colorants, from prehistory to modern time, of their market and their applications, as well as of the most important aspects of the fermentation process to obtain natural colorants. Focus is given to colorants produced by filamentous fungal species, aiming to demonstrate the importance of these microorganisms and biocompounds, highlighting the production performance to get high yields and the aspects of conclusion that should be taken into consideration in future studies about natural colorants.

Extraction and purification of high-value metabolites from microalgae: essential lipids, astaxanthin and phycobiliproteins.

The marked trend and consumers growing interest in natural and healthy products have forced researches and industry to develop novel products with functional ingredients. Microalgae have been recognized as source of functional ingredients with positive health effects since these microorganisms produce polyunsaturated fatty acids, polysaccharides, natural pigments, essential minerals, vitamins, enzymes and bioactive peptides. For this reason, the manuscript reviews two of the main high-value metabolites which can be obtained from microalgae: pigments and essential lipids. Therefore, the extraction and purification methods for polyunsaturated fatty acids, astaxanthin, phycoerythrin and phycocyanin are described. Also, the effect that environmental growth conditions have in the production of these metabolites is described. This review summarizes the existing methods to extract and purify such metabolites in order to develop a feasible and sustainable algae industry.

Improvement of submerged culture conditions to produce colorants by Penicillium purpurogenum.

Safety issues related to the employment of synthetic colorants in different industrial segments have increased the interest in the production of colorants from natural sources, such as microorganisms. Improved cultivation technologies have allowed the use of microorganisms as an alternative source of natural colorants. The objective of this work was to evaluate the influence of some factors on natural colorants production by a recently isolated from Amazon Forest, Penicillium purpurogenum DPUA 1275 employing statistical tools. To this purpose the following variables: orbital stirring speed, pH, temperature, sucrose and yeast extract concentrations and incubation time were studied through two fractional factorial, one full factorial and a central composite factorial designs. The regression analysis pointed out that sucrose and yeast extract concentrations were the variables that influenced more in colorants production. Under the best conditions (yeast extract concentration around 10 g/L and sucrose concentration of 50 g/L) an increase of 10, 33 and 23% respectively to yellow, orange and red colorants absorbance was achieved. These results show that P. purpurogenum is an alternative colorants producer and the production of these biocompounds can be improved employing statistical tool.

Characterization of phenolic compounds in Brazilian pepper (Schinus terebinthifolius Raddi) exocarp.

The objective of this study was to characterize the phenolic composition of Brazilian pepper (Schinus terebinthifolius Raddi) exocarp extract. Using UHPLC-DAD-MS/MS analysis, four anthocyanins, three biflavonoids, gallic acid, and two types of hydrolyzable tannins (galloyl glucoses, galloyl shikimic acids) were tentatively identified. The structure of the so far unknown 7-O-methylpelargonidin 3-O-ß-D-galactopyranoside was elucidated by 2D NMR. Within the group of gallotannins, galloyl shikimic acids with uncommon degrees of galloylation (tetra- to hexagalloyl shikimic acids) were detected. Among the biflavonoids, I3',II8-biapigenin (amentoflavone), I6,II8-biapigenin (agathisflavone), and II-2,3-dihydro-I3',II8-biapigenin were identified, which have already been described for Anacardiaceae. From the results of the present study together with previous findings on the phenolic profile of other Anacardiaceae plants, it is concluded that 7-methoxylated flavonoids are a chemotaxonomic trait frequently found in this family.

Improvement of submerged culture conditions to produce colorants by Penicillium purpurogenum

Safety issues related to the employment of synthetic colorants in different industrial segments have increased the interest in the production of colorants from natural sources, such as microorganisms. Improved cultivation technologies have allowed the use of microorganisms as an alternative source of natural colorants. The objective of this work was to evaluate the influence of some factors on natural colorants production by a recently isolated from Amazon Forest, Penicillium purpurogenum DPUA 1275 employing statistical tools. To this purpose the following variables: orbital stirring speed, pH, temperature, sucrose and yeast extract concentrations and incubation time were studied through two fractional factorial, one full factorial and a central composite factorial designs. The regression analysis pointed out that sucrose and yeast extract concentrations were the variables that influenced more in colorants production. Under the best conditions (yeast extract concentration around 10 g/L and sucrose concentration of 50 g/L) an increase of 10, 33 and 23% respectively to yellow, orange and red colorants absorbance was achieved. These results show that P. purpurogenum is an alternative colorants producer and the production of these biocompounds can be improved employing statistical tool.

Improvement of submerged culture conditions to produce colorants by Penicillium purpurogenum

Safety issues related to the employment of synthetic colorants in different industrial segments have increased the interest in the production of colorants from natural sources, such as microorganisms. Improved cultivation technologies have allowed the use of microorganisms as an alternative source of natural colorants. The objective of this work was to evaluate the influence of some factors on natural colorants production by a recently isolated from Amazon Forest, Penicillium purpurogenum DPUA 1275 employing statistical tools. To this purpose the following variables: orbital stirring speed, pH, temperature, sucrose and yeast extract concentrations and incubation time were studied through two fractional factorial, one full factorial and a central composite factorial designs. The regression analysis pointed out that sucrose and yeast extract concentrations were the variables that influenced more in colorants production. Under the best conditions (yeast extract concentration around 10 g/L and sucrose concentration of 50 g/L) an increase of 10, 33 and 23% respectively to yellow, orange and red colorants absorbance was achieved. These results show that P. purpurogenum is an alternative colorants producer and the production of these biocompounds can be improved employing statistical tool.

Inclusion complexes of red bell pepper pigments with ß-cyclodextrin: preparation, characterisation and application as natural colorant in yogurt.

This work aimed to prepare inclusion complexes between red bell pepper pigments and ß-cyclodextrin using two different procedures (i.e., magnetic stirring and ultrasonic homogenisation), to characterise the prepared inclusion complexes and to evaluate the colour stability of a selected complex added to yogurt. The mass ratio of extract to ß-cyclodextrin was 1:4. The formed extract: ß-cyclodextrin complexes and a physical mixture of extract and ß-cyclodextrin were evaluated by differential scanning calorimetry, Fourier transform-infrared spectroscopy, proton nuclear magnetic resonance, particle size distribution and Zeta potential. The obtained data showed that ultrasonic homogenisation resulted in better yield and inclusion efficiency compared to magnetic stirring. The yogurt with the added complex produced by ultrasonic homogenisation showed slower variations for the a(∗) (redness) and b(∗) (yellowness) indices compared to yogurt with added extract, indicating a higher protection of the colour during storage.

Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae).

Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and ¹H-NMR, 16 different carotenoid molecules were documented in the plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, α-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3'-hydroxy-3-methoxy-ß,ß-carotene-4-one, which we name rupicolin. The diversity of cotinga plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, ß-cryptoxanthin, and ß-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga plumage carotenoid diversity was analyzed with reflectance spectrophotometry of plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors.

Colour evaluation of a phycobiliprotein-rich extract obtained from Nostoc PCC9205 in acidic solutions and yogurt.

BACKGROUND: Phycobiliproteins are coloured proteins produced by cyanobacteria, which have several applications because of their colour properties. However, there is no available information about the colour stability of phycobiliproteins from Nostoc sp. in food systems. The aim of this work was to study the colour stability of a purple-coloured phycobiliprotein-rich extract from the cyanobacterium Nostoc PCC9205 in acidic solutions and yogurt. RESULTS: Variations of pH for Nostoc PCC9205 extract have shown stability for the L* (lightness) and a* (redness) indexes in the range 1.0-7.0. The b* index (blueness), however, increased at pH values below 4.0, indicating loss of the blue colour. The Nostoc PCC9205 extract was used as colorant in yogurt (pH 4.17) stored for 60 days. Instrumental colour analysis showed no changes for the L* and a* indexes during storage, whereas the b* index changed after 20 days of storage. A multiple comparison test showed colour instability after 20 days of storage. A hedonic scale test performed on the 60th day of storage showed acceptability of the product. CONCLUSIONS: The red component of the phycobiliprotein-rich extract from Nostoc PCC9205 presented an improved stability in acidic media and yogurt compared with the blue component of this extract.

Azaphilones from the endophyte Chaetomium globosum.

Six new azaphilones, 5'-epichaetoviridin A (7), 4'-epichaetoviridin F (9), 12ß-hydroxychaetoviridin C (10), and chaetoviridins G-I (11-13), and six known azaphilones, chaetoviridins A-E (1-5) and 4'-epichaetoviridin A (8), were isolated from the endophytic fungus Chaetomium globosum cultivated in PDB medium for 21 days. The structure elucidation and the assignment of the relative configurations of the new natural products were based on detailed NMR and MS spectroscopic analyses. The structure of compound 1 was confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of compounds 4, 7, 8, and 12 were determined using Mosher's method. The antibiotic activity of the compounds was evaluated using an in vivo Caenorhabditis elegans infection model.