Antioxidant properties and UV absorbance pattern of mycosporine-like amino acids analogs synthesized in an environmentally friendly manner

Molecular mechanisms of Marine-Derived Natural Compounds as photoprotective strategies

Excessive exposure of the skin to ultraviolet radiation (UVR) causes oxidative stress, inflammation, immunosuppression, apoptosis, and changes in the extracellular matrix, which lead to the development of photoaging and photodamage of skin. At the molecular level, these pathological changes are mainly caused by the activation of related protein kinases and downstream transcription pathways, the increase of matrix metalloproteinase, the formation of reactive oxygen species, and the combined action of cytokines and inflammatory mediators. At present, the photostability, toxicity, and damage to marine ecosystems of most sun protection products in the market have affected their efficacy and safety. Another way is to use natural products produced by various marine species. Marine organisms have evolved a variety of molecular strategies to protect themselves from the harmful effects of ultraviolet radiation, and their unique chemicals have attracted more and more attention in the research of photoprotection and photoaging resistance. This article provides an extensive description of the recent literature on the potential of Marine-Derived Natural Compounds (MDNCs) as photoprotective and photoprotective agents. It reviews the positive effects of MDNCs in counteracting UV-induced oxidative stress, inflammation, DNA damage, apoptosis, immunosuppression, and extracellular matrix degradation. Some MDNCs have the potential to develop feasible solutions for related phenomena, such as photoaging and photodamage caused by UVR.

Insights into agar and secondary metabolite pathways from the genome of the red alga Gracilaria domingensis (Rhodophyta, Gracilariales)

Gracilariales is a clade of florideophycean red macroalgae known for being the main source of agar. We present a de novo genome assembly and annotation of Gracilaria domingensis, an agarophyte alga with flattened thallus widely distributed along Central and South American Atlantic intertidal zones. In addition to structural analysis, an organizational comparison was done with other Rhodophyta genomes. The nuclear genome has 78 Mbp, with 11,437 predicted coding genes, 4,075 of which did not have hits in sequence databases. We also predicted 1,567 noncoding RNAs, distributed in 14 classes. The plastid and mitochondrion genome structures were also obtained. Genes related to agar synthesis were identified. Genes for type II galactose sulfurylases could not be found. Genes related to ascorbate synthesis were found. These results suggest an intricate connection of cell wall polysaccharide synthesis and the redox systems through the use of L-galactose in Rhodophyta. The genome of G. domingensis should be valuable to phycological and aquacultural research, as it is the first tropical and Western Atlantic red macroalgal genome to be sequenced.

Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family

Mycosporine-like amino acids are a prevalent form of photoprotection in micro- and macro-organisms. Using a combination of natural product extraction/purification and femtosecond transient absorption spectroscopy, we studied the relaxation pathway for a common mycosporine-like amino acid pair, usujirene and its geometric isomer palythene, in the first few nanoseconds following photoexcitation. Our studies show that the electronic excited state lifetimes of these molecules persist for only a few hundred femtoseconds before the excited state population is funneled through an energetically accessible conical intersection with subsequent vibrational energy transfer to the solvent. We found that a minor portion of the isomer pair did not recover to their original state within 3 ns after photoexcitation. We investigated the long-term photostability using continuous irradiation at a single wavelength and with a solar simulator to mimic a more real-life environment; high levels of photostability were observed in both experiments. Finally, we employed computational methods to elucidate the photochemical and photophysical properties of usujirene and palythene as well as to reconcile the photoprotective mechanism.

Mycosporine-Like Amino Acids (MAAs): Biology, Chemistry and Identification Features

Mycosporines and mycosporine-like amino acids are ultra-violet-absorbing compounds produced by several organisms such as lichens, fungi, algae and cyanobacteria, especially upon exposure to solar ultraviolet radiation. These compounds have photoprotective and antioxidant functions. Mycosporine-like amino acids have been used as a natural bioactive ingredient in cosmetic products. Several reviews have already been developed on these photoprotective compounds, but they focus on specific features. Herein, an extremely complete database on mycosporines and mycosporine-like amino acids, covering the whole class of these natural sunscreen compounds known to date, is presented. Currently, this database has 74 compounds and provides information about the chemistry, absorption maxima, protonated mass, fragments and molecular structure of these UV-absorbing compounds as well as their presence in organisms. This platform completes the previous reviews and is available online for free and in the public domain. This database is a useful tool for natural product data mining, dereplication studies, research working in the field of UV-absorbing compounds mycosporines and being integrated in mass spectrometry library software.

Mycosporine-Like Amino Acids for Skin Photoprotection

BACKGROUND

Excessive human exposure to solar ultraviolet radiation (UVR) continues to be a major public health concern, with skin cancer rates increasing year on year. The major protective measure is the use of synthetic UVR filters formulated into sunscreens, but there is a growing concern that some of these chemicals cause damage to delicate marine ecosystems. One alternative is the use of biocompatible mycosporine-like amino acids (MAA), which occur naturally in a wide range of marine species. Their role within nature is mainly thought to be photoprotective. However, their potential for human photoprotection is largely understudied.

OBJECTIVE

To review the role of MAA in nature and assess their potential as natural sunscreens for human skin photoprotection.

METHOD

A literature review of all relevant papers was conducted.

CONCLUSION

MAA are natural photostable compounds that are thought to offer photoprotection to marine species. Initially thought of as protective based on their absorption properties in the solar UVR spectrum, it is clear that MAA are multifunctional photoprotective compounds acting as chemical and biological anti-oxidants. This suggests that MAA may offer a novel eco-friendly approach to human skin photoprotection. Most studies have been carried out in vitro and current data strongly suggest that MAA have potential for development as natural biocompatible sunscreens that protect against a diverse range of solar UVR induced adverse effects on human health.

Mycosporine-Like Amino Acids: Potential Health and Beauty Ingredients

Human skin is constantly exposed to damaging ultraviolet radiation (UVR), which induces a number of acute and chronic disorders. To reduce the risk of UV-induced skin injury, people apply an additional external protection in the form of cosmetic products containing sunscreens. Nowadays, because of the use of some chemical filters raises a lot of controversies, research focuses on exploring novel, fully safe and highly efficient natural UV-absorbing compounds that could be used as active ingredients in sun care products. A promising alternative is the application of multifunctional mycosporine-like amino acids (MAAs), which can effectively compete with commercially available filters. Here, we outline a complete characterization of these compounds and discuss their enormous biotechnological potential with special emphasis on their use as sunscreens, activators of cells proliferation, anti-cancer agents, anti-photoaging molecules, stimulators of skin renewal, and functional ingredients of UV-protective biomaterials.

Chemical Diversity and Biological Properties of Secondary Metabolites from Sea Hares of Aplysia Genus

The marine environment is an important source of structurally-diverse and biologically-active secondary metabolites. During the last two decades, thousands of compounds were discovered in marine organisms, several of them having inspired the development of new classes of therapeutic agents. Marine mollusks constitute a successful phyla in the discovery of new marine natural products (MNPs). Over a 50-year period from 1963, 116 genera of mollusks contributed innumerous compounds, Aplysia being the most studied genus by MNP chemists. This genus includes 36 valid species and should be distinguished from all mollusks as it yielded numerous new natural products. Aplysia sea hares are herbivorous mollusks, which have been proven to be a rich source of secondary metabolites, mostly of dietary origin. The majority of secondary metabolites isolated from sea hares of the genus Aplysia are halogenated terpenes; however, these animals are also a source of compounds from other chemical classes, such as macrolides, sterols and alkaloids, often exhibiting cytotoxic, antibacterial, antifungal, antiviral and/or antifeedant activities. This review focuses on the diverse structural classes of secondary metabolites found in Aplysia spp., including several compounds with pronounced biological properties.

Nrf2 and NF-κB Signaling Pathways Contribute to Porphyra-334-Mediated Inhibition of UVA-Induced Inflammation in Skin Fibroblasts

In this study, we examined the protective effects of porphyra-334 against UVA-irradiated cellular damage and elucidated the underlying mechanisms. Porphyra-334 prevented UVA-induced cell death and exhibited scavenging activities against intracellular oxidative stress induced by UVA irradiation in skin fibroblasts. We found that porphyra-334 significantly reduced the secretion and expression of IL-6 and TNF-α, reduced nuclear expression of Nuclear factor-κB (NF-κB), and sustained NF-E2-related factor 2 (Nrf2) activation. Further mechanism research revealed that porphyra-334 promoted the Nrf2 signaling pathway in UVA-irradiated skin fibroblasts. Our results show that the antioxidant effect of porphyra-334 is due to the direct scavenging of oxidative stress and its inhibitory effects on NF-κB-dependent inflammatory genes, such as IL-6 and TNF-κ. Therefore, we hypothesize that boosting the Nrf2- NF-κB-dependent response to counteract environmental stress is a promising strategy for the prevention of UVA-related damage.

O-Methyltransferase is shared between the pentose phosphate and shikimate pathways and is essential for mycosporine-like amino acid biosynthesis in Anabaena variabilis ATCC 29413

The parent core structure of mycosporine-like amino acids (MAAs) is 4-deoxygadusol, which, in cyanobacteria, is derived from conversion of the pentose phosphate pathway intermediate sedoheptulose 7-phosphate by the enzymes 2-epi-5-epivaliolone synthase (EVS) and O-methyltransferase (OMT). Yet, deletion of the EVS gene from Anabaena variabilis ATCC 29413 was shown to have little effect on MAA production, thus suggesting that its biosynthesis is not exclusive to the pentose phosphate pathway. Herein, we report how, using pathway-specific inhibitors, we demonstrated unequivocally that MAA biosynthesis occurs also via the shikimate pathway. In addition, complete in-frame gene deletion of the OMT gene from A. variabilis ATCC 29413 reveals that, although biochemically distinct, the pentose phosphate and shikimate pathways are inextricably linked to MAA biosynthesis in this cyanobacterium. Furthermore, proteomic data reveal that the shikimate pathway is the predominate route for UV-induced MAA biosynthesis.

Protective effect of porphyra-334 on UVA-induced photoaging in human skin fibroblasts

The significant increase in life expectancy is closely related to the growing interest in the impact of aging on the function and appearance of the skin. Skin aging is influenced by several factors, and solar ultraviolet (UV) irradiation is considered one of the most important causes of skin photoaging. The aim of this study was to examine the anti-photoaging role of porphyra-334 from Porphyra (P.) yezoensis, a mycosporine-like amino acid (MAA), using high-performance liquid chromatography (HPLC), and electrospray ionization-mass spectrometry (ESI-MS). In the present study, extracted UV-absorbing compounds from P. yezoensis included palythine, asterina-330 and porphyra-334. Porphyra-334 was the most abundant MAA in P. yezoensis, and it was therefore used for conducting antiphotoaging experiments. The effect of porphyra-334 on the prevention of photoaging was investigated by measuring reactive oxygen species (ROS) production and matrix metalloproteinase (MMP) levels, as well as extracellular matrix (ECM) components and protein expression in UVA-irradiated human skin fibroblasts. Porphyra-334 suppressed ROS production and the expression of MMPs following UVA irradiation, while increasing levels of ECM components, such as procollagen, type I collagen, elastin. These results suggest that porphyra-334 has various applications in cosmetics and toiletries because of its anti-photoaging activities and may serve as a novel anti-aging agent.

Contrasting patterns of MAAs accumulation in two populations of the copepod Boeckella gracilipes

The bio-accumulation of mycosporine-like amino acids (MAAs) is common in planktonic copepods that inhabit environments exposed to high levels of solar radiation. MAAs accumulation in copepods can be affected both by extrinsic (environmental) and intrinsic factors (local adaptation, genotype, etc.). Laboratory experiments were performed to study the bio-accumulation of MAAs in two geographically-isolated populations of Boeckella gracilipes from a mountain and a piedmont lake of North Patagonia. We performed two series of 10-day incubations of B. gracilipes from the different lakes applying two radiation conditions (PAR + UVR and darkness), at five different temperatures (5 to 20 °C) and providing a MAA-free flagellate as food. We assumed that differences in final MAAs concentrations between copepod populations should be exclusively due to environmental factors, and that any difference in the patterns of MAAs accumulation should exclusively arise from differences in MAAs concentration at the time of collection. MAAs concentration was three fold higher in B. gracilipes from Lake Verde than in copepods from the Lake Morenito. The MAAs suite was dominated (∼90%) by a combination of porphyra-334 and mycosporine-glycine in copepods from Lake Verde, and porphyra-334 and MAA-332 in those from Lake Morenito. Two exclusive MAA compounds were identified, mycosporine-glycine in copepods from Lake Verde and shinorine in the copepod population from Lake Morenito. Laboratory experiments showed that: (i) exposure to PAR + UVR stimulated the accumulation of MAAs in both copepod populations; (ii) temperature affected the response of MAAs and, remarkably, low temperatures stimulated MAAs accumulation even in dark incubations, (iii) the response to radiation and temperature in MAAs accumulation was more pronounced in the population with low initial MAAs than in the population with high initial MAAs concentrations. The differences in intrinsic factors between B. gracilipes populations, such as local adaptation to contrasting UV and temperature scenarios, among others, appear to play an important role in determining levels and patterns of MAAs accumulation in B. gracilipes.