Photoprotective compounds from marine organisms

Abstract

The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth's surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and several other UV-absorbing substances of unknown chemical structure have been identified from different organisms. MAAs form the most common class of UV-absorbing compounds known to occur widely in various marine organisms; however, several compounds having UV-screening properties still need to be identified. The synthesis of scytonemin, a predominant UV-A-photoprotective pigment, is exclusively reported in cyanobacteria. Carotenoids are important components of the photosynthetic apparatus that serve both light-harvesting and photoprotective functions, either by direct quenching of the singlet oxygen or other toxic reactive oxygen species or by dissipating the excess energy in the photosynthetic apparatus. The production of photoprotective compounds is affected by several environmental factors such as different wavelengths of UVR, desiccation, nutrients, salt concentration, light as well as dark period, and still there is controversy about the biosynthesis of various photoprotective compounds. Recent studies have focused on marine organisms as a source of natural bioactive molecules having a photoprotective role, their biosynthesis and commercial application. However, there is a need for extensive work to explore the photoprotective role of various UV-absorbing compounds from marine habitats so that a range of biotechnological and pharmaceutical applications can be found.

Mycosporine-Like Amino Acids from Coral Dinoflagellates

“…Additionally, it has been proposed that MAAs are involved in the stress response during drought, as the production of photoprotective compounds such as MAAs, as well as carotenoids and some other UV-absorbing substances, was influenced by environmental stress, including desiccation (74). A study of cyanobacteria showed a positive correlation between MAA synthesis and exposure to drought and irradiation stress (101).…”

Evaluation of Antioxidant and Cytotoxic Properties of Cyanobacteria, Limnothrix Sp. And Leptolyngbya Sp. From Arabian Sea

“…Flavanoids are a class of low molecular weight natural polyphenoic compounds that have the ability to donate a hydrogen atom or an electron in order to form stable radical intermediates, which renders them antioxidant properties (Hajimahmoodi et al, 2010). Their chemical diversity, absorption properties and biotechnological potentials as antioxidant, antibacterial, antioncogenic and antiinflammatory agents are reviewed (Rastogi et al, 2010;Ververdis et al, 2007). The antioxidant activity of hexane fractions of Limnothrix sp and Leptolyngbya sp were confirmed using ABTS decolouration assay, DPPH radical scavenging activity and total antioxidant activity by FRAP assay.…”

Heterologous Production of Cyanobacterial Mycosporine-Like Amino Acids Mycosporine-Ornithine and Mycosporine-Lysine in Escherichia coli

“…ycosporine-like amino acids (MAAs) are commonly found in marine microbes exposed to high levels of UV radiation, including aquatic fungi, eukaryotic algae, and cyanobacteria (1)(2)(3)(4)(5)(6). These small (Ͻ400 Da), colorless, water-soluble compounds are composed of a 4-deoxygadusol core conjugated with an amino acid or alcohol (7).…”