Antioxidant activity of mycosporine-like amino acids isolated from three red macroalgae and one marine lichen

Abstract

Several standard in vitro assays were performed in order to determine the potential antioxidant capabilities of purified aqueous extracts of the mycosporine-like amino acids (MAAs), porphyra-334 plus shinorine (P-334 + SH), isolated from the red alga Porphyra rosengurttii, asterina-330 plus palythine (AS-330 + PNE), from the red alga Gelidium corneum, shinorine (SH), from the red alga Ahnfeltiopsis devoniensis, and mycosporine -glycine (MGly), isolated from the marine lichen Lichina pygmaea. The scavenging potential of hydrosoluble radicals (ABTS + decolorization method), the antioxidant activity in lipid medium (β-carotene/ linoleate bleaching method) and the scavenging capacity of superoxide radicals (pyrogallol autooxidation assay) were evaluated. In terms of scavenging of hydrosoluble radicals, the antioxidant activity of all MAAs studied was dose-dependent and it increased with the alkalinity of the medium (pH 6 to 8.5). M-Gly presented the highest activity in all pH tested; at pH 8.5 its IC 50 was 8-fold that of L-ascorbic acid (L-ASC) followed by AS-330 + PNE while P-334 + SH and SH showed scarce activity of scavenging of hydrosoluble free radicals. AS-330 + PNE showed high activity for inhibition of β-carotene oxidation relative to vitamin E and superoxide radical scavenging whilst the activity of P-334 +SH and SH were moderate. According to these results, the potential of MAAs in photoprotection can be considered high due to a double function: (1) UV chemical screening with high efficiency for UVB and UVA regions of the solar spectrum, and (2) their antioxidant capacity.

Short-term ecophysiological and biochemical responses of Cystoseira tamariscifolia and Ellisolandia elongata to environmental changes

“…However, the effect of nutrients was reflected by a preferential accumulation of some types of MAAs, but only in E. elongata collected from 2.0 m depth. The relative content of palythine in creased in nutrient-enriched algae, which has been associated with higher antioxidant activities compared to shinorine (de la Coba et al 2009). …”

“…reversible changes in photosynthetic efficiency and capacity, accumulation of ultraviolet screen compounds and increase of antioxidant activity . For instance, brown algae accumulate UV screen compounds (polyphenols) with a strong antioxidant activity under high photosynthetically active radiation (PAR) and UVR (Pavia et al 1997, Connan et al 2004, Cruces et al 2012, whereas the tolerance of most red algae to excessive light, including UV, is driven by the accumulation of mycosporine-like amino acids (MAAs) (de la Coba et al 2009). …”

A novel in situ system to evaluate the effect of high CO2 on photosynthesis and biochemistry of seaweeds

“…Al though no effect on total MAA content was found in E. elongata, a tendency to accumulate relatively more palythine under high CO 2 was ob served. It is known that palythine possesses a higher antioxidant capacity than the other MAAs (De la Coba et al 2009). Thus, even though this species may show a loss of carbonate skeleton under OA, it could still maintain high photoprotective and antioxidant capacities.…”

Mycosporine-Like Amino Acids from Coral Dinoflagellates

“…Beyond the well-recognized role of MAAs as natural sunscreens, some MAAs also demonstrate strong antioxidant capacity during photooxidative stress caused by ROS production. A number of in vitro studies indicated a role for MAAs as an antioxidant in scavenging ROS (30) and suppressing singlet oxygen-induced damage (22,73,97). Exposure to UVR has been shown to lead to DNA damage either directly or indirectly through ROS production, while UVR-induced DNA damage activates DNA repair enzymes or leads to apoptosis (10,12,42).…”