Assessment of the photoprotective potential and structural characterization of secondary metabolites of Antarctic fungus Arthrinium sp.

Interest in Antarctic fungi has grown due to their resilience in harsh environments, suggesting the presence of valuable compounds from its organisms, such as those presenting photoprotective potential, since this environment suffers the most dangerous UV exposure in the world. Therefore, this research aimed to assess the photoprotective potential of compounds from sustainable marine sources, specifically seaweed-derived fungi from Antarctic continent. These studies led to discovery of photoprotective and antioxidant properties of metabolites from Arthrinium sp., an endophytic fungus from Antarctic brown algae Phaeurus antarcticus. From crude extract, fractions A-I were obtained and compounds 1-6 isolated from E and F fractions, namely 3-Hydroxybenzyl alcohol (1), (-)-orthosporin (2), norlichexanthone (3), anomalin B (4), anomalin A (5), and agonodepside B (6). Compounds 1, 2, and 6 were not previously reported in Arthrinium. Fraction F demonstrated excellent absorbance in both UVA and UVB regions, while compound 6 exhibited lower UVB absorbance, possibly due to synergistic effects. Fraction F and compound 6 displayed photostability and were non-phototoxic to HaCaT cells. They also exhibited antioxidant activity by reducing intracellular ROS production induced by UVA in keratinocyte monolayers and reconstructed human skin models (resulting in 34.6% and 30.2% fluorescence reduction) and did not show irritation potential in HET-CAM assay. Thus, both are promising candidates for use in sunscreens. It is noted that Fraction F does not require further purification, making it advantageous, although clinical studies are necessary to confirm its potential applicability for sunscreen formulations.

Investigation of the possible protective effect of Smilax fluminensis steud. leaf in mice subjected to oxidative stress by paracetamol

Paracetamol (PCM) is a drug widely used by the population as an antipyretic and analgesic. If administered in high doses it can cause liver damage, leading to hepatoxicity. The genus Smilax, found in temperate and tropical regions, is traditionally used by the population through the extract of leaves and roots for several conditions, such as in the treatment of syphilis, diabetes, asthma and as a diuretic action. Through this, Smilax fluminensis leaf extracts were used to evaluate the protective effect against oxidative stress induced by a high dose of PCM in mice that received the drug and after receiving treatment with crude extract and fractions. Plasma analysis was performed using as partate aminotransferase (AST), alanine aminotransferase (ALT), glucose, triglycerides and cholesterol, in addition to biochemical techniques such as catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH), ascorbic acid (ASA), substances reactive to thiobarbituric acid (TBARS) and carbonylated proteins (CARBONYL) of liver, brain and kidneys. Fraction 1 of the extract was the most promising, decreasing the plasma levels of AST and ALT, the levels of CAT and GST of the liver, together with GSH and in the renal and brain tissue there was a decrease in carbonylated proteins (PCM + F1 versus PCM ). Besides, fraction 1 proved to be hypoglycemic and hypocholesterolemic. It is concluded that fraction 1 of Smilax fluminensis leaves has good antioxidant activity in the face of the damage caused by the high dose of paracetamol.