Trentin_2025_Biomolecules_15_

Antarctic algae have evolved in extreme environmental conditions, developing unique metabolic adaptations with significant biotechnological potential. In this study, we explored the bioactivity of the sea-ice microalga Microglena antarctica by preparing acetone and methanol extracts from biomass cultivated at 4, 8, and 16 degreesC. These extracts were screened for their in vitro antioxidant properties and inhibitory activities on enzymes related to Alzheimer's disease (acetylcholinesterase: AChE, butyrylcholinesterase: BChE), type 2 diabetes mellitus (T2DM, alpha-glucosidase, alpha-amylase), obesity (lipase), and hyperpigmentation (tyrosinase). Our screening revealed a high capacity of acetone extracts to scavenge the ABTS(+) radical (EC(50) ranging from 3.57 to 4.18 mg mL(-1)), along with strong copper chelating activity in both acetone and methanol extracts (EC(50) values of 6.31 and 6.41 mg mL(-1)). Relevant inhibition towards alpha-amylase (IC(50) values of 3.34 and 4.53 mg mL(-1)) and tyrosinase (with IC(50) ranging from 3.82 to 5.47 mg mL(-1)) was reported for acetone and methanol extracts, respectively. UHPLC-HRMS-based profiling revealed the presence of lipidic molecules, such as glycolipids, phospholipids, and betaine lipids with polyunsaturated carbon chains, together with carotenoids, including canthaxanthin and adonixanthin, which are likely responsible for the observed bioactivities.