Bioprospecting of microalgae for a potential use as enzyme inhibitors, anti-ageing and prebiotic agents

Microalgae are an important source of biologically active metabolites and hold prominence towards pharmaceutical and nutraceutical applications. The current research focused on the discovery of new bioresources with interesting neuroprotective, anti-ageing, prebiotic and antidiabetic potential. Ethanol extracts from Chlamydomonas sp.EL5, Chloroidium saccharophilum. Mon1, and Nostoc. sp were bioprospected for high value biomolecules. Chlamydomonas sp.EL5 had the highest carotenoids content (1.2 mg/gDE) whereas Nostoc sp. had higher total phenolic content (52.5 mgGAE/gDE). All species had potent (>50% inhibition), and moderate (30-50% inhibition) cholinesterase inhibitory activity. The highest anti-diabetic performance (64%) was detected in Nostoc sp.'s extract at 5 mg/ml. The extracts had a prominent capacity to chelate Fe2+ ions even at low concentration (1 mg/ml). The potential value in preventing skin aging could be confirmed through potential of Chlamydomonas sp.EL5 on free radical scavenging ability and collagenase inhibitory activity. The increase in the Lactobacillus plantarum growth performance indicated that these microalgae are serious candidates to be considered as prebiotics. GC-MS analysis indicated that linoleic acid (C18:2.6) and linolenic acid (C18:3.3) are the ones with the highest content among the unsaturated fatty acids. These results strongly suggest that the studied microalgae could be considered sources of high-value co-products that could be used to upgrade the pharmaceutical, cosmeceutical and/or food products value.