Characterization and evaluation of small molecular bioactives and polysaccharides from the phaeophytic marine macroalga Sargassum wightii family Sargassaceae as defense metabolites against oxidative stress induced diseases

Abstract

Marine organisms, specifically marine macroalgae represent an extraordinary reservoir of biologically active chemical entities with potential medicinal characteristics and added health benefits. Among various brown marine macroalgae belonging to the family Sargassaceae, only fewer studies have been reported from Sargassum wightii, even though they are predominantly available in the coastal shelf areas of southeastern coast of Indian subcontinent. The present study envisages a systematic approach to isolate and characterize antioxidative bioactive leads from S. wightii (Greville) J. Agardh and the approach involved chemical profiling coupled with the evaluation of biological activity with reference to inflammation, diabetics, hypertension, and dyslipidemia. newlineAntioxidant, anti-inflammatory, antidiabetic, and antihypertensive activities of ethyl acetate:methanol (EtOAc:MeOH) and chloroform (CHCl3) solvent fractions of S. wightii were evaluated using different in vitro assays. Bio-assay guided fractionation of the EtOAc:MeOH extract of S. wightii yielded two previously undescribed antioxidative aryl polyketide lactones and the title compounds displayed considerably greater 5-lipoxygenase (5-LOX) inhibitory activity (IC50 0.29-0.56 mg/mL) in conjunction with higher selectivity indices {anti-cyclooxygenase-1 (COX-1)IC50/anti- cyclooxygenase-2 (COX-2)IC50 gt 1} compared to the non-steroidal anti-inflammatory drugs (SIaspirin 0.03, SIibuprofen 0.43). Antioxidative fridooleanene triterpenoids isolated from EtOAc:MeOH extract reported significant protein tyrosine phosphatase-1B (PTP-1B) inhibitory activities (IC50 0.09 x 10-2-0.1 x 10-2 mg/mL) and oxygenated labdane diterpenoids from CH2Cl2 extract displayed comparable and#945;-amylase (IC50 0.11-0.13 mg/mL) and and#945;-glucosidase (IC50 0.08-0.11 mg/mL) inhibitory activities with positive control. Molecular docking simulation was employed to describe the PTP-1B inhibitory mechanism and results suggested that the previously undescribed terpenoids might be used as potential antihyperglyca