Chemical characterization of sulfated polysaccharides from Gracilaria gracilis and Ulva lactuca and their radical scavenging, metal chelating, and cholinesterase inhibitory activities

Abstract

This study was designed to evaluate the antioxidant and cholinesterase inhibitory activities of sulfated polysaccharides from Gracilaria gracilis (PGCL) and Ulva lactuca (PULV). PGCL and PULV were extracted and characterized with Scanning electron microscope-energy dispersive x-ray (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and Gas chromatography-mass spectroscopy (GC-MS). The radical (2,2-azinobis-3-ethylbenzothiazoline-6-sulfonate [ABTS] 2,2-diphenyl-1-picrylhydrazyl [DPPH], and hydroxyl [OH]) scavenging and metal chelating activities as well as their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were also determined. SEM-EDX analysis revealed the presence of elements such as carbon, magnesium, calcium, phosphorus, and sulfur. The FTIR analysis also confirmed the presence of sulfate group in the polysaccharide samples. Some sugars such as glucose, galactose, arabinose, xylose, rhamnose, and allose were also identified using GC-MS. PGCL and PULV scavenged ABTS, DPPH and OH radicals in a dose-dependent manner. Moreover, PULV exhibited higher scavenging activity compared to PGCL. PGCL and PULV also reduced the activity of AChE (IC 50 = 132.73 and 106.93 µg/mL) and BChE (IC 50 = 124.93 and 93.45 µg/mL) respectively. PGCL and PULV exhibited antioxidant activity and possess cholinesterase inhibitory activity, hence these polysaccharides could be explored as ingredients for the development of functional foods with neuroprotective potentials.

Carboxymethylated Sulfated Heteroexopolysaccharide from a Haloarchaeal Strain as Potential Biomolecule for Harmless Adjuvant Therapy in Cancer Treatment

“…Interestingly, it exhibited peculiar chemical characteristics, such as high uronic acid and sulfate contents, and importantly specific functional units, such as carboxymethyl, methoxyl, Journal of Chemistry and sulfated groups. Sulfated and/or carboxymethylated EPS have attracted attention in the field of pharmacology for their valuable biological activities [30,33,34]. Moreover, carboxymethylation and sulfation were applied to chemically modify polysaccharides for enhancing their bioactivities [33,34].…”

Sulfated polysaccharides of some seaweeds exhibit neuroprotection via mitigation of oxidative stress, cholinergic dysfunction and inhibition of Zn – induced neuronal damage in HT-22 cells

“…In this study, the effect of some algal polysaccharides on Zn-induced neuronal damage in hippocampal cells was investigated. These polysaccharides have been fully characterized in our previous study and were tentatively identified as fucoidan (PKPM), ulvans (PULV and PULT), and carrageenan (PGCL and PMNP) [19,20]. The presence of sulfate moiety was confirmed in these polysaccharides including monosaccharides such as fucose, rhamnose, glucose, mannose, galactose, xylose, and allose.…”

“…The extraction of the sulfated polysaccharides from E. maxima (PKPM), G. pristoides (PMNP), U. rigida (PURL), U lactuca (PULV) and G. gracilis (PGCL) was done as previously described [19,20]. Each seaweed was dried at 25°C and was ground into powder using a blender, after which they were de-pigmented in different flasks with 400 mL of hexane.…”

Natural Products of Marine Macroalgae from South Eastern Australia, with Emphasis on the Port Phillip Bay and Heads Regions of Victoria

“…Interestingly, compounds 37-39 and 48 were all isolated and characterized from the alga C. fragile and following this study, it was suggested that sterol compounds may prove to be useful biomarkers for this genus allowing for easier taxonomic distinction between other members of the Codiaceae family [44,45]. Much of the literature available for the genus Ulva involves biological activity studies on polysaccharides [46][47][48][49], many of the sterols found within this genus have shown promising in vitro bioactivity. In particular, the glycosidic sterol (47) from U. lactuca has been shown to be an effective anti-bacterial, anti-fungal and anti-inflammatory agent in vitro [41].…”

“…The sterols (see supporting information Figure S5) of U. lactuca (30-36, 40, 47) and U. australis (40,41,42,(44)(45)(46) have been studied extensively [39][40][41][42][43]. Many of the sterols found in the green algae of Port Phillip Bay appear to have a C-19 core skeleton with differing functionalities of the side chain.…”