Abstract
Marinobacter nauticus strain GH3 was isolated from the Red Sea, Sharm Elshiekh, and classified according to cultural attributes, biochemical properties, and the analysis of genetic relationships using 16 S rRNA sequences. A substantial proportion of exopolysaccharides (EPS) in GH3-EPS contained a sulfate content of 25.4%, uronic acid (12.18%), and N-acetylglucosamine (13.6%). The composition of monosaccharides in this fraction consists of glucose, glucoronic acid, arabinose, and xylose by 2:4:3:3, respectively. SEM showed a flower-like shape with white bundles on the GH3-EPS surface. GH3-EPS enhancement of the RAW264.7 macrophage line RAW 264.7 ATTC number J774 cell proliferation via MTT assay for cell viability. GH3-EPS had a high stimulation effect on releasing TNF-alpha and IL-10. Followed by its effect against cyclooxygenase (COX-2) and lipoxygenase (LOX), with IC(50)s of 14.74 and 19.4 µg/ml, respectively. Antioxidant activity was evaluated for GPx-4, GSS, and MDA with highly significant results, and for DPPH, ABTS, and iron chelating with IC(50) (43.51, 31.27, and 84.96 µg/ml, respectively). AChE was inhibited by a mean of 52.92 ± 4.54 and 68.22 ± 5.64 µg/ml. In a fish animal model, GH3-EPS demonstrated a positive treatment effect for AD, supporting biochemical studies, histopathology for some brain parts, and toxicity.