Introduction:
Exopolysaccharides (EPSs) derived from marine microorganisms are a newly recognized reservoir of bioactive therapeutic compounds

Material and methods:
We isolated a high EPS-yielding bacterial strain from the Red Sea, identified as Bacillus rugosus SYG20. Its purified EPS (EPSR9) contains 45.33% uronic acid, 9.98% sulfate groups, and 5.40% N-acetyl glucosamine. The HPLC chromatogram revealed four monosaccharides - glucose, xylose, galacturonic acid, and arabinose, in a distinct molar ratio of 2:3:1:1. EPSR9 showed a wide array of bioactivities.

Results:
It displayed antioxidant activity with an IC50 of 25.6 μg/ml in the DPPH assay and a total antioxidant capacity (TAC) of 417.77μg/ml equivalent AAE and 62.67 μg/ml equivalent AAE in Ferric reducing antioxidant power (FRAP) assays. It exhibited substantial anti-inflammatory properties. The anticoagulant effect of the EPS was demonstrated by a dose-dependent increase in prothrombin time. The scratch assay resulted in a 72.66% increase in wound closure, promoting in vitro wound healing after 48 h. Anti-obesity activity was evidenced by 83.8% lipase inhibition at 1000 μg/ml with IC50 of 107.73μg/ml. EPSR9 demonstrated inhibitory effects on α-amylase with an IC50 value of 14.37μg/ml and α-glucosidase with an IC50 value of 26.73 μg/ml, highlighting its potential as an anti-diabetic agent. Then, EPS showed bactericidal properties with MBC/MIC≤2 against both G+ve and G-ve bacteria, Staphylococcus aureus , Enterococcus faecalis (MIC=3.9μg/ml), Salmonella typhi, and Helicobacter pylori.

Conclusions:
The marine EPSR9 exhibited considerable potential for pharmaceutical applications as a multi-bioactive microbial metabolite. Its in vivo potency and mechanisms of action warrant further investigation.