Unlocking the therapeutic potential of bioactive exopolysaccharide produced by marine actinobacterium Streptomyces vinaceusdrappus AMG31: A novel approach to drug development

Acidic exopolysaccharide (EPS) was produced by a marine actinobacterium Streptomyces vinaceusdrappus strain AMG31 with the highest yield of 10.6 g/l. The synthesized EPS has an average molecular weight of 5.1 x 104 g/ mol and contains arabinose, glucose, galacturonic acid (0.5:2:2 M ratio), with 39.77 % uronic acid residues and 18.8 % sulfate detected. EPS exhibited antioxidant activities with 93.8 % DPPH radical scavenging and 344.7 mu g/ mg total antioxidant capacity. It displayed anti-inflammatory effects by inhibiting 5-LOX and COX-2. Regarding the cytotoxic activity, the IC50 values are 301.6 + 11.8, 260.8 + 12.2, 29.4 + 13.5, 351.3 + 11.2, 254.1 + 9.8, and 266.5 + 10.4 mu g/ml for PC-3, HEP-2, MCF-7, HCT-116, A-549, HepG-2 respectively, which indicate that the produced EPS does not have strong cytotoxic activities. Moreover, the EPS showed anti-Alzheimer activity via inhibition of the Butyrylcholinesterase enzyme, with the highest percentage of 84.5 % at 100 mu g/ml. Interestingly, the EPS showed superior anti-obesity activity by inhibiting lipase enzyme with a rate of 95.3 % compared to orlistat as a positive control (96.8 %) at a concentration of 1000 mu g/ml. Additionally, the produced EPS displayed the highest anti-diabetic properties by inhibiting a-amylase (IC50 31.49 mu g/ml) and a-glucosidase (IC50 6.48 mu g/ml), suggesting antidiabetic potential analogous to acarbose. EPS exhibited promising antibacterial and antibiofilm activity against a wide range of Gram-positive and Gram-negative pathogenic bacteria.