Ghareeb_2024_Int.J.Biol.Macromol__133861

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 10(4) 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 microg/mg total antioxidant capacity. It displayed anti-inflammatory effects by inhibiting 5-LOX and COX-2. Regarding the cytotoxic activity, the IC(50) 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 microg/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 microg/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 microg/ml. Additionally, the produced EPS displayed the highest anti-diabetic properties by inhibiting alpha-amylase (IC(50) 31.49 microg/ml) and alpha-glucosidase (IC(50) 6.48 microg/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.