Antitumor, antioxidant, and antibiofilm activities of chitooligosaccharides by chitosanase from Bacillus cereus.

Chitooligosaccharides (COSs) are hydrophilic short oligomers produced by the action of microbial chitosanases on chitosan. The aim of this study is to assess the antitumor, antioxidant, and antibiofilm activities of bio-produced COSs from B. cereus strain isolated from Egyptian soil. To evaluate the cytotoxicity of COSs, an MTT assay was performed. To find that COSs exhibit antitumor activity against MCF-7, HepG-2, A549, and CACO-2 cell lines with mean IC50 of 818.8 µg/mL, 1845.9 µg/mL, 1293.9 µg/mL, and 1432.9 µg/mL, respectively. In addition, the antioxidant activity of COSs was measured by assessing their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity relative to ascorbic acid. The tested COSs showed strong DPPH radical-scavenging activity at high concentration (98.6 ± 0.10%). Assessing the antioxidant activity of COSs was also carried out using the HFD-mice model by measuring catalase and other enzyme levels in blood, stomach, and liver samples. The 0.5% COS dose increased catalase, GSH, and GPx levels in liver, stomach, and serum specimens (P < 0.05). The antibiofilm activity of the tested COSs was assayed using a microtiter plate assay against P. aeruginosa and S. aureus biofilm-forming microorganisms. The tested COS at 125 µg/mL showed promising activity against biofilm formation by S. aureus and P. aeruginosa, with 51.7 ± 4.2 and 43 ± 2.1, respectively. In conclusion, COSs showed promising antitumor, antibiofilm, and antioxidant activities.