Renin inhibition activity by chitooligosaccharides

Six kinds of chitooligosaccharides (COSs) with different molecular weight (MW) and degree of deacetylation (DD) were prepared using ultrafiltration membrane reactor, and their renin inhibition modes were evaluated. All the COSs showed the renin-inhibitory activities with dose-dependent manner, and 90-COSs had the potent renin-inhibitory activity than that of 50-COSs. Among them, 90-MMWCOS (1000–5000 Da) exhibits the highest activity with IC50 value of 0.51 mg/mL and acts as competitive inhibitor with Ki value of 0.28 mg/mL by Lineweaver-Burk and Dixon plots. These results indicated that DD value and MW of COSs are important factors affecting renin-inhibitory activity.