Bioprocessing shrimp shells for rat intestinal α-glucosidase inhibitor and its effect on reducing blood glucose in a mouse model

The alpha-Glucosidase inhibitors (aGIs) from natural resources have been recognized as a safe and efficacious way to manage type 2 diabetes-an ongoing global health problem. The objective of this study was to synthesize aGIs from demineralized shrimp shell powder (deSSP), a low-cost fishery processing by-product, via microbial fermentation. Its effect on reducing plasma glucose in an ICR mouse model was then evaluated, and its other beneficial bioactivities investigated. Among the various marine chitinous materials, fermented deSSP (fdeSSP) via Paenibacillus conversion demonstrated potent inhibition against rat intestinal alpha-glucosidase that was comparable to acarbose, a commercial anti-diabetic drug, with max inhibition and IC50 values 87% and 120 mu g/mL, and 89% and 110 mu g/mL, respectively. After optimization of the fermentation process, activity increased 1.52-fold (2500-3800 U/mL). By comparing the HPLC fingerprints and bioactivity of fermented and unfermented deSSP, it was confirmed that aGIs were produced as they were not present in the deSSP medium prior to fermentation. In animal tests, at a dose of 100 mg/kg bw, fdeSSP significantly reduced plasma glucose in ICR mice with no signs of diarrhea. The fdeSSP also demonstrated acceptable antioxidant activity (IC50 = 250 mu g/mL) and potential anti-NO activity (70.08 mu g/mL). Though not toxic to normal cells, fdeSSP reduced the viability of some cancer cells, including A549, Hep G2, MCF-7 and WIDR with inhibition values of 78%, 71%, 45% and 35%, respectively. The results above suggest that fdeSSP may be a good candidate for development as a health food or drug, due to its potential hypoglycemic and added value bioactivities.