Anti-diabetic activity of Cordyceps-fermented edible insects by the promotion of glucose absorption

Abstract

Insects are considered important food resources for future diet due to diverse nutrients and pharmacological effects. Fermentation is an important strategy of food processing with various beneficial effects such as increasing nutrients, promoting bioavailability, and reducing anti-nutrients. Cordyceps is a mushroom that grows on insects and produces various active ingredients. Therefore, we investigated the effect of Cordyceps-fermentation of insects on the nutritional composition and functional benefits of the insects. Six edible insects: Bombyx mori, Protaetia brevitarsis, Caelifera, Gryllus bimaculatus, Tenebrio molitor, and Allomyrina dichotoma were fermented with Cordyceps militaris to produce mycelia and fruiting bodies. Analysis of nutritional components showed that protein content was increased whereas carbohydrate content was decreased by the fermentation with Cordyceps. In addition, the fermented insects showed anti-diabetic efficacy by the promotion of glucose absorption as evaluated using differentiated L6-GLUT4myc cells. Quantitation using HPLC analysis suggested that cordycepin was produced in both mycelium and fruiting bodies in Cordyceps-fermented edible insects with different amounts depending on insect type and cultivation conditions. Therefore, the fermentation of insects with Cordyceps is expected to increase nutritional values and bioactive constituents and exert anti-diabetic effects.