Fermentation effects of oligosaccharides of Radix Ophiopogonis on alloxan-induced diabetes in mice

In this study, oligosaccharides extracted from Ophiopogon japonicus vinegar (OOV) by alcoholic and acetic acid fermentation with water extracts from Radix Ophiopogon and oligosaccharides extracted from Radix Ophiopogonis (OOJ) were investigated. Characterization of the extracts indicated that OOV are proteoglycans, whereas OOJ are not. Moreover, compared with OOJ, monosaccharide compositions of OOV only include fructose and galactose and not glucose. MALDI-TOF-mass spectrometric results showed that the molecular weight of OOV was smaller after fermentation. Changes in the characteristics of OOV would inevitably lead to changes in its hypoglycemic properties. The OOV inhibition activity against α-glucosidase was stronger than that of OOJ. The inhibition activity became stronger with higher dosages of OOV. The hypoglycemic effect of OOV on alloxan-induced diabetic mice was stronger than that of OOJ. More important, the ability of OOV to reduce damage on islets in diabetic mice was stronger than that of OOJ. Overall, alcoholic and acetic acid fermentation improved the hypoglycemic activity of OOJ.