Influences on the phytochemical characteristics and multiple bioactivities of Mesona chiensis Benth polysaccharides in response to different drying methods

Abstract

In order to identify a suitable drying method for the extraction of antioxidant and antidiabetic polysaccharides, fresh Mesona chiensis Benth was subjected to various drying methods. These methods included conventional air drying (CD), hot-air drying (HD), freeze drying (FD), microwave drying (WD), and micro-fermentation drying (MD). Following the drying process, five polysaccharides derived from M. chiensis (MBPs) were extracted using hot water extraction. These polysaccharides exhibited variations in chemical composition, molecular weight, monosaccharide composition, and surface morphology. However, they displayed similar core glycosidic residues, crystallinity, and thermal stability. This indicates that the five drying methods exerted different effects on the degradation of polysaccharides, while simultaneously maintaining their fundamental structural characteristics. Additionally, a comprehensive evaluation system employing positive criteria and non-dimensionalization revealed that among five different MBPs, the MBP derived from the MD method exhibited the most potent antioxidant and antidiabetic activities in vitro. The micro-fermentation dried sample demonstrated a substantial DPPH radical scavenging capacity of 83.51% and an impressive inhibition of islet cell apoptosis activity, measured at 99.75%. The findings of this study provide that micro-fermentation drying has been identified as the most effective method for the extraction of significant antioxidant and antidiabetic polysaccharides from M. chiensis.