Simultaneous Use of Stimulatory Agents to Enhance the Production and Hypoglycaemic Activity of Polysaccharides from Inonotus obliquus by Submerged Fermentation

Abstract

This study aimed to determine the effect of applying stimulatory agents to liquid cultured Inonotus obliquus on the simultaneous accumulation of exo-polysaccharides (EPS) and their monosaccharide composition. Different stimulatory agents (VB6, VB1, betulin and birch extract) were investigated for their effects on active exo-polysaccharides by submerged fermentation of I. obliquus. The mycelial biomass, reducing sugar content, EPS yield and α-glucosidase inhibition rate were determined, and the EPS obtained was analyzed for monosaccharide composition. The results showed that the addition of all the four stimulatory agents could significantly increase the inhibitory activity against α-glucosidase of EPS than the control, whereas EPS from 4 μg/mL VB1-containing medium had the best effect with an estimated IC50 value 24.34 μg/mL. Among the four stimulatory agents, VB6 gave maximum production of mycelial biomass and EPS at the concentration of 4 μg/mL with a increase of 50.79% and 114.46%, respectively. In addition, betulin had a significant effect on increasing the EPS yield and activity, and birch extract had a significantly stimulatory effect on the mycelial growth and the polysaccharides activity, only slightly worse than VB6 and VB1. Moreover, the addition of different stimulatory agents changed the monosaccharide composition of polysaccharides, which had a correlation with polysaccharide activity.

Recent Developments in Inonotus obliquus (Chaga mushroom) Polysaccharides: Isolation, Structural Characteristics, Biological Activities and Application

“…Among all the active components in Inonotus obliquus , Inonotus obliquus polysaccharides have the broadest biological activity, such as anticancer, hypoglycemic, anti-inflammatory, and anti-oxidation effects [ 8 , 22 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ]. Through the number of Scopus-indexed publication numbers (archived until 15 March 2021) for polysaccharide bioactivity, Inonotus obliquus , Inonotus obliquus polysaccharide related articles, a certain degree of upward trend can be seen ( Figure 1 ), which means that the medicinal value and health value of Inonotus obliquus have been widely recognized and affirmed [ 5 , 6 , 62 , 63 , 64 ], making it worthwhile to review Inonotus obliquus polysaccharides.…”

Inonotus obliquus – from folk medicine to clinical use

“… 114 To date, it has been shown that I. obliquus polysaccharides have hypoglycemic activity. 115 , 116 Unfortunately, the exact mechanism of action has not been elucidated. It has been described that I. obliquus polysaccharides in streptozotocin (STZ)-induced diabetic Wistar rats reduced blood glucose levels and restored the structure of β-cells after diabetes-induced cellular damage.…”

Bioactive compounds and bioactive properties of chaga ( Inonotus obliquus) mushroom: a review

“…Besides, cultivating the mycelium with the aqueous extracts or methanolic extracts of birch bark, birch core or chitosan could significantly enhance the steroid production of inotodiol, ergosterol peroxide, betulin, ergosterol, cholesterol, lanosterol, stigmasterol, and sitosterol (Kahlos, 1994;Wang et al, 2014). Similarly, the addition of betulin, or various spent substrates such as bark residues of white birch, birch extracts, corn grain and mulberry powder in the medium, or exposing into light at certain wavelengthes to mimic the wild nutritional or host condition could efficiently stimulate the growth of chaga mycelium as well as its polysaccharide yield (Chen et al, 2020b;Fradj et al, 2019;Poyedinok et al, 2015;Wang et al, 2019). Other stimulants such as colloidal metal nanoparticles, AgNPs (silver nanonparticles), could inhibit polysaccharide and flavonoid synthesis but may stimulate melanin synthesis while MgNPs (magnesium nanonparticles) colloid was effective in stimulating the accumulation of endopolysaccharides, flavonoids, and melanin pigments (Poyedinok et al, 2020).…”