Ganoderma lucidum polysaccharides (GLP), a kind of medicinal mushrooms, were widely
used in southeastern countries with putative anti-diabetic effects. In order to unravel
the underlying mechanism of its anti-diabetic effect, this study examines the effects
of GLP on gut microbiota composition and functions in type 2 diabetes mellitus (T2DM)
status. In this study, the effects of GLP on the gut microbiota and fecal metabolites
in high-fat diet and streptozotocin-induced T2DM rats were examined by 16S rDNA sequencing
and 1H NMR profiling. As a result, administration of GLP led to significant decreases
in the levels of fasting blood glucose and insulin. Moreover, GLP treatment reduced
the abundance of harmful bacteria, such as Aerococcus, Ruminococcus, Corynebactrium
and Proteus, and increased the level of Blautia, Dehalobacterium, Parabacteroides
and Bacteroides. The PICRUSt analysis indicated that GLP could restore the disturbed
amino acids metabolism, carbohydrates metabolism, inflammatory substances metabolism
and nucleic acid metabolism of gut bacterial community in T2DM rats and most metabolic
changes observed by metabolomics analysis were consistent with these consequences.
Taken collectively, GLP can restore the disordered gut microbiota of T2DM rats to
a normal level and modify metabolites of the host to realize its antidiabetic effects.