The gut microbiota is important in energy contribution, metabolism and immune modulation, and compositional disruption of the gut microbiota population is closely associated with chronic
metabolic diseases like
type 2 diabetes (T2D) and
non-alcoholic fatty liver disease (
NAFLD).
Metformin (MET) and Flos Lonicera (FL) are common treatments for
metabolic diseases in Western and Oriental medicinal fields. We evaluated the effect of treatment with FL and MET in combination on hepatosteatosis,
glucose tolerance, and gut microbial composition. FL and MET were administered to Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of genetic T2D and
NAFLD. The FL+MET treatment reduced liver weight, serum
cholesterol,
insulin resistance, and hepatic MDA level and modulated the gut microbial composition. More specifically, the genera of Prevotella and Lactobacillus were negatively associated with the body and liver weights, hepatic TG and TC content, and serum
insulin level. However, the relative abundance of these genera decreased in response to the FL+MET treatment. Interestingly, pathway prediction data revealed that the FL+MET treatment attenuated
lipopolysaccharide-related pathways, in keeping with the decrease in serum and fecal
endotoxin levels. FL and MET in combination exerts a synergistic effect on the improvement of hepatosteatosis and
insulin sensitivity in OLETF rats, and modulates gut microbiota in association with the effect.