The regulatory effects of Lonicera japonica flos on fecal microbiota from humans with type 2 diabetes in a SHIME model

Introduction: Lonicera japonica flos, a well-known herbal medicine in Asian countries, has been widely used for the treatment of type 2 diabetes (T2D). The gut microbiota and relevant metabolites have been shown to be involved in the development of T2D. This study was designed to investigate the effects of Lonicera japonica flos on fecal microbiota from humans with T2D using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME) system. Methods: An aqueous extract of Lonicera japonica flos (LJE) was prepared. Colorimetry and high-performance liquid chromatography (HPLC) were used to analyze the chemical composition of LJE. Three colonic compartments of SHIME were inoculated with feces from T2D donors, and LJE was added to SHIME to simulate daily oral administration for 7 days. The microbial community and the concentrations of short-chain fatty acids (SCFAs) of colonic samples were analyzed by 16 S rRNA sequencing technology and gas chromatography, respectively. In addition, polyphenols in LJE before and after fermentation by fecal microbiota were measured using HPLC. Results: LJE is rich in polyphenols and polysaccharides and alters the microbial community, as indicated by the decreased relative abundance of the detrimental genera Shigella and Lactobacillus and the increased abundance of SCFA-producing bacteria, including the genera Prevotella and Bacteroides. LJE significantly promoted SCFA production, including acetic, propionic, and butyric acids, in each colonic compartment. Furthermore, chlorogenic acid in LJE was biotransformed by fecal microbiota. Conclusions: LJE exerted beneficial regulation on the T2D fecal microbial community. The regulatory effects of gut microbiota may partly contribute to the therapeutic action of Lonicera japonica flos on T2D.