Effects of red ginseng extract and red ginseng dietary fiber on the maintenance of intestinal immune and functional homeostasis in diet-induced obese mice.

Background: Obesity is an important risk factor of intestinal inflammatory disease. This study aimed to evaluate the effects of Red ginseng extract powder (RGEP) and Red ginseng dietary fiber (RGDF) on the maintenance of immune and functional homeostasis in recovering obesity-induced impairment of intestinal immunity. Methods: Diet-induced obesity in C57BL/6 male mice was achieved by feeding them a 60 % high-fat diet for six weeks. The diet-induced obese (DIO) mice were administered RGEP (205, 410, or 820 mg/kg), fructooligosaccharide (FOS, 820 mg/kg), or RGDF (410, 820, or 1640 mg/kg) once daily for 4-8 weeks. The effects of RGEP or RGDF administration were evaluated via stool trait and gastrointestinal (GI) motility, inflammatory biomarkers and cytokines in mesenteric lymph nodes and intestine, mucosal protective genes, bacterial toxicity, and histopathological features of the intestines. Results: RGEP or RGDF administration to the DIO mice reduced mucosal barrier damaging factor (α1-antitrypsin), inflammatory cytokine levels, factors related to inflammatory responses (C-reactive protein (CRP), iNOS, NF-κB, MPO, and Calprotectin), and levels of urinary indican and intestinal β-glucuronidase. Conversely, RGEP or RGDF administration increased intestinal motility, levels of short-chain fatty acids (SCFAs) and β-defensin-2, and mucus barrier functional factor (MUC2) expression. Histopathological features of the small intestine recovered to normal levels after RGEP or RGDF administration. Conclusion: Our results demonstrated that RGEP and RGDF were effective for maintaining intestinal immune and functional homeostasis by recovering impaired immune and barrier function in DIO mice.