Effect of Kaempferia galanga L. Polysaccharide on DSS-Induced Colitis and Concomitant Depression-Like Behavior via Regulating Intestinal Microbiota and Protecting the Intestinal Barrier

Abstract

Kaempferia galanga L. (K. galanga L.) serves as a traditional aromatic stomachic and is widely used to alleviate stomach-cold abdominal pain and dyspepsia. In this study, a polysaccharide, designated SJA, was isolated and purified from K. galanga L., and its therapeutic effects on dextran sulfate sodium (DSS)-induced ulcerative colitis and accompanying depressive-like behaviors were investigated. SJA mainly contained galactose, glucosamine, arabinose, mannose, and glucose in a molar ratio of 3.20:3.04:2.91:2.12:1.00, with a molecular weight of 31.5 kDa. In the DSS-induced mouse colitis model, SJA effectively alleviated DSS-triggered body weight reduction, colon shortening, and increased disease activity index (DAI) score. Mechanistically, SJA inhibited the activation of the NLRP3 inflammasome and reduced the secretion of TNF-α and IL-1β, while upregulating the level of IL-10. Furthermore, SJA restored the colonic barrier by elevating goblet cell numbers, ZO-1, and occludin levels. SJA also remodeled gut microbial homeostasis by enriching the genera Dubosiella and Bifidobacterium, and reducing the proliferation of Escherichia-Shigella and Staphylococcus. Additionally, SJA mitigated colitis-triggered depressive-like behaviors in mice by inhibiting cerebral inflammation and glial cell activation. These results indicated that SJA relieved colitis by restoring the colon barrier and reshaping gut microbiota composition. Furthermore, the improvement of colitis-related depressive-like behaviors by SJA was associated with the reduction of brain inflammation and glial cell overactivation.