23-Hydroxybetulinic Acid, A Natural Compound, Alleviates DSS-induced Colitis by Regulating NF-κB Signaling

Article 23-Hydroxybetulinic Acid, A Natural Compound, Alleviates DSS-induced Colitis by Regulating NF-κB Signaling Shuangli Xiang 1, # , Miaojuan Wang 2, # , and Xiuping Chen 2, * 1 Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou Province, China. 2 State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao, China. * Correspondence: xpchen@um.edu.mo, Tel.: +853-88224679, Fax: +853-28841358 # Co-First author. Received: 8 November 2022 Accepted: 2 December 2022 Published: 11 January 2023 Abstract: Ulcerative colitis (UC), an inflammatory intestinal disease, is a growing epidemic affecting people worldwide and requires the development of effective therapeutic drugs. In this study, the effect of 23-hydroxybetulinic acid (23-HBA), a compound isolated from the traditional herb Pulsatilla chinensis (Bunge) Regel, on experimental UC was studied. C57BL/6J male mice were administrated with 3% dextran sodium sulfate (DSS) in drinking water to establish the UC model. 23-HBA was orally administrated at either 3.75, 7.5, or 15 mg/kg for 6 days. Mesalazine was used as a positive control. Examination of the body weight, colon length, disease activity index (DAI), histopathology examination, inflammatory cytokines, oxidative stress, and protein expression was performed. The pathological changes were examined with hematoxylin and eosin (H&E) and Aixian blue-glycogen (AB-PAS) staining. In cultured RAW 264.7 cells, the effects of 23-HBA on lipopolysaccharide (LPS)-stimulated cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and oxidative stress were analyzed. Compared with the colitis model, 23-HBA treatment significantly increased the body weight and colon length and decreased the DAI score. Pathological staining showed that 23-HBA mitigated the damage in intestinal structures, the increase in inflammatory cell infiltration, the increase in submucosa edema, and the decrease in goblet cell number. Furthermore, 23-HBA decreased IL-1β, IL-6, and MDA levels in the colon tissues. In addition, 23-HBA inhibited the protein expressions of COX-2, iNOS, and NF-κB p65 both in the colon tissues and in LPS-stimulated RAW 264.7 cells. In conclusion, these results showed that 23-HBA alleviated DSS-induced acute UC in mice and inhibited LPS-stimulated inflammation in RAW 264.7 cells possibly mediated by regulating the NF-κB pathway.