Chemical Composition of Cynanchum auriculatum Royle Ex Wight and Its Potential Role in Ameliorating Colitis

Abstract

Cynanchum auriculatum Royle ex Wight, commonly known as "Baishouwu," has been traditionally used in China for its medicinal and dietary benefits. Despite its long history of use, the potential therapeutic effects of C. auriculatum in the treatment of colitis have not been fully investigated. This study aims to evaluate the effects of the water extract of C. auriculatum root on colitis and elucidate its potential mechanisms of action. The water extract of C. auriculatum root (CW) was prepared and characterized using UPLC-Q-TOF-MS, identifying thirty-two distinct compounds, including saponins, organic acids, fatty acid derivatives, and alkaloids. The therapeutic efficacy of CW was assessed in a colitis mouse model. CW significantly alleviated colitis symptoms, evidenced by increased colon length, reduced disease activity indices, and decreased colon tissue damage. CW reduced colonic inflammatory cytokine production and enhanced the expression of tight junction proteins, including claudin-1, occludin, and ZO-1, thereby strengthening intestinal barrier integrity. Additionally, CW modulated the gut microbiota by increasing microbial diversity, promoting beneficial Lactobacillus growth, reducing pathogenic Pseudomonas levels, and enhancing short-chain fatty acid production. The results suggest that CW exhibits significant therapeutic potential in the management of colitis by attenuating inflammation, restoring gut barrier function, and modulating the gut microbiota. These findings provide a basis for further exploration of C. auriculatum as a functional food for prevention and treatment of colitis.

Keywords: Cynanchum auriculatum; chemical composition; colitis; gut microbiota; short‐chain fatty acids.

FIGURE 1

Chemical profiles of CW analyzed using UPLC‐Q‐TOF‐MS. Total ion chromatogram of CW in (A) negative and (B) positive models. 1: L‐Arginine, 2: Citric Acid, 3: Yesanchinoside B, 4: Esculentoside A, 5: Tianshic acid, 6: Isoacteoside, 7: Soyasaponin Bb, 8: 3‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐α‐L‐arabinopyranosyl‐28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl oleanolate, 8: Buddleoside, 9: Yuzhizioside IV, 10: Palmitic acid, 11: Songoroside A, 12: Phytolaccagenin, 13: Coronaric acid, 14: Prosapogenin 5, 15: Lablaboside A, 16: Gandoeric acid H, 17: Raddeanoside R0, 18: Phytolaccagenin, 19: Ethyl linolenate, 20: Lobelanidine, 21: Nomilinic acid, 22: Glycerol monostearate, 23: Tribulosin, 24: Asterbatanoside D, 25: 3β‐Acetoxy‐atractylone, 26: Isoacteoside, 27: Cimicifuga Dahurica C, 28: Phytolaccagenin, 29: Platycoside D, 30: Lycopodium Alkaloids, 31: Asterbatanoside D.

FIGURE 2

Ameliorating effect of CW on colonic damage. (A) Schematic overview of experimental design, (B) Body weight changes, (C) DAI, (D) Representative colonic tissue images from each group, (E) Colon length quantification, (F) Spleen weight, (G) H&E staining and (H) AB‐PAS staining of colon tissue, (I) Histopathologic scores, and (J) goblet cell count (n = 3 per group). Data are presented as mean ± SD (n = 7–8). Significance differences: *p < 0.05, **p < 0.01, ***p < 0.001.

FIGURE 3

CW inhibited inflammatory cytokines and enhanced expression of tight junction (TJ) proteins. Analysis of serum cytokine levels of (A) TNF‐α, (B) IL‐1β, and (C) IL‐6, the mRNA levels of (D) TNF‐α, (E) IL‐1β, (F) IL‐6, (G) TLR4, (H) iNOS, (I) IL‐10, (J) ZO‐1, (K) Occludin, (L) Claudin‐1, (M) Representative immunofluorescence images of colonic sections stained for tight junction proteins; green indicates positive protein staining, and nuclei are counterstained in blue, Scale bar = 50 μm. (N–P) Quantitative analysis of protein density for ZO‐1, Occludin, and Claudin‐1 (n = 3 per group). All data are presented as mean ± SD (n = 7–8). Significance differences: *p < 0.05, **p < 0.01, ***p < 0.001.

FIGURE 4

CW enhanced SCFAs levels in DSS‐induced colitis. The impact of CW on the concentrations of SCFAs in (A) serum and (B) colonic contents of mice, the mRNA expression levels of SCFAs receptors in the colon: (C) GPR41, (D) GPR43, and (E) GPR109A. All data are presented as mean ± SD (n = 6–8). Significance differences: *p < 0.05, **p < 0.01.

FIGURE 5

CW treatment modulated gut microbiota structure in DSS‐induced colitis. α‐Diversity indices including (A) Chao1, (B) Shannon, and (C) Simpson; (D) β‐diversity analyzed via principal coordinates analysis (PCoA). The composition of gut microbiota at the phylum level (E), the relative abundances of Firmicutes and Bacteroidetes (F) and the Firmicutes/Bacteroidetes ratio (F/B) (G). The genus‐level taxonomic profiling (H), with significantly altered taxa at the genus level (I). All data are presented as mean ± SD (n = 6). Significance differences: *p < 0.05, **p < 0.01, ***p < 0.001.

FIGURE 6

Influence of CW on gut microbiota composition at the ASV level and correlation analysis of colitis‐related biomarkers with key genera altered by CW treatment. The heatmap displays the relative abundance of 50 ASVs. Circles (○) and dots (●) represent ASVs that are lower or higher, respectively, in the Control and β‐Glucan groups compared to the DSS group, respectively. Stars (☆) indicate ASVs in the Control group altered by DSS treatment that were reversed after CW intervention. Red (blue) squares indicate positive (negative) Spearman correlation coefficient (R) values. Significant correlations are denoted by *p < 0.05, **p < 0.01, ***p < 0.001.