Characterization of the chemical composition of different parts of Dolichos lablab L. and revelation of its anti-ulcerative colitis effects by modulating the gut microbiota and host metabolism.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulcerative colitis (UC) is a non-specific inflammatory disease characterized by long duration and easy relapse. Dolichos lablab L. (DLL) belongs to the family Fabaceae, was listed in a famous Chinese medical classic, Compendium of Materia Medic, and described as possessing features that invigorate the spleen, alleviate dampness, provide diarrhea relief, and other effects. The DLL-dried white mature seeds (DS) and dried flower (DF), which hold significant medicinal value in China, were used in clinical prescriptions to prevent and treat UC. DS and DF have appeared in different editions of the Pharmacopoeia of the People's Republic of China from 1977 to 2020. However, their chemical composition, pharmacological effects, and mechanism of treating UC are unclear. AIM OF THE STUDY: This study aimed to characterize the chemical composition of different parts of DLL (seeds and flowers), further explore their pharmacological effects, and elaborate its underlying mechanism of treating UC. METHODS: The chemical composition of DS and DF crude polysaccharides (DSP and DFP) and ethanolic extracts (DSE and DFE) were characterized by high-performance anion-exchange chromatography (HPAEC), ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), and gas chromatography-mass spectrometry (GC-MS). Then, based on the acute UC mice model, the pharmacodynamic effects were investigated by Western blotting, ELISA, and other methods. Finally, the 16S rRNA gene sequencing and metabonomic analysis were used to explore the regulatory effects of DS and DF on intestinal microbiota and host metabolism. RESULTS: DSE and DFE inhibited the oxidative stress response, reducing proinflammatory factor production and maintaining intestinal barrier integrity in UC mice. The 16S rRNA gene sequencing and metabonomic analysis revealed that DS and DF treated UC by regulating the intestinal microbiota structure and reversing the abnormal metabolism of the host. CONCLUSION: This study suggested that different parts of DLL (flowers and seeds) may be potential medicines for treating UC, which exert their therapeutic effects through various active ingredients and might contribute significantly to reducing the economic pressures and challenges of UC treatment worldwide.

Total flavonoids of Sophora flavescens and kurarinone ameliorated ulcerative colitis by regulating Th17/Treg cell homeostasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulcerative colitis (UC) is relevant to dysregulation of inflammation and immune processes. Sophora flavescens Aiton is a classic medicine widely used in the treatment of UC in ancient and modern China, alkaloids and flavonoids are the main components. Previous studies reveal that Sophora flavescens Aiton total flavonoids extracts (SFE) exert an anti-UC effect by regulating the intestinal microbe structure and restoring the balance of the "host-microbe" co-metabolic network in UC mice. However, whether SFE influences immune inflammation remains unclear, which is the core link to UC disease. It also remains to be verified flavonoids are the material basis that plays a role in SFE. AIM OF THE STUDY: To identify the action mechanism of the immune-inflammatory regulation of SFE and its main active component Kurarinone against UC. METHODS: This study constructed UC mice and abnormal immune RAW 264.7 cell models, and subsequently used western blotting and flow cytometry (FCM) to evaluate the effects of SFE on the NF-κB pathway and the regulation of immunity in UC mice. Kurarinone was screened from flavonoid compounds of SFE by lipopolysaccharide (LPS)-induced RAW 264.7 cells, and its effect was subsequently investigated in UC mice. Western blotting, ELISA, FCM, and RT-PCR were used to determine the regulation of Kurarinone on the Th17/Treg differentiation and the JAK2/STAT3 signaling pathway. RESULTS: SFE regulated the differentiation of Th17/Treg in peripheral blood and inhibited immune-inflammatory response to treat UC. Various flavonoid components in SFE inhibited the synthesis of IL-6 and TNF-α in RAW 264.7 cells, among which Kurarinone had better effect. This study revealed the therapeutic effects of Kurarinone in UC mice for the first time. Kurarinone promoted the secretion of SIgA to improve the regulation of the intestinal mucosal barrier and resistance to pathogens. It also regulated the transcription level of RORγt and Foxp3 in colon, decreased the expression of pro-inflammatory factor IL-17A and up-regulated the expression of immunosuppressive factors TGF-ß1 and IL-10 in colon. Furthermore, Kurarinone restored intestinal immune system homeostasis by down-regulating the JAK2/STAT3 signaling pathway and regulating the balance of Th17/Treg cell differentiation in UC. CONCLUSIONS: SFE, especially the flavonoid ingredients represented by Kurarinone, has significant effects on immunoregulation against UC. And their mechanism of effect is related to inhibiting the activation of JAK2/STAT3 signaling pathway and regulating differentiation of Th17/Treg cells. KEYWORK: Immunoregulatory; Kurarinone; Th17 cells; Treg cells; Ulcerative colitis.