The mechanism of patchouli alcohol in treating IBS-D based on BMP-Smad pathway

Irritable Bowel Syndrome (IBS) is a chronic gastrointestinal condition, and diarrhea predominant (IBS-D) is the most common subtype.The enteric nervous system (ENS) regulates major gastrointestinal motility and function, and the intestinal neuronal BMP-SMAD signaling pathway is closely related to intestinal motility. Patchouli alcohol (PA) has been reported to modulate IBS-D, but whether its mechanism of action ameliorates IBS-D through the BMP-SMAD signaling pathway is unclear.This study preliminarily confirmed the abnormal colonic contraction of IBS-D functional bowel disease, and PA can not only improve gastrointestinal motor function, effectively inhibit the characteristic diarrhea and increased visceral sensitivity in IBS-D rats, but also regulate the neurohomeostasis of the gastrointestinal tract. In this study, in vivo and ex vivo studies confirmed that the neurohomeostatic regulation of patchouli alcohol was related to the increase of BMPRII⁺ neuronal subsets in the intestinal myenteric plexus and the regulation of BMP-SMAD signal pathway; PA increased the phosphorylation level of BMP-SMAD pathway-related proteins in IBS-D rat intestinal neurons.The findings can provide evidence for subsequent clinical research and drug development.