Torreya grandis Kernel Oil Alleviates Loperamide‐Induced Slow Transit Constipation via Up‐Regulating the Colonic Expressions of Occludin/Claudin‐1/ZO‐1 and 5‐HT3R/5‐HT4R in BALB/c Mice

Scope Torreya grandis kernel has traditionally been used to remove intestinal parasites and increases intestinal motility. However, the effect of Torreya grandis kernel oil (TKO) on constipation has not yet been investigated. Therefore, mouse model is used to investigate the effect of TKO on slow transit constipation (STC) and its possible mechanism. Methods and results The effects of TKO on intestinal motility of STC mice are evaluated by fecal weight, fecal water content, colon length, defecation test, and intestinal propulsion test. The mechanism of TKO alleviating STC is explored by detecting biochemical analysis, histological analysis, western blot, qRT‐PCR, immunohistochemistry, and gut microbiota analysis. The results reveal that TKO effectively promotes defecation and intestinal motility, increases the level of endothelin‐1, and restores the histopathological morphology of the colon under LOP pretreatment. The expression levels of occludin, claudin‐1, and zonula occludens‐1 (ZO‐1) mRNA and protein are up‐regulated in mice receiving TKO treatment. The colonic 5‐hydroxytryptamine 3R/4R (5‐HT3R/5‐HT4R) expressions are also increased by TKO supplementation. Additionally, TKO rescues LOP‐caused disorders of the gut microbiota. Conclusion Consumption of TKO is beneficial to STC recovery, and it can alleviate LOP‐induced STC by up‐regulating the colonic expressions of Occludin/Claudin‐1/ZO‐1 and 5‐HT3R/5‐HT4R.