Comparison of the Effects of Essential Oil Obtained from the Crude and Bran-Processed on Lipopolysaccharide-Induced Inflammatory Injury of Human Colonic Epithelial Cells by Downregulating the IKK/NF-B Signaling Pathway.

BACKGROUND

(AL) has been used in traditional Chinese medicine for the treatment of various diseases including digestive disorders. Ulcerative colitis (UC) is a common digestive system disease with a low cure rate and easy recurrence. However, it is still not clear whether AL is suitable for UC treatment. Currently, stir-baking with wheat bran is most commonly used to process AL. Here, we aimed to address the effects of the crude and bran-processed AL on UC in vitro and uncover the underlying mechanism based on regulating the IKK/NF-kappa B signaling pathway.

METHODS

Human colonic epithelial cells (HCoEpiC) were treated with lipopolysaccharide (LPS) to mimic the inflammatory injury of UC in vitro. The essential oil from crude and bran-processed AL was used to treat LPS-induced HcoEpiC cells. The cell viability was detected by an MTT assay. The levels of IL-4, IL-6, IL-8, IL-12, IL-1-, TNF- and NO were determined by ELISA, and the mRNA expressions of IKK-, NF-B, IL-4, IL-6, IL-8, and TNF- were determined by RT-PCR. Meanwhile, the expressions of IKK-, p-IKK-, p-IKK-, NF-B, IL-6, and IL-8 proteins were determined by Western blot.

RESULTS

The essential oil of AL, whether it was from crude or bran-processed AL, could significantly increase the viability of LPS-induced HCoEpiC cells. The treatment of AL essential oil also notably inhibited the productions of IL-6, IL-8, IL-12, IL-1-, TNF-, NO, p-IKK-, p-IKK- and NF-B and downregulated the mRNA expressions of NF-B, IL-6, IL-8, and TNF-. Meanwhile, IL-4 protein and mRNA expression were significantly stimulated by AL essential oil. Moreover, the essential oil from bran-processed AL was more effective than that from crude AL.

CONCLUSION

Both kinds of AL essential oil had the anti-inflammatory effect on LPS-induced HCoEpiC, and the essential oil from bran-processed AL was more effective. The mechanism could be through the IKK/NF-B signaling pathway in vitro.