Chemopreventive and immunomodulatory effects of phenolic-rich extract of Commiphora leptophloeos against inflammatory bowel disease: Preclinical evidence

Ethnopharmacology relevance: Commiphora leptophloeos (Mart.) J.B. Gillet (Burseraceae) is a medicinal plant native to Brazil, popularly known as "imburana". Homemade leaf decoction and maceration were used to treat general inflammatory problems in the Brazilian Northeast population. Our previous research confirmed the anti-inflammatory activity of the C. leptophloeos hydroalcoholic leaf extract.

Aim of the study: Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gut with no ideal treatment to maintain the remissive status. This work aimed to characterize the phytochemical composition and physicochemical properties of the C. leptophloeos hydroalcoholic leaf extract and its efficacy in chemopreventive and immunomodulatory responses in inflammatory bowel disease in non-clinical models.

Materials and methods: Mass spectrometry and physicochemical tests determined the phytochemical profile and physicochemical characteristics of the Commiphora leptophloeos (CL) extract. The chemopreventive and immunomodulatory effects of CL extract (50 and 125 μg/mL) were evaluated in vitro in the RAW 264.7 lipopolysaccharide (LPS) induced cell assay and in vivo in the model of intestinal inflammation induced by 2,4-Dinitrobenzenesulfonic acid (DNBS) in mice when they were treated with CL extract by intragastric gavage (i.g.) at doses of 300, 400 and 500 mg/kg.

Results: Phytochemical annotation of CL extract showed a complex phenolic composition, characterized as phenolic acids and flavonoids, and satisfactory physicochemical characteristics. In addition, CL extract maintained the viability of RAW macrophages, reduced ROS and NO production, and negatively regulated COX-2, iNOS, TNF-α, IL-1β, IL-6, and IL-17 (p < 0.05). In the intestinal inflammation model, CL extract was able to downregulate NF-κB p65/COX-2, mTOR, iNOS, IL-17, decrease levels of malondialdehyde and myeloperoxidase and cytokines TNF-α, IL-1β and IL-6 (p < 0.05).

Conclusion: Based on these findings, CL extract reduced inflammatory responses by down-regulating pro-inflammatory markers in macrophages induced by LPS and DNBS-induced colitis in mice through NF-κB p65/COX-2 signaling. CL leaf extract requires further investigation as a candidate for treating inflammatory bowel disease.