A herbal combination consisting of myrrh, chamomile flower extract and coffee charcoal is used for the treatment of inflammatory bowel disease (IBD) – a chronic condition with an aberrant intestinal immune response driven by a dysregulated cytokine/chemokine homeostasis. Despite existing clinical data, pharmacological data supporting the observed efficacy remain insufficient.
The present study aims to investigate the influence of the single herbal components and a combination thereof on chemokine signalling of cytokine-challenged intestinal epithelial cells.
Thus, the influence of ethanolic myrrh (MY), chamomile flower (KA), coffee charcoal extract (CC) and budesonide (positive control) on chemokine (IL8; CXCL10) release from cytokine-(10 ng/mL TNFα; 5 ng/mL IL1β; 10 ng/mL IFNγ)-challenged Caco2 cells was investigated using an ELISA test system. To characterize the combined effect, concentration-response relations of single components and the combination were compared and IC50 values derived. Interpretation of the data was based on a dose reduction index (DRI; =IC50-single/IC50-comb.) which reported x-fold reduction of the plant extract concentration when applied in combination.
The single plant components inhibited cytokine induced CXCL10 release from Caco2 cells: MY (IC50=41µg/ml; 93%max. inhib.), KA (364µg/ml; 68%max. inhib.) and CC (447µg/ml; 56%max. inhib.), whereby relatively high concentrations are required. However, applied in combination, the IC50 of the plant extracts were significantly reduced: MY (IC50=25µg/ml), KA (124µg/ml) and CC (124µg/ml) (99%max. inhib.), resulting in DRI of MY=1.7, CC=3.6 and KA=2.9. IL8 release was inhibited after MY (IC50=3µg/mL; 28%max inhib.) and CC (IC50=218µg/mL; 75%max inhib.) but increased after KA treatment (EC50=39µg/mL; 29%max stimul.). Treatment with all three plant extracts resulted in a moderate IL8 inhibition with an inverted U-shape concentration-response curve (IC50: MY=56µg/ml; CC=281µg/ml; 77%max. inhib.).
The herbal components myrrh, chamomile flower and coffee charcoal influence chemokine signalling of stimulated intestinal epithelial cells. Additive effects between the plant extracts justify the herbal combination and its usage in IBD.