Phenolic composition of selected herbal infusions and their anti-inflammatory effect on a colonic model in vitro in HT-29 cells

Abstract

Some herbal infusions used in folk medicine in Mexico to treat gastrointestinal disorders were evaluated. Antioxidant activity and phenolic compounds were analyzed on the lyophilized aqueous crude extracts (LACE) of arnica (Aster gymnocephalus), chamomile (Chamaemelum nobile), cumin (Cominum cyminum), desert resurrection plant (DRP) (Selaginella lepidophylla), laurel (Listea glaucescens), marjoram (Origanum majorana), mint (Mentha spicata), salvilla (Buddleia scordioides) and yerbaniz (Tagetes lucida). Total phenolic content ranged from 8.0 to 70.7 μg GAE/mg for DRP and laurel respectively. Major phenolic compounds were identified by gas chromatography–mass spectrometry and high-performance liquid chromatography. The IC50 determined by the degradation of the deoxy-d-ribose ranged from 2,452.53 to 5,097.11 μg/mL. The cytoprotective effect of the LACE alone and on indomethacin-induced oxidative stress in HT-29 cells was tested. The tetrazolium dye MTT assay was performed in concentrations of 0.125–10 mg/mL allowing choosing the lowest concentration for this experimentation. Inflammation markers were measured by Western blotting. None of the extracts inhibited COX-1 by themselves; however, it was observed that extracts have a modulation effect over COX-2, TNFα, NFκB, and IL-8. By the decrease in the expression of pro-inflammatory cytokines, it follows that salvilla, chamomile, and laurel show promising anti-inflammatory effects.