Cistus x incanus L. extract as a complex polyphenolic blend with retained anti-adhesive and anti-inflammatory properties in a model of E. coli-induced UTI following simulated digestion

Cistus x incanus L. is a Mediterranean plant traditionally used to treat infective conditions, including urinary tract infections (UTI). However, experimental validation against uropathogenic Escherichia coli (UPEC) is limited. To investigate the antibacterial and anti-inflammatory effects of a hydroalcoholic extract of aerial parts (CE) in an E. coli -induced UTI model, evaluating stability and efficacy after intestinal digestion. T24 bladder epithelial cells were infected with UPEC CFT073 and treated with CE before and after simulated intestinal digestion (CEd). IL-6 release, bacterial growth, and adhesion were evaluated. Polyphenol content and stability were analyzed using colorimetric assays and LC-MS/MS. A methanol-insoluble fraction (IF) of CE was also tested. CE inhibited IL-6 release with an IC 50 of 16.05 μg/mL during infection and 0.43 μg/mL upon TNF-α stimulation; IL-8 was also reduced. CE markedly decreased UPEC adhesion to T24 cells (−79% at 200 μg/mL). After digestion, CEd retained anti-inflammatory activity (IC 50 for IL-6: 19.05 μg/mL during infection; 1.69 μg/mL with TNF-α). Flavonols remained relatively stable post-digestion, while catechins and procyanidins decreased. IF, rich in glycosidic flavonols and tannins, preserved its anti-inflammatory and antibacterial activity before and after digestion. These findings support, for the first time, the traditional use of Cistus x incanus in UTI, highlighting its ethnopharmacological relevance in the treatment of urinary infections. The mechanism of action, which includes anti-inflammatory and anti-adhesive activities of the extracts, has been investigated. The efficacy was observed at micromolar concentrations, which are supposed to be reached in vivo consuming Cistus x incanus food supplements. These findings lay groundwork for preclinical UTI models. Moreover, the outcomes in the present study warrant clinical investigations to consolidate our findings. • Cistus x incanus extract (CE) reduced inflammation in infected bladder cells. • E. coli anti-adhesive activity of CE was enhanced after intestinal digestion. • A flavonol-rich insoluble fraction reproduced CE’s biological effects. • Glycosylated flavonoids were stable post-digestion, supporting their role.