Gynostemma pentaphyllum exhibits anti-inflammatory properties and modulates antimicrobial peptide expression in the urinary bladder

Gynostemma pentaphyllum (GP) is a traditional Chinese medicine but is also consumed as tea by healthy people for its many beneficial effects. The herb is known for its anti-diabetic effect and immuno-modulatory properties. In patients with diabetes, the incidence of infections, including urinary tract infections, is increased and a common cause for antibiotic treatment. We hypothesized that GP could exhibit a beneficial impact on innate immunity in the urinary tract, thereby fighting such bacterial infections. Our aim was therefore to investigate whether orally taken GP would act on the urinary tract and modulate immune reactions in bladder epithelial cells. The extract was analyzed by NMR and was found to consist almost exclusively of a mixture of several saponins present in different concentrations. Ex vivo infection experiments demonstrated that the pro-inflammatory response to Escherichia coli was attenuated in bladder tissue from diabetic rats receiving GP compared to diabetic animals without treatment. In vitro assays using uroepithelial cells challenged with E. coli corroborated these results. Moreover, GP treatment modulated the expression of antimicrobial peptides. With these properties, GP might be a beneficial supplement for diabetic patients with history of urinary tract infections.