Different Inhibitory Potencies of Oseltamivir Carboxylate, Zanamivir, and Several Tannins on Bacterial and Viral Neuraminidases as Assessed in a Cell-Free Fluorescence-Based Enzyme Inhibition Assay.

Neuraminidaseis a key enzyme in the life cycle of influenza viruses and is present in some bacterial pathogens. We here assess the inhibitory potency of plant tannins versus clinically used inhibitors on both a viral and a bacterial model neuraminidase by applying the 2'-(4-methylumbelliferyl)-α-d--acetylneuraminic acid (MUNANA)-based activity assay. A range of flavan-3-ols, ellagitannins and chemically defined proanthocyanidin fractions was evaluated in comparison to oseltamivir carboxylate and zanamivir for their inhibitory activities against viral influenza A (H1N1) and bacterial neuraminidase (VCNA).