Hyaluronan (HA) is the main component of the extracellular matrix (ECM). Depending on its chain size, it is generally accepted to exert diverse effects. High molecular weight HA is anti-angiogenic, immunosuppressive and anti-inflammatory, while lower fragments are angiogenic and inflammatory. Human hyaluronidase Hyal-1 (Hyal-1) is one of the main enzymes in the metabolism of HA. This makes Hyal-1 an interesting target. Not only for functional and mechanistic studies, but also for drug development. In this work, Hyal-1 was expressed on the surface of E. coli, by applying Autodisplay, to overcome formation of inactive inclusion bodies. With the cells displaying Hyal-1 an activity assay was performed using stains-all dye. Subsequently, the inhibitory effects of four saponins and 14 plant extracts on the activity of surface displayed Hyal-1 were evaluated. The determined IC50 values were 177 mu M for glycyrrhizic acid, 108 mu M for gypsophila saponin 2, 371 mu M for SA1657 and 296 mu M for SA1641. Malvae sylvestris flos, Equiseti herba and Ononidis radix extracts showed IC50 values between 1.4 and 1.7 mg/mL. In summary, Autodisplay enabled the expression of functional human target protein Hyal-1 in E. coli and facilitated an accelerated testing of potential inhibitors.