Screening Study on Serine Protease Inhibitory Activity of 10 Plant Species

In this research, in vitro serine protease inhibitory activity of 10 plant species was evaluated, and extracts that showed strong activity were analyzed through high-performance liquid chromatography (HPLC). Rhododendron caucasicum Pall. (leaf) and Potentilla reptans L. were found to have the highest chymotrypsin inhibitory activities (83.77% and 82.01% inhibition). The highest trypsin inhibitory activity was observed in R. caucasicum (flower) (82.86% inhibition), followed by Cruciata laevipes Opiz (82.22% inhibition). Extracts showing potent enzyme inhibition were fractioned and subjected to activity tests. The highest chymotrypsin inhibitory activity was observed in the n-hexane fraction of P. reptans (92.90% inhibition). In comparison, the highest trypsin inhibitory activity was found in the ethyl acetate fraction of Lythrum salicaria L. (89.81% inhibition). HPLC studies determined that the 80% ethanol extract of P. reptans contained chlorogenic acid. The screened plants were generally rich in phenol and flavonoid content and showed strong antioxidant activity.