140INHIBITORY EFFECT OF AQUEOUS AND ETHANOLIC EXTRACTS OF CRASSULA OVATA ON SERINE PROTEASES ACTIVITIESProteases are enzymes found in all living organisms and are involved in various biological functions. In humans, deregulated proteases activities play a key role in a variety of diseases. Consequently, the discovery of compounds that strictly control or regulate the activities of proteases involved in variety of pathologies is urgently needed. The purpose of this study was to examine the effects of crude aqueous and ethanolic extracts from C. ovata (Crassula ovata) on the activity of serine proteases elastase and trypsin. All two serine proteases tested were inhibited to a greater or lesser extent. Crude aqueous and ethanolic extracts exhibited the best inhibitory effect on elastase, with IC50 values of 1.7 ± 0.2 and 2.2 ± 0.2 µg/ml, respectively. Trypsin was inhibited by crude aqueous and ethanolic extracts with IC50 values of 112.5 ± 8.2 and 117.1 ± 6.8 µg/ml, respectively,These results suggest that Crassula ovata could be a potential source of bioactive compounds for the discovery of new protease inhibitorsjorge.santos@ifsuldeminas.edu.brResearch1022020 Crassula ovata, Serine protease, Elastase, TrypsinFranciele de Cássia Guimarães,Marcelo Augusto dos Reis,Jorge Alexandre,Nogueira SantosInstituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS), Campus Inconfidentes,Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS), Campus Inconfidentes,Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS), Campus Inconfidentes,Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS), Campus Inconfidentes