Os inibidores de proteinases são proteínas extensivamente investigadas nos tecidos de estocagem, mas pouco prospectadas em outros tecidos vegetais. O objetivo deste estudo foi detectar a presença de inibidores de serinoproteinases em extratos foliares de quinze espécies de leguminosas arbóreas da Amazônia. As espécies estudadas foram: Caesalpinia echinata, C. ferrea, Cedrelinga cateniformis, Copaifera multijuga, Dinizia excelsa, Enterolobium contortisiliquum, E. maximum, E. schomburgkii, Leucaena leucocephala, Ormosia paraensis, Parkia multijuga, P. pendula, P. platycephala, Swartzia corrugata e S. polyphylla. Folhas foram coletadas, secas a 30ºC durante 48 h, trituradas e submetidas à extração com NaCl (0,15 M, 10% p/v) resultando no extrato total. Ensaios foram executados para determinar a concentração de proteínas e detectar a atividade inibitória contra a tripsina e quimotripsina bovina. Os teores de proteínas bruta e solúvel nos extratos foliares variaram de 7,9 a 31,2% e 1,3 a 14,8%, respectivamente. A atividade inibitória sobre a tripsina e quimotripsina foi observada em todos os extratos foliares. Contudo, nos extratos de E. maximum, L. leucocephala, P. pendula, S. corrugata e S. polyphylla a inibição foi maior sobre a tripsina, enquanto o extrato de P. multijuga foi mais efetivo contra a quimotripsina. Nós concluímos que nos extratos foliares de leguminosas arbóreas têm inibidores de serinoproteinases e exibem potencial aplicações biotecnológicas.

The proteinase inhibitors are proteins extensively investigated in tissue storage, but few prospected in other plant tissues. The aim of this study was to detect the presence of serine proteinase inhibitors in leaf extracts from fifteen species of leguminous trees of the Amazon forest. The species studied were Caesalpinia echinata, C. ferrea, Cedrelinga cateniformis, Copaifera multijuga, Dinizia excelsa, Enterolobium contortisiliquum, E. maximum, E. schomburgkii, Leucaena leucocephala, Ormosia paraensis, Parkia multijuga, P. pendula, P. platycephala, Swartzia corrugata and S. polyphylla. Leaves were collected, dried at 30ºC for 48 h, crushed and subjected to extraction with NaCl (0.15 M, 10% w/v), resulting in the total extract. Tests were performed to determine the concentration of proteins and to detect of inhibitory activity against bovine trypsin and chymotrypsin. The content of crude and soluble protein in leaf extracts varied from 7.9 to 31.2% and 1.3 to 14.8%, respectively. The inhibitory activity on trypsin and chymotrypsin was observed in all leaf extracts. However, in extracts of E. maximum, L. leucocephala, P. pendula, S. corrugata and S. polyphylla, the inhibition was greater on trypsin, while extract of P. multijuga was more effective against chymotrypsin. We conclude that leaf extracts of leguminous trees have serine proteinase inhibitors and show potential biotecnological applications.