Assessment of Cytotoxic Effects of Plant Protease Inhibitors on Cancerous Cell Lines

Protease inhibitors, whether natural or synthetic, show promise in cancer treatment by targeting dysregulated proteolytic activity linked to tumor progression and metastasis. This study evaluated trypsin inhibitory activity and cytotoxic effects of selected plant extracts. Screening twenty-six plant extracts revealed twelve extracts contain trypsin inhibitors, and eighteen plant extracts showed cytotoxicity to the HT29 cell line, with the highest cytotoxicity shown by Senna alatta extract (98.45 ± 0.44 %). When plant extracts containing protease inhibitors were subjected to proteinase K digestion, the protease inhibitor activity as well as cytotoxicity was reduced. For example, extracts from Chassalia curviflora, Senna alata, and Grewia nervosa showed high trypsin inhibition as well as cytotoxicity, both of which were reduced by proteinase K treatment. This indicates that there is some correlation between cytotoxicity and trypsin inhibition (r = 0.52) and proteinaceous trypsin inhibitors or other proteins are involved in the cytotoxicity. These findings highlight the potential role of trypsin inhibitors in cytotoxicity against cancer cell lines.