Investigating the Molecular Mechanisms of the Anticancer Effects of Eugenol and Cinnamaldehyde Against Colorectal Cancer (CRC) Cells In Vitro

Colorectal cancer is one of the leading causes of cancer-associated mortality, and multifactorial resistance remains one of the main challenges in its treatment. Essential oils and their main compounds show interesting anticancer properties, but their mechanism of action is yet to be defined. This study aims to assess the cytotoxic effects of eugenol (EU) and cinnamaldehyde (CN) on colorectal cancer (CRC) cells, highlighting possible mechanisms of action. These compounds were tested on normal immortalized colonocytes (NCM-460) and two CRC cell lines: Caco-2, a human colon epithelial adenocarcinoma cell line, and SW-620, colon cancer cells derived from a lymph node metastatic site. The efficacy of EU and CN was evaluated through CellTiter-Glo^® and clonogenic assays and by determining proinflammatory cytokine secretion. Transcriptome analysis was used to identify possible pathways affected by EU and CN treatments. The results confirmed that EU and CN were selectively cytotoxic and pro-apoptotic against CRC cells, with different putative mechanisms. While EU drove cytotoxicity through robust transcriptional remodeling, CN yielded a stronger anti-inflammatory action. We confirmed that EU and CN are promising natural candidates in CRC prevention and treatment, even in association with chemotherapeutic drugs.