PO-025 Antiproliferative effects of rosemary (rosmarinus officinalis, L.) extract in colon cancer cells lines

Introduction Rosmarinus officinalis L. , commonly called rosemary, is a shrub from Labiatae ( Lamiaceae ) family that is mostly distributed throughout the Mediterranean area. Its beneficial effects have been attributed to the high content in bioactive compounds, such as phenolic diterpenes, flavonoids and other phenolic compounds. Rosemary extracts (RE) and their main compounds have demonstrated various health-beneficial activities, including antioxidant, hepatoprotective, antimicrobial, anti-inflammatory, anti-cancer and antidiabetic, in vitro and in vivo models. Material and methods In this work, a RE obtained using supercritical CO 2 extraction has been assayed for the antitumor activity in three colon cancer cell lines (HGUE-C-1, HT-29 and SW480). Cell cycle distribution analysis, apoptosis and mitochondrial membrane potential (MMP) in RE treated cells was performed using flow cytometry. Necrosis was also measured using a lactate dehydrogenase (LDH) release detection kit. Results and discussions Results showed that RE induced cell cycle arrest by increasing the population of cells in the G 2 /M. This effect was accompanied by a significant increase of late apoptotic cells and mitochondrial membrane depolarization, both in a concentration dependent manner. In addition, RE treatment provoked a higher release of LDH activity in the three colon cancer cell lines. Taken together, these results suggest that a necrotic death is occurring and provide a new understanding of the cytotoxic effects of RE in colorectal cancer cell lines. Conclusion Our results show that the antiproliferative effects of RE on colon cancer cells are mediated by a combination of cell cycle arrest and further necrosis as cell death mechanism. RE promoted both cytostatic and cytotoxic effects in all the colorectal cancer cell lines. We hypothesise that main compounds such as diterpenes (carnosic acid and carnosol) and triterpenes (betulinic and ursolic acid) may be the responsible for the observed antiproliferative activity.