Antioxidant and Antiproliferative Activities of Bioactive Compounds Contained in Rosmarinus officinalis Used in the Mediterranean Diet

Background. Rosmarinus officinalis (R. officinalis) is a medicinal plant called rosemary, largely used in the Mediterranean diet for many decades ago. Objective. The aim of the present study was to investigate the polyphenolic content, the antioxidant activity, and the antiproliferative effect against human prostate cancer cell lines (LNCaP) of carnosol and carnosic acid as bioactive compounds contained in R. officinalis growing in Morocco. Materials and Methods. Polyphenolic content of R. officinalis ethanolic extract was studied using colorimetric assay. Carnosol and carnosic acid contained in R. officinalis extract were quantified using high-performance liquid chromatography (HPLC). The antiproliferative effect of the studied extracts on LNCaP was evaluated by WST-1 bioassay, and the antioxidant activity was assessed using DPPH assay. Results. The extracts of R. officinalis showed an important polyphenolic content ranging from 74.15 μg·GAE/mg to 146.63 μg·GAE/mg. The percentage of carnosol and carnosic acid in rosemary crops ranges from 11.7 to 17.3% and 1.09% to 3%, respectively. The extracts of R. officinalis exhibited a promoting antioxidant activity with IC50 ranging from 0.236 mg/mL to 0.176 mg/mL. Regarding the antiproliferative effect, the WST-1 assay revealed that all the tested extracts reduced notably the cell viability with IC50 values ranging from 14.15 to 15. 04 μg/mL. Conclusion. In the current work, carnosol and carnosic acid exhibit antioxidant and antiproliferative activities in a concentration-dependent manner.