In vitro antioxidant and antiproliferative activity of three rosemary (Rosmarinus officinalis L.) extract formulations

Summary Antioxidant and antiproliferative activities of three rosemary extract formulations (VivOX 20, VivOX 40 and Inolens 50) with different contents of carnosic acid, carnosol and methylcarnosol were tested in vitro. Electron spin resonance measurements revealed that Inolens 50 extract that contained highest amount of carnosic acid was the most potent scavenger of hydroxyl (concentration of extract where 50% of its maximal scavenging activity is observed, that is, EC50, 109.54 μg mL−1), superoxide anion (EC50 = 7.94 μg mL−1) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (EC50 = 27.4 μg mL−1)-free radicals. Comparison of the radar charts of standard antioxidants and rosemary extracts showed similarity between antioxidant characteristics of Inolens 50 and chlorogenic and caffeic acids. Tested rosemary extracts exhibited significant (P ≤ 0.01) antiproliferative effect in cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT-29) cell lines. In both MCF7 and HeLa cell lines, the extracts yielded very low IC50 values (concentration of extract needed to inhibit cell growth by 50%), the most pronounced being for Inolens 50 in MCF7 (IC50 = 9.95 μg mL−1) and VivOX 20 in HeLa cell line (IC50 = 10.02 μg mL−1). The obtained results may provide support for the use of tested rosemary extracts as nutraceuticals and phytopharmaceuticals.