Abstract: Objective: Our aim is to investigate the inhibitory effects of four bioactive compounds from rosemary (carnosic acid, carnosol, rosmanol and rosmarinic acid) against oxidative stress and inflammatory response in lipopolysaccharide (LPS)-induced RAW264.7 cells. Methods: The effects of these compounds on reactive oxygen species (ROS), inflammatory factors and related enzymes were characterized by various methods including colorimetry, fluorescence quantitative polymerase chain reaction (PCR) and Western blot. Results: All four compounds had significant inhibitory effects on the expression or production of ROS, malonic dialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) in LPS-induced cells. They had a significant protective effect on the activity of superoxide dismutase (SOD) and catalase (CAT) in a concentration-dependent manner. Carnosic acid at 10 μg/mL had a better inhibitory effect on the LPS-induced increases in relative ROS levels, NO release, TNF-α mRNA expression and MDA levels, and a better protective effect on SOD and CAT activity. Rosmanol at 10 μg/mL had a better inhibitory effect on the LPS-induced increases the relative mRNA expression levels of IL-1β and IL-6 and the relative protein expression levels of iNOS and COX-2. Conclusion: All four compounds from rosemary have antioxidant and anti-inflammatory effects and alleviates inflammatory responses. The effective concentration of water-soluble rosmarinic acid is significantly higher than that of the other three compounds.

Key words: rosemary; RAW264.7 cells; oxidative stress; inflammation; protection