Effect of Borago Officinalis Extract on Markers of Oxidative Stress in Lipopolysaccharide and Hydrogen Peroxide-Activated Raw 264.7 Macrophages

There are many plant herbs which are known to be rich sources of phenolic compounds and are used widely because of their anti-inflammatory and antioxidative properties. Borage (Borago officinalis) is a plant herb which is found widely in Mediterranean regions and in some parts of Asia and has been used for the treatment of chronic conditions and diseases. Gamma-linolenic acid (GLA) an omega-6 fatty acid and phenolic acids are important components found in borage, which are known for their antioxidative properties. Therefore, it is important to further examine the antioxidative properties of borage. The main aim of this study was to investigate the effect of Borago officinalis extract (BOE) on levels of biomarkers of oxidative stress including nitric oxide (NO), and reactive oxygen species (ROS) and levels of the anti-oxidant enzyme catalase in lipopolysaccharide (LPS) and hydrogen peroxide (H2O2) stimulated RAW 264.7 macrophages. High-performance liquid analysis (HPLC) analysis was used to determine the total polyphenolic content of BOE. After confirmation from the cell viability test, dosages of BOE (0, 50, 100, 200 and 300 µg/ml), followed by treatment with LPS (50 ng/ml) or H2O2 (50 ng/ml) were used in this in vitro study. Media was collected for testing the levels of NO, and the cell lysates were collected for determining levels of catalase. BOE and LPS treated cells were further examined to assess levels of ROS. The total polyphenolic content of BOE was 102.4 mg/g, with rosmarinic acid being the most abundant polyphenol. BOE decreased (P<0.05) levels of NO when induced with LPS at 300 µg/ml and when cells were stimulated with H2O2 decreased (P<0.05) NO at dosages of 100, 200, and 300 µg/ml and ROS at all dosages of BOE. The level of catalase was an increased (P<0.05) in H2O2 stimulated macrophages treated with 300 µg/ml BOE. The results of this study suggest that borage possesses antioxidative properties through a reduction in NO and ROS. Further analysis is required to examine the pathways responsible.