Evidence for Anti-inflammatory and Antioxidative Properties of Dried Plum Polyphenols in Macrophage RAW 264.7 Cells

JOURNAL: Food and Function (Food Funct). 2015,6:1719.

AUTHORS: Hooshmand S, Kumar A, Zhang JY, Johnson SA, Chaid SC and Arjmandi BH.

According to the abstract, the researchers investigated the anti-inflammatory and antioxidative properties of dried plum (Prunus domestica L.) polyphenols in macrophage RAW 264.7 cells. They hypothesized that dried plum polyphenols have strong anti-inflammatory and antioxidant properties against lipopolysaccharide (LPS)-induced production of the pro-inflammatory markers, nitric oxide (NO) and cyclooxygenase-2 (COX-2), and the lipid peroxidation product, malondialdehyde, in activated macrophage RAW 264.7 cells. Macrophage RAW 264.7 cells were stimulated with either 1 μg ml_1 (for measurement of NO production) or 1 ng ml_1 (for measurement of COX-2 expression) of LPS to induce inflammation and were treated with different doses of dried plum polyphenols (0.0, 0.1, 1, 10, 100 and 1000 μg ml_1). Dried plum polyphenols at a dose of 1000 μg ml_1 was able to significantly (P < 0.05) reduce NO production by 43%. Additionally, LPS-induced expression of COX-2 was significantly (P < 0.05) reduced by 100 and 1000 μg ml_1 dried plum polyphenols. To investigate the antioxidant activity of dried plum polyphenols, macrophage RAW 264.7 cells were stimulated with 100 μg ml_1 of FeSO4 + 1 mM ml_1 of H2O2 to induce lipid peroxidation. Dried plum polyphenols at a dose of 1000 μg ml_1 showed a 32% reduction in malondialdehyde production. These findings indicate that dried plum polyphenols are potent anti-inflammatory and antioxidative agents in vitro. The investigators state that these cell culture findings cannot be directly extrapolated to in vivo conditions and that additional studies are needed to explore the bioactivity, metabolism, and tissue distribution and excretion mechanisms of dried plum polyphenols using an animal model of inflammation to confirm the findings.