Effect of stilbene derivative on superoxide generation and enzyme release from human neutrophils in vitro

Abstract

Neutrophils represent the body's primary line of defense against invading pathogens. They most rapidly reach the site of injury or infection, liberate antimicrobial proteins, proteases and produce reactive oxygen species. Prolonged or excessive liberation of these very effective and toxic substances could intensify the inflammatory process and enhance tissue damage in many diseases, such as allergies, infections and rheumatoid arthritis. Pterostilbene belongs to stilbenoids, structural analogues of resveratrol, which act as natural protective agents in defending the plant against viral and microbial attack. It possesses anticancerous, antidiabetic and anti-inflammatory properties.The study provides new information on the effect of pterostilbene [0.01-100 µmol/l] on superoxide generation in and myeloperoxidase (MPO) release from azurophil granules of isolated human neutrophils. PMA [1µmol/l], which activates NADPH-oxidase via protein kinase C, was used for stimulation of neutrophils Unstimulated cells showed neither superoxide generation nor myelopereoxidase release after preincubation with the drug studied. Pterostilbene dose dependently decreased superoxide generation in and MPO release from stimulated human neutrophils, however a significant decrease was recorded only in the concentration 100 µmol/l. The effect of pterostilbene was more pronounced on superoxide generation in comparison to MPO release. Our results suggest that the effect of pterostilbene may prove beneficial in controlling inflammation.

Keywords: human neutrophils; myeloperoxidase; pterostilbene; superoxide generation.

Figure 1

Structure of pterostilbene.

Figure 2

Effect of pterostilbene on PMA [1 µmol/l, 15 min/37°C] stimulated superoxide generation in human neutrophils. Results are mean ± SEM, n = 6–8, p<0.05 compared to control value without pterostilbene. Results are expressed as percentage of absolute average control value (PMA) of superoxide generation 50.41±2.14nmoles/10⁶ neutrophils /min.

Figure 3

Effect of pterostilbene on PMA [1 µmol/l, 15 min/37°C] stimulated myeloperoxidase release from human neutrophils. Results are mean ± SEM, n = 6–8, *p<0.05 compared to control value without pterostilbene. Results are expressed as percentage of absolute average control value (PMA) of MPO release 3.09 ± 0.29 ΔA/Δt (calculated as area under curve).