Inhibition of NADPH oxidase in TNF-α stimulated cells treated with mastic gum and attenuation PMA-stimulated superoxide production. (A) Activity of NADPH oxidase was measured as NADPH-dependent O2* production in membrane fractions using ESR as described in Materials and Methods . NADPH oxidase activity was analyzed in membrane fractions of control unstimulated RASMC or RASMC stimulated with 20 ng/ml TNF-α for 4-hours. Mastic gum (10 μg/ml) was applied for 15-minutes prior to isolation of membrane fractions. Direct supplementation of mustic gum to membrane fractions isolated from control or TNF-α stimulated RASMC did not affect NADPH oxidase activity. Data are average from three to six separate experiments ± Standard Error (*P < 0.01 vs Control, **P < 0.01 vs TNF-α). (B) Production of intracellular O2* was measured by DHE following accumulation of 2-hydroxyethidium using HPLC  in control or PMA-stimulated RASMC (1 μM PMA, 4-hours) supplemented with various doses of mastic gum (0-10 μg/ml) for 15-minutes prior to measurements of superoxide. Data are average from six separate experiments ± Standard Error (*P < 0.01 vs Control, #P < 0.05 vs TNF-α, **P < 0.01 vs TNF-α).
Triantafyllou et al. Nutrition Journal 2011 10:64 doi:10.1186/1475-2891-10-64