Involvement of antioxidant defenses and nf-κb/erk signaling in anti-inflammatory effects of pterostilbene, a natural analogue of resveratrol

Pterostilbene (PTE), a natural stilbenoid occurring in grapes and berries, is recognized as a dimethylated analogue of resveratrol. This compound shows numerous notable pharmacological activities, including antiaging, anticancer, antidiabetes, antioxidant, and neuroprotection. This study investigates the anti-inflammatory properties of PTE in macrophage cells (RAW 264.7) against the lipoteichoic acid (LTA) stimulation. The expression of inflammatory tumor necrosis factor (TNF-α), interleukin-1β (IL-1 β), and inducible nitric oxide synthase (iNOS) and the content of nitric oxide (NO) were detected in LTA-induced cells. In addition, a Western blot assay was used to detect mitogen-activated protein kinases: extracellular signal-regulated kinase (ERK)1/2, p38 MAPK, and c-Jun N-terminal kinase (JNK). The phosphorylation of IκB and p65 and translocation of nuclear factor kappa B (NF-κB) were assessed by Western blot and immuno-fluorescence staining. The results showed that PTE significantly attenuated NO production and TNF-α, IL-1 β, and iNOS expression in LTA stimulated cells. Among the activation of ERK, JNK, and p38 in cells treated with LTA, PTE at higher concentration had only inhibited ERK activation. However, PTE blocked IκB phosphorylation, phosphorylation and nuclear translocation of p65NF-κB. Fascinatingly, PTE enhanced antioxidant defense molecules as verified by the enhanced heme oxygenase-1 (HO-1) expression, catalase (CAT) antioxidant enzyme, and non-enzymatic antioxidant, and reduced glutathione (GSH) in LTA-induced RAW 264.7 cells. These results suggest that PTE exerts an anti-inflammatory property via attenuating NF-κB/ERK signaling pathways as well as enriching antioxidant defense mechanisms.