Influence of apple polyphenols on inflammatory gene expression

Abstract

Apples (Malus spp., Rosaceae) and products thereof contain high amounts of polyphenols which show diverse biological activities and may contribute to beneficial health effects, like protecting the intestine against inflammation initiated by chronic inflammatory bowel diseases (IBD). IBD are characterized by an excessive release of several proinflammatory cytokines and chemokines by different cell types which results consequently in an increased inflammatory response. In the present study we investigated the preventive effectiveness of polyphenolic juice extracts and single major constituents on inflammatory gene expression in immunorelevant human cell lines (DLD-1, T84, MonoMac6, Jurkat) induced with specific stimuli. Besides the influence on proinflammatory gene expression, the effect on NF-kappaB-, IP-10-, IL-8-promoter-, STAT1-dependent signal transduction, and the relative protein levels of multiple released cytokines and chemokines were studied. DNA microarray analysis of several genes known to be strongly regulated during gastrointestinal inflammation, combined with quantitative real-time PCR (qRT-PCR) revealed that the apple juice extract AE04 (100-200 microg/mL) significantly inhibited the expression of NF-kappaB regulated proinflammatory genes (TNF-alpha, IL-1beta, CXCL9, CXCL10), inflammatory relevant enzymes (COX-2, CYP3A4), and transcription factors (STAT1, IRF1) in LPS/IFN-gamma stimulated MonoMac6 cells without significant effects on the expression of house-keeping genes. A screening of some major compounds of AE04 revealed that the flavan-3-ol dimer procyanidin B(2 )is mainly responsible for the anti-inflammatory activity of AE04. Furthermore, the dihydrochalcone aglycone phloretin and the dimeric flavan-3-ol procyanidin B(1 )significantly inhibited proinflammatory gene expression and repressed NF-kappaB-, IP-10-, IL-8-promoter-, and STAT1-dependent signal transduction in a dose-dependent manner. The influence on proinflammatory gene expression by the applied polyphenols thereby strongly correlated with the increased protein levels investigated by human cytokine array studies. In summary, we evaluated selected compounds responsible for the anti-inflammatory activity of AE04. In particular, procyanidin B(1), procyanidin B(2), and phloretin revealed anti-inflammatory activities in vitro and therefore may serve as transcription-based inhibitors of proinflammatory gene expression.

Dried apple enriched with mandarin juice counteracts tamoxifen-induced oxidative stress in rats

“…According to data in the literature apples contain more phenols (Jung et al, 2009) and mandarins more vitamin C and specific flavonoids and carotenoids (Sentandreu et al, 2007). This finding is in accordance with that of previous studies in which animals supplemented with different fruits shown different responses in the parameters of oxidative stress (Pajk et al, 2006).…”

Polymeric proanthocyanidins from Sicilian pistachio (Pistacia vera L.) nut extract inhibit lipopolysaccharide-induced inflammatory response in RAW 264.7 cells

“…Values not sharing the same letter were significantly different (p \ 0.05, Fisher's test) PGE 2 , and TNF-a, with oligomers poorly effective with respect to polymers that contributed almost entirely to the HPE activity. These data may be the reflection of the amounts of proanthocyanidins assayed and/or indicate a different ability of oligomers and polymers to affect the macrophage response, as observed in other researches [44,[46][47][48][49]. To further highlight the role of these components, PF was also found almost effective as the whole HPE in inhibiting phosphorylation, and then activation, of IjB-a.…”

Ganodermycin, a novel inhibitor of CXCL10 expression from Ganoderma applanatum

“…Transient transfections of MonoMac6 cells were performed by electroporation (Bio-Rad, Munich, Germany, Gen Pulser) 3Â10 7 cells ml À1 in 0.4 ml RPMI 1640 medium Ganodermycin, a novel inhibitor of CXCL10 expression M Jung et al containing 25 mM HEPES buffer together with 40 mg of the indicated plasmids at 200 V and 975 mF. 19 After electroporation the cells were seeded at 1Â10 6 cells ml À1 RPMI 1640 medium containing 10% fetal calf serum in a 24-well plate with and without test compounds, and luciferase expression was induced with 1 mg ml À1 LPS and 10 ng ml À1 IFN-g. Luciferase activity was measured 4 h after induction using the luciferase assay system (Promega) according to the manufacturer's instructions with a luminometer. For analyzing CXCL10 synthesis, MonoMac6 cells were starved for 16 h in RPMI 1640 medium containing 0.5% fetal calf serum, pretreated for 1 h with the test compound and subsequently induced with 1 mg ml À1 LPS and 10 ng ml À1 IFN-g for additional 16 h. Subsequently, the cells were centrifuged and the cell culture supernatant was analyzed using the CXCL10 ELISA kit (R&D Systems, Wiesbaden-Nordenstadt, Germany) according to the manufacturer's instructions.…”