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

Abstract

Background Positive effects of pistachio nut consumption on plasma inflammatory biomarkers have been described; however, little is known about molecular events associated with these effects. Purpose We studied the anti-inflammatory activity of a hydrophilic extract from Sicilian Pistacia L. (HPE) in a macrophage model and investigated bioactive components relevant to the observed effects. Methods HPE oligomer/polymer proanthocyanidin fractions were isolated by adsorbance chromatography, and components quantified as anthocyanidins after acidic hydrolysis. Isoflavones were measured by gradient elution HPLC analysis. RAW 264.7 murine macrophages were pre-incubated with either HPE (1-to 20-mg fresh nut equivalents) or its isolated components for 1 h, then washed before stimulating with lipopolysaccharide (LPS) for 24 h. Cell viability and parameters associated with Nuclear Factor-jB (NF-jB) activation were assayed according to established methods including ELISA, Western blot, or cytofluorimetric analysis. Results HPE suppressed nitric oxide (NO) and tumor necrosis factor-a (TNF-a) production and inducible NO-synthase levels dose dependently, whereas inhibited prostaglandin E 2 (PGE 2 ) release and decreased cyclooxygenase-2 content, the lower the HPE amount the higher the effect. Cytotoxic effects were not observed. HPE also caused a dose-dependent decrease in intracellular reactive oxygen species and interfered with the NF-jB activation.Polymeric proanthocyanidins, but not isoflavones, at a concentration comparable with their content in HPE, inhibited NO, PGE 2 , and TNF-a formation, as well as activation of IjB-a. Oligomeric proanthocyanidins showed only minor effects. Conclusions Our results provide molecular evidence of anti-inflammatory activity of pistachio nut and indicate polymeric proanthocyanidins as the bioactive components. The mechanism may involve the redox-sensitive transcription factor NF-jB. Potential effects associated with pistachio nut consumption are discussed in terms of the proanthocyanidin bioavailability.

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“…The cellular toxicity of punicalagin was determined by (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay (13). After 24 hr of incubation with the cells, punicalagin were removed by washing the cultured cells three times with medium.…”

Mediterranean Diet and Healthy Ageing: A Sicilian Perspective

“…Table 1 reports a brief description of some foods characterizing Sicilian countryside dietary habits [27,28,29,30,31,32]. As previously stated, olive oil plays a central role in MedDiet [2,11,33,34,35] and a glass of wine with meals may be assumed every day [2,11].…”

Oligomeric Cocoa Procyanidins Possess Enhanced Bioactivity Compared to Monomeric and Polymeric Cocoa Procyanidins for Preventing the Development of Obesity, Insulin Resistance, and Impaired Glucose Tolerance during High-Fat Feeding

“…EC and CPCs have been shown to possess antiobesity and anti-diabetic properties [24][25][26] . Emerging data suggest that these bioactivities may be highly correlated to flavanol DP [27][28][29] . Recently, Yamashita et al 30 demonstrated that a tetrameric cocoa flavanol significantly improved insulin secretion in mice compared to monomeric, dimeric, and trimeric flavanols (EC, PC B 2 , and PC C 1 , respectively) 30 .…”