Phytochemical Characterization, Anti‐inflammatory and Lipolytic Activities of Pistachio Hulls, Skins, and Kernels

Abstract

Anti‐inflammatory, antioxidant, and lipolytic properties of pistachio hull, skin, and kernel extracts were evaluated here. All pistachio fractions reduced nitric oxide (NO) levels in Lipopolysaccharide (LPS)‐induced RAW 264.7 mouse macrophage cell line, at 50 µg/mL. Hulls polar fraction inhibited the LPS‐induced intracellular reactive oxygen species (ROS) to basal levels. Total phenolic contents of pistachio polar extracts represent 37%, 26% and 5% for hulls, skin and kernels, respectively; that is, the phenolic concentration in hulls, was significantly higher than skins and kernels. Hull polar subfractions indicated reductions in mRNA expression levels for the inflammatory markers Cox‐2 and IL‐6 up to 40% and 25%, respectively. LC‐ESI‐MS and NMR analyses of hull polar components showed the presence of quercetin and myricitin galloyl glucopyranosides, quercetin glucuronide, quercetin glucopyranoside, 1,5‐di‐galloyl‐2,3 hexahydroxy‐diphenoly‐scyllo‐quercitol, tri‐galloyl quinoic acid, tri‐galloyl glucopyranoside and gallic acid as main constituents. Assays with 3T3L1 mouse adipocytes demonstrated that all pistachio fractions decreased lipid accumulation up to 17%, with skin non‐polar fraction most active. GC‐MS analysis of the non‐polar fractions indicated that linoleic acid (C18:2) represents a predominant fatty acid in the skin tissue. Our results indicate that pistachio and its bioactive molecules present therein decrease inflammatory biomarkers as well as inhibit lipid accumulation. Results support the potential of pistachio to inhibit biomarkers associated with inflammation and obesity. Also, pistachio hulls represent a rich source of polyphenol antioxidant components.