Evaluation of the nutraceutical, antioxidant and cytoprotective properties of ripe pistachio (Pistacia vera L., variety Bronte) hulls

• Organic extracts are rich in phenolic acids and flavonoids.
• RP-HPLC-DAD-FLU let us to identify twenty bioactive compounds.
• Ripe pistachio hulls have strong antioxidant and cytoprotective activity.

Every year tons of pistachio hulls are separated and eliminated, as waste products, from pistachio seeds. In this study the hulls of ripe pistachios were extracted with two organic solvents (ethanol and methanol) and characterized for phenolic composition, antioxidant power and cytoprotective activity. RP-HPLC-DAD-FLU separation enabled us to identify 20 derivatives, including and by far the most abundant gallic acid, 4-hydroxybenzoic acid, protocatechuic acid, naringin, eriodictyol-7-O-glucoside, isorhamnetin-7-O-glucoside, quercetin-3-O-rutinoside, isorhamnetin-3-O-glucoside and catechin. Methanol extraction gave the highest yields for all classes of compounds and presented a higher scavenging activity in all the antioxidant assays performed. The same was found for cytoprotective activity on lymphocytes, lipid peroxidation and protein degradation. These findings highlight the strong antioxidant and cytoprotective activity of the extract components, and illustrate how a waste product can be used as a source of nutraceuticals to employ in manufacturing industry.