Modulation of Oxidative Stress in Thrombin-Stimulated Platelets by Almond by-Product

Abstract

Almond (Al) green hulls are waste materials that are generated annually in the almond harvest and recently gained much attention due to their antioxidant properties. However, paucity information is in literature relevant to the modern pharmacological effects of Al green hulls. The aim of this study was to evaluate anti-platelet activity of Persian Al hull extract. The antioxidant activity of Al hull extract was investigated employing various established in vitro system including total antioxidant activity in linoleic acid emulsion system and DPPH assay. Platelet aggregation was monitored by spectrophotometer and intracellular ROS activity was evaluated by flow cytometry. Chemical composition of extract was determined by gas chromatography-mass spectrometry. In vitro study showed that Al hull extract at 100 μg/ml inhibited thrombin-induced platelet aggregation and protein secretion by 50%, without any cytotoxic effects on platelets. Moreover, based on different free radical trapping assay, it has been revealed that the examined extract had high antioxidant capacity and could suppress ROS generation in thrombin-stimulated platelets. GC-MS analyses revealed that Al hull extract contains a variety of phenolic and benzoic acid compounds dominated by ferulic acid, p-coumaric acid, quercetin, homovanilic acid, catechin and methoxysalsylic acid. Collectively high antioxidant capacity of Al hull extract and also its anti-platelet activity with lack of toxicity, give validity to this agricultural waste material as appropriate candidate for treatment of cardiovascular diseases and thrombosis.