Methyl salicylate treatments of sweet cherry trees increase antioxidant systems in fruit at harvest and during storage

Abstract

Sweet cherry trees (Prunus avium L.) were treated with methyl salicylate (MeSa) at 1 mM at 3 key events on fruit development on-tree to analyze the effect of MeSa on bioactive compounds, total antioxidant activity (TAA) and antioxidant enzymes at harvest and during 28 days storage. The experiments were performed during two consecutive years, by using two sweet cherry cultivars, ‘Sweet Heart’ and ‘Sweet Late’ in 2013 and another more cultivar, ‘Lapins’, in 2014. Both total phenolics and anthocyanins content were significantly higher in MeSa-treated than in control fruit at harvest and during storage, leading to fruit with higher hydrophilic TAA (H-TAA). The activity of the antioxidant enzymes catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD) decreased along storage for all cultivars and experimental years, although those fruit treated with MeSa exhibited higher activities of these antioxidant enzymes than controls. Thus, MeSa treatment of cherry trees could increase healthpromoting properties of cherry fruit consumption, due to its effect on increasing antioxidant and bioactive compounds, with additional effect on delaying the fruit postharvest senescence process by increasing the activity of the enzymes involved in reactive oxygen species (ROS) scavenging