ASCORBIC ACID, ASCORBATE PEROXIDASE, AND H2O2 IN FRESHLY HARVESTED FRUITS OF SWEET CHERRY LANDRACES OF CAMPANIA (ITALY)

ASCORBIC ACID, ASCORBATE PEROXIDASE, AND H2O2 IN FRESHLY HARVESTED FRUITS OF SWEET CHERRY LANDRACES OF CAMPANIA (ITALY) MIRTO A., IANNUZZI F., VACCA F., WOODROW P., CARILLO P., FUGGI A. Department of Environmental Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via A.Vivaldi 43, 81100 Caserta (Italy) sweet cherry,vitamin C, ascorbate peroxidase, hydrogen peroxide,redox potential Ascorbate (AsA) has a key role in many metabolic processes, regenerating other metabolites like tocopherols from oxidative damages and protect many enzymes from irreversible inactivation by oxidation mainly caused by the oxidative stress. It is among the main component of the redox homeostasis buffering mechanism (ascorbate - glutathione cycle and is involved in many redox signalling processes. Ascorbate peroxidase (APX) as enzyme of the ascorbate-glutathione cycle uses ascorbate as electron donor to scavenge hydrogen peroxide (H2O2) produced in normal and stress enhanced aerobic metabolism. (Ascorbate (vitamin C) is essential for human health and its main dietary source are plant-derived foods. In addition high level of ascorbate in fruits and vegetables improve their post-harvesting storage properties. In the aim of conservation and valorization of agro-biodiversity of sweet cherry germoplasm of Campania (Italy) a study has been conducted to measure AsA, dehydroascorbate (DHA) and hydrogen peroxide (H2O2) contents, as well as APX activities in the harvested fruits. The redox state of the fruits was also evaluated. Freshly harvested fruits from 23 landraces cultivated at the Regione Campania – Improsta farm were used for the analyses. The sweet cherry fruit extracts of the landraces varied significantly in contents of AsA and DHA as well as in the DHA/AsA ratio. The redox potential showed the lowest value in the extracts from the “Patanara” and “Lauretana” ones that did not show particularly high contents of AsA. The highest potential was found in those from “Melella” and “Tamburella” that had relatively low AsA content. Extracts from “Melella” were among those with the highest APX activity, while those from “Tamburella” were from those with the lowest APX activity, as were also the extract from Lauretana. The H2O2 contents also were not simply related to AsA content, APX activity and redox potential, in agreement with the view that ascorbate concentration is dependent on biosynthesis, catabolism and recycling. Anyway as considering that the oxidative stress in postharvest increase it can be suggested that fruits with the lowest redox potential closer to the physiological one, at the harvest,contains the overall most efficient antioxidant system and may be more suitable for postharvest storage. The work was funded by "Regione Campania, PSR 2007/2013, Measure 214, Action f2, project “Agrigenet".