Metais traço e aminas bioativas em alface proveniente da agricultura urbana

Abstract

Urban agriculture is an activity being practiced in every city of the world. Its practice has provided several benefits to growers, among them, availability of fresh vegetables, source of vitamins, minerals and bioactive compounds such as polyamines, which have shown antioxidant activity. However, urban agriculture can be a risk in case the vegetables are contaminated with metals. Therefore, the objective of this study was to investigate if three lettuce cultivars produced in different urban gardens within the metropolitan region of Belo Horizonte, MG (Cafezal, Productive Garden and Metropolitan Center for Urban and Familiar Agriculture), would offer contamination risks due to the presence of cupper, cadmium and lead. Furthermore, the impact of these metals on plant growth was investigated by means of bioactive amines, which were investigated in the leaves and stems of the lettuce by ion pair HPLC. Every sample analyzed contained levels of these metals below the limits established by Brazilian legislation and also by Codex Alimentarius. Therefore, the safety of the lettuce regarding these metals was warranted. The levels of cadmium were affected by the cultivar and the levels of every metal investigated were affected by the location of the garden. Spermidine, spermine and putrescine were detected in every sample analyzed. Spermidine and putrescine were the prevalent amines in the leaves whereas spermidine and spermine were prevalent in the stem. Agmatine was detected in 33% of the samples. In the leaves, the levels of putrescine and spermidine were affected by the cultivar and location of the garden. In the stems, only putrescine levels were affected by the cultivar.