Growth conditions and abiotic factors affect final concentration of bioactive compounds in broccoli sprouts

The beneficial effects of Brassica vegetables on human health have been attributed to their complex mixture of phytochemicals such as glucosinolates and anthocyanins. Glucosinolates have attracted great interest from both toxicological and pharmacological point of view, as they are able to induce phase 2 detoxication enzymes and protect animals against chemically induced cancer. Young broccoli plants are an especially good source of chemoprotective glucosinolates, whose levels are greater than in mature plants. Anthocyanins, responsible for the red, purple and blue colours of many vegetables and fruits, have been reported to be antioxidants and vasoprotectors, inhibit inflammation and the growth of cancerous cells and have anti-obesity effects. The quali-quantitative composition of bioactive compounds in vegetables is strongly affected by various factors, such as, growing conditions and abiotic stresses. In this work, the influence of different light and temperature regimes, as well as, of some chemical and hormonal treatments on glucosinolates and anthocyanins production in broccoli sprouts was investigated. A rapid and sensitive LC-MS/MS (MRM) method was developed to analysed and quantify glucosinolates in broccoli sprouts. Total anthocyanins content was determined by a spectrophotometric method and by HPLC-DAD. The results showed that glucosinolates and anthocyanins content significantly increased in broccoli sprouts exposed to light respect to sprouts grown in the dark. Also, abiotic stresses (sucrose, mannitol, NaCl) and some hormones involved in plant stress responses were able to increase accumulation of anthocyanins and glucosinolates, with sucrose being the most effective one. This work was supported by Italian Ministry of Agriculture, Food & Forestry (MiPAAF) grant “NUTRIGEA” (DM 30281 23/12/2009).