Exposure of kale root to NaCl and Na2SeO3 increases isothiocyanate levels and Nrf2 signalling without reducing plant root growth

Abstract

A plant factory is a closed cultivation system that provides a consistent and modified environment for plant growth. We speculated that treatment of kale (Brassica oleracea) grown in a plant factory with NaCl, Na2SeO3, or both would increase the bioactive phytochemical levels including glucosinolates (GLSs) and isothiocyanates (ITCs), the key molecules in cancer prevention. The kale was harvested and analysed after treatment with NaCl and Na2SeO3 alone or in combination for 1 or 2 weeks. Exposure to NaCl alone but not Na2SeO3 increased plant root growth. Levels of sinigrin were increased by a 2-week exposure to Na2SeO3 alone or in combination with NaCl, whereas no changes were observed in glucoraphanin and gluconasturtiin gluconasturtiin levels. Importantly, the ITC concentration was affected by 2-week treatment with both compounds. To evaluate the bioactivity of kale, HepG2 human hepatoma cells were treated with plant extract for 6 h. Only the extract of kale roots exposed to a combination NaCl and Na2SeO3 for 2 weeks showed an increased expression of nuclear factor erythroid 2-related factor (Nrf2), which regulates genes encoding antioxidant proteins. These data suggest that co-treatment with NaCl and Na2SeO3 increased the ITC content and chemopreventive effects of kale root.

Selenium biofortification in the 21st century: status and challenges for healthy human nutrition

“…(Melrose 2019 ; Prieto et al 2019 ). Increased accumulation of ITC has been recently observed in kale ( Brassica oleracea L.) roots in response to selenite and NaCl joint application, thus making this food crop superior for chemopreventive effects (Kim et al 2018 ).…”

Exposure to Salinity and Light Spectra Regulates Glucosinolates, Phenolics, and Antioxidant Capacity of Brassica carinata L. Microgreens

“…Extracts of desulfated GLs were prepared following previously published protocols [21,39], with minor modifications. Freeze-dried sample (0.05 g) was immersed in 70% methanol (1 mL) and heated at 90 • C in a heating block for 30 min.…”

“…Sodium chloride (NaCl) salt stress for instance causes physiological and biochemical perturbations in plants providing a strategy to increase GLs biosynthesis [20]. In particular, salt stress demonstrated to be effective in enhancing GLs in broccoli, kale, and radish [21] and thus has shown potential industrial applications [22,23].…”

Bioaccessibility and Potential Biological Activities of Lutein, Glucosinolates, and Phenolic Compounds Accumulated in Kale Sprouts Treated with Selenium, Sulfur, and Methyl Jasmonate

“…These findings agree with a previous study reporting that Se (2 mg/L) treatment induces the accumulation of glucosinolates in 6 week old kale. 46 After intestinal digestion, total glucosinolate values showed a significant decrease in all kale samples (Table 5). These results agree with the study of Girgin and Nehir 47 who reported a decrease of glucosinolates by 26.4% in raw cauliflower after in vitro digestion.…”