The influence of different wavelengths of LED light on the production of glucosinolates and phenolic compounds and the antioxidant potential in in vitro cultures of Nasturtium officinale (watercress)

Cultures of Nasturtium officinale were cultivated in vitro under illumination with different wavelengths of light-emitting diode (LED) light (white LED light—WLED, blue light—B, red light—R, 70% red and 30% blue light—RB, 50% green, 35% red and 15% blue light—RBG, 50% yellow, 35% red and 15% blue light—RBY, 50% far red, 35% red and 15% blue light—RBfR, 50% UV, 35% red and 15% blue light—RBUV, darkness—D), and under white fluorescent light (WF)—control conditions. The study investigated the influence of the applied lighting conditions on biomass growth and the production of glucosinolates, phenolic compounds, as well as photosynthetic pigments, and soluble sugars. The study showed a significant beneficial effect of the RBG light on biomass growth (Gi = 11.81 after 20 days) and the production of glucosinolates. The total glucosinolate content under these conditions increased 5.8 and 1.4 times in comparison with the WF light and D condition, respectively, reaching 237.92 mg 100 g−1 DW. The production of phenolic compounds, sugars, and photosynthetic pigments was comparable to the production under the control conditions. The antioxidant potential of extracts from the cultivated biomass was assessed by the CUPRAC, DPPH, and FRAP assays. Extracts obtained from the biomass of cultures grown under the RBG light had an antioxidant potential similar to that of the control cultures. This is the first report providing evidence of the stimulating effect of light quality on the biomass yield and production of glucosinolates by N. officinale microshoot cultures in vitro. The studies of different LED light quality on Nasturtium officinale microshoot cultures were proven that combination of 50% green, 35% red and 15% blue lights stimulated the production of glucosinolates, phenolic compounds, photosynthetic pigments, and influenced on the antioxidant potential of biomass extracts.