Biotechnological Studies on Nasturtium officinale (Watercress): an Endangered Species of Significant Relevance in Medicine, Cosmetic, and Food Industries

The chapter discusses the importance of plant biotechnology research on Nasturtium officinale (watercress), an endangered species of valuable pharmaceutical, cosmetic, and nutritional properties. This is a comprehensive study focusing on the development of N. officinale in vitro cultivation methods with the aim of stimulating the production of glucosinolates (GSLs) and polyphenols—compounds that are important from the perspective of plant utility. In addition, optimization of N. officinale in vitro culture conditions is discussed in detail, e.g., influence of plant growth regulators (PGRs) (cytokinins and auxins), LED light wavelength spectrum, and duration of growth periods on the production of bioactive metabolites in agar and agitated N. officinale microshoot cultures. Furthermore, the antioxidant profile of the tested in vitro culture extracts is evaluated using the following assays: cupric reducing antioxidant capacity (CUPRAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric reducing ability of plasma (FRAP). The highest total GSL content was achieved in the agar-grown microshoots over 20 days on the Murashige and Skoog (MS) medium containing 1 mg/L 6-benzyladenine (BA) and 1 mg/L 1-naphthylacetic acid (NAA) under a combination of 50% green, 35% red, and 15% blue lights (RBG). The highest total polyphenol content was detected in agar cultures cultivated over 10 days on the MS medium with 1 mg/L zeatin (Zea) and 1 mg/L NAA. The experimental cultures showed a high antioxidant potential. The optimal antioxidant activity was found for the extracts of N. officinale agitated microshoot cultures grown for 20 days on the MS medium containing 1 mg/L kinetin (KIN) and 1 mg/L 3-indolylacetic acid (IAA), as determined using the abovementioned methods.