Changes in growth, antioxidant, anti-Alzheimer, and antidiabetic potential of lamb’s lettuce Valerianella locusta grown hydroponically and on soil in response to salinity

Abstract

The purpose of this study was to provide new insights into the effects of salinity on growth and nutritional value of lamb’s lettuce Valerianella locusta grown in two different culture systems, hydroponic and soil, and subjected to 0 and 50 mM NaCl for 3 weeks. Salinity treatment reduced shoot dry weight (DW) by 50% in both growing media, root DW by 41% only on hydroponics, relative growth rate (RGR) also decreased, and K+/Na+ ions ratio in Valerianella locusta grown both hydroponically and in soil. Salinity also lowered shoot total phenolic content (TPC), total flavonoids content (TFC), radical scavenging activity (ABTS), anti-amylase, and anti-acetylcholinesterase (AChE) activities. In contrast, it promoted shoot total antioxidant activity (TAA) in both growing systems. When comparing both growing systems, soil-grown Valerianella locusta was found to have significantly higher TPC (41.6 and 28.1 mg GAE g-1 DW) and TFC (39.6 and 35.6 mg CE g-1 DW) for control and salt treated shoots, respectively. Further, it showed a better TAA and ABTS scavenging ability, as well as superior anti-α-amylase (94.3 and 39.5 mg ACE. g-1 DW) and anti-AChE (307.4 and 228.3 μg DE. g-1 DW) activities, under control and salt stress conditions respectively. Additionally, soil-grown Valerianella locusta showed better K+/Na+ ions homoeostasis compared to the hydroponically-grown. This study highlighted two main points: first, it revealed that lamb’s lettuce is a sensitive crop to be grown on saline lands, and second it underlined the distinct differences in growth aspects and nutritional quality between hydroponics and soil cultivation. Additionally, this study is the first to shed some light on the interesting medicinal quality of lamb’s lettuce as a leafy vegetable.