Effect of Pre-soaking Mustard Green Seeds Prior to Cold Plasma Treatment on Bioactive Aspects of Microgreens doi.org/10.26538/tjnpr/v5i8.16

Abstract

Microgreens have been reported to contain higher phytochemicals than mature plants. Mustard green (MG) is rich in glucosinolates that produce isothiocyanates (ITCs) upon degradation. ITCs have well-known chemopreventive benefits. Previously, non-thermal plasma treatment on MG seeds could enhance bioactive content; However, seed pretreatment before non-thermal plasma treatment was yet to be studied. The aim of this work was to evaluate the impact of pre-soaking MG seeds overnight before non-thermal plasma treatment at 21 kV for 5 min on phytochemicals and activities of MG microgreens. Plasma-treated pre-soaked (PTPS) seeds and control seeds (no plasma treatment) received deionized water for 7 days. No difference in germination percentage, stem height or fresh/dried weight of MG between PTPS seeds and the control was observed. Total ITC content in MG microgreens from PTPS seeds (1.62 mmol/100 g DW) was significantly higher than control seeds (1.00 mmol/100 g DW). Antioxidant capacity and total phenolic/flavonoid compounds were similar in both MG microgreens. Lower IC50 values were recorded for MG microgreens from PTPS seeds at most time intervals, indicating higher cytotoxicity against MCF-7 and HepG2, and greater effectiveness in cancer proliferation inhibition than the control. No differences in Bax, Caspase-3 and Bcl-2 mRNA expressions were detected for all samples; however, MMP-9 mRNA expression was reduced in MG microgreens from PTPS seeds for HepG2. Pre-soaking MG seeds before plasma treatment at 21 kV for 5 min increased ITC levels and increased anticancer activities of MG microgreens without adverse effects compared to MG microgreens from control seeds.