Comparison of metabolic profiles, regulatory pathways, and quorum sensing inhibition activity of brown mustard seeds (Brassica juncea L.) post germination and roasting treatments

Abstract

While mustard seeds offer an enormous wealth of biologically valuable compounds, the obtainable data unveiling the effect of germination and roasting treatments on the metabolic patterns and quorum-sensing (QS) antagonistic effect is limited and demands further investigation. The current study emphasizes proffering a glimpse of the metabolic fluctuations post mustard seeds germination and roasting treatments through UPLC-MS/MS analysis coupled with chemometrics, and its potential entanglements on disrupting the QS system in Pseudomonas aeruginosa PAO1. Correspondingly, 74 chromatographic signals embracing amino acids, phenolic acids, glucosinolates, flavonoids, fatty acids, phospholipids, and terpenoids were chemically characterized. Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA) models demonstrated perceivable chemical discrepancies among the processed samples, where phenolic acids and flavonoids witnessed a relatively marked rise in germinated and roasted samples compared to raw matches. Nevertheless, aliphatic glucosinolates, primarily sinigrin, glucocheirolin, gluconapin, and progoitrin, along with indole glucosinolates as glucobrassicin, witnessed a moderate elevation with a fold increase (2.5-4.5) in germinated seeds. In contrast, they offered a significant down-regulating tendency following roasting treatment, demonstrating the thermal degradation of glucosinolates into isothiocyanates and canolol. Following germination and roasting treatments, omega-3 fatty acid (linolenic acid and its hydroxylated form) presented a significant upward trend. Most amino acids, primarily serine and tyramine, as well as phospholipids, were continuously diminished throughout the germination and roasting processes. These metabolic shifts were mainly regulated by phenylalanine, tyrosine, and tryptophan biosynthesis, phenylpropanoid biosynthesis, flavonoid biosynthesis, glucosinolate biosynthesis, and glycerophospholipid metabolism pathways. Experimentally speaking, the germinated samples presented the most leading inhibitory effects against pyocyanin production, biofilm formation, twitching, and swarming motility by 75%, 91%, 76%, and 92%, respectively. The OPLS-derived coefficient plot unveiled that the germinated samples were significantly augmented with biologically credited compounds such as syringic acid, syringetin-3-O-glucoside, daidzein, progoitrin, hydroxyglucobrassicin, as well as eicosapentaenoic acid, which might synergistically underlie the QS inhibitory effect. Such integrative work offers meritorious insights into incorporating mustard sprouts and their bioactives in varying nutraceutical and biological applications for circumventing the development of antibiotic resistance.