Integrated Assessment of Bioactive Properties of Nine Thlaspi Species: Antioxidant Activity, Enzyme Inhibition and LC–MS/MS Polyphenolic Characterization

Brassicaceae plants, among the most widely consumed vegetables worldwide, are recognized as rich sources of biologically active compounds. In this study, nine species belonging to the cruciferous genus Thlaspi were investigated, including T. alliaceum, T. arvense, T. violascens, T. aghricum, T. cataonicum, T. annuum, T. watsonii, T. cariense, and T. elegans. In the past, pennycress species were consumed to alleviate hunger and provide nutritional support during periods of food scarcity. To evaluate the antioxidant capacities of methanol and water extracts obtained from Thlaspi species, several complementary assays were employed, including 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical (ABTS•+) scavenging, 1,1-diphenyl-2-picrylhydrazyl free radicals (DPPH•) scavenging, N,N-dimethylphenylenediamine radicals (DMPD•+) scavenging, Fe3+-2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)-reducing, Fe3+ ion-reducing, and Cu2+ ion-reducing assays. The IC50 values of both methanol and water extracts from the aerial parts of Thlaspi species for ABTS•+, DPPH•, and DMPD•+ scavenging activities were studied compared with antioxidant standards, including α-tocopherol, Trolox, butylated hydroxytoluene (BHA), and butylated hydroxyanisole (BHT). The total phenolic and flavonoid contents of the extracts ranged from 8.29 to 49.14 mg gallic acid equivalent (GAE)/g extract and from 2.33 to 74.66 mg quercetin equivalent (QE)/g extract, respectively. Furthermore, the inhibitory effects of water and methanol extracts of Thlaspi species against α-amylase, acetylcholinesterase (AChE), and carbonic anhydrase (CA II) enzymes were evaluated. The IC50 values were determined to range from 122.4 to 245.9 μg/mL for α-amylase, from 17.3 to 24.1 μg/mL for AChE, and from 41.9 to 256.5 μg/mL for CA II inhibition. In addition, the phenolic profiles of Thlaspi species were comprehensively characterized by LC-MS/MS analysis using 53 reference standards. The findings demonstrated that the aerial parts of Thlaspi species are rich in polyphenolic antioxidants and may serve as promising natural sources with potential applications in the management of diabetes, Alzheimer’s disease (AD), glaucoma, epilepsy, and cancer.