An Investigation on Yellow (<i>Sinapis alba</i>) and Black (<i>Brassica nigra</i>) Mustard Seed Extracts: Antioxidant, Anticholinergic Activities, and Phenolic Analysis via Liquid Chromatography‐Tandem Mass Spectrometry

In this study, the biological activities of water and ethanol extracts from Sinapis alba and Brassica nigra seeds were evaluated using various bioanalytical methods and spectrophotometric analyses. Antioxidant capacities were assessed through cupric reducing antioxidant capacity, ferric reducing antioxidant power assay, and ferric ion reducing assays, while radical scavenging abilities were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH)• and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonate) diammonium salt (ABTS)•+ assays. Total phenolic content (TPC) and total flavonoid content (TFC) were quantified as gallic acid equivalents (GAE) and quercetin equivalents (QE), respectively. Additionally, anticholinergic activity was determined by Ellman's method. Qualitative and quantitative analyses of phenolic compounds in extracts were performed using liquid chromatography-tandem mass spectrometry. Reference standards were employed for the comparison. The half-maximal inhibitory concentration (IC₅₀) values of S. alba and B. nigra seed extracts were in the range 1199-1799 µg/mL for DPPH• and 786.6-1259 µg/mL for ABTS•+ radical scavenging activities. TPC levels for S. alba and B. nigra water and ethanol extracts varied between 12.35 and 28.82 mg GAE/g extract, while TFC values ranged from 12.18 to 28.36 mg QE/g extract. The extracts also showed potent acetylcholinesterase inhibitory effects, with IC₅₀ values in the range of 0.167-0.194 µg/mL. These significant biological activities are attributed to the rich phytochemical composition of the seed extracts, indicating their potential as natural sources of antioxidant and anticholinergic agents.