Phytochemical Profile and Biological Activities of Biscutella laevigata: A Comparative Study of Leaves, Seeds, and Microshoot Cultures

Biscutella laevigata (Brassicaceae) is an endemic species confined to European mountain regions, with a distribution range extending from the Iberian Peninsula through the Carpathians to the Balkans. The objective of this study was to investigate the phytochemical composition and biological properties of extracts obtained from leaves, seeds, and in vitro-derived microshoot cultures. UHPLC-DAD-MS/MS profiling of glucosinolates (GSLs) revealed six compounds exclusively present in seed extracts, with glucohirsutin identified as the predominant constituent (15.06 mg/100 g DW). No glucosinolates were detected in either leaf or microshoot extracts. Notably, 8-(methylsulfonyl)octyl GSL was reported in B. laevigata for the first time. The seed extract exhibited the highest total polyphenol content (TPC, 25,701.00 mg GAE/100 g DW), while leaf and microshoot extracts contained similar amounts (16,244.00 and 16,552.00 mg GAE/100 g DW, respectively). Among phenolic compounds, rutin was the most abundant, reaching up to 1609.21 mg/100 g DW in leaf extracts. Antioxidant capacity, assessed by ABTS and DPPH assays, was strongest in the seed extract (90.56% and 69.24% inhibition, respectively). The same extract demonstrated the greatest anti-elastase activity (12.68%), whereas the microshoot extract displayed a considerable Fe2+-chelating ability (12.48%). All tested extracts showed antimicrobial potential against Staphylococcus aureus, Escherichia coli, Cutibacterium acnes, and the fungus Candida albicans.