This study presents the bio-guided chemical investigation of 80% methanol extract of aerial parts of bladder tree or Colutea arborescens. Liquid-liquid partitioning in solvents of increasing polarity combined with biological screening showed that the EtOAc and n-BuOH soluble fractions were the most active parts of the extract. These fractions were chemically profiled by a 13C NMR-based dereplication method, resulting in the identification of fifteen compounds. The dereplication process was completed by purification of minor compounds of the n-BuOH fraction. Fourteen known compounds (1–14) were isolated, including two tri-glycosylated flavonoids containing an apiofuranose unit (12 and 14). Their structures were elucidated by spectroscopic methods including 1D and 2D NMR and high-resolution electrospray ionization mass spectrometry. The antioxidant activity of fractions and isolated compounds were evaluated using 2,2,1-diphenyl-1-picrylhydrazyl and hydroxyl radicals scavenging and by cupric ion reducing antioxidant capacity assays. In parallel, their inhibitory properties against mushroom tyrosinase and human neutrophil elastase enzymes were assessed. Quercetin-type flavonoids showed the best antioxidant activities and a tri-glycosylated quercetin exhibited both antioxidant and anti-elastase activities. Phenylethyl-glucoside exhibited a significant tyrosinase inhibitory activity.
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