Advanced liquid chromatography strategies for identifying antioxidative compounds in Tragacantha emarginata extracts

The leaf and stem tissues of Tragacantha emarginata, a plant with a history of use in Lebanese folk medicine, were examined for their antioxidant properties. Various solvent extracts were initially screened for radical-neutralizing activity using TEAC, ORAC, and DPPH assays, with the 30% ethanol extract showing the strongest effects. This extract was further analyzed using a combined high-performance liquid chromatography–ABTS$þ system to detect antioxidant-active constituents, followed by ultra-high-performance liquid chromatography separation and characterization through high-resolution mass spectrometry paired with UV-visible diode array detection. Around 40 distinct compounds were identified, primarily comprising hydroxycinnamic acid derivatives (including caffeic, ferulic, and p-coumaric acid forms) and flavonoid derivatives (such as quercetin, luteolin, apigenin, and isorhamnetin). Caffeic acid derivatives and quercetin glycosides were particularly linked to the observed antioxidant activity, with the presence of catechol groups appearing critical. These results demonstrate that T. emarginata leaf and stem extracts are rich in natural antioxidants, supporting their traditional therapeutic applications.