Determination of antioxidant activity and phenolic content of Lupinus albus L. (white bitter lupin, tirmiye) grown in different regions of Türkiye by RP-HPLC-PDA

Lupinus albus L. (white bitter lupin) is an important legume species widely cultivated in the Mediterranean region. This study aimed to comparatively evaluate the antioxidant capacity and phenolic composition of L. albus samples collected from different regions of Türkiye. Samples were obtained from Konya (Central, Akşehir, Doğanhisar), Isparta (Central), and Burdur (Central). Total phenolic content, total flavonoid content and antioxidant activities of samples were determined using FRAP and DPPH assays. Additionally, the qualitative and quantitative profiles of phenolic compounds were analyzed by RP-HPLC-PDA.The total phenolic content was determined to be in the range of 1.955–2.471 mg GAE/g, whereas flavonoids were not detected in any of the samples. The results demonstrated that Lupinus albus L. extracts exhibited notable antioxidant activity, with FRAP values ranging from 1.135 to 1.947 µmol Fe²⁺/g and DPPH (SC₅₀) values ranging from 37.979 to 56.595. The phenolic composition analysis revealed the presence of major compounds including p-hydroxybenzoic acid, p-coumaric acid, ferulic acid, chrysin, pinocembrin, and galangin.Overall, the results indicate that L. albus exhibits moderate antioxidant potential despite its relatively low phenolic content, and its phenolic composition is influenced by geographical origin.