Determination of chokeberry (Aronia melanocarpa) polyphenol components using liquid chromatography–tandem mass spectrometry: Overall contribution to antioxidant activity

•Polyphenols in Korean chokeberry leaves were determined by HPLC–MS/MS.•Six polyphenols were characterised in the leaves for the first time.•The antioxidant activity of leaf extracts were evaluated. The type and content of plant polyphenols can be influenced by maturity. Korean chokeberry (Aronia melanocarpa) leaves of three different maturities (young, mature, and aged) were extracted with 70% aqueous methanol. The polyphenols in the leaves were analysed for the first time using high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) and comparison with reported data. Among the 12 characterised components, five flavonoids, 3, 4, and 10–12, and a dicaffeoylquinic acid derivative, 6, were characterised for the first time in chokeberry leaves. Each polyphenol component was validated and quantified using a representative polyphenol standard of the same group. The antioxidant activity of the three different mature leaf extracts was determined. The antioxidant activity was highest for young leaves, followed by mature and aged leaves. The results suggest that younger chokeberry leaves may be more favourable for processing a higher quality functional tea due to their higher polyphenol content.