UV-Vis spectra for the oxidation of L-DOPA.

Black, 100 μg/ml L-DOPA; Pink, 100 μg/ml L-DOPA+50 μg/ml CT; Blue, 100 μg/ml L-DOPA +100 μg/ml CT; Purple, 100 μg/ml L-DOPA+100 μg/ml NaIO₄; Green, 100 μg/ml L-DOPA+100 μg/ml NaIO₄+50 μg/ml CT; Red, 100 μg/ml L-DOPA+ 100 μg/ml NaIO₄+100 μg/ml CT. The green and red spectra of the insert is corresponding to the green and red spectra of the main figure after subtraction of the corresponding condensed tannins absorption from the spectra, while the purple spectra of the insert is the same as the purple in the main figure. a, leaves condensed tannins; b, fruit condensed tannins; c, stem bark condensed tannins; CT, condensed tannins. The assay was performed in 3 ml of 50 mM sodium phosphate buffer (pH 6.8) at 30°C.