Anthocyanin-rich fractions of blackberry extracts reduce UV-induced free radicals and oxidative damage in keratinocytes

Hull blackberries were purified using solid phase extraction to obtain anthocyanin-rich methanol fractions. This method concentrated phenolics and anthocyanins, recovering 97% and 76% of the total yield in puree or powder extracts, respectively, which represented a 24-63 fold increase of the total antioxidant capacity when compared with either the water fraction or the original extract. The ability of these fractions to protect primary keratinocytes against UV-induced oxidative damage was assessed. Anthocyanin-rich methanol fractions derived from either blackberry powder or puree exhibited strong antioxidant properties, protecting against UV-induced ROS nearly as efficiently as N-acetyl cysteine. Furthermore, the fractions up-regulated the expression of catalase, MnSOD, Gpx1/2 and Gsta1 antioxidant enzymes. Thus, it is concluded that blackberry extracts may protect keratinocytes against UV-mediated oxidative damage.