Antioxidant and anti-inflammatory activities of polyphenolics from Southeastern U.S. range blackberry cultivars

The antioxidant and topical anti-inflammatory activities of low and high molecular weight phenolic fractions (LMPF and HMPF, respectively) isolated from three blackberry cultivars (i.e., Navaho, Kiowa, and Ouachita), bred to tolerate the warm and humid climatic conditions of the southeastern United States, were investigated by the in vitro ferric reducing antioxidant power (FRAP) assay and an in vivo mouse ear edema model. Seventy percent (v/v) acidified acetone was employed to extract phenolics from the Georgia-grown blackberry cultivars, which were subsequently cleaned up on an Amberlite XAD-16 column and then further fractionated with Sephadex LH-20 to LMPF and HMPF. The anti-inflammatory response from topical application of solutions of the LMPF and HMPF as well as indomethacin, a potent nonsteroidal anti-inflammatory drug, was assessed in the TPA mouse ear model. All treatments significantly (P < 0.05) reduced TPA-induced irritation injury. Furthermore, mouse ear myeloperoxidase (MPO) activity, an indicator of polymorphonuclear leukocyte infiltration, was assessed and found to be significantly (P < 0.05) reduced after topical application of indomethacin and all blackberry preparations. Correlation coefficients of 0.925 and 0.923 (P < 0.01) were determined when the anti-inflammatory activities of the blackberry fractions were compared to their total phenolics contents and antioxidant activities (i.e., FRAP values), respectively.