Identification and characterisation of anthocyanins from wild mulberry (Morus nigra L.) growing in Brazil

Anthocyanin pigments from the wild mulberry (Morus nigra L.) growing in Brazil, were extracted with methanol/water/acetic acid (70:30:5v/v), and the crude methanolic extract (CME) was cleaned up by polyamid solid-phase extraction (SPE). Two major anthocyanins were isolated by paper chromatography, and their chemical structures were identified by spectral analyses, HPLC/DAD and mass spectroscopy. Information from HPLC profiles, saponification and acid hydrolysis of the mulberry anthocyanins showed that the two major pigments were cyanidin-3-glucoside (ca. 71% of the total) and cyanidin-3-glucosylrhamnoside (ca. 19% of the total), with no cinnamoyl groups. The CME (at 10 mu m gallic acid equivalent), neutral flavonoids (NF) and acidic flavonoids (AF) eluate from SPE (at 1 mu M GAE), showed a higher antioxidant activity than quercetin and synthetic antioxidant (butyrate hydroxytoluene (BHT)) at 10 mu M, by the beta-carotene bleaching method.