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

摘要

Anthocyanin pigments from wild mulberries (Morus nigra) growing in Brazil, were extracted and characterized. Extraction was performed with methanol/water/acetic acid (70:30:5 v/v), and the crude methanolic extract (CME) was cleaned up by polyamide solid-phase extraction (SPE). 2 major anthocyanins were isolated by paper chromatography, and their chemical structures were identified by spectral analyses, HPLC with diode array detection and MS. Information from HPLC profiles, saponification and acid hydrolysis of the mulberry anthocyanins showed that the 2 major pigments were cyanidin-3-glucoside (approx. 71% of the total) and cyanidin-3-glucosylrhamnoside (approx. 19% of the total), with no cinnamoyl groups. The CME (at 10 muM gallic acid equivalent (GAE)), a neutral flavonoids (NF) eluate and an acidic flavonoids (AF) eluate from SPE (at 1 muM GAE), demonstrated higher antioxidative activity than quercetin and BHT at 10 muM, according to the beta-carotene bleaching assay.