Anthocyanins from the fruits of Rubus croceacanthus and Rubus sieboldii, wild berry plants from Okinawa, Japan

Anthocyanins from the fruits of Rubus croceacanthus and Rubus sieboldii, wild berries from Okinawa, Japan, were extracted using 80% methanol containing 0.5% acetic acid, and the extracts were separated by a DIAION HP-20 column. The major anthocyanins were purified by preparative HPLC and their structures were determined by NMR and MS spectrometry. Cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside were identified from R. croceacanthus, and their contents were 81.44 ± 1.01 mg and 170.02 ± 4.36 mg/100 g fresh weight, respectively. Pelargonidin-3-O-glucoside and pelargonidin-3-O-rutinoside were identified from R. sieboldii, and their contents were 10.04 ± 0.34 mg and 15.08 ± 0.48 mg/100 g fresh weight, respectively. An ORAC assay indicated that the two Okinawan wild berries, especially R. croceacanthus, had potent antioxidant activity compared to raspberry (Rubus idaeus).

► Major anthocyanins in the Okinawan wild berries were isolated and identified.
► Rubus croceacanthus had a high content of anthocyanins.
► Okinawan wild berries had potent antioxidant activity compared to raspberry.