Separation and elucidation of anthocyanins in the fruit of mockstrawberry (Duchesnea indica Focke)

Abstract

Anthocyanin pigments in the fruit of mockstrawberry (Duchesnea indica Focke), were extracted with 0.1% HCl in ethanol, and the crude anthocyanin extract was purified by a C18 Sep-Pak cartridge open-column chromatography. High-performance liquid chromatography (HPLC) with photodiode array detection and mass spectrometry (MS) was applied for the isolation and composition analysis of anthocyanins in the fruit of mockstrawberry and their aglycones from acid hydrolysis. Three anthocyanins were found in the fruit of mockstrawberry and they were identified as cyanidin 3-O-rutinoside (61%), peonidin 3-O-rutinoside (34%), and petunidin 3-O-rutinoside (5%), respectively, by spectroscopic methods (UV-vis and MS). The two major anthocyanins were isolated by preparative HPLC, and their chemical structures were further characterised by H¹ NMR. On the basis of chromatographic data, the total anthocyanin content was 205 mg g⁻¹ of the fresh fruit of mockstrawberry.

Keywords:

• anthocyanins
• mockstrawberry
• Duchesnea indica Focke
• natural colourants
• composition analysis

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (20672086), China Postdoctoral Science Foundation (20070411144) and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Personnel Ministry of China (2007).