Major anthocyanins from purple asparagus ( Asparagus officinalis)

Anthocyanins from the spears of purple asparagus ( Asparagus officinalis) were isolated and identified as cyanidin 3-[3″-( O-β- d-glucopyranosyl)-6″-( O-α- l-rhamnopyranosyl)- O-β- d-glucopyranoside] and cyanidin 3-rutinoside, respectively. ORAC assays suggest that they have high antioxidant activities. Two major anthocyanins (A1 and A2) were isolated from peels of the spears of Asparagus officinalis cv. Purple Passion. They were purified by column, paper and high-performance liquid chromatographic separations, and their structures were elucidated by high-resolution Fourier transform ion cyclotron resonance mass spectrometry (HR-FT-ICR MS), 1H, 13C and two-dimensional NMR spectroscopic analyses and either acid or alkaline hydrolysis, respectively. A1 was identified as cyanidin 3-[3″-( O-β- d-glucopyranosyl)-6″-( O-α- l-rhamnopyranosyl)- O-β- d-glucopyranoside], whereas A2 was cyanidin 3-rutinoside, which is widely distributed in higher plants. Oxygen radical absorbance capacity (ORAC) assays proved their high antioxidant activities.