Rutin, a major flavonoid glycoside found in many higher plants, was exposed at 25 kGy of γ-ray and produced three new hydroxymethylated products 2-4 in the C-ring by γ-irradiation. Structures of the new compounds, including absolute configurations, were elucidated based on spectroscopic interpretation (NMR, UV, [α]D, MS, and circular dichroism (CD)). The new unusual rutin derivatives 2 and 3 exhibited significantly enhanced inhibitory effects against α-glucosidase with IC50 values of 23.1±1.2 and 11.2±0.7 µM, respectively, when compared to the parent rutin.
Keywords: hydroxymethylation; radiolysis; rutin; α-glucosidase; γ-irradiation.