Isolation of astragalin from flowers of Rhododendron mucronulatum for. albiflorum

Abstract

A flavonoid was isolated from the flowers of Rhododendron mucronulatum Turcz. for. albiflorum T. Lee by column chromatography. Interpretation of the spectroscopic analysis revealed the structure of the flavonoid to be astragalin. A reverse phase column was used, and a gradient solvent system of water and acetonitrile was employed as the mobile phase. The flow rate was kept constant at 1.0 mL per minute, and the peaks were identified using UV absorbance at 330 nm. The content of astragalin was measured in the flowers of R. mucronulatum (2.67 mg center dot g(-1)) and R. mucronulatum Turcz. for. albiflorum T. Lee (2.96 mg center dot g(-1)) by HPLC/UV analysis. In addition, astragalin from R. mucronulatum Turcz. for. albiflorum T. Lee flowers showed aldose reductase inhibitory activity (IC50 value of 3.88 M) that was comparable to that of the positive control, quercetin (IC50 value of 2.52 M). This is first report regarding the isolation of astragalin from R. mucronulatum Turcz. for. albiflorum T. Lee. R. mucronulatum Turcz. for. albiflorum T. Lee may be used as a possible source material for natural health supplements in the future.