Scopoletin from the flower buds of Magnolia fargesii inhibits protein glycation, aldose reductase, and cataractogenesis Ex Vivo
Five compounds previously known structures, scopoletin (1), northalifoline (2), stigmast-4-en-3-one (3), tiliroside (4), and oplopanone (5) were obtained from the flower buds of Magnolia fargesii using chromatographic separation methods. The structures of 1–5 were identified by the interpretation of their spectroscopic data including 1D- and 2D-NMR as well as by comparison with reported values. Three compounds 1–3 were found from M. fargesii for the first time in this study. All the isolates (1–5) were subjected to in vitro bioassays to evaluate the inhibitory activity on advanced glycation end products formation and rat lens aldose reductase (RLAR). Compound 1 showed a remarkable inhibitory activity on advanced glycation end products formation with IC50 value of 2.93 μM (aminoguanidine: 961 μM), and showed a significant RLAR inhibitory activity with IC50 value of 22.5 μM (3.3-tetramethyleneglutaric acid: 28.7 μM). Compound 4 exhibited potent inhibitory activity against RLAR (IC50 = 14.9 μM). In the further experiment ex vivo, cataractogenesis of rat lenses induced with xylose was significantly inhibited by compound 1 treatment.
Key wordsMagnolia fargesii Scopoletin Advanced glycation end products Rat lens aldose reductase Cataractogenesis Diabetic complications
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