Antioxidant Effects of Diarylheptanoid Derivatives from Alnus japonica on Human LDL Oxidation

Abstract

Two diarylheptanoids, oregonin (1) and hirsutanone (2), were isolated by bioassay-guided fractionation of the methanol extracts of the leaves of Alnus japonica Steud and their structures were elucidated from their spectroscopic data. Compounds 1 and 2 exhibited significant low-density lipoprotein (LDL)-antioxidant activities, e. g., thiobarbituric acid-reactive substances (TBARS) assay (1: IC₅₀ = 3.2 μM, 2: IC₅₀ = 1.5 μM), lag time (1 : 162 min, 2 : 230 min at 2.0 μM, control: 63 min), relative electrophoretic mobility (REM, inhibition of 1 : 71 %, 2 : 75 % at 10 μM), apoB-100 fragmentation (inhibition of 1 : 27.3 %, 2 : 40.3 % at 10 μM) and macrophage-mediated LDL oxidation (inhibition of 1 : 82 %, 2 : 84 % at 1 μM).

Key words

Alnus japonica - Betulaceae - low-density lipoprotein (LDL) - oregonin - hirsutanone

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