Abstract
Bioassay-guided fractionation of the 60% ethanol extract of the stems of Dendrobium nobile using the DPPH assay led to the isolation of two new bibenzyl derivatives, nobilin D (1) and nobilin E (2), and a new fluorenone, nobilone (3), together with seven known compounds (4-10). Their structures were determined on the basis of spectroscopic analyses. Compounds 1, 2, 4, 7, 8, and 10 exhibited significant antioxidant activity higher than or equivalent to vitamin C in the DPPH assay, and compounds 1, 3, 4, and 7-10 displayed higher antioxidant activity than vitamin C in the ORAC assay. Compounds 1, 2, and 10 also exhibited stronger inhibitory effects on NO production than resveratrol.
MeSH terms
-
Antioxidants / chemistry
-
Antioxidants / isolation & purification*
-
Antioxidants / pharmacology
-
Bibenzyls / chemistry
-
Bibenzyls / isolation & purification*
-
Bibenzyls / pharmacology
-
Biphenyl Compounds
-
Dendrobium / chemistry*
-
Drugs, Chinese Herbal / chemistry
-
Drugs, Chinese Herbal / isolation & purification*
-
Drugs, Chinese Herbal / pharmacology
-
Fluorenes / chemistry
-
Fluorenes / isolation & purification*
-
Fluorenes / pharmacology
-
Nitric Oxide / biosynthesis
-
Nitric Oxide / metabolism
-
Picrates / pharmacology
-
Plant Stems / chemistry
-
Plants, Medicinal / chemistry*
-
Resveratrol
-
Sesquiterpenes, Germacrane
-
Stilbenes / pharmacology
Substances
-
Antioxidants
-
Bibenzyls
-
Biphenyl Compounds
-
Drugs, Chinese Herbal
-
Fluorenes
-
Picrates
-
Sesquiterpenes, Germacrane
-
Stilbenes
-
nobilin D
-
nobilin E
-
nobilone
-
Nitric Oxide
-
1,1-diphenyl-2-picrylhydrazyl
-
Resveratrol