Phenolic antioxidants from the whole plant of Phyllanthus urinaria.
The 1,1-diphenyl-2-picrydydrazyl (DPPH) assay on the extract of Phyllanthus urinaria L. (Euphorbiaceae) displayed considerable radical-scavenging activity (SC50 = 14.3 microg/ml). Further bioassay-guided purification of the extract led to the isolation of a series of 15 phenolic compounds, including the ellagitannins 1-7, the flavonoids 8-10, and the simple hydroxylated (or glycosylated) aromatic acids 11-15. Their structures were identified by spectroscopic analyses and comparison with authentic samples or literature data. The structure of repandinin B (1) was for the first time fully assigned by 1D- and 2D-NMR experiments. The phenolic compounds 1, 3, 4, 6, 9, 11, and 15 have not been isolated before from the title plant. The antioxidant activities and mushroom-tyrosinase-inhibitory activities of all compounds were determined by DPPH-radical-scavenging and mushroom-tyrosinase-inhibitory assays (Table 2).
Xu
Min
M
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China.
Zha
Zhong-Jun
ZJ
Qin
Xue-Ling
XL
Zhang
Xiang-Lan
XL
Yang
Chong-Ren
CR
Zhang
Ying-Jun
YJ
D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006834:Hydrazines / Q000737:chemistry; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D029803:Phyllanthus / Q000737:chemistry*; D010851:Picrates; D010936:Plant Extracts / Q000737:chemistry
D000975:Antioxidants; D001713:Biphenyl Compounds; D005419:Flavonoids; D006834:Hydrazines; D047348:Hydrolyzable Tannins; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; C004931:1,1-diphenyl-2-picrylhydrazyl; D014442:Monophenol Monooxygenase