✍ Scribed by Min Xu; Zhong-Jun Zha; Xue-Ling Qin; Xiang-Lan Zhang; Chong-Ren Yang; Ying-Jun Zhang
No coin nor oath required. For personal study only.
The 1,1‐diphenyl‐2‐picrydydrazyl (DPPH) assay on the extract of Phyllanthus urinaria L. (Euphorbiaceae) displayed considerable radical‐scavenging activity (SC~50~=14.3 μg/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).
📜 SIMILAR VOLUMES
Metabisulfite, diethyldithiocarbamate, and thiourea are potent phenoloxidase inhibitors commonly used during the extraction of plant proteins. Their effects on several amino acid derivatives and peptides are reported. Important and pH-dependent changes are induced by metabisulfite in the uv-absorpti