OBJECTIVETo isolate and identify the tyrosinase inhibitory constituent from Angelica dahurica.

METHODA tyrosinase inhibitory constituent was isolated by silica gel column chromatography combined with a bioassay-linked HPLC method.

RESULTAn extract of heat-processed A. dahurica roots showed more potent tyrosinase inhibitory activity than that of the crude drug. Tyrosinase inhibitory furanocoumarin, 8-hydroxy-5-methoxypsoralen,was isolated. It express stronger tyrosinase inhibition than the known tyrosinase inhibitor, kojic acid (IC50 = 0.0907 mmol x L(-1)) with IC50 value of 0.0086 mmol x L(-1). Therefore, it is contributive to the increased tyrosinase inhibitory activity of the heat-processed A. dahurica.

CONCLUSIONThe active constituent was 8-hydroxy-5-methoxypsoralen from the heat-processed A. dahurica.

Angelica ; chemistry ; Chromatography, High Pressure Liquid ; Enzyme Inhibitors ; analysis ; isolation & purification ; pharmacology ; Inhibitory Concentration 50 ; Monophenol Monooxygenase ; antagonists & inhibitors ; Plant Roots ; chemistry

To investigate the chemical constituents of Saussurea deltoidea, 10 compounds were isolated from the title plant by various chromatography methods such as silica gel, RP-18 silica gel, Sephadex LH-20 column chromatography, HPLC, et al. Their structures were elucidated by spectral analysis. Five isoprenoids and Five phenylpropanoids were isolated and elucidated as (3R, 6R, 7E) -3-hydroxy-4, 7-megastigmadien-9-one (1), (3S, 5R, 6S, 7E) -5, 6-epoxy-3-hydroxy-7-megastigmen-9-one (2), 3-hydroxy-beta-damascone (3), S-(+) -dehydrovomifoliol (4), megastigman-5-ene-3beta, 9R-diol (5), coniferaldehyde (6), beta-hydroxypropiovanillone (7), 3-hydroxy-1-(4-hydroxy-3, 5-dimethoxyphenyl) -1-propanone (8), dihydrosyringenin (9), 4-[(1S) -3-hydroxy-1-methoxypropyl]-2, 6-dimenthoxyphenol (10). All the compounds were isolated from S. deltoidea for the first time.
Saussurea ; chemistry ; Terpenes ; isolation & purification

OBJECTIVETo identify the tyrosinase inhibitory constituent quickly from Potentilla bifurca.

METHODThe active constituent was found through fraction collecting and tyrosinase inhibitory activity by bioassay-linked HPLC method.

RESULTThe methanol extracts and BuOH fraction of Potentilla bifurca showed strong tyrosinase inhibitory activities. From BuOH fraction of Potentilla bifurca, the tyrosinase inhibitory constituent was isolated and identified as flavonoid, quercetin-4'-O-beta-D-glucoside. It express stronger tyrosinase inhibition than the known tyrosinase inhibitor, kojic acid (IC50 = 0.28 mmol x L(-1)) with IC50 value of 0.001 9 mmol x L(-1).

CONCLUSIONBioassay-linked HPLC fractionation method was provided for determination the active constituents quickly from herbal medicines.

Enzyme Inhibitors ; chemistry ; isolation & purification ; Kinetics ; Peptides ; chemistry ; isolation & purification ; Plant Extracts ; chemistry ; isolation & purification ; Potentilla ; chemistry