Hee Wook Park

Acetylcholinesterase inhibitors from the aerial parts ofCorydalis speciosa

In a bioassay-guided search for acetylcholinesterase inhibitors from Korean natural resources, four isoquinoline alkaloids, corynoxidine (1), protopine (2), palmatine (3), and berberine (4) have been isolated from the methanolic extract of the aerial parts ofCorydalis speciosa. Structures of these compounds were elucidated on the basis of spectroscopic techniques. These compounds inhibited acetylcholinesterase activity in a dose-dependent manner, and the IC50 values of compounds1-4 were 89.0, 16.1, 5.8, and 3.3 μM, respectively.

Phytochemical constituents fromdiodia teres

All ten compounds were isolated from the methanolic extract of the whole plants ofDiodia teres through repeated silica gel and Sephadex LH-20 column chromatography. Their chemical structures were elucidated as three iridoid glycosides, asperuloside, geniposidic acid and asperulosidic acid, a coumarin glycoside, scopolin, and six flavonoids, rutin, kaempferol-3-O-rutinoside, quercitrin, astragalin, isoquercitrin and quercetin by spectroscopic analysis.

Antitumor and antiinflammatory constituents from celtis sinensis

Eight compounds were isolated from the methanolic extract of the twigs ofCeltis sinensis through repeated silica gel and Sephadex LH-20 column chromatography. Their chemical structures were elucidated as two triterpenoids, germanicol and epifriedelanol, two amide compounds, frans-N-caffeoyltyramine andcis-N-coumaroyltyramine, two lignan glycoside, pinoresinol glycoside and pinoresinol rutinoside, and two steroids by spectroscopic analysis.

Cytotoxic isoquinoline alkaloids from the aerial parts ofCorydalis incisa

Three known isoquinoline alkaloids were isolated from the chloroform-soluble fraction of the methanolic extract of the aerial parts ofCorydalis incisa (Papaveraceae) through repeated column chromatography. Their chemical structures were elucidated as corynoline (1), corynoloxine (2) and 6-oxocorynoline (3) using spectroscopic analysis. Compounds 1-3 exhibited cytotoxicity against human A549, SK-OV-3, SK-MEL-2 and HCT15 tumor cells.

A new cytotoxic prenylated chalcone fromsophora flavescens

We have isolated a new prenylated chalcone from the roots of Sophora flavescens (Leguminosae). We determined that structure of this compound is 7,9,2’,4’-tetrahydroxy-8-isopentenyl-5-methoxychalcone (1) on the basis of spectroscopic analysis (1D and 2D NMR data). Compound 1 exhibited potent cytotoxicity against human acute promyelocytic (HL60), mouse lymphocytic (L1210) and human histiocytic (U937) leukemia cells.

Farnesyl protein transferase inhibitory components of Polygonum multiflorum

The methanolic extract of the roots of Polygonum multiflorum (Polygonaceae) was found to show inhibitory activity towards farnesyl protein transferase (FPTase). Bioassay-guided fractionation of the methanolic extract resulted in the isolation of two anthraquinone glycosides, as inhibitors of FPTase. These compounds inhibited the FPTase activity in a dose-dependent manner.

Cytotoxic germacranolide sesquiterpenes from the bark of Magnolia kobus.

A new (3) and three known germacrane-type sesquiterpenoids were isolated from the chloroform-soluble fraction of the methanolic extract of the bark of Magnolia kobus (Magnoliaceae) through repeated silica gel and Sephadex LH-20 column chromatography. Their chemical structures were elucidated as costunolide (1), parthenolide (2), isobisparthenolidine (3), and bisparthenolidine (4) by spectroscopic analysis. Compounds 1–4 exhibited cytotoxicity against human A549, SK-OV-3, SK-MEL-2, and HCT15 tumor cells.

Inhibitory activity of isorhamnetin from Persicaria thunbergii on Farnesyl Protein Transferase.

The methanolic extract of the aerial parts ofPersicaria thunbergii was found to show inhibitory activity on Farnesyl Protein Transferase (FPTase). Bioassay-guided fractionation of the methanolic extract resulted in the isolation of isorhamnetin, as an inhibitor on FPTase. This compound inhibited FPTase activity in a dose-dependent manner, and the IC50 value of isorhamnetin was 37.5 μM.