Biomedical subjects

Hokoon Park

Publications and source records attributed to Hokoon Park.

6 recordsLinked to original sources

PubMed2002

A prenylated flavonol, sophoflavescenol: a potent and selective inhibitor of cGMP phosphodiesterase 5.

During the search for naturally occurring cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5) inhibitors, it was found that the extracts from Sophora flavescens exhibit potent inhibitory activity against cGMP PDE5 prepared from rat diaphragm. Therefore, the inhibitory activities of five flavonoids, kushenol H (1), kushenol K (2), kurarinol (3), sophoflavescenol (4) and kuraridine (5), isolated from S. flavescens were measured against cGMP PDE5 to identify potent cGMP PDE5 inhibitory constituents. Among tested compounds, sophoflavescenol (4), a C-8 prenylated flavonol, showed the most potent inhibitory activity (IC(50)=0.013 microM) against cGMP PDE5 with 31.5- and 196.2-fold selectivity over PDE3 and PDE4, respectively. Kinetic analysis revealed that sophoflavescenol was a mixed inhibitor of PDE5 with a K(i) value of 0.005 microM.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2002

Styrylquinazoline derivatives as HIV-1 integrase inhibitors.

Styrylquinazoline derivatives were prepared by Perkin condensation and evaluated for inhibitory activity against HIV-1 integrase. Among them, compound 5c containing a free catechol ring was the most potent (IC(50)=0.8 +/- 1.9 microM)and showed 6-fold more potency than the corresponding styrylquinoline compound (IC(50) = 130.7 +/- 8.6 microM).

HIV Integrase Inhibitors↗

PubMed2002

7-Substituted-[1,4]dioxano[2,3-g]quinazolines as inhibitors of epidermal growth factor receptor kinase.

With the aim of developing inhibitors of EGFR tyrosine kinase, the 7-methoxymethyl-[1,4]dioxano[2,3-g]quinazolines (3a-b) and 7-mono- or di-alkylaminomethyl-[1,4]dioxano[2,3-g]quinazolines (4a-i) were prepared and evaluated for the inhibition of EGFR tyrosine kinase and the growth inhibition of human tumor cell lines. Among them, compounds 4d and 4h showed potencies against both EGFR tyrosine and the A431 cell line similar to that of PD153035 with greater aqueous solubilities of their HCl salts.

ErbB Receptors↗

PubMed2002

New iridoids from Asperula maximowiczii.

Three new dimeric iridoid glucosides, named asperuloides A (1), B (2), and C (3), were isolated from Asperula maximowiczii, along with the known compound picconioside II. The structures of the new compounds were determined by spectroscopic and chemical methods and by the single-crystal X-ray diffraction analysis of 1.

Chromatography, High Pressure Liquid↗

PubMed2002

New diarylheptanoids from the stems of Carpinus cordata.

Two new diarylheptanoids, carpinontriols A (1) and B (2), were isolated from the stems of Carpinus cordata, along with the known diarylheptanoid, casuarinondiol (3), and five known compounds, (+)-catechin (4), methyl gallate (5), methyl gallate 3-O-beta-D-glucopyranoside (6), methyl gallate 4-O-beta-D-glucopyranoside (7), and methyl gallate 3-O-beta-D-(6'-O-galloyl)-glucopyranoside (8). The structures of 1 and 2 were elucidated by spectral methods. Among the isolated compounds, compounds 4-6 and 8 showed radical-scavenging activity in the DPPH assay.

Antioxidants↗

PubMed2002

HIV gp41 binding phenolic components from Fraxinus sieboldiana var. angustata.

By means of HIV gp41 binding affinity directed chromatographic fractionation, three phenylethanoid glycosides; calceolarioside A ( 1), calceolarioside B ( 2) and acteoside ( 3), along with four hydroxycoumarins; esculin ( 4), fraxin ( 5), fraxetin ( 6) and esculetin ( 7), and one lignan, (-)-olivil ( 8) were isolated from the n-butyl alcohol fraction of Fraxinus sieboldiana var. angustata. Among the isolated compounds, calceolarioside B ( 2) and esculetin ( 7) showed moderate binding affinity on HIV gp41 with IC 50 values of 0.1 mg/ml and 0.5 mg/ml, respectively. Calceolarioside A ( 1), calceolarioside B ( 2), acteoside ( 3), and (-)-olivil ( 8) were isolated for the first time from this plant.

Binding, Competitive↗