Ming-Hong Yen

Phenolics from Hypericum geminiflorum

Abstract Five new constituents were isolated from the heartwood and roots of Hypericum geminiflorum. The structures were characterized as (2R,3R)-3,5,7,2′,5′-pentahydroxyflavan, 3,5- dimethoxy-4-hydroxy -1-O-β- d -glucoside , 3′-[γ-hydroxymethyl-(Z)-γ-methylallyl]-2′,4′,4-trihydroxychalcone 11′-O-ferulate, named gemichalcone A, 3′-[γ-hydroxymethyl-(Z)-γ-methylallyl]-2′,4′,4-trihydroxychalcone 11′-O-coumarate, named gemichalcone B, and 3′-[γ-hydroxymethyl-(E)-γ-methylallyl]-2′,4′,4-trihydroxychalcone 11′-O-coumarate, named isogemichalcone B.

Revised structure for five acetophenones from Cynanchum taiwanianum

Abstract The structures of the acetophenones cynandione A-D and cynanchone A isolated from Cynanchum taiwanianum have been revised following re-examination of their NMR spectral properties.

Artocarpol A. a Novel Constituent with Potent Anti-inflammatory Effect. Isolated from Artocarpus rigida

A novel phenolic compound, artocarpol A (1), was isolated from the root bark of Artocarpus rigida and its structure determined by spectroscopic methods and by comparison with its diacetate derivative. Compound 1 strongly inhibited superoxide formation in phorbol 12-myristate 13-acetate (PMA) stimulated rat neutrophils in a concentration-dependent manner with an IC50 value of 13.7±0.7u2005μM. Compound 1 also showed a significant inhibitory effect on tumor necrosis factor-α (TNF-α) formation in lipopolysaccharide(LPS)-stimulated RAW 264.7 cells.

A flavone C-glycoside and an aromatic glucoside from Gentiana species☆

Abstract A new aromatic glucoside, 2-hydroxy-3-methoxybenzoic acid glucose ester, was isolated from the whole plant of Gentiana formosana while a new flavone C -glycoside, isoorientin 6″- O -caffeate, and isoorientin 6″- O -glucoside and isoorientin were identified from G. arisanensis . The new compounds were characterized by spectral methods and chemical reactions.

Acetophenones from Cynanchum taiwanianum

A novel acetophenone derivative, cynanchone A, and a biacetophenone dimer, cynandione D, were isolated from the rhizomes of Cynanchum taiwanianum. Their structures were characterized by spectral methods.

New Pterocarpanoids of Crotalaria pallida and Crotalaria assamica

Four new pterocarpanoids crotafurans A (1), B (2), C (3), and D (4) were isolated from the bark of Crotalaria pallida and the seeds of the C. assamica, respectively. The structures, including relative configurations were elucidated by spectroscopic data.

Chingazumianine, a Novel Dichlorinated Alkaloid from Corydalis koidzumiana

A dichlorinated alkaloid with a novel skeleton, chingazumianine (1), was isolated from the herb Corydalis koidzumiana, and its structure elucidated by spectroscopic data and X-ray crystallographic analysis. In citrate-treated human platelet-rich plasma (PRP), known compounds, i.e., protopine (2), (±)-tetrahydropalmatine (3), and palmatine (4), isolated from this plant, showed significant inhibition of secondary aggregation induced by adrenaline in a concentration-dependent manner, suggesting that the antiplatelet effects of these compounds is mainly due to an inhibitory effect on thromboxane formation.

Hypertricone, a Constituent with a Novel Skeleton, Isolated from Hypericum geminiflorum

A novel compound containing an oxepane ring, hypertricone (1), was isolated from the leaves of Hypericum geminiflorum. Its structure, including the relative configuration, was elucidated from spectroscopic data and a computer-generated plot for the 3D structure.

The Cytotoxic Constitunets of Euphorbia Makinoi

One new triterpene, cycloart-24β-methoxy-3β-ol (1), and seven known com pounds, were isolated from the whole herb of Euphorbia makinoi. Their structures were established by spectral methods, and their cytotoxic activities were evaluated against three different cell lines. Com pound 1 showed marginal cytotoxic activity against the three human cancer cell lines while 3 showed marginal cytotoxic activity against Hep 3B and HT-29 cells in vitro.