Mei-Ing Chung

Synthesis and Anti-inflammatory Effects of Xanthone Derivatives

Eighteen synthetic xanthone derivatives were tested for their inhibitory effects on the activation of mast cells and neutrophils.

Synthesis and Antithrombotic Effect of Xanthone Derivatives

A series of xanthone derivatives was synthesized and tested in‐vitro for their ability to inhibit aggregation of rabbit washed platelets and human platelet‐rich plasma (PRP) induced by various inducers.

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.

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±0.7 μM. 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.

PRENYLFLAVONOIDS OF ARTOCARPUS HETEROPHYLLUS

Abstract Six prenylflavonoids, including two new compounds, have been isolated from the root bark of Artocarpus heterophyllus . The new prenylflavones have been characterized as 8-(γ,γ-dimethylallyl)-5,4′-dihydroxy-7,2′-dimethoxyflavone and 3,3′-di-(γ,γ-dimethylallyl)-5,7,2′,5′-tetrahydroxy-4′-methoxyflavone, respectively.

Flavonol and anthraquinone glycosides from Rhamnus formosana.

Two new flavonol triglycosides, and a new anthraquinone glycoside, have been isolated from the roots of Rhamnus formosana. These compounds have been characterized as rhamnazin 3-O-[alpha-L-rhamopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----6 )]-beta-D-galactopyranoside (rhamnazin 3-isorhamninoside), rhamnocitrin 3-O-isorhamninoside and 1,6,8-trihydroxy-3-methylanthraquinone 1-O-rhamnosyl(1----2)glucoside, respectively.

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.

Studies on the Constituents of Formosan Gentianaceous Plants. Part VII Constituents of Swertia Randaiensis Hayata and Pharmacological Activity of Norswertianolin

Bellidifolin (XI) was first isolated from the fresh whole plant of Swertia randaiensis Hayata (Gentianaceae). Further, oleanolic acid, a constituent of this plant, reported by Wu et al, wasreinvestigated by C NMR spectroscopy, being revised into ursolic acid. Pharmacological studies on the xanthone glycoside, norswerianolin, which was previously isolated from this plant, showed that it posseses a depressant activity on the central nervous system.