Bor-Jinn Shieh

Flavonoids isolated from Draconis Resina

One new chalcone, 4,6-dihydroxy-2-methoxy-3-methyldihydrochalcone (4), together with four known compounds, dammaradienol (1), (−)-5-methoxyflavan-7-ol (2), 5-methoxy-6-methyl-2-phenyl-7H-chromen-7-one (3), and dracorhodin (5), were isolated from Draconis Resina. The structures of these compounds were determined by spectral methods. Among these five compounds, compounds 1, 2, and 3 exhibited cytotoxicity against KB and HepG2 cells.

Isoprenylated flavonols of formosan Broussonetia papyrifera

Abstract Two new isoprenylated flavonols, broussoflavonol E [8,2′,6′-tri-(3,3-dimethylallyl)-5,7,3′,4′-tetrahydroxy-flavonol], broussoflavonol F [8,3′-di-(3,3-dimethylallyl)-5,7,4′ trihydroxyflavonol]; five known compounds, squalene, octacosan-1-ol, lignoceric acid, 4′-hydroxy- cis -cinnamic acid octacosyl ester, and (−)-marmesin; and a mixture of 4′-hydroxy- trans -cinnamates were further isolated and characterized from the root bark of Formosan Broussonetia papyrifera .

Revised structure of broussoflavonol G and the 2D NMR spectra of some related prenylflavonoids

Abstract The structure of broussoflavonol E (8,2′,6′-triprenyl-3,5,7,3′,4′-pentahydroxyflavone), renamed broussoflavonol G, from Formosan Broussonetia papyrifera , has been revised to be 8,5′,6′-triprenyl-3,5,7,3′,4′-pentahydroxyflavonol. The 13 C NMR spectra of the prenylflavonoids, cyclomorusin, cycloartomunin and dihydroisocycloartomunin, from Formosan Artocarpus communis , were reassigned using 2D techniques.

Two new glycosides from Leonurus japonicus

Two new glycosides, 1,6-di-O-syringoyl-β-d-glucopyranose (1) and quercetin 3-O-[(3-O-syringoyl-α-l-rhamnopyranosyl)-(1 → 6)-β-d-glucopyranoside] (2), along with seven known compounds were isolated from the MeOH extract of Leonurus japonicus. The structures of these compounds were elucidated by spectral analysis.

Studies on the Synthesis of Some Xanthonoid Derivatives Possessing Antiplatelet Effects

Abstract— 2,3‐ and 3,4‐Dihydroxyxanthone react with ethyl 2,3‐dibromopropanoate to form the new, substituted 1,4‐benzodioxanes 3 and 4, respectively. The regioisomers 3a and 3b; 4a and 4b were separated by column chromatography and characterized for evaluation of the antiplatelet effects in rabbit washed platelets and human platelet‐rich plasma. The ethoxycarbonyl derivatives 3a (20 μm) and 3b (20 μm) strongly inhibited the aggregation of rabbit washed platelets induced by arachidonic acid and collagen. The compound 4b showed the most potent inhibition of rabbit washed‐platelet aggregation induced by arachidonic acid (IC50 = 8·3 μm). Of the compounds tested in human platelet‐rich plasma, compound 4b exhibited the most potent inhibition of primary and secondary aggregation induced by adrenaline (IC50 = 8·6 μm). We conclude that the antiplatelet effects of these four ethoxycarbonyl derivatives are mainly due to an inhibitory effect on thromboxane formation and interference in the adrenaline‐receptor interaction.

Two new anthraquinones from Hemerocallis fulva

Two new anthraquinones, 7-hydroxy-1,2,8-trimethoxy-3-methylanthraquinone (1) and 7,8-dihydroxy-1,2-dimethoxy-3-methylanthraquinone (2), were isolated from the roots of Hemerocallis fulva. Their structures were established on the basis of spectral evidence (NMR and MS).