Reen Yen Kuo

Antiplatelet activity of N-methoxycarbonyl aporphines from Rollinia mucosa

Bioassay-directed fractionation of the stems of Rollinia mucosa led to the isolation of new N-methoxycarbonyl aporphine alkaloids, romucosine A (1), romucosine B (2), romucosine C (3), and romucosine D (4), along with the known alkaloid, N-methoxylcarbonyl-nornuciferine (5). Alkaloids 1 and 4 exhibited significant inhibition of collagen, arachidonic acid, and platelet activating factor-induced platelet aggregation, and alkaloid 3 also showed an inhibitory effect on arachidonic acid induced platelet aggregation.

Antiplatelet activity of benzylisoquinoline derivatives oxidized by cerium(IV) ammonium nitrate.

Oxidation of 1-benzyl-3,4-dihydroisoquinolines with cerium(IV) ammonium nitrate (CAN) under mild condition yielded the mixture of corresponding 1-benzylisoquinolines (b-type) and 1-benzoylisoquinolines (a- or c-type) in an equal yields. The selective oxidation products (c-type) can be prepared by using MeCN instead of MeOH. In the antiplatelet assays, four inducers were employed, including AA, Col, PAF, and Thr. In the PAF or Col induced platelet aggregation, compounds belonging to a- and b-type showed stronger inhibitory effects than aspirin.

Antiplatelet activity of synthetic pyrrolo-benzylisoquinolines

Pyrrolo-benzylisoquinolines were prepared as target compounds and their antiplatelet aggregation activity, adreno-receptor affinity, and cytotoxicity were screened. Compounds 1d-9d showed specific antiplatelet aggregation activity induced by arachidonic acid and collagen. Among them, 8d and 9d exhibited better activity than the reference drug, aspirin and 9d also showed inhibition of platelet aggregation by all four inducers.

A new propentdyopent derivative, rollipyrrole, from Rollinia mucosa Baill.

Abstract Rollipyrrole 1 , a novel pyrromethenone derivative was isolated from the leaves of Rollinia mucosa in the continuing research into Formosan annonaceous plants. This type of compound was isolated from plants for the first time and the structure of 1 was elucidated mainly on the basis of 1D and 2D NMR spectroscopic data.

Effect of active synthetic 2-substituted quinazolinones on anti-platelet aggregation and the inhibition of superoxide anion generation by neutrophils.

Quinazolinones, 2-substituted and 3-substituted, mainly synthesized by microwave irradiation, were subjected to anti-platelet aggregation and inhibition of superoxide anion generation assays. Interestingly, 2-phenyl-4-quinazolinone (4) exhibited significant inhibitory activities toward platelet aggregation and neutrophil activation, and it might therefore serve as a prototype lead compound.

A New Phenanthrene Alkaloid, Romucosine I, form Rollinia mucosa Baill

Bioactivity-directed fractionation led to the isolation of a new N-(methoxycarbonyl) phenanthrene alkaloid, romucosine I (1), along with three known N-(methoxycarbonyl) alkaloids, romucosine C (2), tuduranine (3), and promucosine (4). The structures of these compounds were identified on the basis of spectral data and chemical evidence. A proposed biogenesis about these isolates is also reported in this paper

Chemical Constituents and Their Pharmacological Activities from Formosan Annonaceous Plants

The Annonaceous plants are well known as folk medicines for the treatment of septic infections, coughing, hepatomegaly, hepatospleenomegaly, diarrhea and cancers. In the last two decades, eighteen of the Formosan Annonaceous plants (Annona cherimola, A. glabra, A. montana A. muricata, A. reticulata, A. squamosa, A. artemoya (A. cherimola x squamosa), A. purpurea, Artabotrys hexaptalus, A. uncinatus, Cananga odorata, Fissistigma glaucescens, F. oldhamii, Goniothalamus amuyon, Polyalthia longifolia, P. longifolia” Pendula”, Rollinia mucosa, and Uvaria rufa) and one plant collected from Mainland China, F. balansae, have been studied. The chemical constituents were isolated and screened for their biological effects (cardiovascular, cytotoxic and other pharmacological activities). Some of the compounds are potentially useful for the further development of clinical drugs.

Microwave enhanced acetylation of alcohols

Microwave irradiation of alcohols with acetic anhydride in the presence of a catalytic amount of NaOH for a few minutes yielded the corresponding acetylated products in excellent yield.