Yu Yi Chan

Nothapodytines A and B from Nothapodytes foetida

Two new naturally occurring alkaloids, nothapodytines A and B, were isolated and characterized from the stems of Nothapodytes foetida.

Structure and synthesis of [n]-dehydroshogaols from Zingiber officinale

Three new dehydroshogaols have been isolated from the rhizomes of Zingiber officinale. Their structures were established by spectroscopic analysis and synthesis.

Phenylalkynes from Artemisia capillaris

Eight new phenylalkynes, capillaridins A-H, together with three known compounds, capillin, capillene and O-methoxycapillene, were isolated and identified from the aerial parts of Artemisia capillaris.

Sodium aristolochate derivatives from leaves of Aristolochia foveolata

Abstract Three new sodium aristolochate derivatives, sodium aristolochate-I, -C and sodium 7-hydroxyaristolochate-A, together with 11 known compounds, were isolated from fresh leaves of Aristolochia foveolata . Their structures were determined by spectral and chemical methods. IR and 1 H NMR methods to distinguish aristolochic acid from its salt are discussed. This is the first reported isolation of sodium aristolochates from natural sources.

A flavonoid and indole alkaloid from flowers of Murraya paniculata

Abstract A new naturally occurring flavonoid, 3,5,7,3′,4′,5′-hexamethoxyflavone, and a new indole alkaloid, murrayaculatine, were isolated and characteriz

Tetranortriterpenoid insect antifeedants from Severinia buxifolia

Abstract Two new tetranortriterpenoids, severinolide and cycloseverinolide, together with four known compounds, were isolated and characterized from the root bark of Severinia buxifblia. Severinolide, atalantin and cycloepiatalantin showed significant antifeeding effects against Plutella xylostalla.

The constituents of roots and stems of Illigera luzonensis and their anti-platelet aggregation effects

Phytochemical investigation of the roots and stems of Illigera luzonensis afforded two new aporphine alkaloids (1) and (2), one new bisdehydroaporphine alkaloid (3), and one new benzenoid (4), along with 28 known structures. The structures of new compounds were elucidated by spectral and MS analysis. Among the isolated compounds, (1) and (4–13) were subjected into the examination for their inhibitory effects on the aggregation of washed rabbit platelets.

Chemical constituents and pharmacology of the Formosan Aristolochia species

Aristolochia is an important genus widely cultivated and used in traditional Chinese medicine. The genus has attracted much interest and has been the subject of numerous chemical studies. In the last twelve years, all the Formosan species of Aristolochia have been investigated by our group for their chemical constituents and biological activities. They are sources of a number of physiologically active compounds of different classes, and various types of phenanthrene derivatives, terpenes, alkaloids, flavonoids, lignoids, benzenoids, and steroids have been isolated from Formosan Aristolochia species. The nature of these constituents is compiled in this review together with their bioactivities in an effort to show the rapid development in the phytochemistry and the therapeutic applications of the Aristolochia species.

A secoiridoid and other constituents of Gonocaryum calleryanum

Investigation of the leaves, branch, stem and root bark of Gonocaryum calleryanum resulted in the isolation of a new secoiridoid glycoside, gonocaryoside E, together with 14 known compounds. Their structures were elucidated by spectral analysis and chemical transformation. Gonocaryoside E was shown to be a derivative of kingiside in which the lactone ring was open, and with the 8-hydroxy group esterified with tiglic acid. Alkaline hydrolysis of these secoiridoids is discussed.

Three sesquiterpenes from the roots and stems of Aristolochia heterophylla hemsl with novel skeletons

Abstract Three novel skeleton sesquiterpenes, namely, madolin-F (1), -G (2a), and -H (3), were isolated and characterised from the fresh roots and stems of Aristolochia heterophylla. Madolin-F belongs to a novel skeleton, normaaliane type. Madolin-G and -H were constructed from three- and eleven-membered rings and named madolin type.