Ichiro Takano

Guaiane sesquiterpene lactones from Curcuma aeruginosa

Abstract Two guaiane derivatives were isolated from the rhizomes of Curcuma aeruginosa ( = C.zedoaria) . Their structures [ (1S ∗ , 4S ∗ , 5S ∗ , 8R ∗ , 10S ∗ )-4,10- dihydroxyguai-7(11)-en-12,8-olide (zedoalactone A) and (1R ∗ , 4S ∗ , 5R ∗ , 10R ∗ )-1,4,10- trihydroxyguai-7(11),8-dien-12,8-olide (zedoalactone B)] were established by 1 H and 13 CNMR spectroscopic studies and by comparison with closely related compounds. In addition, the already known guaianolide zedoarondiol was isolated from the same source.

Ester-type cephalotaxus alkaloids from Cephalotaxus harringtonia var. Drupacea

Three alkaloids, neoharringtonine, homoneoharringtonine and 3S-hydroxyneoharringtonine, were isolated from the leaves and stems of Cephalotaxus harringtonia var. drupacea. Their structures were established by spectroscopic methods, including two-dimensional NMR and CD spectra, and their antileukaemic activity was evaluated using P-388 leukaemia cells.

DRUPANGTONINE, A NOVEL ANTILEUKEMIC ALKALOID FROM CEPHALOTAXUS HARRINGTONIA VAR. DRUPACEA

Abstract Drupangtonine ( 1 ), a novel Cephalotaxus alkaloid, has been isolated from Cephalotaxus harringtonia var. drupacea , and its structure has been elucidated based on spectroscopic analyses. Compound 1 strongly inhibits the growth of P-388 leukemia cells.

Alkaloids from Cephalotaxus harringtonia

Abstract Four alkaloids, 5′-des- O -methylharringtonine, 3′ S -hydroxy-5′-des- O -methylharringtonine, 5′-des- O -methylhomoharringtonine and 5′-des- O -methylisoharringtonine, were isolated from the leaves and stems of C. harringtonia var. drupacea. Their structures were established by 1 H and 13 C NMR spectroscopic studies, chemical conversions to known alkaloids and applying the advanced Moshers method for the secondary alcohol moiety.

Cephalotaxidine, a novel dimeric alkaloid from Cephalotaxus harringtonia var. drupacea

Abstract Cephalotaxidine (1), a novel Cephalotaxus dimeric alkaloid, has been isolated from Cephalotaxus harringtonia var. drupacea, and its structure has been elucidated based on spectroscopic analyses. Alkaloid 1 has a unique Cue5f8C bridge between the two mother skeletons which are composed of homoharrigtonine and its oxygenated congener.