Thirty-one bioactive styryl-lactones, with six different basic skeletons, have been isolated from Goniothalamus species. Aspects of their isolation, structural elucidation, biogenesis and biological activity are reviewed. Copyright © 1999 John Wiley & Sons, Ltd.

Styryl-lactones from Goniothalamus species— A review

Nine minor new tirucallane (1−7) and euphane (8 and 9) triterpenoids including five hydroperoxides, together with 18 known compounds, have been isolated from an ethanolic extract of the roots of Euphorbia micractina. Their structures including absolute configurations were elucidated by spectroscopic and chemical analysis. In the in vitro assays, betulin (10) showed a selective cytotoxic activity against A2780 ovarian cells with an IC50 value of 6.1 μM and inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 15.3 μM. Jolkinol B (11) showed a potent activity against HIV-1 replication with an IC50 value of 12.6 μM. However, compounds 1−9 and the other known compounds were inactive in the three assays used.

Chemical Constituents of the Roots of Euphorbia micractina.

Selective targeting of breast cancer cells through ROS-mediated mechanisms potentiates the lethality of paclitaxel by a novel diterpene, gelomulide K

Three new abietane diterpene lactones, 3alpha-hydroxyjolkinolide A (1), ent-8alpha,14beta-dihydroxy-13(15)-ene-16(12alpha)-abietanolide (2) and ent-8alpha,14alpha-dihydroxy-13(15)-ene-16(12alpha)-abietanolide (3) as well as a known abietane diterpene jolkinolide A (4) were isolated from the roots of Euphorbia wallichii. Their structures were elucidated on the basis of spectroscopic analysis.

Three New Diterpenoids from Euphorbia wallichii

Cytotoxic ent-abietane diterpenes from Gelonium aequoreum.

Stereostructures and conformations of four diterpene lactones from Gelonium multiflorum

Absolute configurations of goniodiol, goniodiol monoacetate and other related dihydropyrones from synthetic, circular dichroism and x-ray crystallogra phic evidence

A reinvestigation of bicarbonate induced oligomerization of ethyl acetoacetate : one-pot biomimetic synthesis of dimethylcoumarin, trimethylcoumarin a nd condensed coumarin derivatives

K. Biswas

Papers

Stereostructures and conformations of four diterpene lactones from Gelonium multiflorum

Absolute configurations of goniodiol, goniodiol monoacetate and other related dihydropyrones from synthetic, circular dichroism and x-ray crystallogra phic evidence

A reinvestigation of bicarbonate induced oligomerization of ethyl acetoacetate : one-pot biomimetic synthesis of dimethylcoumarin, trimethylcoumarin a nd condensed coumarin derivatives

Some Interesting Reactions of Gelomulides, the Natural Diterpene Lactones

Friedel-crafts reaction with arylcarbinols : one-pot synthesis of 10-methylbenzo afluoranthene