Two new cycloartanes from the leaves of Combretum quadrangulare growing in Vietnam and their biological activities

Two new cycloartanes, combretanones G and H (1 and 2), were isolated from the leaves of Combretum quadrangulare. Their structures were elucidated by applying a set of spectroscopic methods, while their relative configurations were determined using DFT-NMR chemical shift calculations and subsequent assignment of DP4 probabilities. Compounds 1 and 2 are C-23/C-24 stereoisomers of the previously-reported euphonerin E. Both exhibited moderate cytotoxicity against three human cancer cell lines. Compound 2 was shown to be a potent antiparasitic. Our results confirm the traditional medicinal uses of Combretum quadrangulare in Vietnam.     

Chemical Constituents of the Leaves of Artocarpus integer

Chemistry of Natural Compounds -     

Chemical Constituents of the Endophytic Fungus Bipolaris maydis Derived from the Kandelia candel

Chemistry of Natural Compounds -     

A New Sesquiterpene Glycoside from Leaves of Bombax ceiba

Chemistry of Natural Compounds - A new sesquiterpene glycoside, ceibanoside (1), was isolated from the leaves of Bombax ceiba, together with the previously-reported quercetin (2), kaempferol (3),...     

Synthesis and α-Glucosidase Inhibitory Activity of Ursolic Acid,Lupeol, and Betulinic Acid Derivatives

Chemistry of Natural Compounds - Seven synthetic derivatives of ursolic acid, lupeol, and betulinic acid (1a–1b, 2a–2b, and 3a–3c) were synthesized to study their...     

Secondary Metabolites of the Lichen Parmotrema cristiferum

Chemistry of Natural Compounds - A new C41-spiroterpenoid, norreticulatin (1), has been isolated from the thalli of Parmotrema cristiferum together with four known compounds, anadensin (2),...