Three new dibenzofurans from Mill.

Phytochemical investigation of Mill. collected in Xinjiang province, China, led to the isolation and identification of three new dibenzofurans (-) along with one known compound (). Their structures were elucidated based on HRESIMS, spectroscopic data (IR, UV, 1D, 2D NMR) and X-ray diffraction analysis.

Jatrophane diterpenoids from Euphorbia helioscopia and their lipid-lowering activities.

The phytochemical study of Euphorbia helioscopia led to the isolation of 33 jatrophane diterpenoids (1-33), of which six (1-6) were new. This small jatrophane library was established to screen for potential lipid modulators. LDL-Uptake screening assay demonstrated that most of them improved LDL-Uptake rate in HepG2 cells, with compounds 16, 21 and 26 exhibiting more outstanding effects.

Resin glycosides from the seeds of Ipomoea muricata and their multidrug resistance reversal activities.

Resin glycosides represent an important chemotaxonomic marker of the Convolvulaceae family and possess multidrug resistance (MDR) reversal activity. In our recent study, nine previously undescribed resin glycosides, Calonyctins B-J, were isolated from the seeds of Ipomoea muricata. Their structures with the absolute configuration were established on the basis of comprehensive spectroscopic analysis and chemical methods.

Jatrophanes as promising multidrug resistance modulators: Advances of structure-activity relationships.

The phytochemical study of Euphorbia helioscopia afforded euphornin (1) in a large amount. Alkaline hydrolysis of 1 using potassium carbonate yielded the main product monodeacetyleuphornin (2), whose structural modification at 14-OH gave rise to 21 acylated derivatives euphornoate A-U (3-23). Thus, a mini compound library of jatrophanes was established to screen for MDR modulators.

Serratene-type triterpenoids from Palhinhaea cernua.

Phytochemical investigation of the 95% ethanol extract of the whole plant of Palhinhaea cernua afforded five new serratene-type triterpenoids (1-5) together with four known analogues (6-9). The structures of the new compounds were elucidated by extensive spectroscopic analysis and X-ray crystallographic data. Compounds 1-3 triggered apoptosis of Hela cell with EC values of 3.

(19αH)-lupane and (9βH)-lanostane triterpenes from Euphorbia helioscopia trigger apoptosis of tumor cell.

Chemical investigation of Euphorbia helioscopia resulted in the identification of seven new triterpenes named euphorbatrine A-G (1-7), including two (19αH)-lupane (1-2) and three (9βH)-lanostane (4-6), which are very rare metabolites from plants. Their structures were elucidated by extensive spectroscopic analysis, X-ray crystallography and chemical methods. Compounds 5 and 6 triggered apoptosis of Hela cell with EC values of 1.

Scubatines A-F, new cytotoxic neo-clerodane diterpenoids from Scutellaria barbata D. Don.

Phytochemical investigation of the 70% acetone extract of the whole plant of Scutellaria barbata D. Don afforded six new neo-clerodane diterpenoids, scubatines A-F (1-6), and four known analogues (7-10). Their structures were elucidated on the basis of extensive spectroscopic analyses.

Crassins A-H, Diterpenoids from the Roots of Croton crassifolius.

Phytochemical investigation of the 70% acetone extract of Croton crassifolius roots afforded eight new diterpenoids, crassins A-H (1-8), and 19 known compounds. The structures of the new compounds were determined by spectroscopic methods, and their absolute configurations were determined by electronic circular dichroism, single-crystal X-ray diffraction analysis, comparison with literature data, and biogenetic considerations. Crassins A (1) and B (2) are new ring B-rearranged diterpenoids, whereas crassin C (3) is a new ring A-rearranged diterpenoid.

A new patchoulane-type sesquiterpenoid glycoside from the roots of Croton crassifolius.

A new patchoulane-type sesquiterpenoid glycoside (1), together with five known sesquiterpenoids (2-6), was isolated from the roots of Croton crassifolius. Their structures were elucidated on the basis of spectroscopic methods. This is the first report about the sesquiterpenoid glycoside from C.

Directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes.

A directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes using TBHP as an oxidant was described. This methodology which showed the advantages of base, ligand free, short routes and functional group tolerance could be used as an alternative protocol for the classical esterification reactions.

Ruthenium-catalyzed oxidative coupling of 2-aryl-4-quinazolinones with olefins: synthesis of pyrrolo[2,1-b]quinazolin-9(1H)-one motifs.

A ruthenium-catalyzed oxidative coupling of 2-aryl-quinazolinones with olefins via C-H bond activation followed by an intramolecular aza-Michael reaction is described. This strategy allows the direct and efficient construction of pyrrolo[2,1-b]quinazolin-9(1H)-one scaffolds.

Multidrug resistance-reversal effects of resin glycosides from Dichondra repens.

Investigation of hydrophobic extract of Dichondra repens (Convolvulaceae) led to the isolation of three new resin glycosides dichondrins A-C (1-3), and three known resin glycosides cus-1, cus-2, and cuse 3. All the isolated resin glycosides with an acyclic core were evaluated for their multidrug resistance reversal activities, and the combined use of these compounds at a concentration of 25μM increased the cytotoxicity of vincristine by 1.03-1.

Merremins A-G, resin glycosides from Merremia hederacea with multidrug resistance reversal activity.

Five new pentasaccharide resin glycosides, named merremins A-E (1-5), two new pentasaccharide resin glycoside methyl esters, named merremins F and G (6, 7), and four known resin glycosides, murucoidin IV, murucoidin V, stoloniferin IV, and murucoidin XVII, were obtained from the aerial parts of Merremia hederacea. This is the first report of resin glycosides obtained from M. hederacea.

Map-based cloning of zb7 encoding an IPP and DMAPP synthase in the MEP pathway of maize.

IspH is a key enzyme in the last step of the methyl-D-erythritol-4-phosphate (MEP) pathway. Loss of function of IspH can often result in complete yellow or albino phenotype in many plants. Here, we report the characterization of a recessive mutant of maize, zebra7 (zb7), showing transverse green/yellow striped leaves in young plants.

A new QTL for resistance to Fusarium ear rot in maize.

Understanding the inheritance of resistance to Fusarium ear rot is a basic prerequisite for an efficient resistance breeding in maize. In this study, 250 recombinant inbred lines (RILs) along with their resistant (BT-1) and susceptible (N6) parents were planted in Zhengzhou with three replications in 2007 and 2008. Each line was artificially inoculated using the nail-punch method.