Euphorins A-H: bioactive diterpenoids from Euphorbia fischeriana.

Phytochemical investigation of the roots of Euphorbia fischeriana resulted in the isolation of 23 diterpenoids (1-23), which were classified into five subtypes, namely, ent-rosane (1-9), ent-abietane (10-16), ent-kaurane (17), ingenane (18-22), and lathyrane (23). The chemical structures of eight new compounds, namely, euphorin A (4), B (5), C (7), D (9), E (13), F (14), G (15), and H (16), were elucidated on the basis of extensive 1D and 2D NMR spectroscopic analyses, as well as single crystal X-ray structure analysis. A number of compounds (2, 6, 7, 10, 11, 13, 16, 19, 20, 22, and 23) showed inhibitory activity on the formation of mammospheres in human breast cancer MCF-7 cells at a final concentration of 10 µM, suggesting the potential of these bioactive diterpenoids for further investigation of the action targeting cancer stem cells.

ent-Atisane diterpenoids from Euphorbia fischeriana inhibit mammosphere formation in MCF-7 cells.

The discovery of new drugs that target cancer stem cells (CSCs) is a critical approach to overcome the major difficulties of the metastasis, chemotherapeutic resistance and recurrence for successful cancer therapy. Chemical investigation of the roots of Euphorbia fischeriana resulted in the isolation of eight ent-atisane diterpenoids (1-8), including two new compounds: 19-O-ß-D-glucopyranosyl-ent-atis-16-ene-3,14-dione (7) and 19-O-(6-galloyl)-ß-D-glucopyranosyl-ent-atis-16-ene-3,14-dione (8). The structures were elucidated on extensive spectroscopic analyses, as well as chemical transformations. ent-3ß-Hydroxyatis-16-ene-2,14-dione (5), 7 and its aglycon, ent-19-hydroxy-atis-16-ene-3,14-dione (7a), showed significant inhibitory activity on mammosphere formation in human breast cancer MCF-7 cells at a final concentration of 10 µM.

A simple and rapid method to identify and quantitatively analyze triterpenoid saponins in Ardisia crenata using ultrafast liquid chromatography coupled with electrospray ionization quadrupole mass spectrometry.

Ardisia plant species have been used in traditional medicines, and their bioactive constituents of 13,28-epoxy triterpenoid saponins have excellent biological activities for new drug development. In this study, a fast and simple method based on ultrafast liquid chromatography coupled to electrospray ionization mass spectrometry (UFLC-MS) was developed to simultaneously identify and quantitatively analyze triterpenoid saponins in Ardisia crenata extracts. In total, 22 triterpenoid saponins, including two new compounds, were identified from A. crenata. The method exhibited good linearity, precision and recovery for the quantitative analysis of eight marker saponins. A relative quantitative method was also developed using one major saponin (ardisiacrispin B) as the standard to break through the choke-point of the lack of standards in phytochemical analysis. The method was successfully applied to quantitatively analyze saponins in commercially available plant samples. This study describes the first systematic analysis of 13,28-epoxy-oleanane-type triterpenoid saponins in the genus Ardisia using LC-ESI-MS. The results can provide the chemical support for further biological studies, phytochemotaxonomical studies and quality control of triterpenoid saponins in medicinal plants of the genus Ardisia.

A dihydrochalcone and several homoisoflavonoids from Polygonatum odoratum are activators of adenosine monophosphate-activated protein kinase.

Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a major cellular energy sensor and master regulator of metabolic homeostasis; thus, AMPK plays a central role in studies on diabetes and related metabolic diseases. From the rhizomes of Polygonatum odoratum (Mill.) Druce, six homoisoflavonoids (1-6) and one dihydrochalcone (7) were isolated, and the structures of polygonatones A-D (4-7) were elucidated by various spectroscopic analyses. Compounds 1-7 were evaluated for their effect on AMPK activation. The amount of active phosphorylated AMPK and acetyl-CoA carboxylase in rat liver epithelial IAR-20 cells increased when the cells were incubated with the aforementioned compounds. Specifically, (3R)-5,7-dihydroxyl-6-methyl-8-methoxyl-3-(4'-hydroxylbenzyl)-chroman-4-one (1), (3R)-5,7-dihydroxyl-6,8-dimethyl-3-(4'-hydroxylbenzyl)-chroman-4-one (2), (3R)-5,7-dihydroxyl-6-methyl-3-(4'-hydroxylbenzyl)-chroman-4-one (3), and polygonatone D (7) exhibited significant activation effects.

Isolation, structure determination, and anti-HIV evaluation of tigliane-type diterpenes and biflavonoid from Stellera chamaejasme.

Five novel tigliane-type diterpenes, stelleracins A-E (3-7), a novel flavanone dimer, chamaeflavone A (8), and six known compounds were isolated from the roots of Stellera chamaejasme. Their structures were elucidated by extensive spectroscopic analyses. The isolated compounds were evaluated for anti-HIV activity in MT4 cells. New compounds 3-5 showed potent anti-HIV activity (EC90 0.00056-0.0068 µM) and relatively low or no cytotoxicity (IC50 4.4-17.2 µM). These new compounds represent promising new leads for development into anti-AIDS clinical trial candidates.

Labdane-type diterpenoids from hairy root cultures of Coleus forskohlii, possible intermediates in the biosynthesis of forskolin.

Significant attention has been devoted to studying hairy root cultures as a promising strategy for production of various valuable secondary metabolites. These offer many advantages, such as high growth rate, genetic stability and being hormone-free. In this study, a detailed phytochemical investigation of the secondary metabolites of Coleus forskohlii hairy root cultures was undertaken and which resulted in the isolation of 22 compounds, including four forskolin derivatives and a monoterpene. Their structures were elucidated by extensive spectroscopic analyses. These compounds could be classified into four groups viz.: labdane-type diterpenes, monoterpenes, triterpenes and phenylpropanoid dimers. Apart from one compound, all labdane type diterpenes are oxygenated at C-11 as in forskolin and a scheme showing their biosynthetic relationships is proposed.