Eight pairs of epimeric triterpenoids involving a characteristic spiro-E/F ring from Abies faxoniana

Five pairs of new epimeric lanostane-type triterpenoids, abiespirones A-D (1-4) and G (7), two pairs of new epimeric cycloartane-type triterpenoids, abiespirones E and F (5, 6), and a pair of new epimeric 7(8→9)abeo-spirolanostane abiespirones H (8) with spiro-B/C and -E/F ring systems were isolated from Abies faxoniana as inseparable mixtures of C-23 epimers in a specific proportion. The HPLC plots showed that each purified isomer rapidly equilibrated with the C-23 epimer in solution. The structures of compounds 1-8 were elucidated by analysis of the NMR spectra and single-crystal X-ray diffraction. Compound 6 showed cytotoxicity against three hepatoma cell lines, namely, HepG2, Huh7, and SMMC7721, with IC50 values of 9.8, 7.5, and 10.7 μM, respectively, but exerted low cytotoxicity on normal QSG7701 hepatic cells, indicating its selective cytotoxicity for hepatoma cells. Compound 6 arrests the cell cycle at G2/M and induces cell apoptosis in Huh7 cells. In addition, the generation of reactive oxygen species (ROS) was detected in Huh7 cells when treated with compound 6, and a ROS scavenger partly blocked the effects of compound 6-induced Huh7 cell death, suggesting that compound 6-induced apoptosis is associated with elevated levels of ROS in Huh7 cells.

Diterpenoid lanceolatins A–G from Cephalotaxus lanceolata and their anti-inflammatory and anti-tumor activities

Seven new diterpenoids lanceolatins A–G (1–7)were isolated from the branches and leaves of Cephalotaxus lanceolata, and in vitro anti-inflammatory and antitumor activities were evaluated.

Structurally novel C17-sesquiterpene lactones from Ainsliaea pertyoides

Pertyolides A (1) and B (2), two unprecedented C₁₇-eudesmanolides with extended side chains, and one rare C₁₇-guaianolide, pertyolide C (3), along with 15 known sesquiterpene lactones were isolated from the whole plant of Ainsliaea pertyoides.

Abieslactone induces cell cycle arrest and apoptosis in human hepatocellular carcinomas through the mitochondrial pathway and the generation of reactive oxygen species

Abieslactone is a triterpenoid lactone isolated from Abies plants. Previous studies have demonstrated that its derivative abiesenonic acid methyl ester possesses anti-tumor-promoting activity in vitro and in vivo. In the present study, cell viability assay demonstrated that abieslactone had selective cytotoxicity against human hepatoma cell lines. Immunostaining experiments revealed that abieslactone induced HepG2 and SMMC7721 cell apoptosis. Flow cytometry and western blot analysis showed that the apoptosis was associated with cell cycle arrest during the G₁ phase, up-regulation of p53 and p21, and down-regulation of CDK2 and cyclin D1. Furthermore, our results revealed that induction of apoptosis through a mitochondrial pathway led to upregulation of Bax, down-regulation of Bcl-2, mitochondrial release of cytochrome c, reduction of mitochondrial membrane potential (MMP), and activation of caspase cascades (Casp-9 and -3). Activation of caspase cascades also resulted in the cleavage of PARP fragment. Involvement of the caspase apoptosis pathway was confirmed using caspase inhibitor Z-VAD-FMK pretreatment. Recent studies have shown that ROS is upstream of Akt signal in mitochondria-mediated hepatoma cell apoptosis. Our results showed that the accumulation of ROS was detected in HepG2 cells when treated with abieslactone, and ROS scavenger partly blocked the effects of abieslactone-induced HepG2 cell death. In addition, inactivation of total and phosphorylated Akt activities was found to be involved in abieslactone-induced HepG2 cell apoptosis. Therefore, our findings suggested that abieslactone induced G₁ cell cycle arrest and caspase-dependent apoptosis via the mitochondrial pathway and the ROS/Akt pathway in HepG2 cells.

Chemical constituents of Abies delavayi

Systematic phytochemical investigations on Abies delavayi afforded 110 compounds, including 49 terpenoids, 13 lignans, 20 flavonoids, three coumarins, and 25 other chemical constituents. By detailed analysis of one- and two-dimensional NMR spectroscopic and high-resolution mass spectrometric data, 10 previously unreported compounds were identified: they comprised three sesquiterpenoids, two diterpenoids, one triterpenoid, one monoterpenoid, one flavonoid, and two phenols. These 10 compounds and some previously known ones were subjected to two cytotoxic bioassays against three human tumor cell lines and NO production inhibition on RAW264.7 macrophages, respectively. (25R)-24,25-Dihydroabieslactone had the strongest cytotoxic activity against Colo-205 cells with an IC50 value of 19.0±3.7μg/mL. (+)-T-cadinol, 8,11,13-abietatrien-15-ol-18-yl acetate, 18-acetoxy-13-epi-manool, imperatorin, bergapten, and 5,7-O-dimethyl poriol exhibited weak inhibitory activity against LPS-induced NO production in RAW264.7 macrophages with IC50 values of approximately 50μg/mL.

Two novel lignans from Gaultheria yunnanensis

Two new lignans, 9-salicyl-(+)-isolariciresinol (1) and gaultheroside G (2), together with seven known compounds, were isolated from the ethanolic extract of the whole plant of Gaultheria yunnanensis. Their structures were determined by extensive NMR and MS analyses. Gaultheroside G (2) was found to have an unusual ether linkage between the 2 and 9' positions of aryl-tetralin lignan skeleton. All nine compounds were assayed for inhibitory effects against nitric oxide and pro-inflammatory cytokines TNF-α and IL-6 release in LPS-induced RAW 246.7 macrophages, while no significant activities were observed for the evaluated compounds.

Inula sesquiterpenoids: structural diversity, cytotoxicity and anti-tumor activity

INTRODUCTION

The plants of the genus Inula (Asteraceae) are widely distributed throughout Europe, Africa and Asia, and many of these plants have long been used in folk medicine. This genus is a rich source of sesquiterpenoids, which exhibit a wide range of biological activities. Recently, a series of bioactive sesquiterpenoid dimers, with unusual carbon skeletons, have been reported and these have gathered considerable interest.

AREAS COVERED

This article systematically reviews sesquiterpenoids isolated from the genus Inula that have appeared in literature up to August 2013, critically highlighting their anti-tumoral activities and relevant mechanistic insights. The authors also discuss the initial structure-activity relationships for the cytotoxic and anti-tumoral activities of the Inula sesquiterpenoids. Finally, the authors discuss the challenges and potential applications of these sesquiterpenoids in the future.

EXPERT OPINION

Cytotoxic and anti-tumor activities of Inula sesquiterpenoids have been extensively studied since the 1970s. One promising compound, Japonicone A, a dimeric sesquiterpene lactone from traditional herb Inula japonica, has displayed potent in vitro and in vivo anti-tumor activity against Burkitt's lymphoma. Additionally, acetylbritannilactone is thought to be capable of suppressing the abnormal vascular smooth muscle cell proliferation, with the induction of apoptosis in vivo and in vitro. In this regard, it may be worthwhile further investigating acetylbritannilactone in patients with vascular restenosis. Furthermore, given the anti-inflammatory property of britanin, clinical studies on chronic bronchitis and asthma, using the ethanol extract of I. japonica, are currently underway in South Korea. However, despite demonstrating good therapeutic effects, additional pharmacological and toxicological studies are still needed.

Bioactive eudesmane and germacrane derivatives from Inula wissmanniana Hand.-Mazz

Phytochemical investigation of Inula wissmanniana Hand.-Mazz. afforded 21 eudesmane and germacrane derivatives, including rare 4,5-secoeudesman-12,5-olide, eudesman-12,5-olide, 3,4-secoeudesman-12-oic acid, and germacra-4-en-12,6-olides. Their structures were elucidated by combinative analyses of MS, NMR, electronic circular dichroism, and X-ray crystallography data. Moreover, most of the isolates exhibited inhibition against lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophages and cytotoxicity in HepG2, PC-3, and MGC-803 tumor cells.

Pseudolarenone, an unusual nortriterpenoid lactone with a fused 5/11/5/6/5 ring system featuring an unprecedented bicyclo[8.2.1]tridecane core from Pseudolarix amabilis

A phytochemical investigation of the cone of Pseudolarix amabilis led to the isolation of pseudolarenone (), a structurally novel pentacyclic (5/11/5/6/5) nortriterpenoid lactone with an unprecedented carbon skeleton featuring a unique bicyclo[8.2.1]tridecane core. Its structure and absolute configurations were elucidated by spectroscopic analysis and single crystal X-ray diffraction (CuK(α)).

Simultaneous determination and characterization of tannins and triterpene saponins from the fruits of various species of Terminalia and Phyllantus emblica using a UHPLC-UV-MS method: application to triphala

Terminalia species are a rich source of tannins. Many preparations of these species are used in traditional medicine and have many different ethnobotanical applications. A simple UHPLC method was developed for the simultaneous analysis of such hydrolysable tannins and triterpene saponins from the fruit rinds of different species of Terminalia (T. chebula, T. arjuna, T. bellirica) and Phyllantus emblica. A separation by LC was achieved using a reversed-phase column and a water/acetonitrile mobile phase, both containing formic acid, using a gradient system and a temperature of 40°C. Eight hydrolysable tannins (gallic acid, gallic acid methyl ester, corilagin, chebulagic acid, 1,2,3,6-tetra-O-galloyl-β-D-glucose, ellagic acid, chebulinic acid, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose) and six triterpene saponins (arjunglucoside-I, arjunglucoside-III, chebuloside II, bellericoside, arjunetin, and arjunglucoside-II) could be separated within 20 minutes. The wavelength used for detection with the diode array detector was 254 and 275 nm for tannins and 205 nm for triterpene saponins. The method was validated for linearity, repeatability, limits of detection, and limits of quantification. The developed method is economical, fast, and especially suitable for quality control analysis of tannins and triterpene saponins in various plant samples and commercial products of Terminalia.

Characterization of chlorinated valepotriates from Valeriana jatamansi

HPLC-PDA-MS and TLC analysis were used to look for minor cytotoxic chlorinated valepotriates from whole plants of Valeriana jatamansi (syn. Valeriana wallichii DC.). This resulted in isolation of 15 chlorinated valepotriates, designated as chlorovaltrates A-O, together with six known analogues, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1,5-dihydroxyvalechlorine, volvaltrate B, chlorovaltrate, rupesin B, (1S,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine, and (1R,3R,5R,7S,8S,9S)-3,8-epoxy-1-O-ethyl-5-hydroxyvalechlorine. Their structures were elucidated by spectroscopic methods including homo- and heteronuclear two-dimensional NMR experiments. Chlorovaltrates K-N, chlorovaltrate and rupesin B showed moderate cytotoxicity against lung adenocarcinoma (A 549), metastatic prostate cancer (PC-3M), colon cancer (HCT-8) and hepatoma (Bel 7402) cell lines with IC₅₀ values of 0.89-9.76 μM.

Domain wall propagation through spin wave emission

We theoretically study field-induced domain wall motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Domain walls can propagate along a dissipationless wire through spin wave emission locked into the known soliton velocity at low fields. In the presence of damping, the usual Walker rigid-body propagation mode can become unstable for a magnetic field smaller than the Walker breakdown field.

New alkaloids from Lycopodium japonicum

Three new alkaloids (1-3), together with ten known alkaloids, were isolated from the ethanolic extract of the whole plants of Lycopodium japonicum THUNB. Their structures were elucidated on the basis of spectroscopic analysis, including MS and NMR methods. All alkaloids isolated were assayed for cytotoxic activity against four human cancer cell lines and acetylcholinesterase (AChE) inhibitory activity. No alkaloid showed either cytotoxic activity against four human cancer cell lines or AChE inhibitory activity.