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Satratoxins, members of the trichothecene mycotoxin family, have been known to be harmful to health. However, the mechanisms underlying the toxicity still remain unclear. The present study is undertaken to elucidate the mechanisms of the satratoxin H-induced cytotoxicity in PC12 cells. Satratoxin H caused cytotoxicity, which was reflected from apoptosis determined by chromatin staining and flow cytometry. Satratoxin H stimulated the phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Pre-incubation with SB203580, a p38 MAPK inhibitor, or SP600125, a JNK inhibitor, but not PD98059, an ERK inhibitor, reduced satratoxin-induced cytotoxicity. Co-incubation of cells with glutathione, N-acetyl-L-cysteine or glutathione reductase inhibited cytotoxicity and the phosphorylation of p38 MAPK induced by satratoxin H. Our data suggest that satratoxin H-induced apoptosis in PC12 cells is dependent on the activation of p38 MAPK/JNK and the increase in reactive oxygen species.

Two guaiane-type compounds, nardoguaianone J and K (1 and 2) and two aristolane-type compounds, kanshone F and G (3 and 4), were isolated from Nardostachys chinensis roots. The structures including the absolute configurations were elucidated by spectral means and by comparison of their CD spectra.

Five novel guaianoids, nardoguaianone E–I ( 1 – 5 ), were isolated from Nardostachys chinensis roots. They possessed a dienone moiety in their molecules. The relative structures were elucidated by spectral means and chemical transformation, and the absolute configurations were determined using the modified Mosher's method and by comparison of their CD spectra.

Febrifugine (1) and isofebrifugine (2), isolated from the roots of Dichroa febrifuga Lour. (Chinese name: Cháng Shan), are active principles against malaria. Adducts of 1 and 2 with acetone, Df-1 (3) and Df-2 (4), respectively, were obtained using silica gel and acetone. They showed high activity against P. falciparum malaria in vitro. Compound 3 was found to be equally effective against P. berghei in vivo as the clinically used drug chloroquine, whereas 4 showed only 1/24 of the activity of 3. Metabolism studies of these compounds revealed that compound 4 is readily metabolized in mouse liver. Accordingly, the dose of 4 must be higher than that of 3 to attain blood levels sufficient for a favorable therapeutic effect.

(Z)-3-(2, 4, 5-Trimethoxy-3-methylbenzylidene)-1, 6-dimethylpiperazine-2, 5-dione (7a) was prepared by a simple regioselective C-monomethylation of (Z)-4-(4-methoxybenzyl)-3-(2, 4, 5-trimethoxy-3-methylbenzylidene)-1-methyl-piperazine-2, 5-dione (3) followed by deprotection. Compound 7a was also prepared from (S)-1, 4-diacetyl-3-methylpiperazine-2, 5-dione (8) and the benzaldehyde derivative (9) in five steps as an optically active form. It was shown to be a useful intermediate for the preparation of novel octahydro-1, 5-imino-3-benzazocin-4, 7, 10-trione derivatives having a methyl group at the C-2 position, as ABC ring models of saframycins.

Febrifugine (1) and isofebrifugine (2), isolated from the roots of Dichroa febrifuga Lour. (Chinese name: Chang Shan), are active principles against malaria. Adducts of 1 and 2 with acetone, Df-1 (3) and Df-2 (4), respectively, were obtained using silica gel and acetone. They showed high activity against P. falciparum malaria in vitro. Compound 3 was found to be equally effective against P. berghei in vivo as the clinically used drug chloroquine, whereas 4 showed only 1/24 of the activity of 3. Metabolism studies of these compounds revealed that compound 4 is readily metabolized in mouse liver. Accordingly, the dose of 4 must be higher than that of 3 to attain blood levels sufficient for a favorable therapeutic effect.

Satratoxin H, a mycotoxin, is thought to induce apoptosis of PC12 cells through the activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) in a glutathione (GSH)-sensitive manner. The present study was undertaken to further elucidate the mechanism by which satratoxin H induces cell death in PC12 cells. Satratoxin H caused apoptosis of PC12 cells within 24-h, as determined by DNA fragmentation and flow cytometric analysis. Satratoxin H increased reactive oxygen species (ROS) production and lipid peroxidation, as determined by malondialdehyde formation. These effects were attenuated by incubation of cells with GSH, suggesting that satratoxin H-induced increase in apoptosis of serum-deprived PC12 cells may be partially mediated through the generation of ROS.

Five novel guaianoids, nardoguaianone E–I ( 1 – 5 ), were isolated from Nardostachys chinensis roots. They possessed a dienone moiety in their molecules. The relative structures were elucidated by spectral means and chemical transformation, and the absolute configurations were determined using the modified Mosher's method and by comparison of their CD spectra.