Yi Chen Chia

Gallic acid, a major component of Toona sinensis leaf extracts, contains a ROS-mediated anti-cancer activity in human prostate cancer cells

Prostate cancer, the most frequently diagnosed malignancy in elderly males of the United States, has become a major health issue in Asia. Previous studies have demonstrated that leaf extracts of Toona sinensis Roem. contain cytotoxic activity on several cancer cells including prostate cancer cells. In this study, gallic acid is identified as the major anti-cancer compound in T. sinensis leaf extracts. It is cytotoxic to DU145 prostate cancer cells, through generation of reactive oxygen species (ROS) and mitochondria-mediated apoptosis, which were reversed by antioxidants catalase and N-acetylcysteine. Furthermore, gallic acid is shown to block the growth of DU145 cells at G2/M phases by activating Chk1 and Chk2 and inhibiting Cdc25C and Cdc2 activities. In addition, gallic acid has a synergistic effect with doxorubicin in suppressing the growth of DU145 cells. Taken together, our results suggest that gallic acid has the potential to be developed into an anti-prostate cancer drug and is worthy of further studies.

Potent inhibition of superoxide anion production in activated human neutrophils by isopedicin, a bioactive component of the Chinese medicinal herb Fissistigma oldhamii

Fissistigma oldhamii is widely used in traditional Chinese medicine to treat rheumatoid arthritis. Activation of neutrophils is a key feature of inflammatory diseases. Herein, the anti-inflammatory functions of isopedicin, a flavanone derived from F. oldhamii, and its underlying mechanisms were investigated in human neutrophils. Isopedicin potently and concentration-dependently inhibited superoxide anion (O(2)(*)(-)) production in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils with an IC(50) value of 0.34+/-0.03 microM. Furthermore, isopedicin displayed no superoxide-scavenging ability, and it failed to alter subcellular NADPH oxidase activity. The inhibitory effect of isopedicin on O(2)(*)(-) production was reversed by protein kinase A (PKA) inhibitors. Moreover, isopedicin increased cAMP formation and PKA activity in FMLP-activated human neutrophils, which occurred through the inhibition of phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function. In addition, isopedicin reduced FMLP-induced phosphorylation of extracellular regulated kinase and c-Jun N-terminal kinase, which was reversed by the PKA inhibitor. In contrast, isopedicin failed to alter FMLP-induced phosphorylation of p38 mitogen-activated protein kinase and calcium mobilization. In summary, these results demonstrate that inhibition of O(2)(*)(-) production in human neutrophils by isopedicin is associated with an elevation of cellular cAMP and activation of PKA through its inhibition of cAMP-specific PDE.

Protoberberine alkaloids from Fissistigma balansae

Chromatography of the ethanolic extracts from the twigs of Fissistigma balansae led to the isolation of a new protoberberine alkaloid, fissisaine, along with four known protoberberine alkaloids thaipetaline, kikemanine, columbamine and dehydrodiscretamine. The structures of these isolates were established by means of mass and related spectral experiments

FISSOHAMIONE, A NOVEL FURANONE FROM FISSISTIGMA OLDHAMII

Fissohamione (1), a novel (R)-4,5-dimethoxy-3-(4′-phenyl-2′-oxobutyl)-5H-furan-2-one, has been isolated from Fissistigma oldhamii. The structure of 1 was elucidated by spectroscopic methods.

Two novel cyclopentenones from Fissistigma oldhamii

Abstract Two novel cyclopentenones, stigmahamone I (1) and stigmahamone II (2), have been isolated from the seeds of Fissistigma oldhamii. The structures of 1 and 2 were elucidated by spectroscopic methods.