Constituents from Clausena excavata.

Three new coumarins containing a C(10) terpenoid side chain, clauslactones R - T (1 - 3), together with 14 known coumarins (4 - 17) and 11 known carbazole alkaloids (18 - 28), were isolated from the leaves and stems of Clausena excavata. Their structures were established by detailed spectroscopic analyses. Furthermore, the stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis, which was the first example among coumarins with a C(10) terpenoid side chain.

Salvicine functions as novel topoisomerase II poison by binding to ATP pocket.

Salvicine, a structurally modified diterpenoid quinone derived from Salvia prionitis, is a nonintercalative topoisomerase II (topo II) poison. The compound possesses potent in vitro and in vivo antitumor activity with a broad spectrum of anti-multidrug resistance activity and is currently in phase II clinical trials. To elucidate the distinct antitumor properties of salvicine and obtain valuable structural information of salvicine-topo II interactions, we characterized the effects of salvicine on human topo IIalpha (htopo IIalpha), including possible binding sites and molecular interactions.

Anti-proliferative effects, cell cycle G2/M phase arrest and blocking of chromosome segregation by probimane and MST-16 in human tumor cell lines.

Background: Anticancer bisdioxopiperazines, including ICRF-154, razoxane (Raz, ICRF-159) and ICRF-193, are a family of anticancer agents developed in the UK, especially targeting metastases of neoplasms. Two other bisdioxopiperazine derivatives, probimane (Pro) and MST-16, were synthesized at the Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. Cytotoxic activities and mechanisms of Raz (+)-steroisomer (ICRF-187, dexrazoxane), Pro and MST-16 against tumor cells were evaluated by MTT colorimetry, flow cytometry and karyotyping.