New cytotoxic 19-norbufadienolide and bufogargarizin isolated from Chan Su.

One new 19-norbufadienolide (1) and one new bufogargarizin (2), together with twelve known bufadienolides (3-14, resp.) were isolated from Chan Su, a traditional Chinese medicine that is used in the treatment of cancer. Their structures were elucidated on the basis of detailed spectroscopic analysis and comparison of corresponding data that is previously reported. The cytotoxic activities of the isolated compounds were evaluated on HeLa and A549 cell lines. Though 1 and 2 showed weak cytotoxic activities on both cell lines, compounds 4 and 5 showed lower IC50 values than bufalin, the most widely studied bufadienolide in Chan Su. Furthermore, four 3-ester derivatives (15-18) of compound 4 were synthesized and their cytotoxic activities were also evaluated. Analysis of the structure-activity relationship indicated that bufadienolides with aldehyde group at C-10 or α-hydroxyl group at C-11 exhibit stronger cytotoxic activities on both cell lines. The cytotoxic activity of arenobufagin-3-ester derivative 17 was 4-fold higher than compound 4.

Cardenolides from the bark of Calotropis gigantea.

Three new cardenolides (1-3) were isolated from the 90% ethanolic extract of the bark of a wild-type Calotropis gigantea. Their structures were determined by using NMR spectra and LC-MS analysis. Their inhibitory activities were evaluated against non-small cell lung carcinoma (A549) and human cervix epithelial adenocarcinoma (HeLa) cell lines. Compounds 1 and 3 exhibited strong inhibitory effect on two cancer cell lines.

Cytotoxic cucurbitane triterpenoids isolated from the rhizomes of Hemsleya amabilis.

Two new cucurbitane triterpenoids, 7ß-hydroxycucurbitacin F-25-O-acetate (1) and 2ß,3ß,20(S),26,27-pentahydroxy-16α,23(S)-epoxycucurbita-5,24-dien-11-one (2) along with eleven known cucurbitane triterpenoids (3-13, resp.) were isolated from the rhizomes of Hemsleya amabilis Diels. The chemical structures of the new isolated compounds were elucidated unambiguously by spectroscopic data analysis. The cytotoxic activities of the isolated cucurbitane triterpenoids were evaluated against the HeLa human cancer cell lines. Hemslecin A (5), the main ingredient of H. amabilis, exhibited the significant cytotoxicity with IC50 value of 0.389 µM.

Phenanthrenes, 9,10-dihydrophenanthrenes, bibenzyls with their derivatives, and malate or tartrate benzyl ester glucosides from tubers of Cremastra appendiculata.

Eleven previously unknown compounds and 23 known compounds, including 20 phenanthrene or 9,10-dihydrophenanthrene derivatives, five bibenzyls, seven malate or tartrate benzyl ester glucosides, adenosine and gastrodin were isolated from tubers of Cremastra appendiculata. Among the obtained compounds, two are the first isolated dimers with one phenanthrene or bibenzyl unit connected to C-3 of 2,3,4,5-tetrahydro-phenanthro[2,1-b]furan moiety. In addition, 33 of these compounds were evaluated in vitro for their cytotoxic activity against two cancer cell lines. Among the compounds examined, one compound showed moderate cytotoxic activity, while five showed weak cytotoxic activity against the A549 cell line.

Synthesis and structure-activity relationships study of cytotoxic bufalin 3-nitrogen-containing-ester derivatives.

A series of bufalin 3-nitrogen-containing-ester derivatives (2-6) were designed, synthesized, and evaluated for their proliferation inhibition activities against human cervical epithelial adenocarcinoma (HeLa) and non-small-cell lung cancer (A549) cell lines. The structure-activity relationships (SARs) of this new series were described in this paper. Cytotoxicity data revealed that C3 moiety had important influence on cytotoxic activity. On two cell lines, the bufalin-3-piperidinyl-4-carboxylate compound 2 (IC50 values on HeLa and A549 cell lines were 0.76 nM and 0.34 nM, respectively) displayed a significant cytotoxic potency compared to the parent compound bufalin.