Spirostanoids with 1,4-dien-3-one or 3ß,7α-diol-5,6-ene moieties from Solanum violaceum.

Bioassay-guided fractionation of the CHCl3 layer of Solanum violaceum areal parts methanolic extract led to the isolation of four new steroidal sapogenins, indiosides L-O (1-4), along with eight known steroids, one lignin, and a coumarin. Indioside L is a rare spirostanoid possessing a 1,4-dien-3-one moiety in ring A. Moreover, compounds 3 and 4 represent rare examples of spirostene with the 3ß,7α-diol-5,6-ene moiety compared to the normal 3ß,7ß-diol-5,6-ene derivatives. The cytotoxic activity of the isolates (5-14) was evaluated against human hepatoma (HepG2 and Hep3B), human lung carcinoma (A549), and human breast carcinoma (MDA-MB-231 and MCF-7).

Deltonin induces apoptosis in MDA­MB­231 human breast cancer cells via reactive oxygen species­mediated mitochondrial dysfunction and ERK/AKT signaling pathways.

Deltonin, a steroidal saponin isolated from Dioscorea zingiberensis Wright, exhibits high cytotoxic activity in cancer cells. In the present study, the effects of deltonin on cell proliferation and apoptosis were evaluated in the MDA­MB­231 human breast carcinoma cell line. Following treatment with deltonin, the viability of MDA­MB­231 cells was analyzed using MTT assay and apoptosis, mitochondrial membrane potential (∆Ψm) alternation and intracellular reactive oxygen species (ROS) generation was determined by flow cytometry. In addition, western blot analysis was performed to examine the expression of apoptosis­associated proteins. The results demonstrated that deltonin induced apoptosis in MDA­MB­231 cells in a time­ and concentration­dependent manner. Apoptosis was associated with depolarization of ∆Ψm and time­dependent ROS generation. Deltonin treatment also resulted in Bax upregulation, Bcl-2 downregulation, activation of caspase­3 and ­8 and poly (ADP ribose) polymerase cleavage. Decreased levels of phosphorylated extracellular signal­regulated kinase (ERK) and phosphorylated AKT were also observed. Results indicate that the proliferation inhibitory effect of deltonin is associated with its apoptosis­inducing effect, which may correlate with ROS­mediated mitochondrial dysfunction as well as activation of the ERK/AKT signaling pathways. Therefore, deltonin may be a potential chemotherapeutic agent for the treatment of breast cancer.

Steroidal glycosides from Furcraea foetida and their cytotoxic activity.

Two new spirostanol glycosides (1, 2) and a new furostanol glycoside (3), together with nine known steroidal glycosides (4-12) were isolated from the leaves of Furcraea foetida (Agavaceae). The structures of the new compounds were determined by spectroscopic analysis and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activities against HL-60 human leukemia cells, A549 human lung adenocarcinoma cells, HSC-2 human oral squamous carcinoma cells, and HSC-4 human oral squamous carcinoma cells.

Steroidal saponins from the aerial parts of Dracaena draco and their cytostatic activity on HL-60 cells.

Chemical examination of the aerial parts of Dracaena draco has led to the isolation of a total of nine steroidal saponins, including five new ones. The structures of the new saponins were determined by spectral data and a few chemical transformations to be (23S,24S)-spirosta-5,25(27)-diene-1 beta,3 beta,23,24-tetrol 1-O-{O-(2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl)-(1-->2)-alpha-L -arabinopyranosyl} 24-O-beta-D-fucopyranoside, (23S,24S)-spirosta-5,25(27)-diene-1 beta,3 beta, 23,24-tetrol 1-O-{O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L -arabinopyranoside}, (23S,24S)-spirosta-5,25(27)-diene-1 beta,3 beta,23,24-tetrol 1-O-{O-(4-O- acetyl-alpha-L-rhamnopyranosyl)-(1-->2)-alpha-L-arabinopyransoide} , (23S)-spirosta-5,25(27)-diene-1 beta,3 beta,23-triol 1-O-{O-alpha-L- rhamnopyranosyl)-(1-->2)-alpha-L-arabinopyranoside} and (23S,24S)-spirosta-5,25(27)-diene-1 beta,3 beta,23-triol 1-O-{O-(4-O-acetyl-alpha-L-rhamnopyranosyl)-(1-->2)-alpha-L- arabinopyranoside}. The isolated saponins were evaluated for their cytostatic activity on leukemia HL-60 cells.