Vallesiachotamine

Arch Pharm Res. 2012 Mar;35(3):565-71.

In vitro antiproliferative effects of the indole alkaloid vallesiachotamine on human melanoma cells.[Pubmed: 22477204]

Vallesiachotamine was isolated from the leaves of Palicourea rigida (Rubiaceae) collected in the Brazilian Cerrado.
METHODS AND RESULTS:
The structure was determined by spectroscopic methods, mainly 1D- and 2D-NMR and its biological activities were investigated on cultured human (SK-MEL-37) melanoma cells. In vitro cytotoxicity was evaluated by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The inhibitory concentration (IC(50)) was 14.7 ± 1.2 μM for 24 h of drug exposure. Flow cytometry analysis revealed that Vallesiachotamine induced G0/G1 arrest and increased the proportion of sub-G1 hypodiploid cells (at 11 μM and 22 μM) and this effect was not dependent on time of incubation. At these concentrations, a typical ladder was observed by agarose gel electrophoresis of the extracted DNA. Treatment of cells with 50 μM Vallesiachotamine for 24 h caused extensive cytotoxicity and necrosis.
CONCLUSIONS:
Our results demonstrated that the indole alkaloid Vallesiachotamine exhibited important cytotoxicity toward human melanoma cells and that apoptosis and necrosis might be responsible for the observed events.

Planta Med. 1983 Feb;47(2):83-6.

Alkaloids from Tabernaemontana psorocarpa.[Pubmed: 17405098 ]

The isolation of the alkaloids from two different samples of stem bark of Tabernaemontana psorocarpa is described.
METHODS AND RESULTS:
Both samples contained 16-epi-isositsirikine as the major alkaloid but differed from each other in the number and quantity of the other alkaloids. The following minor alkaloids were identified: 12-methoxy-14,15-dehydro-vincamine, Vallesiachotamine, isoVallesiachotamine, tetrahydroalstonine, coronaridine and voacangine.