Cytotoxicity on Human Leukemic and Rat Hepatoma Cell Lines of Alkaloid Extracts of Psychotria forsteriana

Zhang

Chemistry & Biodiversity

et al. 2016

Psychotria is a genus of ca. 1500 species in the family Rubiaceae. Up to now, 41 species of the Psychotria genus have been chemically investigated, and 159 compounds, including alkaloids of indole, quinoline and benzoquinolizidine type, terpenoids, steroids, phenolics and aliphatic compounds have been isolated. These compounds show potent bioactivities, such as antimicrobial, antiviral, and antiparasitic activities.

Section: Biological Activitiesmentioning

confidence: 99%

Chemical Constituents of Plants from the GenusPsychotria

Zhang

Chemistry & Biodiversity

et al. 2016

“…1c In addition, selected quadrigemines are reported to be analgesics, 31,38,40 antagonists of the somatostain receptor (SRIF), 9b inhibitors of human platelet aggregation, 41 and to display cytotoxic activity against solid and blood tumors. 42 To gain some insight into the relationship between the three-dimensional structures of higher-order polypyrrolidinoindoline alkaloids and their antitumor activity, the in vitro cytotoxicities of the 2+2 quadrigemines prepared in this study, and several additional polypyrrolindoline alkaloids prepared in our laboratories (depicted in Figure 5), were determined against two invasive cancer cell lines: DU145 (human prostate cancer) and A2058 (human melanoma). Several trends emerge from the cytotoxicity data summarized in Table 4: (a) In general, cytotoxicity increases as a function of molecular weight (increasing number of pyrrolidinoindoline units); only one dodecacyclic alkaloid (the minor meso -quadrigemine 4 , entry 3) was less active than the nonacyclic alkaloids (entries 7–11).…”

Section: Resultsmentioning

confidence: 99%

“…The first two of these trends are in accord with cytotoxicity data reported previously for a few cyclotryptamine alkaloids. 42 …”

Section: Resultsmentioning

confidence: 99%

Stereocontrolled enantioselective total synthesis of the [2+2] quadrigemine alkaloids

et al. 2015

A unified strategy for enantioselective total synthesis of all stereoisomers of the 2+2 family of quadrigemine alkaloids is reported. In this approach, two enantioselective intramolecular Heck reactions are carried out at the same time on precursors fashioned in four steps from either meso- or (+)-chimonanthine to form the two critical quaternary carbons of the peripheral cyclotryptamine rings of these products. Useful levels of catalyst control are realized in either desymmetrizing a meso precursor or controlling diastereoselectivity in elaborating C2-symmetic intermediates. None of the synthetic quadrigemines are identical with alkaloids isolated previously and referred to as quadrigemines A and E. In addition, we report improvements in our previous total syntheses of (+)- or (−)-quadrigemine C that shortened the synthetic sequence to 10 steps and provided these products in 2.2% overall yield from tryptamine.

“…[43] The cytotoxicity of Psychotria forsteriana extracts against cultured rat hepatoma cell lines has been attributed to their tetrameric and pentameric polypyrrolidino [2,3-b]indoline alkaloid content. [39,44,45] …”

Section: Introductionmentioning

confidence: 99%

Total Synthesis of Complex Cyclotryptamine Alkaloids: Stereocontrolled Construction of Quaternary Carbon Stereocenters

2007

Our ability to access the more complex members of the cyclotryptamine family of alkaloids, and to exploit their disparate biological activities, is limited by the synthetic challenge posed by their oligomeric, polyindoline structures. A recurring structural theme within these molecules is the presence of multiple quaternary stereocenters in close proximity to one another. Over the last decade, we have developed a set of transformations that allow rapid access to polyindolines, a number of which exploit the ability of catalytic levels of palladium to orchestrate carbon-carbon bond formation with impressive levels of regio- and stereocontrol. This review tells the story behind the development of this toolbox of synthetic methods, and their validation through the total synthesis of a number of structurally complex cyclotryptamine alkaloids. It also highlights an aspect of asymmetric catalysis that has received little attention, the ability of catalytic asymmetric reactions to selectively elaborate complex, polyfunctional molecules.