David G I Kingston

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Natural products continue to provide a diverse and unique source of bioactive lead compounds for drug discovery, but maintaining their continued eminence as source compounds is challenging in the face of the changing face of the pharmaceutical industry and the changing nature of biodiversity prospecting brought about by the Convention on Biological(More)
Bioassay-guided fractionation of an ethanolic extract of the infructescences of Polyscias amplifolia resulted in the isolation of two new oleanolic acid saponins, polyfoliolides A (1) and B (2), in addition to the two known saponins 3-O-beta-D-galactopyranosyloleanolic acid (3) and 3-O-beta-D-galactopyranosyl-(1-->4)-beta-D-galactopyranosyloleanolic acid(More)
This review provides an overview of the discovery, structures, and biological activities of anticancer natural products that act by inhibiting or promoting the assembly of tubulin to microtubules. The emphasis is on providing recent information on those compounds in clinical use or in advanced clinical trials. The vinca alkaloids, the combretastatins,(More)
The history of the development of Taxol (paclitaxel) as an anticancer drug is reviewed, and some aspects of the phytochemistry of Taxus species and of the medicinal chemistry of taxol are discussed. The nature of the taxol-tubulin interaction is then described, with an emphasis on studies that led to the discovery and experimental proof of the T-taxol(More)
Bioassay-guided fractionation of an EtOH extract obtained from the roots of the Madagascan plant Albizia gummifera led to the isolation of three new cytotoxic oleanane-type triterpenoid saponins, gummiferaosides A-C (1-3). The structures of these new compounds were elucidated using 1D and 2D NMR experiments and mass spectrometry. Compounds 1-3 showed(More)
Bioassay-guided fractionation of the cytotoxic leaf and flower extract of Casearia nigrescens led to the isolation of four new clerodane diterpenoids, designated caseanigrescens A-D (1-4). These compounds were subject to hydrolysis to dialdehydes when stored in CDCl3. The structures of compounds 1-4 were determined using 1D and 2D NMR spectroscopy. All four(More)
This review covers advances in the discovery, preclinical and clinical development of potential anticancer agents based upon the diterpenoid taxane skeleton. The anticancer properties of approved clinical agents of this class are not discussed, but the review documents how, 13 years post-approval of paclitaxel (Taxol), the base taxane structure is still(More)
Bioassay-guided fractionation of the EtOAc extract of the twigs of Garcinia macrophylla from Suriname produced the known benzophenone, guttiferone A (1), and a new guttiferone analogue, guttiferone G (2). Friedelin was also isolated. The structures of compounds 1 and 2 were elucidated using 1D and 2D NMR spectroscopy. Compounds 1 and 2 were weakly cytotoxic(More)
 A room temperature biochemical assay, based on centrifugal removal of tubulin polymer, was developed to permit ready detection of paclitaxel analogs more active than the parent compound and to permit reliable quantification of differences in activity relative to paclitaxel in terms of drug concentration. The assay was validated by comparing paclitaxel to(More)
Natural products or secondary metabolites, whether from the microbial, plant or marine worlds, represent the results of evolutionary pressures to preserve and enhance the life of their producing organism. They have evolved into structurally and usually stereochemically complex compounds with specific bioactivities. They thus represent a diverse(More)