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Mechanism-based yeast bioassays

The methodologies involved in our search for DNA-damaging natural products with potential ariticancer activity include extraction, bioassay, bioactivity-guided fractionation, dereplication, structure elucidation and structure-activity relationship (SAR) studies. In this section the general methodologies used by us for extraction, mechanism-based yeast bioassay and bioactivity-guided fractionation will be... [Pg.463]

Extraction of shade-dried plant material is carried out with inert solvents under mild conditions to avoid any chemicai transformations and/or decompositions that may occur otherwise. Idealiy 50-100 g of piant material is allowed to soak three times in methyl ethyl ketone (MEK), followed by methanol. Extracts obtained with each solvent are separately combined and evaporated yielding two extracts. These are dried, weighed and subjected to our mechanism-based yeast bioassays. [Pg.464]

Fig. 5. Basis of mechanism-based yeast bioassay for the detection of DNA-damaging agents... Fig. 5. Basis of mechanism-based yeast bioassay for the detection of DNA-damaging agents...
In an effort to uncover anticancer active metabolites in Brazilian plants, in early 1993 we initiated active collaboration with several Brazilian natural products chemists. Out of the large number of extracts brought to our laboratory by Dr. Vanderlan da S. Bolzani and screened in our mechanism-based yeast bioassay, extracts derived from two leguminous plants were selected for further studies. Based on preliminary investigation the bioactive methanolic chloroform extract of the leaves of Cassia leptophylla which was shown to contain bioactive alkaloidal constituents was further processed for alkaloids. The alkaloid fraction thus obtained was fractionated by column chromatography on alumina, followed by Silica gel preparative TLC and reversed-phase TLC to afford seven piperidine alkaloids [55] (-)-spectaline (68), (-)-spectalinine (69), canavaline (70), leptophyllin A (71), 3-acetylleptophyllin A (72), iso-... [Pg.486]

Mechanism-based bioassays involving DNA repair or recombination deficient yeast mutants have been increasingly utilized in attempts to monitor the isolation of natural products... [Pg.151]

See other pages where Mechanism-based yeast bioassays is mentioned: [Pg.457]    [Pg.461]    [Pg.464]    [Pg.469]    [Pg.474]    [Pg.481]    [Pg.492]    [Pg.497]    [Pg.498]    [Pg.457]    [Pg.461]    [Pg.464]    [Pg.469]    [Pg.474]    [Pg.481]    [Pg.492]    [Pg.497]    [Pg.498]    [Pg.85]    [Pg.84]    [Pg.157]    [Pg.486]    [Pg.497]    [Pg.499]    [Pg.227]   
See also in sourсe #XX -- [ Pg.20 , Pg.461 , Pg.462 , Pg.464 ]



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