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A method, utilizing brine shrimp (Artemia salina Leach), is proposed as a simple bioassay for natural product research. The procedure determines LC (50) values in microg/ml of active compounds and extracts in the brine medium. Activities of a broad range of known active compounds are manifested as toxicity to the shrimp. Screening results with seed extracts(More)
In RBL-2H3 rat tumor mast cells, antigens that cross-link the high affinity cell surface IgE receptor, Fc epsilon R1, activate at least two receptor-associated protein-tyrosine kinases, Lyn and Syk, and cause the tyrosine phosphorylation of the receptor beta and gamma subunits, PLC gamma 1, Vav, and other proteins. Cross-linking antigens also induce(More)
Extracts of paw paw ( Asimina triloba, Annonaceae) are among the most potent of the 3500 species of higher plants screened for bioactive compounds in our laboratories at Purdue University. The paw paw is a small tree native to eastern North America; its edible fruits (sometimes referred to as "Indiana Bananas") have nurtured mankind for centuries.(More)
An HPLC method and an acid hydrolysis HPLC method for the analysis of anthocyanins and anthocyanidins in bilberry extracts have been developed. The HPLC method coupled with a mass detector has identified 11 anthocyanins in bilberry extracts. The method provides anthocyanin profiles that are very useful in verifying the identity of botanical raw materials,(More)
Bioactivity-directed fractionation of the seeds of Annona muricata L. (Annonaceae) resulted in the isolation of five new compounds: cis-annonacin (1), cis-annonacin-10-one (2), cis-goniothalamicin (3), arianacin (4), and javoricin (5). Three of these (1-3) are among the first cis mono-tetrahydrofuran ring acetogenins to be reported. NMR analyses of(More)
  • A. Alkofahi, J. K. Rupprecht, Y. -M. Liu, C. -J. Chang, D. L. Smith, J. L. McLaughlin
  • 1990
Gigantecin (I), a novel tetrahydroxy-di-tetrahydrofuran fatty acid γ-lactone (acetogenin), was isolated from an ethanolic extract of the stem bark ofGoniothalamus giganteus Hook. f., Thomas (Annonaceae), by means of activity-directed fractionation (brine shrimp lethality test). This new compound is extremely cytotoxic to human tumor cells, inhibits crown(More)
Piceatannol (3,4,3'5'-tetrahydroxy-trans-stilbene), a plant secondary natural product that had previously been identified as an antileukemic principle, has been shown to be an inhibitor of protein-tyrosine kinase activity. Piceatannol inhibits the purified thymocyte protein-tyrosine kinase, p40, by competing for the peptide or protein substrate binding site(More)
Screening of crude extracts of the bark of Annona bullata showed cytotoxic and pesticidal activities. By monitoring with brine-shrimp lethality, two novel, extremely potent acetogenins, bullatacin [1] and bullatacinone [2], were isolated. Spectral and chemical methods identified bullatacin as a diastereomer of asimicin. Bullatacinone represents bullatacin(More)
4-Deoxyannomontacin (1) and a mixture of (2,4-cis and trans)-annomontacinone (2), new bioactive mono-tetrahydrofuran (THF) gamma-lactone and keto-lactone acetogenins, respectively, as well as five known mono-THF acetogenins [xylomaticin, longifolicin, longicoricin, (2,4-cis and trans)-gigantetrocinone, and (2,4-cis and trans)-gigantetroneninone], were(More)
Using activity-directed fractionation, two new bioactive acetogenins, cis-gigantrionenin (1) and 4-acetyl gigantetrocin A (2), have been isolated from the bark of Goniothalamus giganteus (Annonaceae). Compound 1 has a cis-mono-THF ring with one flanking hydroxyl and possesses a cis-double bond at C-21/22 of the aliphatic chain; it represents only the second(More)