Biomedical subjects

Lynn F James

Publications and source records attributed to Lynn F James.

3 recordsLinked to original sources

PubMed2004

Biomedical applications of poisonous plant research.

Research designed to isolate and identify the bioactive compounds responsible for the toxicity of plants to livestock that graze them has been extremely successful. The knowledge gained has been used to design management techniques to prevent economic losses, predict potential outbreaks of poisoning, and treat affected animals. The availability of these compounds in pure form has now provided scientists with tools to develop animal models for human diseases, study modes of action at the molecular level, and apply such knowledge to the development of potential drug candidates for the treatment of a number of genetic and infectious conditions. These advances are illustrated by specific examples of biomedical applications of the toxins of Veratrum californicum (western false hellebore), Lupinus species (lupines), and Astragalus and Oxytropis species (locoweeds).

Abnormalities, Drug-Induced↗

PubMed2002

Polyhydroxy alkaloids: chromatographic analysis.

Polyhydroxy alkaloids are a burgeoning category of natural products that encompass several structural types and generally exhibit potent activity as inhibitors of glycosidases. As presently defined the group consists of monocyclic or bicyclic aLkaloids of the pyrrolidine, piperidine, pyrrolizidine, indolizidine and tropane classes, bearing two or more hydroxyl groups. These structural features render the compounds highly water soluble and frequently quite insoluble in non-hydroxylic solvents, so that their isolation and analysis by chromatographic means are consequently difficult. This problem is further confounded by the lack of a chromophore which would permit their detection by UV absorption. This review presents chromatographic techniques that have been successfully applied to the problem of isolating, purifying, detecting and analyzing polyhydroxy alkaloids.

Alkaloids↗

PubMed2002

Preparation of tetrahydroagathic acid: a serum metabolite of isocupressic acid, a cattle abortifacient in ponderosa pine.

Isocupressic acid (1) was used to synthetically prepare a mixture of (8S,13R,S)-labda-15,19-dioic acid (tetrahydroagathic acid) (5) via a two-step oxidation procedure followed by hydrogenation of the double bonds at C13 and C8. Reduction of the C8,17 double bond was stereospecific producing only the 8S isomer and confirmed by the nOe interaction between the resulting C17 and C20 methyl groups. The 13R and 13S isomers of 5 were separated and analyzed by HPLC/MS, and (13S)-tetrahydroagathic acid was isolated and identified by comparison to a standard prepared by hydrogenation of naturally occurring (13S)-dihydroagathic acid (4). (13R,S)-dihydroagathic acid was prepared by selective sodium metal-catalyzed hydrogenation of the C13,14 allylic double bond of agathic acid (3). The prepared compounds were then used as standards to confirm the presence of 4 and 5 and their respective 13R and 13S isomers in bovine serum samples. Tetrahydroagathic acid was shown to be the only metabolite detected in serum samples taken from a suspected cattle abortion case submitted for diagnosis; and, thus, 5 could be a valuable diagnostic marker for pine needle-induced abortions.

Abortifacient Agents↗