Studies on South African cardiac glycosides. I. Isolation of toxic principles of Homeria glauca (W. & E.) N.E. Br. and observations on their chemical and pharmacological properties

The main toxic principle (1α, 2α-epoxyscillirosidin, a new bufadienolide cardiac aglycone) was isolated by very mild isolation techniques constantly correlated with semi-quantitative toxicity determinations in guinea-pigs. Extraction from plant material was effected at room temperature by suspending it in acetic acid solution and then extracting with chloroform. The residue was extracted with ethanolic citrate buffer and from this phase the toxic components were re-extracted with chloroform. The final separation was done by column chromatography on silica gel. The main toxic component (MTC) constituted 0,044% by mass of the dried plant material. The presence of several other related toxic components was indicated. Certain physical and chemical characteristics of the MTC were determined. The MTC had a subcutaneous LD₅₀ of 0,194 (0,183 to 0,203) mg/kg for guinea-pigs and 3,6 (2,9 to 4,46) mg/kg for mice. The clinical signs were nervous in nature: in guinea-pigs a generalized curare-like paralysis resulted in death from respiratory failure while in mice a convulsive syndrome was encountered. The MTC had potent local anaesthetic properties.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Some toxic, physical and chemical properties of the oral secretion of the sand tampan, Ornithodoros savignyi Audouin (1827)

Mice, exposed to the effects of the oral secretion of Ornithodorus savignyi by injection, revealed that a potent toxin is present in the secretion. Electrophoretic and chromatographic separations of the secretion showed a heterogeneous pattern of protein-like substances. Toxicity trials on these fractions showed that the toxic principle is protein in nature and fairly heat stableThe articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acroabt XI was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Preparation and properties of a crude extract toxic to guinea-pigs from Pachystigma pygmaeum, a plant causing heart failure in ruminants

Pachystigma pygmaeum is a rubiaceous plant which causes heart failure after ingestion by ruminants. Isolation or characterization of a toxic entity has hitherto been unsuccessful. Extraction of the plant material with water or organic solvents gave poor yields of toxicity in guinea-pigs because of some unusual properties of the toxic entity. We present a method whereby liberation of a toxic entity from the plant material was achieved by fermentation with baker's yeast to give a crude extract with sufficient yield of toxicity for use in further isolation work.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Department of Agriculture.am201

Enrichment of a fraction toxic to guinea-pigs from Pachystigma pygmaeum (Schltr.) Robyns

Pachystigma pygmaeum is one of several species of rubiaceous plants which cause delayed heart failure among ruminants after their ingestion at relatively high doses. Using guinea-pigs for toxicity determinations, we were able to separate and enrich a toxic fraction from a fermentation extract of the plant material by countercurrent distribution. It contained virtually no potassium salts, passed through a 500 dalton selective membrane, exhibited lability under acid conditions and was toxic at 1 g/kg per os, with a delayed response of 3-4 days.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Department of Agriculture

An investigation into the toxic principle in eggs of the tick Amblyomma hebraeum

A purification procedure involving iso-electric focusing by means of which a toxic principle may be obtained in a pure form from crude egg extracts of Amblyomma hebraeum is described. The molecular mass of the toxin is approximately 10 000 according to sedimentation equilibrium sedimentation, Sodium dodecyl sulphate (SDS) gradient gel electrophoresis and calculations from the amino acid composition. Non-competitive proteinase inhibitory activity was found to be associated with the toxin. Histopathological lesions, observed in guinea-pigs inoculated with crude egg extracts or the purified toxin, included the following : focal areas of necrosis in the liver, with mineralization and oedema of the mucosa of the urinary bladder, and vacuolation of the lining epithelium. The genesis of the lesions in the various organs appears to be vascular.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Proteins and free amino acids in the salivary secretion and hemolymph of the tick Amblyomma hebraeum

Electrophoretic and chromatographic separations of the salivary secretion of Amblyomma hebraeum showed a less complex protein pattern than that of Ornithodoros savignyi. A hyaluronidase active component was isolated. The haemolymph protein pattern showed a major protein fraction with a mobility slightly faster than that of bovine serum albumin.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format