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Novel pneumotoxic metabolites of the pyrrolizidine (Crotalaria) alkaloid, monocrotaline
3/6
8th World Congrem on A.tm=l, Plant and Microbial Toxins
NOVEL PNEUMOTOXIC METABOLITES OF THE PYRROLIZIDINE (CROTALARIA) ALKALOID, MONOCROTALINE By R.J. Huxtable and W.M. Lafranconl. Dept of Pharmacology, University of Arizona, Tucson, AZ 85724, U.S.A. Monocrotallne is a pyrrolizldlne alkaloid present in the seeds of Crotalarla spectabills. Perfusion of monocrotallne, through the isolated perfused rat liver resulted in the appearance of Ehrlich-posltive metabolites in both the perfusate and bile. Livers from male rats released greater quantities of metabollte into both bile and perfusate. Metabolite release was stimulated by pretreatment wlth phenobarbital. Livers of phenobarbltal-pretreated male rats perfused with 398 uM monocrotallne produced blliary metabollte concentrations in excess of 5 mM. Metabollte release was inhibited by anoxlc perfuslon, low temperature and pretreatment with SKF-525A. Above 150 uM monocrotallne, bile became the predominant route of excretion. On perfusion through the isolated lung of the rat, blle and perfusate metabolltes were equally effective In inhibiting serotonln transport. A single Ehrlich-positive peak was obtained on silica gel column chromatography of blle containing metabolite. Mass spectrometry revealed the major component of thls peak to have a molecular weight of 281, indicating a novel pyrrole metabollte In which the esterifylng acid present in monocrotaline, monocrotalic acid, had been partially degraded. This compound mimics the pneumotoxlc action of monocrotaline given in vivo, and its availability should prove a valuable tool In the--61uc-~atlon of the mechanism of pyrrolizidlne toxicity. Supported by USPHS HL 25258.
A MONOCLONAL ANTIBODY ACTIVE AGAINST THE I-IAEMORRHAGIN' OF NIGEi~IAN ECI'~S CARINA'I3JS (CARPET VIPER) VENOM By D. [DDON9 R.D.P-. THEAKSTON and M. HOMMEL. Liverpool School of Tropical Medicine, Pembroke Place, Liverpool LJ 5QA, UK Ethic cladnatl~ is probably the most dangerous snake in the world to man (Reid~ 1974). In savanna West Africa -lone it has been estimated that approximately 2O,OOO people a year die following envenoming by this species (Pugh and Thoal~ton, 1980), and its distribution covers a vast area ranging from the West coast of Africa through North, Central and East Africa to India end Srl Lanks. The venom is primarily haemorrhagic as well as possessing procoagcdant, defibrinogenating and necrotlzing properties. In man severe envenoming causes non-clotting blood, occasional necrosis and subsequent subarachnoid heemorrhage. The heemorrhagic principle In the venom is also the effect that leads to death in man producing severe damage to the vascular endothalium and subsequent haemorrhage Into the tissues, including the brain (Reid, 1968). A monoclonal antibody has bean raised against the haemorrhagic principle of Nigerian Ecfll= oarinatuo venom which is capable of neutralizing both the haemorrhaglc and necrotising activities. No significant neutrallsing effect was observed with respect to procoagulent and deflbrinogenating properties. The antibody is highly specific immunologically (by EI_[SA) against West African, in particular Nigerian F_.carlnatua venom. No reaction occurred against the venoms of E.cm-irmtue originating In Omen, Saudi Arabia end India. A f f i n i t y chromatography was used to purify the antigen. Because of the high specificity, the 'anti-haemorrhagin' antibody should be of considerable value in studying the kinetics of the main lethal fraction of Nigerian E..e~rinatue venom, thus clarifying the pathogenesis of poisoning by this species, which is generally considered to be the snake responsible for the largest number of deaths due to snake bite throughout the world. Pugh, R.N.PL and Theakston, R.D.G. (1980) Limcol~ 11, tt81-118• Reid, H.A. (1968) lnt Venomous animals and their venoms~ Vol 1, Chapter 20, 611-641 Reid, H.A. (1974) Abstract No. 166 Trop.Di=.BulL, 71, 80-81 KEY WORDS ¢~rirmtu~ monoclonsl antibody, haemorrhagin
8th World Congrem on A.tm=l, Plant and Microbial Toxins
NOVEL PNEUMOTOXIC METABOLITES OF THE PYRROLIZIDINE (CROTALARIA) ALKALOID, MONOCROTALINE By R.J. Huxtable and W.M. Lafranconl. Dept of Pharmacology, University of Arizona, Tucson, AZ 85724, U.S.A. Monocrotallne is a pyrrolizldlne alkaloid present in the seeds of Crotalarla spectabills. Perfusion of monocrotallne, through the isolated perfused rat liver resulted in the appearance of Ehrlich-posltive metabolites in both the perfusate and bile. Livers from male rats released greater quantities of metabollte into both bile and perfusate. Metabolite release was stimulated by pretreatment wlth phenobarbital. Livers of phenobarbltal-pretreated male rats perfused with 398 uM monocrotallne produced blliary metabollte concentrations in excess of 5 mM. Metabollte release was inhibited by anoxlc perfuslon, low temperature and pretreatment with SKF-525A. Above 150 uM monocrotallne, bile became the predominant route of excretion. On perfusion through the isolated lung of the rat, blle and perfusate metabolltes were equally effective In inhibiting serotonln transport. A single Ehrlich-positive peak was obtained on silica gel column chromatography of blle containing metabolite. Mass spectrometry revealed the major component of thls peak to have a molecular weight of 281, indicating a novel pyrrole metabollte In which the esterifylng acid present in monocrotaline, monocrotalic acid, had been partially degraded. This compound mimics the pneumotoxlc action of monocrotaline given in vivo, and its availability should prove a valuable tool In the--61uc-~atlon of the mechanism of pyrrolizidlne toxicity. Supported by USPHS HL 25258.
A MONOCLONAL ANTIBODY ACTIVE AGAINST THE I-IAEMORRHAGIN' OF NIGEi~IAN ECI'~S CARINA'I3JS (CARPET VIPER) VENOM By D. [DDON9 R.D.P-. THEAKSTON and M. HOMMEL. Liverpool School of Tropical Medicine, Pembroke Place, Liverpool LJ 5QA, UK Ethic cladnatl~ is probably the most dangerous snake in the world to man (Reid~ 1974). In savanna West Africa -lone it has been estimated that approximately 2O,OOO people a year die following envenoming by this species (Pugh and Thoal~ton, 1980), and its distribution covers a vast area ranging from the West coast of Africa through North, Central and East Africa to India end Srl Lanks. The venom is primarily haemorrhagic as well as possessing procoagcdant, defibrinogenating and necrotlzing properties. In man severe envenoming causes non-clotting blood, occasional necrosis and subsequent subarachnoid heemorrhage. The heemorrhagic principle In the venom is also the effect that leads to death in man producing severe damage to the vascular endothalium and subsequent haemorrhage Into the tissues, including the brain (Reid, 1968). A monoclonal antibody has bean raised against the haemorrhagic principle of Nigerian Ecfll= oarinatuo venom which is capable of neutralizing both the haemorrhaglc and necrotising activities. No significant neutrallsing effect was observed with respect to procoagulent and deflbrinogenating properties. The antibody is highly specific immunologically (by EI_[SA) against West African, in particular Nigerian F_.carlnatua venom. No reaction occurred against the venoms of E.cm-irmtue originating In Omen, Saudi Arabia end India. A f f i n i t y chromatography was used to purify the antigen. Because of the high specificity, the 'anti-haemorrhagin' antibody should be of considerable value in studying the kinetics of the main lethal fraction of Nigerian E..e~rinatue venom, thus clarifying the pathogenesis of poisoning by this species, which is generally considered to be the snake responsible for the largest number of deaths due to snake bite throughout the world. Pugh, R.N.PL and Theakston, R.D.G. (1980) Limcol~ 11, tt81-118• Reid, H.A. (1968) lnt Venomous animals and their venoms~ Vol 1, Chapter 20, 611-641 Reid, H.A. (1974) Abstract No. 166 Trop.Di=.BulL, 71, 80-81 KEY WORDS ¢~rirmtu~ monoclonsl antibody, haemorrhagin