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The Toxicology of the Astragalus genus

Astragalus

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Members of the genus Astragalus are known by a number of different names. Those most widely used are locoweed and milkvetch. There are over 2000 species in this genus that are known currently, of which many are known to carry various toxins. (Williams, 1984) They can be found in North and South America, Asia, Europe, Northern Africa and Australia. There are nearly 400 species in North America whose range extends over most of most of the continent. (Ralphs, 1992) They are predominantly in the central plains and grassland regions of the United States where they are the most common of the Leguminosiae. Due to their range and toxicity, livestock poisoning by locoweed is the most widespread toxic plant problem in the western U.S.,(Ralphs, James, Nielsen, Baker, Molyneux, 1988) costing millions of dollars both in livestock loss and in cost of plant control (Williams, 1984) Despite the unpleasant effects of Astragalus poisoning, animals often become habituated to eating, fueling their further intoxication by the plant.(Ralphs, Panter, James, 1990)

Astragali poison in three main ways:

  1. With the indolizidine alkaloid swainsonine as in the case of A. lentiginosus and A. lusitanicus
  2. With the nitropropanol bearing glycoside miserotoxin as in the case of A. miser
  3. With toxic levels of selenium metabolites (Se) as in the case of A. bisulcatus

In this series of web pages I'd like to present a compilation of some of the toxicological information available on Astragalus. This will include a description of the specific toxicants named above, their modes of action, the physiological effects and the common symptoms of poisoning by swainsonine, miserotoxin and Se excess, as well as some general effects of Astragalus intoxication. Also in these pages will be some means to identify Astragalus, (whenever I could find them) and that researchers have explored to control poisoning by these plants.

Works cited and Bibliography

Ralphs, MH; James, LF; Nielsen, DB; Baker, DC; Molyneux, RJ: Cattle grazing Wahweap Milkvetch in southeastern Utah J. Anim Sci 1988. 66:3124-3130

Ralphs, MH; Panter, KE; James, LF: Feed preferences and habituation of sheep poisoned by Locoweed J Anim Sci 1990. 68:1354-1362

Rasmussen, MA: Andersen, RC; Allison, MJ: Ruminal metabolism of nitropropanol; Enrichment and isolation of a nitropropanol metabolizing bacterium. J Anim Sci 1995. 73(suppl. 1) 207

MacDiarmid, RE; Majak, W: Conversion of 3-nitropropanol to 3-nitropropionic acid by equine alcohol dehydrogenase. J Toxicol - Toxin Reviews, 1986 5(2) 253

Kirkpatrick, JG; Burrows, GI: Locoism in horses . Vet Hum Toxicol 1990 32(2) 168-169

Smith, GS; Allred, KW; Kiehl,DE: Swainsonine Content of New Mexican Locoweeds . J Anim Sci 1992 70 (suppl. 1) 124

Smith, GS; Edrington, T; Valastegui, W; Stavanja, M: Organ weights and serum components of rats fed locoweed stems, leaves or seedpods. J Anim Sci 1992 70(suppl. 1) 122

Molyneux, RJ; James, LF; Panter, KE: Occurence and detection of swainsonine in locoweeds . J Toxicol - Toxin Reviews 1986 5(2) 255

Baker, DC; JAmes, LF; Panter, KE; Mayland, HF; Pfister, JA : Selenosis in developing pigs fed selenium from various sources . J Anim Sci 1987. 65 (suppl. 1) 351

Stegelmeier, BL; James, LF; Panter, KE; Molyneux: Tissue and serum concentratoins in sheep ingesting Astragalus lentiginosus (locoweed). Vet Hum Toxicol 37 (4) 1995

Garcia-Roman, A; Moyano-Salvago, MR; Infante-miranda, F; Soler-Rodriguez, F: Physiopathologic changes in lambs fed with Astragalus lusitanicus lam Vet Hum Toxicol 29 (5) 1987

WEIMER-P-J. HATFIELD-R-D. BUXTON-D-R. INHIBITION OF RUMINAL CELLULOSE FERMENTATION BY EXTRACTS OF THE PERENNIAL LEGUME CICER MILKVETCH ASTRAGALUS-CICER APPL ENVIRON MICROBIOL 59 (2). 1993. 405-409.

COWGILL-U-M. LANDENBERGER-B-D. : THE CHEMICAL COMPOSITION OF ASTRAGALUS VARIATIONS WITHIN THE PLANTS OVER A 6-YEAR PERIOD BOT J LINN SOC 107 (4). 1991. 333-348.

RALPHS-M-H. PANTER-K-E. JAMES-L-F. FEED PREFERENCES AND HABITUATION OF SHEEP POISONED BY LOCOWEED J ANIM SCI 68 (5). 1990. 1354-1362.

EL-HAMIDI-M. LEIPOLD-H-W. POISONING OF SHEEP BY ASTRAGALUS-LUSITANICUS IN MOROCCO FIELD AND EXPERIMENTAL STUDIES J VET MED SER A 36 (2). 1989. 115-121.

RALPHS-M-H. JAMES-L-F. NIELSEN-D-B. BAKER-D-C. MOLYNEUX-R-J. CATTLE GRAZING WAHWEAP MILKVETCH IN SOUTHEASTERN UTAH USA J ANIM SCI 66 (12). 1988. 3124-3130.

MAJAK-W. QUINTON-D-A. DOUWES-H-E. HALL-J-W. MUIR-A-D. THE EFFECT OF CLIPPING ON THE GROWTH AND MISEROTOXIN CONTENT OF COLUMBIA MILKVETCH J RANGE MANAGE 41 (1). 1988. 26-29.

PANTER-K-E. BUNCH-T-D. JAMES-L-F. SISSON-D-V. ULTRASONOGRAPHIC IMAGING TO MONITOR FETAL AND PLACENTAL DEVELOPMENTS IN EWES FED LOCOWEED ASTRAGALUS-LENTIGINOSUS AM J VET RES 48 (4). 1987. 686-690.

RALPHS-M-H. ECOLOGY CONTROL AND GRAZING MANAGEMENT OF LOCOWEEDS IN THE WESTERN USA JAMES, L. F., ET AL. (ED.). POISONOUS PLANTS; THIRD INTERNATIONAL SYMPOSIUM, LOGAN, UTAH, USA, 1988. XV+661P. IOWA STATE UNIVERSITY PRESS: AMES, IOWA, USA. ILLUS. MAPS. ISBN 0-8138-1241-0. 0 (0). 1992. 528-533.

MAJAK-W. BENN-M-H. NEW GLYCOSIDES OF 3 NITROPROPANOL FROM ASTRAGALUS-MISER- VAR- SEROTINUS JAMES, L. F., ET AL. (ED.). POISONOUS PLANTS; THIRD INTERNATIONAL SYMPOSIUM, LOGAN,UT 1988. IOWA STATE UNIVERSITY PRESS: AMES, IA,1992. 523-527.

JAMES-L-F. PANTER-K-E. MOLYNEUX-R-J. SELENIUM POISONING IN LIVESTOCK JAMES, L. F., ET AL. (ED.). POISONOUS PLANTS; THIRD INTERNATIONAL SYMPOSIUM, LOGAN, UT 1988. IOWA STATE UNIVERSITY PRESS: AMES, IOWA,1992. 153-158.

WILLIAMS-M-C. OLSEN-J-D. TOXICITY TO CHICKS OF COMBINATIONS OF MISEROTOXIN NITRATE SELENIUM AND SOLUBLE OXALATE JAMES, L. F., ET AL. (ED.). POISONOUS PLANTS; THIRD INTERNATIONAL SYMPOSIUM, LOGAN, UT 1988. IOWA STATE UNIVERSITY PRESS: AMES, IOWA,1992.143-147.

CAO-G-R. LI-S-J. DUAN-D-X. MOLYNEUX-R-J. JAMES-L-F. WANG-K. TONG-C. THE TOXIC PRINCIPLE OF CHINESE LOCOWEEDS OXYTROPIS AND ASTRAGALUS TOXICITY IN GOATS JAMES, L. F., ET AL. (ED.). POISONOUS PLANTS; THIRD INTERNATIONAL SYMPOSIUM, LOGAN, UT 1988. IOWA STATE UNIVERSITY PRESS: AMES, IOWA,1992. 117-121.

SMITH-G-S. ALLRED-K-W. KIEHL-D-E. SWAINSONINE CONTENT OF NEW MEXICAN LOCOWEEDS MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, WESTERN SECTION, FORT COLLINS, COLORADO JULY 8-10, 1992. J ANIM SCI 70 (SUPPL. 1). 1992. 124.

VELASTEGUI-W. SMITH-G-S. EDRINGTON-T-S. STAVANJA-M. KIEHL-D- E. SWAINSONINE CONTENT AND COMPARATIVE TOXICITY OF SEEDPODS LEAVES AND STEMS FROM HALFMOON LOCOWEED ASTRAGALUS-ALLOCHROUS MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, WESTERN SECTION, FORT COLLINS, COLORADO JULY 8-10, 1992. J ANIM SCI 70 (SUPPL. 1). 1992. 124.

STAVANJA-M. SMITH-G-S. EDRINGTON-T. VELASTEGUI-W. ORGAN WEIGHTS AND SERUM COMPONENTS OF RATS FED LOCOWEED STEMS LEAVES OR SEEDPODS MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, WESTERN SECTION, FORT COLLINS, COLORADO JULY 8-10, 1992. J ANIM SCI 70 (SUPPL. 1). 1992.. 122.

KEELER-R-F. LIVESTOCK MODELS OF HUMAN BIRTH DEFECTS REVIEWED IN RELATION TO POISONOUS PLANTS SYMPOSIUM ON POISONOUS PLANTS AND ANIMAL TOXICOSES HELD AT THE 79TH ANNUAL MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, LOGAN, UTAH, JULY 31, 1987. J ANIM SCI 66 (9). 1988. 2414-2427.

MOLYNEUX-R-J. JAMES-L-F. PANTER-K-E. OCCURRENCE AND DETECTION OF SWAINSONINE IN LOCOWEEDS ASTRAGALUS AND OXYTROPIS SPECIES SYMPOSIUM ON NATURAL TOXINS HELD AT THE 8TH ROCKY MOUNTAIN REGIONAL MEETING OF THE AMERICAN CHEMICAL SOCIETY, DENVER, COLORADO, JUNE 8-12, 1986. J TOXICOL TOXIN REV 5 (2). 1986. 255.

BAKER-D-C. JAMES-L-F. PANTER-K-E. MAYLAND-H-F. PFISTER-J-A. SELENOSIS IN DEVELOPING PIGS FED SELENIUM FROM DIFFERENT SOURCES ANNUAL MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, LOGAN, UTAH, JULY 28-31, 1987. J ANIM SCI 65 (SUPPL. 1). 1987. 351.

Stegelmeier-B-L. Ralphs-M-H. Gardner-D-R. Molyneux-R-J. James-L-F. Locoweed intoxication in range cattle and sheep: Serum alpha- mannosidase activity and clinicopathologic alterations. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. CAB International: Tucson, Arizona, 1994. 501-506.

Ralphs-M-H. Pfister-J-A. Conditions of livestock poisoning and management strategies to reduce risks. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. . CAB International: Tucson, Arizona 1994. 478-483.

James-L-F. Hartley-W-F. Panter-K-E. Stegelmeier-B-L. Gould-D. Mayland-H-F.. Selenium poisoning in cattle. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. . CAB International: Tucson, Arizona 1994. 416-420.

Panter-K-E. James-L-F. Gardner-D-R. Molyneux-R-J. The effects of poisonous plants on embryonic and fetal development in livestock. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. . CAB International: Tucson, Arizona, USA. 1994. 325-332.

McFarlane-I-J. Watts-R-M. Quantitative assay for the indolizidine alkaloid, swainsonine in the plant genera Swainsona, Astragalus and Oxytropis. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. . CAB International: Tucson, Arizona, 1994. 113-118.

Molyneux-R-J. James-L-F. Ralphs-M-H. Pfister-J-A. Panter-K-E. Nash- R-J. Polyhydroxy alkaloid glycosidase inhibitors from poisonous plants of global distribution: Analysis and identification. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. CAB International: Tucson, Arizona, 1994 107-112

James-L-F. Panter-K-E. Molyneaux-R-J. Stegelmeier-B-L. Wagstaff-D-J. Plant toxicants in milk. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. CAB International: Tucson, Arizona, 1994 83-88.

MCDIARMID-R-E. MAJAK-W. YOST-G-S. CONVERSION OF 3 NITROPROPANOL TO 3 NITROPROPIONIC ACID BY EQUINE ALCOHOL DEHYDROGENASE J TOXICOL TOXIN REV 5 (2). 1986. 253.

TULSIANI-D-R-P. SKUDLAREK-M-D. ORGEBIN-CRIST-A-C. SWAINSONINE INDUCES THE PRODUCTION OF HYBRID GLYCOPROTEINS AND ACCUMULATION OF OLIGOSACCHARIDES IN MALE REPRODUCTIVE TISSUES OF THE RAT BIOL REPROD 43 (1). 1990. 130-138.

TULSIANI-D-R-P. BROQUIST-H-P. JAMES-L-F. TOUSTER-O.. PRODUCTION OF HYBRID GLYCOPROTEINS AND ACCUMULATION OF OLIGOSACCHARIDES IN THE BRAIN OF SHEEP AND PIGS ADMINISTERED SWAINSONINE OR LOCOWEED ARCH BIOCHEM BIOPHYS 264 (2). 1988. 607-617.

Schmutz , EM; Hamilton, LB Plants that Poison Northland Press, Flagstaff, AZ 1979

Linder, MC, ed.; Nutritional Biochemistry and Metabolism 2nd ed. Appleton and Lange Norwalk, CT 1991

Pammel, LH; A Manual of Poisonous Plants The Torch press, Cedar Rapids, IA 1911

Stegelmeier-B-L. Ralphs-M-H. Gardner-D-R. Molyneux-R-J. James-L-F. Locoweed intoxication in range cattle and sheep: Serum alpha- mannosidase activity and clinicopathologic alterations. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. xiii+581p. CAB International: Tucson, Arizona, USA. ISBN 0-85198- 909-8.. 0 (0). 1994. 501-506.

Ralphs-M-H. Pfister-J-A Conditions of livestock poisoning and management strategies to reduce risks. . Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. xiii+581p. CAB International: Tucson, Arizona, USA. ISBN 0-85198- 909-8..0 (0). 1994. 478-483.

James-L-F. Hartley-W-F. Panter-K-E. Stegelmeier-B-L. Gould-D. Mayland-H-F. Selenium poisoning in cattle. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. xiii+581p. CAB International: Tucson, Arizona, USA. ISBN 0-85198- 909-8.. 0 (0). 1994. 416-420.

Panter-K-E. James-L-F. Gardner-D-R. Molyneux-R-J. The effects of poisonous plants on embryonic and fetal development in livestock. Colegate, S. M. and P. R. Dorling (Ed.). Plant-associated toxins: Agricultural, phytochemical and ecological aspects; 4th International Symposium on Poisonous Plants (ISOPP4), Fremantle, Western Australia, Australia, September 26-October 1, 1993. xiii+581p. CAB International: Tucson, Arizona, USA. ISBN 0-85198- 909-8.. 0 (0). 1994. 325-332.

Anderson-R-C. Rasmussen-M-A. Allison-M-J. Ruminal metabolism of nitropropanol, the toxic aglycone of miserotoxin; enrichment and isolation of a nitropropanol metabolizing bacterium. J Anim Sci 73 (SUPPL. 1). 1995. 207.

Amdur, MO; Doull, J; Klaassen, CD, eds.: Casarett and Doull's Toxicology: The Basic Science of Poisons, 4th edition Pergamon press, MacMillan Publishing, 1991