Bufotalin

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Bufotalin
Bufotalin.png
Identifiers
CAS number 471-95-4 YesY
PubChem 10119
ChemSpider 16735710 YesY
ChEMBL CHEMBL463064 YesY
Jmol-3D images Image 1
Properties
Molecular formula C26H36O6
Molar mass 444.56 g mol−1
Appearance crystalline solid
Hazards
Main hazards Toxic
LD50 4.13 mg·kg−1 (mouse, IV)

0.4 mg·kg−1 (mouse, SC)
0.136 mg·kg−1 (cat, IV)[1]

Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Bufotalin is a cardiotoxic bufanolide steroid, cardiac glycoside analogue, secreted by a number of toad species.[2][3] Bufotalin can be extracted from the skin parotoid glands of several types of toad.

Sources[edit]

Rhinella marina (Cane toad), Rhaebo guttatus (Smooth-sided toad), Bufo melanostictus (Asian toad), and Bufo bufo (common European toad) are sources of bufotalin.[2][3][4]

Traditional medicine[edit]

Bufotalin is part of Ch'an Su, a traditional Chinese medicine used for cancer. It is also known as Venenum Bufonis or senso (Japanese).[5]

Toxicity[edit]

Specifically, in cats the lethal median dose is 0.13 mg/kg.[1] and in dogs is 0.36 mg/kg (intravenous).[6]

Knowing this it is advisable to monitor those functions continuously using an EKG. As there is no antidote against bufotalin all occurring symptoms need to be treated separately or if possible in combination with others. To increase the clearance theoretically, due to the similarities with digitoxin, cholestyramine, a bile salt, might help.[6] Recent animal studies have shown that taurine restores cardiac functions.[7]

Symptomatic measures include lignocaine, atropine and phenytoin for cardiac toxicity and intravenous potassium compounds to correct hyperkalaemia from its effect on the Na+/K+ ATPase pump.[6]

Pharmacology and mechanism of action[edit]

Bufotalin is found to inhibit myocardial Na+/K+ ATPase activity by that increasing myocardial contractile force. Furthermore bufotalin was not found to affect the heart-rate with those changes in myocardial Na+/K+ ATPase activity.[8]

After a single intravenous injection, bufotalin gets quickly distributed and eliminated from the blood plasma with a half-time of 28.6 minutes and a MRT of 14.7 min. After 30 minutes after an administration of bufotalin, the concentrations within the brain and lungs are significantly higher than those in blood and other tissues.[9] It also increases cancer cell's susceptibility to apoptosis via TNF-α signalling by the BH3 interacting domain death agonist and STAT proteins.[10]

Bufotalin induces apoptosis in vitro in human hepatocellular carcinoma Hep 3B cells and might involve caspases and apoptosis inducing factor (AIF).[11] The use of bufotalin as a cancer treating compound is still in the experimental phase. It also arrests cell cycle at G(2)/M, by up- and down- regulation of several enzymes.

Pharmacokinetics[edit]

The mechanism of the biotransformation of bufotalin is still unknown. Researches found, that bufotalin is biotransformed into at least 5 different compounds.[12]

The five known biotransformation products of bufotalin.

Chemical properties[edit]

If bufotalin is esterified with suberyl arginine, the bufotalin-like steroid bufotoxin is obtained.[13]

References[edit]

  1. ^ a b "Datasheet: Bufotalin sc-202509" Santa Cruz Biotechnology, Inc.http://datasheets.scbt.com/sc-202509.pdf
  2. ^ a b Kwan, T; Paiusco, AD; Kohl, L (September 1992). "Digitalis toxicity caused by toad venom." (PDF). Chest 102 (3): 949–50. doi:10.1378/chest.102.3.949. PMID 1325343. 
  3. ^ a b Jan, SL; Chen, FL; Hung, DZ; Chi, CS (November–December 1997). "Intoxication after ingestion of toad soup: report of two cases.". Zhonghua Minguo xiao er ke yi xue hui za zhi 38 (6): 477–80. PMID 9473822. 
  4. ^ Ferreira, PM; Lima, DJ; Debiasi, BW; Soares, BM; Machado Kda, C; Noronha Jda, C; Rodrigues Dde, J; Sinhorin, AP; Pessoa, C; Vieira GM, Jr (September 2013). "Antiproliferative activity of Rhinella marina and Rhaebo guttatus venom extracts from Southern Amazon.". Toxicon 72: 43–51. doi:10.1016/j.toxicon.2013.06.009. PMID 23796725. 
  5. ^ Zhang, DM; Liu, JS; Tang, MK; Yiu, A; Cao, HH; Jiang, L; Chan, JY; Tian, HY; Fung, KP; Ye, WC (October 2012). "Bufotalin from Venenum Bufonis inhibits growth of multidrug resistant HepG2 cells through G2/M cell cycle arrest and apoptosis.". European Journal of Pharmacology 692 (1-3): 19–28. doi:10.1016/j.ejphar.2012.06.045. PMID 22841670. 
  6. ^ a b c Spoerke, DG (November 1986). "Toad Toxins". 
  7. ^ Ma, Hongyue; Jiang, J; Zhang, J; Zhou, J; Ding, A; Lv, G; Xu, H; You, F; Zhan, Z; Duan, J (January 2012). "Protective effect of taurine on cardiotoxicity of the bufadienolides derived from toad (Bufo bufo gargarizans Canto) venom in guinea-pigs in vivo and in vitro". Toxicology Mechanisms and Methods 22 (1): 1–8. doi:10.3109/15376516.2011.583295. PMID 22150009. 
  8. ^ Garg, AD; Hippargi, RV; Gandhare, AN (2008). "Toad skin-secretions: Potent source of pharmacologically and therapeutically significant compounds". The Internet Journal of Pharmacology 5 (2). doi:10.5580/18b6. 
  9. ^ Yu, CL; Hou, HM (25 December 2010). "Plasma pharmacokinetics and tissue distribution of bufotalin in mice following single-bolus injection and constant-rate infusion of bufotalin solution". European Journal of Drug Metabolism and Pharmacokinetics 35 (3-4): 115–121. doi:10.1007/s13318-010-0017-6. PMID 21302038. 
  10. ^ Waiwut, P; Inujima, A; Inoue, H; Saiki, I; Sakurai, H (January 2012). "Bufotalin sensitizes death receptor-induced apoptosis via Bid- and STAT1-dependent pathways." (PDF). International Journal of Oncology 40 (1): 203–8. doi:10.3892/ijo.2011.1182. PMID 21887462. 
  11. ^ Su, CL; Lin, TY; Lin, CN; Won, SJ (14 January 2009). "Involvement of Caspases and Apoptosis-Inducing Factor in Bufotalin-Induced Apoptosis of Hep 3B Cells". Journal of Agricultural and Food Chemistry 57 (1): 55–61. doi:10.1021/jf802769g. PMID 19055367. 
  12. ^ Zhang, X; Ye, M; Dong, YH; Hu, HB; Tao, SJ; Yin, J; Guo, DA (October 2011). "Biotransformation of bufadienolides by cell suspension cultures of Saussurea involucrata.". Phytochemistry 72 (14-15): 1779–85. doi:10.1016/j.phytochem.2011.05.004. PMID 21636103. 
  13. ^ Müller-Schwarze, D (2006). Chemical ecology of vertebrates. Cambridge: Cambridge University Press. p. 255. ISBN 978-0521363778.