Telocinobufagin (Telobufotoxin)

Telocinobufagin is a cardiotonic steroid that has been found in skin secretions of the toad B. rubescens and has diverse biological activities.^1,2,3,4 It inhibits human kidney Na⁺/K⁺-ATPase with an IC₅₀ value of 44.2 nM.³ Telocinobufagin (9.9 μg/ml) increases contraction force in isolated frog ventricle strips by 30.2%.² It is cytotoxic to HL-60, HCT8, SF295, MDA-MB-435 cancer cells and human peripheral blood lymphocytes (IC₅₀s = 0.06, 0.06, 0.03, 0.11, and 0.05 μM, respectively).⁴ Telocinobufagin is also active against E. coli and S. aureus (MICs = 64 and 128 μg/ml, respectively).²

1.Pavlovic, D.The role of cardiotonic steroids in the pathogenesis of cardiomyopathy in chronic kidney diseaseNephron Clin. Pract.128(1-2)11-21(2014) 2.Cunha Filho, G.A., Schwartz, C.A., Resck, I.S., et al.Antimicrobial activity of the bufadienolides marinobufagin and telocinobufagin isolated as major components from skin secretion of the toad Bufo rubescensToxicon.45(6)777-782(2005) 3.Touza, N.A., P??as, E.S., Quintas, L.E.M., et al.Inhibitory effect of combinations of digoxin and endogenous cardiotonic steroids on Na+/K+-ATPase activity in human kidney membrane preparationLife Sci.88(1-2)39-42(2011) 4.G.A., C.-F., Resck, I.S., Cavalcanti, B.C., et al.Cytotoxic profile of natural and some modified bufadienolides from toad Rhinella schneideri parotoid gland secretionToxicon.56(3)339-348(2010)