Bufadienolides from parotoid gland secretions of Cuban toad Peltophryne fustiger (Bufonidae): Inhibition of human kidney Na+/K+-ATPase activity

Abstract

Parotoid gland secretions of toad species are a vast reservoir of bioactive molecules with a wide range of biological properties. Herein, for the first time, it is described the isolation by preparative reversed-phase HPLC and the structure elucidation by NMR spectroscopy and/or mass spectrometry of nine major bufadienolides from parotoid gland secretions of the Cuban endemic toad Peltophryne fustiger: ψ-bufarenogin, gamabufotalin, bufarenogin, arenobufagin, 3-(N-suberoylargininyl) marinobufagin, bufotalinin, telocinobufagin, marinobufagin and bufalin. In addition, the secretion was analyzed by UPLC-MS/MS which also allowed the identification of azelayl arginine. The effect of arenobufagin, bufalin and ψ-bufarenogin on Na(+)/K(+)-ATPase activity in a human kidney preparation was evaluated. These bufadienolides fully inhibited the Na(+)/K(+)-ATPase in a concentration-dependent manner, although arenobufagin (IC50 = 28.3 nM) and bufalin (IC50 = 28.7 nM) were 100 times more potent than ψ-bufarenogin (IC50 = 3020 nM). These results provided evidence about the importance of the hydroxylation at position C-14 in the bufadienolide skeleton for the inhibitory activity on the Na(+)/K(+)-ATPase.

Toad Venom Antiproliferative Activities on Metastatic Melanoma: Bio-Guided Fractionation and Screening of the Compounds of Two Different Venoms

“…In mammals, they are produced in the adrenal cortex through a pathway independent of cholesterol side-chain cleavage [47]. Bufadienolides regulates the Na + /K + -ATPase pump by inhibiting the cardiotonic steroid dependent-site [15,23]. In cancer cells, the Na + /K + -ATPase pump also acts as a scaffolding protein when localized in caveolae.…”

“…In this work, we wanted to evaluate the antiproliferative effect of toad venoms and their components on melanoma cells. This project was initiated because studies have indicated that these venoms act on the Na + /K + ATPase [14,15] which is overexpressed in many cancer types, including metastatic melanoma [24]. More interestingly so, a recent study indicated that bufalin, a molecular compound found in toad venom, was endogenously expressed in human serum and the concentrations were decreased in the case of hepatocellular carcinoma [25].…”

Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells

“…Cruz Jdos S et al also reported arenobufagin, as a potent Na+/K+ pump inhibitor, depressed the delayed rectifier K+ current of single guinea-pig ventricular cells in the whole-cell patch-clamp configuration[ 22 ]. Perera Córdova WH et al reported arenobufagin fully inhibited the Na, K-ATPase activity of normal human renal tissues in a concentration-dependent manner[ 23 ]. Li M et al reported arenobufagin inhibited vascular endothelial growth factor (VEGF)-mediated angiogenesis through suppression of VEGFR-2-mediated signaling cascades[ 24 ].…”

Application of Metabolomic Tools for Studying Low Molecular-Weight Fraction of Animal Venoms and Poisons

“…The most interesting trait seems a promising antitumor activity of bufadienolides including inhibition of cell proliferation and migration, induction of cell differentiation, inhibition of cancer angiogenesis, induction of apoptosis, disruption of the cell cycle, reversal of multi-drug resistance and enhancement of cytotoxic drug activity. One of the proposed molecular mechanisms of this anticancer activity is the inhibition of Na + /K + -ATPase [ 61 , 62 , 63 ]. However, medical use of bufadienolides is highly restricted due to their narrow therapeutic margins, short drug half-life and toxicity [ 64 ].…”