Biochemical and Biological Profile of Parotoid Secretion of the AmazonianRhinella marina(Anura: Bufonidae)

Abstract

Skin secretions of frogs have a high chemical complexity. They have diverse types of biomolecules, such as proteins, peptides, biogenic amines, and alkaloids. These compounds protect amphibians’ skin against growth of bacteria, fungi, and protozoa and participate in defense system against attack from predators. Therewith, this work performed biochemical and biological profile of macroglands parotoid secretion from cane toad. For poison analysis, we performed molecular exclusion and reverse phase chromatography, electrophoresis, and mass spectrometry. Antimicrobial, antiplasmodial, leishmanicidal, cytotoxicity, genotoxicity, and inflammatory activity of crude and/or fractions of R. marina secretion were also evaluated. Fractionation prior to filtration from poison showed separation of low mass content (steroids and alkaloids) and high molecular mass (protein). Material below 10 kDa two steroids, marinobufagin and desacetylcinobufagin, was detected. Crude extract and fractions were active against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Plasmodium falciparum, Leishmania guyanensis, and Leishmania braziliensis. Crude extract was also active against cancer cells although it was not cytotoxic for normal cells. This extract did not show significant DNA damage but it showed an important inflammatory effect in vivo. The information obtained in this work contributes to the understanding of the constituents of R. marina secretion as well as the bioactive potential of these molecules.

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

“…The IC 50 for Rhinella marina methanolic crude extract is around 0.05 µg/mL in both sensitive and resistant cell lines (excepted for MM074-R IC 50 = 11.50 µg/mL). Previous studies had already reported the antiproliferative activity of Rhinella marina crude extracts on different cancer types (gastric, bladder, lung, liver, colorectal and breast cancers), but with IC 50 values 1.5 to 800 times higher than the ones we obtained on melanoma cells [27,36]. Its antiproliferative properties on chemo-resistant cancer cells has also been highlighted on leukemia cells harboring multidrug resistance with an IC 50 = 0.18 µg/mL [26].…”

The Parotoid Gland Secretion from Peruvian Toad Rhinella horribilis (Wiegmann, 1833): Chemical Composition and Effect on the Proliferation and Migration of Lung Cancer Cells

“…The composition and biological effects of the PGS of the Amazonian R. marina has been extensively studied [8,18,26], while that of R. horribilis remained unknown. In this study, some 55 constituents, including argininyl diacids, bufadienolides argininyl diacids, bufadienolides, and alkaloids were identified/tentatively identified in the PGS of R. horribilis for the first time.…”

“…An interestingly mechanistic explanation of these effects may be proposed, taking into consideration the effects of current MTA on cancer cells mentioned above [16]. Although certain bufadienolides present in the poison secretion of toads produce cell cycle arrest in S-phase [48], reduce the activity and protein levels of topoisomerases [49,50] and intercalates with DNA [51]; other DNA damage-independent mechanisms have also been recently described [8,26]. For example, the major constituents of the PGS of Rhinella species such as bufalin, marinobufagin, telocinobufagin, and hellebrigenin exhibit strong binding affinities to tubulin in vitro and in vivo conditions, producing dysregulated microtubule arrangement and G2/M cell cycle arrest in cancer cells [8].…”

“…Little is known on the PGS composition and bioactivity of toad defensive compounds for the western South American Andes. No information is available on the secretion constituents of the recently known species of the northern Peru Rhinella horribilis ( Figure 1 C), which was extensively confused with Rhinella marina [ 24 ], a highly invasive species with well-known toxicological effects and bioactivities [ 8 , 18 , 25 , 26 ].…”

Relationships Between Chemical Defenses of Common Toad (Bufo bufo) Tadpoles and Bacterial Community Structure of their Natural Aquatic Habitat

“…Several toad species in the family Bufonidae are known to synthesize bufadienolides de novo in the serous glands of their skin already from early larval stages on (Hayes et al 2009a;Ujszegi et al 2017;Üveges et al 2017). These skin-toxins may be effective against natural enemies including predators (Denton and Beebee 1991;Hantak et al 2016;Kruse and Stone 1984;Peterson and Blaustein 1991;Shine 2010), competitors (Bókony et al 2018) and potential pathogens (Barnhart et al 2017;Cunha Filho et al 2005;De Medeiros et al 2019;Tempone et al 2008). However, little is known about what evolutionary processes and environmental factors influence bufadienolide synthesis.…”