Amphibian Skin and Skin Secretion: An Exotic Source of Bioactive Peptides and Its Application

Abstract

Amphibians have been consumed as an alternative protein source all around the world due to their delicacy. The skin of edible amphibians, particularly frogs and giant salamanders, always goes to waste without further utilization. However, these wastes can be utilized to extract protein and bioactive peptides (BPs). Various BPs have been extracted and reported for numerous biological activities such as antioxidant, antimicrobial, anticancer, antidiabetic, etc. The main BPs identified were brevinins, bombesins, dermaseptins, esculentins, magainin, temporins, tigerinins, and salamandrins. This review provides a comprehensive discussion on various BPs isolated and identified from different amphibian skins or skin secretion and their biological activities. The general nutritional composition and production statues of amphibians were described. Additionally, multiple constraints against the utilization of amphibian skin and secretions are reported. Finally, the prospective applications of BPs in food and biomedical industries are presented such as multifunctional food additives and/or supplements as well as drug delivery agents.

A Comprehensive Review of Patented Antimicrobial Peptides from Amphibian Anurans

“…As reviewed in the literature among the main AMP families isolated from anurans, we can find bombinin, magainin, XPF, dermaseptin, brevinin, caerin, esculentin, ranalexin, rugosin, temporin, uperin, ranatuerin, maculatin, citropin, aurein, phylloxin, palustrin, kassinatuerin, tigerinin, pseudin, distinctin, nigrocin, dahlein, japonicin, ranacyclin, ocellatin, ascaphin, phylloseptin, lividin, pelophylaxin, dybowskin, pleurain, odorranain, hyposin, fallaxidin, nigroain, andersonin, cathelicidin, hymenochirin, frenatin, defensin, and kassorins. ,,− ,− ,,,,, Additionally, this analysis includes other significant peptides isolated from anurans due to their biological significance (Table and Supporting Information 1.2).…”

“…Simultaneously, we searched APD3 for the main families of antimicrobial peptides isolated from anurans described in the scientific literature. ,,− ,,,,, Additionally, the taxonomy of all anurans mentioned in this article was updated using data from the Amphibians of the World database as of October 2023…”

“…Despite the large amount of scientific evidence supporting anuran AMPs as promising candidates for drug development, ,,− ,− ,,,,, the current status of the potential advancements is, with a few exceptions, unknown. − In-depth knowledge of patent information enables researchers to use existing patented technologies, compounds, or methodologies to advance drug development and supports interinstitutional research collaborations. Some databases compile patent information; the most prominent are the Derwent World Patents Index (DWPI) database, Google patent, Espacenet patent search, and others. − DWPI offers comprehensive global patent information, encompassing over 14.3 million primary innovations from nearly 60 patent-issuing authorities worldwide.…”

“…The high diversity of AMPs reported from amphibians in the last five decades has been summarized in several reviews focusing on their structure, physicochemical properties, and biological activities and also describing their biomedical potential. ,,− ,− ,,,,, This information has also been compiled in publicly accessible databases such as the Data Repository of Antimicrobial Peptides (DRAMP 3.0) and the Collection of Antimicrobial Peptides (CAMP R3 ) . One limitation of DRAMP 3.0 and CAMP R3 is that they contain many predicted peptide sequences not linked to any biological activity and, thus, cannot be referred to as AMPs. ,− The APD3 is currently one of the most cited databases due to its inclusion criteria: (i) natural AMPs with (ii) a known amino acid sequence, (iii) biological activity, and (iv) less than 100 residues in size. , …”

“…During the last 30 years, the study of anuran skin secretion has been a topic of great interest due to its unique chemical properties and the associated biosynthetic pathways, which make it a powerful source of natural compounds with biological activities. − ,,,− The vast diversity of molecules found in anurans’ dermal glands can be classified into five main groups: (1) peptides and proteins, (2) alkaloids, (3) other biogenic amines, (4) steroid bufadienolides, and (5) volatile organic compounds. − ,,− ,,,− In recent years, our group has been working on the analysis of amphibian skins’ secretions using spectrometry for the study of toxins, volatile organic compounds, pigmentation, and AMPs’ diversity, − analyzing chemical diversity in terms of their ecological relevance. More specifically, we now have a more comprehensive understanding, suggesting that many defense substances can also be interpreted regarding host-symbiotic relationships .…”