Figainin 1, a Novel Amphibian Skin Peptide with Antimicrobial and Antiproliferative Properties

Abstract

Amphibian skin secretions are abundant in bioactive compounds, especially antimicrobial peptides. These molecules are generally cationic and rich in hydrophobic amino acids, have an amphipathic structure and adopt an α-helical conformation when in contact with microorganisms membranes. In this work, we purified and characterized Figainin 1, a novel antimicrobial and antiproliferative peptide from the cutaneous secretion of the frog Boana raniceps. Figainin 1 is a cationic peptide with eighteen amino acid residues—rich in leucine and isoleucine, with an amidated C-terminus—and adopts an α-helical conformation in the presence of trifluoroethanol (TFE). It displayed activity against Gram-negative and especially Gram-positive bacteria, with MIC values ranging from 2 to 16 µM, and showed an IC50 value of 15.9 µM against epimastigote forms of T. cruzi; however, Figanin 1 did not show activity against Candida species. This peptide also showed cytolytic effects against human erythrocytes with an HC50 of 10 µM, in addition to antiproliferative activity against cancer cells and murine fibroblasts, with IC50 values ranging from 10.5 to 13.7 µM. Despite its adverse effects on noncancerous cells, Figainin 1 exhibits interesting properties for the development of new anticancer agents and anti-infective drugs against pathogenic microorganisms.

In Vitro Evaluation of Antimicrobial Peptides from the Black Soldier Fly ( Hermetia Illucens ) against a Selection of Human Pathogens

“…In addition to the primary toxicity screening against human fibroblasts, a hemolytic assay was performed using human red blood cells. The outer membrane leaflets of red blood cells are rich in sialic acid residues, which gives them a lower negative charge than other mammalian cell types ( 32 , 33 ). This negative charge makes them prone to interactions with the positively charged AMPs.…”

Purification and Biological Properties of Raniseptins-3 and -6, Two Antimicrobial Peptides from Boana raniceps (Cope, 1862) Skin Secretion

“…Raniseptins-3 and -6 are cationic peptides (+4), hydrophobic and demonstrate GRAVY scores of 0.300 and 0.169, respectively ( Table 1 ), features commonly found in AMPs [ 36 , 40 ].…”

“…The cutaneous secretion of amphibians includes a great variety of substances, and these compounds can be more or less expressed according to certain variables, such as food, the season of year (rainy or dry), cycle or phase of the individual’s development and even the animal collection location. For the genus Boana , few antimicrobial peptides have been isolated and characterized so far, and among them, Hylaseptin-P1 was found in the secretion of B. punctata [ 41 ], Hylin-a1 was isolated from B. albopunctatus [ 42 ], Cinerascetins was found in B. cinerascens [ 17 ] and Raniseptin-1 [ 38 ] and Figainins were isolated from the cutaneous secretion of B. raniceps [ 36 , 40 ].…”

The Complex Bridge between Aquatic and Terrestrial Life: Skin Changes during Development of Amphibians

“…Figainin 1 also exhibits cytolytic effects against human erythrocytes as well as antiproliferative activity against cancer cells. Although it has adverse effects on noncancerous cells, this peptide shows interesting features for the improvement of new drugs against cancer and infections [ 61 ].…”