Banca de QUALIFICAÇÃO: RITA DE KASSIA OLIVEIRA DA COSTA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RITA DE KASSIA OLIVEIRA DA COSTA
DATE: 28/08/2025
TIME: 08:00
LOCAL: VIDEOCONFERÊNCIA
TITLE:

Bioactive molecules analogous to Stigmurina with antimicrobial, antibiofilm, and healing Properties.

KEY WORDS:

Antimicrobial peptide; Biofilm; Cytotoxicity; Antifungal activity; Wound healing.

PAGES: 92
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:

Antimicrobial resistance has become increasingly alarming given the risks it poses

to the global economy and public health. The irrational use of antimicrobials has

contributed greatly to this microbial resistance to conventional drugs. Given this problem

and the chronic nature of infections with and by biofilm formation in skin wounds,

antimicrobial peptides (AMPs) emerge as promising alternatives for the development of

new drugs. StigA15 and StigA28 are peptides analogous to Stigmurin, found in the venom

of the scorpion Tityus stigmurus, and correspond to promising AMPs obtained through

rational molecule design. In this study, pharmacokinetic activity and molecular dynamics

simulation (in silico) were evaluated, in addition to cytotoxicity, minimum inhibitory

concentration, minimum bactericidal concentration, biofilm - for bacteria and fungi (in

vitro) - and healing activity in uninfected wounds (in vivo). In this context, the objective

of the study was to obtain data on the applicability and safety of biomolecules in

biological, antimicrobial, and healing activity. It was through changes in the amino acid

chain of stigmurin, designed by our research group using bioinformatics

(FFSLIPSLVGGLISAFK-NH₂), that the analog peptides StigA15

(FFSLIPKLVGGLIKAFK-NH₂)

and StigA28 (FFKLIPKLVGKLIKAFK-NH₂)

emerged. The substitutions of glycine for lysine increased the net charge of the analogues,

reduced cytotoxicity, intensified the peptide-microorganism interaction, and conferred

promising antimicrobial activity to both peptides, tested against different Gram-positive,

Gram-negative bacteria, and yeasts (patent granted by the INPI, No. BR 102015029044-

6). As a result, a favorable spectrum of action of PAMs was observed both in the

minimum inhibitory concentration (MIC) and in antibiofilm activity, especially in the late

phase, in addition to a positive healing effect on uninfected wounds. The peptides StigA15

and StigA28 demonstrated potent antimicrobial activity against Gram-positive, Gram

negative bacteria, and yeasts of the genus Candida spp. at non-cytotoxic concentrations.

In addition, they exhibited bactericidal and fungicidal effects, indicating a broad spectrum

of action. In murine models, they also promoted the healing of skin wounds, suggesting

their potential as bioactive agents with a dual function: antimicrobial and healing.

COMMITTEE MEMBERS:
Interna - ***.557.824-** - ALLANNY ALVES FURTADO - UFRN
Externa à Instituição - DEBORAH MUNIQUE NOGUEIRA DE SOUSA FONTOURA - UFRN
Presidente - 3652554 - FRANCISCO CANINDE DE SOUSA JUNIOR