Banca de DEFESA: Tatiane de Melo Pereira

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Tatiane de Melo Pereira
DATE: 29/09/2023
TIME: 08:30
LOCAL: Auditório Central da Embrapa Recursos Genéticos e Biotecnologia
TITLE:

" Development of plant liposomes with multiple biological functions entrapped in hydrogels".

KEY WORDS:

vegetable liposome, secondary metabolites, bioactivities, MTT

PAGES: 172
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Liposomes are concentric vesicles formed by phospholipids, and find applications in various industries, including pharmaceuticals, food, and agriculture, often serving as carriers for isolated compounds. This study aimed to extract phospholipids from fresh botanical materials and formulate liposomes for transporting extracts of the same botanical origin to confer antimicrobial and antioxidant activities without adverse effects on eukaryotic cells for future topical applications. Using a previously patented adapted technology, phospholipids were successfully extracted from the leaves and stems of 20 plant species, with at least 17 of them allowing for liposome formulation, either containing water (Empty Liposome - LpV) or extract (Loaded Liposome - LpC). An advantage of this method is the absence of membrane extrusion or other uniformization techniques, making liposome production more accessible. Raman spectroscopy confirmed liposome formation in LpV, further substantiated by the presence of phospholipids in nanostructures via thermogravimetry. These nanoformulations were tested against Escherichia coli and Staphylococcus aureus, with only four of them showing activity against S. aureus. Among these, liposomes carrying lavender and oregano extracts at a concentration of 250 mg/mL demonstrated antimicrobial and antioxidant potential, preserving eukaryotic cell viability. In yeast Saccharomyces cerevisiae assays, lavender and oregano LpC exhibited fungistatic activity, whereas free extracts did not, and only oregano LpC displayed fungicide activity. The encapsulation rates for lavender and oregano LpC were found to be 56.33% and 91.70%, respectively. Atomic force microscopy confirmed the presence of concentric structures consistent with liposome formation. To enhance liposome stability and sustained delivery, a hydrogel was formulated with 3% agarose and 2.5% carboxymethylcellulose. This hydrogel exhibited suitable swelling behavior for therapeutic applications, particularly topical ones, and showed activity against S. aureus. Dialysis membrane release testing revealed that the hydrogel required 35 hours to release 90% of the liposomal content, maintaining sustained release at relatively constant rates for most of the time. Based on these results, it was possible to formulate liposomes of 100% plant origin with antimicrobial activity (against Grampositive bacteria and yeast), antioxidant activity, and no toxicity to eukaryotic cells.

COMMITTEE MEMBERS:
Externa à Instituição - KELLIANE ALMEIDA DE MEDEIROS
Externa à Instituição - Juliana Junqueira Pinelli - EMBRAPA
Presidente - ***.882.851-** - LUCIANO PAULINO DA SILVA - UnB
Externo ao Programa - 6404569 - RICARDO BENTES DE AZEVEDO - nullExterna à Instituição - ROSA DE BELEM DAS NEVES ALVES - EMBRAPA