Banca de DEFESA: GIULIAN CÉSAR DA SILVA SÁ
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : GIULIAN CÉSAR DA SILVA SÁ
DATE: 28/03/2022
TIME: 09:00
LOCAL: Anfiteatro das Aves - Centro de Biociências
TITLE:
Tephrosia toxicaria (Sw.) Pers. EXTRACTS: PROSPECTION OF ANTI-Aedes, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES
KEY WORDS:
Natural Resources; Botanical Extracts; Timbó; Arboviruses; Oxidative Stress.
PAGES: 160
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:
The search for new natural adjuvant formulations for the management of diseases, vectors and pathogens shows that plant extracts are still promising, especially considering the great Brazilian biodiversity, they are obtained from renewable sources, their toxic selectivity to target organisms and environmental compatibility. The development of the present research was stimulated by the possibility of expanding the repertoire of options for natural adjuvants, which aimed to investigate the bioactive potential and biosecurity of aqueous and hydroethanolic extracts from seeds, roots, stems and leaves of Tephrosia toxicaria (Sw.) Pers. This legume, occurring in the Northeast region of Brazil, attracts the attention of researchers by acting as a matrix for obtaining broad spectrum bioactivity formulations. This thesis was structured in two chapters; the first chapter deals with a bibliographic review of the current state of art on the use of botanical insecticides in the integrated management of arbovirus vectors, with emphasis on control of species belonging to the genera Aedes, Culex and Anopheles. Numerous botanical insecticides formulations are presented throughout the review and its likely modes of action for different stages of insects. The second chapter describes the versatility of T. toxicaria extracts in the Aedes control, highlighting the hydroethanolic root extract (RHA) as the most promising larvicidal extract, demonstrating the lowest lethal concentration for 50% (300 µg/mL) and 90% (840 µg/mL) of Aedes larvae, observed at 24 h post-exposure. In field tests, RHA (840 µg/mL) is a promising oviposition deterrent agent, reducing Aedes egg laying by approximately 90%. In addition to manifesting insecticidal properties, RHA manifests antioxidant activity, mainly in control of metal ion homeostasis and restoration of the metabolic activity of cells under oxidative stress conditions, under low concentrations (100 µg/mL). Although leishmanicidal molecules are also expressed in RHA, its solubilization was less pronounced, requiring a higher concentration of extract to inhibit the growth of Leishmania amazonensis promastigotes (IC50 = 3.53 mg/mL). The extraction conditions did not favor the concentration of antimicrobial molecules against the bacterial and fungal strains investigated, in assays employing serial dilutions of RHA (1024 – 32 μg/mL). RHA concentrates carbohydrates, phenolic compounds and proteins, with estimated molecular masses between 10 and 24 kDa. Protein analyzes suggest the expression of protease inhibitors and lectins in RHA. The bioinsecticidal, antioxidant and leishmanicidal effects, associated with the absence of toxicity events against non-target organisms (Lactuca sativa) and cell lines (HepG2 and 3T3), suggest T. toxicaria as a natural source to be sustainably exploited to obtain extracts with wide biological and pharmacological use.
BANKING MEMBERS:
Presidente - 1549705 - ADRIANA FERREIRA UCHOA
Interna - 1453487 - KATIA CASTANHO SCORTECCI
Interna - 350500 - MARIA DE FATIMA FREIRE DE MELO XIMENES
Externa à Instituição - PATRÍCIA MARIA GUEDES PAIVA - UFPE
Externa à Instituição - SELENE MAIA DE MORAIS - UECE