Banca de DEFESA: ADRIANO LOPES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ADRIANO LOPES DA SILVA
DATE: 29/04/2022
TIME: 08:00
LOCAL: Por videoconferência
TITLE:

CHEMICAL COMPOSITION AND EVALUATION OF THE ANTIOXIDANT AND LARVICIDE ACTVITIES OF THE EXTRACTS, FATTY ACIDS AND METHYL ESTERS OF THE PERICARP OF Tecoma stans (L.) Juss. Ex Kunth (BIGNONIACEAE).

KEY WORDS:

Keywords: Fatty Acids, Tecoma stans, insecticide, antioxidant activity, larvicidal activity, Culex quinquefasciatus, FAME.

PAGES: 64
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:

Currently, there is a growing interest in antioxidants and insecticides from plant extracts from aromatic and medicinal plants, cereals, fruits, considered sources of natural antioxidants and bioinsecticides, and this is also economically interesting. The control of insects with synthetic insecticides causes a great impact on the environment and, consequently, on public health, as they are not biodegradable and because they are bioaccumulative. In this context, the ipê-mirim, guarã-guarã, ipê-de-jardim, amarelinho and yellow caroba, some of the names by which the species Tecoma stans (L.) Juss. Ex Kunth (Bignoniaceae) is known, it becomes interesting. Thus, this study aimed to evaluate the antioxidant activities and larvicidal potential of the T. stans pericarp from hexane extracts (HE), methanol extract (ME) and their fatty acids (FA) and methyl esters (FAMES). The extracts were obtained with hexane and methanol in a Soxhlet apparatus, hydrolyzed and esterified to obtain AG and FAME, respectively, and analyzed by Gas Chromatography and Mass Spectrometry (GC-MS) to determine their composition. In the phytochemical screening, the presence of steroids, triterpenes, alkaloids and coumarins was detected for HE, whereas for ME only the presence of alkaloids and coumarins was verified. In the analysis by GC-MS, the nonacosane hydrocarbon was identified as the major compound (81.69%) in the hexane extract. In FAME (EH), the major compounds were methyl hexadecanoate or palmitate (C16:0), methyl 9, 12-octadecadienoate or linoleate (C18:2) and methyl 9, 12, 15-octadecatrienoate or linolenate (C18:3), whereas in FAME (ME), the major compound was methyl hexacosanoate (C26:0). In the evaluation of antioxidant activity, the samples were effective at all concentrations tested (1, 10, 100, 250 and 500 µg/mL) by the DPPH method, with antioxidant potential, with percentages of inhibition ranging from 63.70 to 96.10% at a concentration of 500 µg/mL. The samples were more effective than BHT in capturing DPPH radicals, because they had lower EC₅₀ values. In the FRAP test, the samples showed a lower antioxidant potential. By this methodology, the highlight was for the methanolic extract that had an activity like that of BHT. The results for lethality in A. salina showed that the FAME of the hexane extract and the FAME of the methanolic extract can be considered toxic with LD₅₀ < 1000 µg/mL. In the susceptibility test in Culex quinquefasciatus larvae, it was possible to observe that the hexane extract and its fatty acids have larvicidal activity, because they promoted larval mortality. However, this effect is considered ineffective according to the literature. Thus, it can be concluded that this work is unprecedented and important because it contributed to the identification of compounds present in the pericarp of T. stans, as well as to the evaluation of the biological activities of this species.

BANKING MEMBERS:
Presidente - 1540495 - LUCIANA ALVES RODRIGUES DOS SANTOS LIMA
Externa à Instituição - NATHÁLIA LUCCA SILVA - UNA
Externo à Instituição - MAIRON CESAR COIMBRA - UFSJ