Banca de DEFESA: RUSCELI DIEGO DE ARAUJO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RUSCELI DIEGO DE ARAUJO
DATA : 14/09/2018
HORA: 08:00
LOCAL: Sala 3F2
TÍTULO:

CHEMICAL AND BIOLOGICAL INVESTIGATION OF Eugenia luschnathiana: toxicity, antioxidante profile and ursane and oleanane triterpenes

PALAVRAS-CHAVES:

Oleanane, Ursane, Essential oil, antioxidant, toxicity, antibacterial.

PÁGINAS: 238
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Química dos Produtos Naturais
RESUMO:

Since ancient times the plants have been shown to be a rich source of the most varied substances with chemical skeletons and diverse biological properties. Its use in popular medicine like teas, ointments and infusions is spread throughout the world, to the point that in certain underdeveloped countries it is one of the main forms of treatment. Among several families belonging to the plant kingdom, we can highlight the family Myrtaceae, which is part of the group of 10 largest families of angiosperms in the world and several studies have already been carried out with genera belonging to it. Among these genera, Eugenia stands out, which, like others in the family, develops well in tropical regions such as northern South America and South Asia. Diuretic, anti-inflammatory, microbicidal and antidiabetic activities, among others, have already been reported for the genus, so that some species were selected by the Renisus program as target plants for chemical and biological studies. The literature reports the genus as a source of chemical structures belonging to the classes of flavonoids, coumarins, derivatives of floroglucinol, tannins and terpenes, thus representing a rich source of the most diverse secondary metabolites. Thus, the present work proposes the chemical and biological investigation of Eugenia luschnathiana, a species on which there are still no reports of phytochemical studies on the literature. This work is divided into two chapters: the first one refers to obtaining the extracts ethanol from the stem (ELSE), leaves (ELLE) and their fractions (hexane - H, chloroform - C / dichloromethane - D, acetate - AcOEt and hydroalcoholic - HA), as well as fruit (ELFE) and decoto (ELD) and evaluation of its antioxidant and toxicity activities. These extracts, besides the fixed oil obtained from the leaves, were saponified and esterified to investigate their chemical composition. The isolation and characterization of 10 isolated metabolites of the stem and leaves were also carried out, with the predominance of ursane and oleanane type triterpenes;
the second one deals with obtaining essential oil from the leaves of E. luschnathiana (EOEL) collected at three different times of the year, in order to evaluate the differences in its chemical composition and its impacts on antioxidant, toxicity and bacterial activities. The evaluation of the antioxidant activity against the DPPH radical of the ethanol extracts of the leaves and stem and hexane, chloroform/dichloromethane fractions, ethyl acetal and hydroalcoholic residue presented good results, where we can highlight the ELCE-AcOEt and ELCE-HA fractions with concentrations of IC₅₀=59,755±0,756 and 37,451±0.001 μg/mL, respectively. From the leaves we can indicate the ELFE-AcOEt fraction and also the decoy (ELD) with values of IC₅₀=56.913±0.164 and 66.114±0.052 μg/mL respectively. The toxicity test against microcrustacean A. salina showed that all fractions are non-toxic, which highlights the possible use of this plant in folk medicine. However, the three essential oil samples were highly toxic at concentrations of DL₅₀=72,629±3,992, 14,241±0,937 and 9,588±0,615 μg/mL for samples 1, 2 and 3. GC-MS analysis of the essential oil allowed the identification of 39 molecules for the different oil samples, presenting a majority composition of oxygenated and non-oxygenated sesquiterpenes, emphasizing the spathulenol and the caryophyllene oxide in very significant quantities. This analysis was also applied to the saponifiable and unsaponifiable fractions and several compounds were identified, proving the lipid richness present in this species. The chromatographic procedures performed with the stem allowed the isolation of two constituents: phytosterol β-sitosterol (EL-1) and an oleanane skeleton triterpene, arjunolic acid (EL-2), and by reaction acetylated derivative thereof, 2,3,3-triacetoxyolean-12-en-28-oic acid (EL-3). Of the leaves, 4 mixtures containing terpenes were isolated: oleanoic acids and ursolic acid (EL-4), very common in the Myrtaceae family; α-amirine and 3β, 19α-dihydroxy-urs-12-ene (EL-5), the latter unpublished in the literature; clovane-1,9-diol uncommon in family and genus, isolated only from the seeds of E. jambolana and 4,4,8-trimethyl-13-oxatetracyclo[6.3.1.11,9.02,5]tridecane (EL-6), in which it is the first record of its spectroscopic data, and unpublished in the genus Eugenia. In addition to the previously unpublished 3-p-couaroyl-tormentico (70) (EL-7), ursane-like skeleton.

MEMBROS DA BANCA:
Presidente - 1569526 - RENATA MENDONÇA ARAUJO
Interno - 1803692 - FABRICIO GAVA MENEZES
Externo ao Programa - 1490222 - SILVANA MARIA ZUCOLOTTO LANGASSNER
Externo à Instituição - JULIANA FÉLIX DA SILVA
Externo à Instituição - YANNA CAROLINA FERREIRA TELES