Banca de DEFESA: SIMONE ALVES SERAFIM ROCHA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : SIMONE ALVES SERAFIM ROCHA
DATE: 28/02/2023
TIME: 14:00
LOCAL: videoconferência
TITLE:

Contribution to the chemical and biological knowledge of the species: Marsdenia megalantha (Apocynaceae) and Varronia dardani (Boraginaceae)

KEY WORDS:

Marsdenia megalantha; Polyoxypregnane; Apocynaceae; Varronia dardani; cordiaquinones

PAGES: 164
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

The Caatinga is a unique heritage on the planet; its semi-arid climate allows for immense varieties of landscapes and unique biodiversity. To contribute to the chemical and biological knowledge of the species belonging to the Caatinga flora, as well as to aid in the discovery of new drugs to cure diseases, this study describes the phytochemical study and the investigation of some biological properties of two plant species endemic to this ecosystem: Marsdenia megalantha and Varronia dardani. M. megalantha, known as "mata-calado", has been the target of studies because it causes poisoning in animals after ingestion of its roots. The chemical study of the hydroalcoholic extract of M. megalantha roots allowed the isolation of five compounds: Megalanthosideo A, B and C and 24-methyl-polinast-5, 23-dien-3,15-diol, being reported for the first time in the literature, besides Lanosterol, revealing that this species is a promising source of saponins with pregnane skeleton, substances that present cytotoxic, antidyslipidemic, antioxidant and anti-HIV properties reported in the literature.  V. dardani, popularly known as "moleque-duro", allowed the chemical study of the ethanolic extract of the roots of V. dardani resulting in the isolation and structural identification of two naphthoquinones: the 2-ethoxy-cordiaquinone A, being unpublished in the literature and the Cordiaquinone B. All isolated chemical constituents were characterized by spectroscopic techniques such as hydrogen (NMR1H) and carbon (NMR 13C) nuclear magnetic resonance, including two-dimensional techniques (COSY, HMQC, HMBC and NOESY) and the spectra compared with data available in the literature. The compounds isolated from V. dardani were subjected to cytotoxicity test and they inhibited 50% of the growth of cell lines (IC50) against human tumor cell lines showing respectively IC50 of 2.7 - 4.2 g.mL-1 and 1.0 - 1.4 g. mL-1 for HCT-116 (colorectal adenocarcinoma) and IC50 3.0 - 4.2 g.mL-1 and 1.6 - 2.3 g.mL-1 for MDA-MB-231 (breast adenocarcinoma) respectively, demonstrating a strong potential of cytotoxic activity and stimulating the continuity of this study with perspective in the discovery of anticancer molecules. The essential oil from the leaves of V. dardani, obtained by hydrodistillation, was analyzed, and chemically characterized by Gas Chromatography coupled to Mass Spectrometry (GC-MS) and Gas Chromatography with Flame Ionization Detector (GC-FID). The analysis resulted in the identification of twenty-five (25) chemical constituents, corresponding to a total of 99.9% of the chemical composition of the oil, consisting basically of monoterpenes and sesquiterpenes. This essential oil showed antimicrobial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and antifungal activity against two yeasts, Candida albicans and Candida parapsilosis. In addition, the essential oil was also subjected to larvicidal bioassays, showing an LC50 of 97.93 (± 1.25). This study contributed to the chemical and biological knowledge of two endemic species of the Caatinga, enabling the discovery of new unknown substances in M. megalantha, besides unprecedented biological assays related to antimicrobial, antifungal, larvicidal and cytotoxic activities in the species V. dardani.

COMMITTEE MEMBERS:
Presidente - 1569526 - RENATA MENDONÇA ARAUJO
Interno - 1803692 - FABRICIO GAVA MENEZES
Externa ao Programa - 1490222 - SILVANA MARIA ZUCOLOTTO LANGASSNER - UFRNExterno à Instituição - ANDERSSON BARRISON - UFSCAR
Externa à Instituição - CALINE GOMES FERRAZ - UFBA