Banca de DEFESA: RODRIGO CESAR FERNANDES BARBOSA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RODRIGO CESAR FERNANDES BARBOSA
DATA : 17/02/2020
HORA: 13:30
LOCAL: Instituto de Química
TÍTULO:

PROSPECTING MARINE MACRO ALGAE TO EVALUATE THE ACTIVITY AGAINST Leishmania infantum AND DETERMINATION OF THE PROFILE OF STEROLS OF Neobenedenia melleni

PALAVRAS-CHAVES:

Leishmania infantum, Neobenedenia melleni, Benthic Algae.

PÁGINAS: 70
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Química dos Produtos Naturais
RESUMO:

Benthic algae proliferate through the retention of nutrients present in the water. Growing faster in high organic contents water. This uncontrolled proliferation cause an oxygen water concentration decrease, which impacts the fauna of the ecosystem in question, motivating the removal of algae from these sites by the environmental protection agencies, which guarantees the viability of biomass for phytochemical studies, without causing environmental impacts. Marine plants need to produce secondary metabolites related to predators defense, in a critical concentration enough to mitigate the seawater dilution effect. Thus, marine natural products tend to have high biological activity in low concentrations. The perspective of compounds with biological activities of interest to human health justifies the study of marine natural products, especially using tools such as molecular modeling and structural modification, as a way of equating the relation between activity and toxicity, which motivated the accomplishment of this study about of the activity of seaweed extracts against Leishmania infantum and Neobenedenia melleni. The genus Leishmania comprises digenetics protozoa, that live alternately in vertebrate hosts and vectors insects, wich is responsible for the transmission of the parasite from one host to another. L. infantum is one of the species responsible for leishmaniasis visceral occurrence, a clinical form of the disease that affects, in addition to humans, other vertebrates, mainly dogs. Different concentrations of crude extracts and basic fractions of Ulva fasciata, Ulva flexuosa, Dictyota menstrualis and Sargassum vulgare against L. infantum promastigotes were tested, where after the incubation period of 72 hours at 26ºC the reagent resazurin, an indicator of mitochondrial metabolic activity. With the exception of the basic fraction of D. menstrualis, the others extracts and fractions showed no activity against the parasite, at the concentrations tested (0 - 128 μg/mL). The basic fraction of D. menstrualis presented IC50 of 55.08 μg/mL, which shows the potential of natural marine products as a source of bioactive compounds. The bioguided fractionation of the basic fractions of D. menstrualis and H. musciformis originated the HBH and F2' fractions, respectively presenting IC50 values = 30,4 and 62,2 µg/mL, demonstrating the importance of the fractionation steps, for optimization biological activity. N. melleni is an ectoparasite of marine fish, with a marked occurrence in culture systems, responsible for large losses for the mariculture industry. It is mainly fixed in the host's eyes, causing blindness, erratic swimming and difficulty in feeding, which can lead to death if not treated. The main treatment is through freshwater baths, which cause osmotic shock and consequent detachment of the parasite. Due to the logistics and high costs involved in this form of treatment, it is of great interest to develop alternative treatments for the control of this parasite. Given the few studies about its physiology and metabolism, previous studies on the potential pharmacological targets to be explored are necessary. In this context, the main sterols present in the lipid extract prepared from the tissues of the parasite were identified by Bligh & Dyer (1959), and evaluated by TLC and GC-MS. It was found that the parasite presents the precursors squalene and desmosterol, as well as cholesterol and cholesterol esters, indicating that the parasite possesses the enzymatic complex necessary for cholesterol biosynthesis and its storage as esters. In this way, the enzymes involved in cholesterol biosynthesis represent potential pharmacological targets for the control of N. melleni.

MEMBROS DA BANCA:
Presidente - 2181682 - MARCIA CRISTINA CAMPOS DE OLIVEIRA
Externo à Instituição - VALTER VIANA ANDRADE NETO - FIOCRUZ
Externa à Instituição - MARIA RAQUEL GARCIA VEGA - UENF