Banca de DEFESA: ARIELLE ARAUJO SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ARIELLE ARAUJO SANTOS
DATA : 25/02/2019
HORA: 13:30
LOCAL: Auditório da Congregação, 2º andar, Instituto de Ciências da Saúde, UFBA
TÍTULO:

EVALUATION OF ANTIMICROBIAL ACTIVITY, TOXIC AND
ANTIOXIDANT OF MARINE ALGAE EXTRACTS

PALAVRAS-CHAVES:

Artemia salina, Diatoms, DPPH, Phenol, Rhodophyta.

PÁGINAS: 100
GRANDE ÁREA: Ciências Biológicas
ÁREA: Biologia Geral
RESUMO:

In the bioprospecting scenario of natural products, seaweed gained prominence due to the synthesis of bioactive metabolites structurally complex, from the secondary metabolism, which are assigned biological several properties. The objectives of this study were to evaluate antimicrobial and antioxidant activities, and toxicity using brine shrimp (Artemia salina Leach), as well as quantifying the content of total polyphenols and flavonoids extracts of red algae Enantiocladia duperreyi (C.Agardh) Falkenberg and Amansia multifida J.V. Lamouroux, and of diatoms Thalassiosira pseudonana Hasle & Heimdal and Chaetoceros muelleri Lemmermann. The seaweed were collected on beaches of the Bahian coast and microalgae were grown in the laboratory of Bioprospecting of biotechnology of the Federal University of Bahia. Extracts were prepared by maceration in hexane, acetate and ethanol. The antimicrobial activity was assessed by disk-diffusion method in agar (extracts at concentrations of 10 and 100 mg/mL) and microdilution in broth (3.9 to 500 µg/mL) for six bacteria and three fungi; the antioxidant activity (AAO) was evaluated by the method of radical inhibition 2.2-diphenyl-1-picrilhidrazil (DPPH) at concentrations of 0.045 to 3.0 mg/mL, the same used to quantify phenolic compounds by the Folin-Ciocalteau assay method. Total flavonoids were quantified by reaction with aluminium chloride. As for the antimicrobial activity using disk-diffusion method, extracts of E. duperreyi (Saquaíra) inhibited the growth of six microorganisms, and those of T. pseudonana inhibited the growth of four, with better performance of hexane extracts. Using microdilution, all extracts showed activity, and the minimum inhibitory concentration (MIC) was 62.5 µg/mL for ethanol extract of T. pseudonana for Micrococcus luteus. Five extracts presented % AAO ˃ 50, being 81.32 ± 1.0% the highest percentage observed, attributed to ethyl acetate extract of E. duperreyi (Saquaíra). The highest content of phenolic compounds was quantified in the ethyl acetate extract of E. duperreyi (Jauá), which also has the highest flavonoid content. As for toxicity, only extracts of T. pseudonana e E. duperreyi (Jauá) showed low to moderate toxicity. The others were non-toxic. Differences were observed between the Rodophyta of the same species collected in different beaches. Hexane and ethyl acetate were the best solvents to extract algal compounds. Since C. muelleri showed no antimicrobial activity on disk-diffusion, and low antioxidant activity, it would be interesting to test other forms of extraction for this species. The results are promising considering the biotechnological point of view, however it is necessary the peformance of new biological assays, and phytochemical characterization of these extracts to isolate subsequently the bioactive molecules.

MEMBROS DA BANCA:
Externo à Instituição - MARCOS DA COSTA SILVA - UNEB
Interno - 1674313 - SUZANA TELLES DA CUNHA LIMA
Externo à Instituição - VERA LUCIA COSTA VALE - UNEB