Atividades Antimicrobiana e Citotóxica de Extratos de Macroalgas da Antártica

Abstract

The marine environment has been studied focusing on the discovery of new compounds for therapeutic purposes. In this environment, macroalgae have provided metabolites with interesting biological activities and high therapeutic potential. Antarctica is characterized by the extremely abundant aggregations of macroalgae, however, the literature has little information about the bioactivity of these seaweeds. This study evaluated the antimicrobial potential and cytotoxic activity on tumoral and non tumoral cell lines of different extracts (hexane, chloroform, ethyl acetate and ethanol) of four seaweeds from Antarctic: Cystosphaera jacquinotii, Iridaea cordata, Himantothallus grandifolius and Pyropia endiviifolia. The antimicrobial activity was evaluated by the broth microdilution method. The extracts were assessed against Staphylococcus aureus ATCC 19095, Enterococcus faecalis ATCC 4083, Escherichia coli ATCC29214, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 62342 and clinical isolates from the human oral cavity of C. albicans (3), C. parapsilosis, C. glabrata, C. lipolytica e C. famata. Cytotoxicity was evaluated on human epidermoid carcinoma (A-431) and mouse embryonic fibroblast (NIH/3T3) cell lines by MTT colorimetric assay. Ethyl acetate extract of H. grandifolius showed noticeable antifungal activity against all fungal strains tested, including fluconazole resistant samples. Findings of cytotoxicity investigation on cancer cell line revealed that ethyl acetate extract of I. cordata shows very strong activity against A-431 cancer cell line, increasing the inhibitory ratio to 91.1% and 95.6% at the concentration of 500 μg mL-1 after 24 and 48h of exposure, respectively. Most of algal extracts tested showed very low or no cytotoxicity effect on normal cell line. The data demonstrate the bioactive profile of seaweeds extracts from Antarctica, suggesting that seaweeds from this region may be promising for the isolation of substances with important biological potential.