Antibacterial properties of a glycolipid-rich extract and active principle from Nunavik collections of the macroalgae C. Agardh (Fucaceae).

This study investigated the antibacterial activity of glycolipid-rich extracts of the brown macroalga in cell culture. Accessions were collected on the Arctic coast of Ungava Bay, Nunavik, Quebec. The crude ethyl acetate extract of these accessions showed strong antibacterial activity (≥4 log10 cfu) against , , (ATCC and clinical isolate), and at 100 µg/mL. This algal extract inhibited by 3 log10 and methicillin-resistant , whereas , , , and were not significantly affected. Further investigations of the activity of a glycolipid-rich fraction, extracted with dichloromethane, against Propionibacterium acnes showed an MIC100 of 50 µg/mL, with an inhibition of more than 99% at only 7.8 µg/mL. The main active compound, a β- d-galactosyl O-linked glycolipid, was synthesized for the bioassay and showed an MIC100 of 50 µg/mL but lost its activity more quickly with only 50% of inhibition at 12.5 µg/mL. Therefore, the semipurified F. evanescens extract could be a good choice for future research into the development of alternative treatments for acne therapy. [ABSTRACT FROM AUTHOR]