Evaluation of methanolic extracts from two species of gracilaria (Rodophyta) as antibacterial agents

Evaluación de extractos metanólicos de dos especies de gracilaria (Rodophyta) como agentes antibacterianos

The antibacterial activity of methanol extracts of G. blodgettii and G. damaecornis (Rhodophyta) collected in the sector Punta Bello municipality of San Antero-Córdoba, this activity was estimated taking into account the collection period of macroalgae, the reproductive cycle and diferent dilutions: 5120, 2560, 1280, 640, 320, 160, 80, 40 ppm (parts per million), it was used bacterias strains E. coli (ATCC 25923) and S. aureus (ATCC 25922) following the agar diffusion method using sensidiscs (Bauer et al., 1966). The results show that both undiluted extracts obtained from the algae collected in the different sampling periods, showed inhibition in the growth of E. coli and S. aureus strains. The algal extracts on bacterial strain S. aureus showed a positive response to high dilution, unlike bacterial strain E. coli that do not show inhibitory activity in the other dilution. The predominant phase corresponds to tetrasporofito stadium. This constitutes the research first local report in relation to the antibacterial activity of the methanol extracts of G. blodgettii y G. damaecornis in E. coli y S. aureus.