Bactericide, antioxidant and cytotoxic activities from marine algae of genus laurencia collected in Baja California sur, México

Background and Objective: Marine environment represents countless and diverse resource for new drugs to combat major diseases. Extracts from four Laurencia species (L. johnstonii, L. pacifica, L. gardneri and L. papillosa) from Baja California Sur, México were evaluated for their antioxidant, antibacterial and cytotoxic activity. Methodology: The antioxidants activity of Laurencia sp. were evaluated using the radical scavenging activity in three in vitro radicals: 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2,2'-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and nitric oxide (NO). The antibacterial activity was evaluated by the broth microdilution method to determinate the Minimum Inhibitory Concentrations (MIC) against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Micrococcus luteus, Pseudomonas aeruginosa and Klebsiella pneumoniae. The cytotoxicity was analyzed on HeLa (cervix adenocarcinoma) and Vero (kidney epithelial) cells, using the reduction of tetrazolium salt WST-1. Results: The seaweed of genus Laurencia demonstrated an overall low activity, with half maximal effective concentration (EC₅₀) values >1.5 mg mLG¹. Laurencia pacifica showed the best biocide effects with MIC of 6.25 µg mLG¹ against Gram positive bacterial and cytotoxic potential with half inhibitory concentration (IC₅₀) <30 µg mLG¹ against Vero and HeLa cells. Conclusion: Some Laurencia species have a great antibacterial and cytotoxic activity which could be considered for future studies.