Caulerpa Filiformis (Suhr) Hering, a New Antibacterial Option

Abstract

Introduction: Among the potential bioactive natural products are marine macroalgae. Such is the case of the genus Caulerpa, studies on the bioactivity of extracts in several species of the genus include its antimicrobial activity, nematicidal activity, antioxidant activity, anti-inflammatory, antileishmania and antiviral activity against dengue.

Objective: To determine the secondary metabolites, total polyphenols and antioxidant activity of the alga Caulerpa filiformis (Suhr) Hering in ethereal and ethanolic extract and its antibacterial activity against gram-positive and gram-negative bacteria as an alternative in the treatment against bacterial strains resistant to commercial antibiotics.

Methods: The biological material consisted of dry samples of Caulerpa filiformis seaweed, collected from El Chaco beach (Paracas Bay), whose strains are certified as positive control ciprofloxacin at a concentration of 5 µg/mL. Secondary metabolites, antioxidant activity by diphenylpicrylhydrazyl assay methods and total antioxidant capacity of plasma were determined, and evaluation of the antibacterial activity of different extracts at concentrations 100, 200, 300 and 400 mg/mL by the well diffusion method, measuring the percentage of relative inhibition.

Results: Polyphenol content of 20 mg EAG/g and 22 mg EAG/g of extract was determined in the ethereal and ethanolic extracts; antioxidant activity by the diphenylpicrylhydrazyl assay method of IC50 = 28.89 and 31.85 mg of extract; by the plasma total antioxidant capacity method 57.9 mM ET/g and 56.2 mM ET/g for the ethereal and ethanolic extracts, respectively. The 20% ethanolic extract showed higher antibacterial capacity against Klebsella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Shigella dysenteriae, having a relative inhibition percentage of 50%, 62.50%, 53.12%, 44, 12%, respectively, while the ethereal extract at 20% showed a higher capacity against the pathogenic bacteria Bacillus cereus and Staphylococcus aureus with a relative inhibition percentage of 57.69%, 70.83%, respectively.

Conclusion: The alga Caulerpa filiformis (Suhr) Hering can be a new antimicrobial alternative.