Antioxidant Properties of Algae in the U.S. Virgin Islands

Abstract

Compounds high in antioxidant activity counteract the formation of free radicals, which are linked to many human diseases and cancers. The objectives of this study were to quantify the hydrophilic antioxidant activity (HAA), lipophilic antioxidant activity (LAA), and the total antioxidant activity (TAA) of algae collected in the US Virgin Islands. The three algae divisions collected are Rhodophyta, Chlorophyta, and Phaeophyta. We hypothesize that the HAA will be greater than the LAA for all algae species. We also hypothesized that Phaeophyceae would have the highest TAA compared to the other classes. In this study, 28 species of algae were collected on St. Croix, USVI. The ABTS, H₂O₂, horseradish peroxidase decoloration method was used to determine the antioxidant activity then scanned using a UV-VIS Spectrophotometer at 730 nm. The antioxidant activities were reported as µmol Trolox Equivalent (TE)/g Dry Weight (DW). For all of the samples tested, Caulerpa prolifera had the highest TAA (97.281 ± 18.475 µmol TE/g DW) while Dictyota jamaicensis had the lowest TAA (1.999 ± 0.889 µmol TE/g DW). Chlorophyta had the highest mean (23.754 ± 29.710 µmol TE/g DW ) of antioxidant activity and Phaeophyta  (12.595 ± 11.861 µmol/g DW) had the lowest mean. A one-way ANOVA test showed significant difference between the HAA and LAA (p = 0.0509). A one-way ANOVA test comparing all three groups revealed that there was no statistical difference between their TAA (p = 0.621). Based on this, we didn’t find any significant difference among the antioxidant levels between the groups tested.