Objective: The purpose of this study was to determine if Porphyra tenera extract (PTE) has immune-enhancing effects and is safe in healthy adults. Methods: Subjects (3x10³ ≤ peripheral blood leukocyte levels < 8x10³ cells/μl) who met the inclusion criteria were recruited for this study. Enrolled subjects (n=120) were randomly assigned to either the PTE group (n=60) who were given 2.5 g/day of PTE (as Porphyra tenera extract) in capsule form or the placebo group (n=60) who were given crystal cellulose capsules with the identical appearance, weight, and flavor as the PTE capsules for 8 weeks. Outcomes were assessed by measuring natural killer cell (NK-cell) activity, cytokines, and upper respiratory infection (URI), and safety parameters were assessed at baseline and 8 weeks. Results: Compared to baseline, NK cell activity (%) increased for all effector cell to target cell ratios in the PTE group after 8 weeks, but there were no changes in the placebo group (p<0.1). Subgroup analysis of 101 subjects without an URI revealed that NK-cell activity in the PTE group tended to be increased for all E:T ratios (E:T=12.5:1 p=0.068; E:T=25:1 p=0.036; E:T=50:1 p=0.081) compared to the placebo group. There was a significant difference between these two groups for the E:T=25:1 ratio, which increased from 20.3±12.0% at baseline to 23.2±12.4% after 8 weeks in the PTE group (p=0.036). There was no significant difference in levels of cytokines between these two groups. Conclusions: PTE supplementation appears to enhance immune function by improving NK-cell activity without adverse effects in healthy adults.

Hypercholesterolemia is a major risk for the development of cardiovascular diseases (CVDs), the main cause of mortality worldwide, and it is characterized by high levels of circulating cholesterol. The drugs currently available for hypercholesterolemia control have several side effects, so it is necessary to develop new effective and safer therapies. Seaweeds serve as sources of several bio-active compounds with claimed beneficial effects. Eisenia bicyclis (Aramé) and Porphyra tenera (Nori) are edible seaweeds which were previously recognized as rich in bioactive compounds. In the present study, we aim to evaluate the anti-hypercholesterolemia effect of these two seaweeds ex-tracts and their health potential. Both extracts, but more efficiently Aramé extract demonstrated to have liver 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitory activity and to reduce approximately 30 % cholesterol permeation through human Caco-2 cells simulating the intestinal lining, targets for hypercholesterolemia treatments. An untargeted metabolomic assay on human intestinal Caco-2 and liver Hep-G2 cells lines exposed to Aramé and Nori extracts revealed changes in the cell’s metabolism as indicators of the extract’s health beneficial effects. The metabolic pathways affected by exposure to both extracts were associated to lipid metabolism, such as phospholipids, and fatty acid metabolism, pathways of amino acid, cofactors and vitamins and cellular respiration metabolism. More profound for Aramé treated cells, but also seen for Nori ex-posed cells, the metabolites modifications were associated with the protection against CVDs and other diseases and, to the improvement of cells oxidative stress tolerance. The results obtained for the anti-hypercholesterolemia properties, in addition to the revelation of the positive impact on cells metabolism, are an important contribution for further evaluation of these seaweeds extracts as functional foods or for CVDs prevention.