Osteoarthritis is thought to be induced by the ageing-related loss of homeostatic balance between degeneration and repair mechanism around cartilage tissue in which inflammatory mediators such as reactive oxygen species, cytokines and prostaglandins are prone to over-production under undesirable physiological conditions. Phlorotannins are unique polyphenolic compounds bearing dibenzo-1,4-dioxin skeleton which are not found in terrestrial plants but found only in some brown algal species such as Ecklonia and Eisenia families. Phlorotannin-rich extracts of Ecklonia cava including LAD103 showed significant antioxidant activities such as DPPH radical scavenging, ferric ion reduction, peroxynitrite scavenging, and inhibition of LDL oxidation, indicating their possible antioxidative interference both in onset and downstream consequences of osteoarthritis. LAD103 also showed significant down regulation of PGE2 generation in LPS-treated RAW 246.7 cells, and significant inhibition of human recombinant interleukin-1alpha-induced proteoglycan degradation, indicating its beneficial involvement in pathophysiological consequences of osteoarthritis, the mechanism of which needs further investigation. Since LAD103 showed strong therapeutic potentials in arthritic treatment through several in vitro experiments, it is highly encouraged to perform further mechanistic and efficacy studies.

The effects of 12-week supplementation with a polyphenol extract from Ecklonia cava (ECP) on anthropometry, serum biochemistry and hematology have been investigated. Ninety-seven overweight male and female adults (average age 40.5 ± 9.2 yr and body mass index (BMI) of 26.5 ± 1.6 kg/m²) were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design. Subjects were randomly allocated into three groups designated as PC (placebo), LD (low-dose, 72 mg-ECP/day) and HD (high-dose, 144 mg-ECP/day). Both LD and HD groups showed significant decreases in BMI, body fat ratio, waist circumference, waist/hip ratio, total cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol/high-density lipoprotein (HDL) cholesterol and atherogenic index (AI) after 12 weeks, as compared with the placebo group. The HD group also showed a significant increase in serum HDL cholesterol as compared with the placebo group. Only the HD group showed significant decreases in serum glucose and systolic blood pressure after 12 weeks. There was no significant adverse event related with ingestion of ECP, and serum biochemical and hematological parameters were maintained within normal range during the intervention period. In conclusion, these results demonstrated that ECP supplementation significantly contributed to lowering body fat and serum lipid parameters such as total and LDL cholesterols with dose dependence. Further studies using different populations, dosages or biological markers are highly recommended to better understand the physiological features of this polyphenol.

Several polyphenolic compounds and complex mixtures were isolated from brown algae species. The 1,1-diphenyl-2-picryhydarzyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) of these compounds were evaluated to determine their physiological usefulness as antioxidants for vascular protection. The antioxidative protection of low-density lipoprotein (LDL) was also evaluated and compared with that of catechin, because the generation of oxidized LDL is one of the most active and specific risk factors contributing to atherogenesis. Oral administration to rats of a commercially available sample (VNP) containing 30% of these polyphenolic compounds and 70% dietary fiber revealed that the serum reducing capacity measured in terms of FRAP value was significantly elevated 30 min after the treatment, but declined rather quickly thereafter, indicating the good oral absorption of the compounds and their fast binding to the lumenal surface of the blood vessels. An eight-week, human, clinical trial (n=31) of VNP showed significant improvement in erectile function measured by IIEF (international index of erectile function) score. These results collectively demonstrated the usefulness of these polyphenolic compounds as fundamental chemopreventive agents against vascular risk factors originating from oxidative stress.

Ecklonia cava polyphenol (ECP) is a potent antioxidant and procirculatory agent that may contribute to improvement of endurance performance during highly intense exercise. This study evaluated the acute effect of an ECP-supplemented drink against a placebo on maximum endurance capacity and related physiological parameters. Twenty men 18-23 yr old volunteered as participants. Each performed 2 randomized trials with a 1-week interval between them. One trial was with ECP and the other with a placebo drink. Participants in this randomized, placebo-controlled, crossover design ingested either a placebo or ECP drink 30 min before each exercise trial. Time to exhaustion, VO(2max), and postexercise blood glucose and lactate levels were evaluated. ECP supplementation increased time to exhaustion (2.39 min) compared with placebo. This result was accompanied by a 6.5% higher mean VO(2max) in the ECP group, although the difference was not statistically significant. The blood glucose level in the ECP group at 3 min after exhaustive exercise was significantly higher than that of the placebo group (+ 9.9%). The postexercise blood lactate levels in the ECP group showed a decreasing trend compared with placebo, but it was nonsignificant. This study was not able to determine any physiological mechanisms behind the improved endurance performance, but, based on these results, it is speculated that the ECP supplementation may have contributed to enhanced oxidation of glucose and less production of lactate during intense exercise, possibly by its free-radical-scavenging and procirculatory activities. However, careful verification is required to elucidate the correct mechanism.

We evaluated the efficacy and safety of Ecklonia cava polyphenol (Seapolynol™, a polyphenol antioxidant and anti-inflammatory agent purified from E. cava) during a 12-week treatment period (400 mg orally once daily) in individuals with hypercholesterolemia and performed subgroup analysis for metabolic syndrome (MetS). As a noncomparative study, forty-six individuals (M:F=22:24, mean age=54±11 years) with fasting total cholesterol concentration >240 mg/dL or low-density lipoprotein cholesterol (LDL-C) concentration >130 mg/dL were enrolled. Hip circumference (100±7 cm vs. 98±7 cm, P<.01), total cholesterol (244±25 mg/dL vs. 225±37 mg/dL, P<.01), LDL-C (161±24 mg/dL vs. 146±34 mg/dL, P<.01), and C-reactive protein (2.51±3.55 mg/L vs. 1.37±1.32 mg/L, P<.05) were significantly decreased without significant adverse effect. A differential assessment according to the presence [MetS(+) group, n=18] and absence [MetS(-) group, n=28] of MetS showed that Hb(A1c) decreased significantly following 12-week Seapolynol treatment in the MetS(+) compared with the MetS(-) group (-0.3%±0.5% vs. 0.1%±0.3%, P<.01). In conclusion, although our results showed that Seapolynol treatment is effective and safe without significant adverse events or abnormal laboratory findings during a 12-week period in individuals with hypercholesterolemia, more research in a larger population with a longer-term follow-up period in a randomized placebo-controlled study is needed to confirm the results.