Phlorotannins (Ecklonia cava)

Phlorotannins from Ecklonia cava are bioactive polyphenolic compounds, not a macronutrient source. Key composition: Phlorotannin content in Ecklonia cava extract typically ranges from 6–15% dry weight, significantly higher than terrestrial plant tannins. Primary bioactive fractions include dieckol (most studied, ~0.1–2.0 mg/g dry extract), eckol, phlorofucofuroeckol-A, 6,6-bieckol, 8,8-bieckol, and triphlorethol-A. Molecular weights range from 126 Da (phloroglucinol monomer) to over 650 Da for oligomeric forms. These are exclusively marine-derived phloroglucinol (1,3,5-trihydroxybenzene) polymers with no terrestrial equivalent. No meaningful macronutrient contribution (protein, fat, carbohydrate) in isolated compound form. No significant vitamin or mineral content in purified phlorotannin extracts. Bioavailability: Moderate oral bioavailability estimated at 20–45% depending on molecular weight; smaller oligomers absorb more readily. Lipid solubility is notably higher than terrestrial polyphenols due to the phloroglucinol backbone, enabling better membrane permeability. Half-life in plasma approximately 2–4 hours post-ingestion. Stability is pH-dependent; degradation occurs above pH 7.5. Commercial standardized extracts (e.g., Seanol) typically standardized to ≥10% phlorotannin content.