Ecklonia cava

Ecklonia cava is a brown marine alga (class Phaeophyceae) native to the coastal waters of Korea, Japan, and China. It is harvested primarily for its polyphenolic compounds—particularly phlorotannins—that are marketed as dietary‑supplement ingredients for antioxidant, anti‑inflammatory and metabolic support.

• Hallmark constituents: Ecklonia cava’s hallmark constituents are phlorotannins, polyphenolic polymers of phloroglucinol (C₆H₆O₃).
• Dieckol: The most studied compound, dieckol, has the molecular formula C₃₆H₂₂O₁₈, IUPAC name [1,2,3,4,5,6‑hexahydroxy‑7‑(3‑hydroxy‑5‑hydroxy‑6‑hydroxy‑hydroxy‑phenoxy)‑2‑(3‑hydroxy‑5‑hydroxy‑6‑hydroxy‑phenoxy)‑...] (simplified: a dimeric eckol). It contains multiple ether linkages and hydroxyl groups, conferring high antioxidant capacity (ORAC > 10 000 µmol TE/g).
• Other phlorotannins: Other notable phlorotannins include eckol (C₁₈H₁₂O₆) and 7‑phloroeckol (C₁₈H₁₂O₇).
• Membrane penetration: These molecules are water‑soluble but have increased lipophilicity due to aromatic rings, facilitating membrane penetration.
• Other constituents: The extracts also contain fucoidan (sulfated polysaccharide) and trace minerals (iodine, potassium).

• Harvesting location: Ecklonia cava is harvested from the subtidal zones of the Korean and Japanese coasts, where the seaweed grows on rocky substrates at 5–30 m depth.
• Harvesting process: Commercially, the algae are harvested by divers or mechanical harvesters during low‑tide periods to preserve bioactive content.
• Processing: The harvested biomass is washed, freeze‑dried, and milled into a fine powder.
• Extraction: Extraction typically employs 70 % ethanol or aqueous–ethanol (1:1) under controlled temperature (40–60 °C) to maximise phlorotannin yield while preserving structural integrity. Super‑critical CO₂ extraction is emerging to reduce solvent residues.
• Standardization: Good Manufacturing Practice (GMP) facilities standardise extracts to 20–30 % total phlorotannins, verified by HPLC‑DAD or LC‑MS.
• Quality markers: Quality markers include dieckol ≥ 10 % of total phlorotannins and low heavy‑metal (< 0.5 ppm lead, arsenic) levels.
• Sustainability: Sustainable sourcing certifications (e.g., Marine Stewardship Council) are increasingly used to ensure ecological impact is minimized.