# Coral Seaweed (Corallina officinalis)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/coral-seaweed
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Marine-Derived
**Also Known As:** Corallina officinalis, Common coralline, Red coralline algae, Calcified red algae, Coral weed, Hard seaweed, Calcareous algae

## Overview

Coral Seaweed (Corallina officinalis) is a calcareous red alga rich in sulfated polysaccharides, phlorotannins, and carotenoids that exert antioxidant and cytotoxic effects primarily through free radical scavenging and disruption of cancer cell proliferation pathways. Its bioactive compounds interact with [reactive oxygen species](/ingredients/condition/antioxidant) and demonstrate selective toxicity against malignant cell lines in controlled laboratory conditions.

## Health Benefits

• [Antioxidant activity](/ingredients/condition/antioxidant): In vitro studies show dose-dependent radical scavenging up to 78.26% ABTS inhibition (preliminary evidence only)
• Anti-cancer potential: Acetone extracts demonstrated cytotoxicity against HCT-15 colon cancer cells with IC50 of 25.895 µg/mL (in vitro evidence only)
• [Antimicrobial](/ingredients/condition/immune-support) effects: Showed activity against Bacillus species at MIC 0.156 mg/mL (in vitro evidence only)
• [Anti-inflammatory](/ingredients/condition/inflammation) properties: Sulfated polysaccharides exhibited anti-inflammatory effects in non-human models (preliminary evidence)
• Free radical neutralization: Polysaccharide hydroxyl and sulfate groups act as DPPH/ABTS inhibitors (mechanism demonstrated in vitro only)

## Mechanism of Action

Sulfated polysaccharides and phlorotannins in Corallina officinalis neutralize [reactive oxygen species](/ingredients/condition/antioxidant) by donating hydrogen atoms to free radicals, directly inhibiting lipid peroxidation cascades. Acetone-extracted cytotoxic compounds appear to induce apoptosis in colon cancer cells (HCT-15 line) via [mitochondrial](/ingredients/condition/energy) membrane disruption and caspase pathway activation, achieving an IC50 of 25.895 µg/mL. [Antimicrobial](/ingredients/condition/immune-support) activity is attributed to phenolic compounds interfering with bacterial cell membrane integrity and inhibiting key metabolic enzymes.

## Clinical Summary

Current evidence for Corallina officinalis is limited exclusively to in vitro and preliminary laboratory studies, with no published human clinical trials to date. ABTS radical scavenging assays demonstrated dose-dependent [antioxidant activity](/ingredients/condition/antioxidant) reaching 78.26% inhibition, while acetone extracts showed cytotoxicity against HCT-15 colon cancer cells with an IC50 of 25.895 µg/mL. [Antimicrobial](/ingredients/condition/immune-support) studies have shown activity against select bacterial and fungal strains, though minimum inhibitory concentrations vary widely by extract preparation. Translating these findings to human health outcomes requires rigorous pharmacokinetic studies and randomized controlled trials, which are currently absent from the literature.

## Nutritional Profile

Corallina officinalis is a calcified red alga (Rhodophyta) with a distinctive mineral-rich composition due to its calcareous skeleton. **Minerals:** Exceptionally high in calcium carbonate (CaCO₃), comprising 80–90% of dry weight as calcite/aragonite; also contains magnesium (Mg, ~2–5% dry weight as MgCO₃ substitution in calcite lattice), iron (Fe, ~150–500 mg/kg DW), zinc (Zn, ~20–80 mg/kg DW), manganese (Mn, ~50–200 mg/kg DW), iodine (trace amounts typical of red algae), and strontium (trace). **Protein:** Relatively low compared to non-calcified seaweeds, approximately 3–8% of dry weight (limited by high mineral fraction); amino acid profile includes glutamic acid, aspartic acid, and glycine as predominant residues. **Carbohydrates & Fiber:** Sulfated polysaccharides (sulfated galactans/carrageenans typical of Corallinaceae) estimated at 5–15% DW; dietary fiber content modest at ~5–10% DW due to calcification. **Lipids:** Low total lipid content (~1–3% DW); fatty acid profile includes polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA, C20:5 n-3) at ~15–30% of total fatty acids, and palmitic acid (C16:0) as dominant saturated fatty acid. **Bioactive Compounds:** Phenolic compounds (~5–20 mg GAE/g extract depending on solvent), including bromophenols and phenolic acids contributing to [antioxidant](/ingredients/condition/antioxidant) capacity; carotenoids including β-carotene and zeaxanthin (trace to low levels); phycobiliproteins (phycoerythrin) present but at lower concentrations than fleshy red algae (~0.1–0.5 mg/g DW); sulfated polysaccharides with reported bioactivity. **Vitamins:** Likely contains vitamin C (ascorbic acid, trace), B-vitamins (B₁₂ analogs common in red algae but bioavailability uncertain), and vitamin E (tocopherols, trace). **Bioavailability Notes:** The calcium in Corallina is in a highly crystalline calcite form, and bioavailability may be comparable to or slightly lower than calcium from commercial coral-derived calcium supplements (~25–40% absorption); magnesium bioavailability from calcite matrix is not well characterized. Phenolic compound bioavailability is likely limited by low extraction efficiency from the calcified matrix. Sulfated polysaccharides have limited gastrointestinal absorption but may exert [prebiotic](/ingredients/condition/gut-health) or local gut effects. EPA bioavailability from algal lipids is generally moderate. Overall nutritional data for this species is limited, and most values are extrapolated from related coralline algae or general red algal profiles.

## Dosage & Preparation

No clinically studied human dosages exist. In vitro studies used concentrations of up to 1.25 mg/mL for [antimicrobial](/ingredients/condition/immune-support) effects and 25.895 µg/mL IC50 for cytotoxicity, but these cannot be translated to human dosing. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

No human safety data or formal toxicology studies for Corallina officinalis supplementation have been published, making definitive risk assessment impossible at this time. Its high calcium carbonate (calcite) skeleton content raises theoretical concerns about hypercalcemia if consumed in large quantities, particularly in individuals with impaired renal function or those taking calcium-elevating medications such as thiazide diuretics. Iodine content typical of marine algae may interact with [thyroid](/ingredients/condition/hormonal) medications including levothyroxine or antithyroid drugs, and individuals with thyroid disorders should exercise caution. Pregnant and breastfeeding women should avoid supplemental use until safety data from controlled studies are available.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses have been conducted on Corallina officinalis. All available research is limited to in vitro studies examining [antioxidant activity](/ingredients/condition/antioxidant), cytotoxicity against cancer cell lines, and [antimicrobial](/ingredients/condition/immune-support) effects using acetone or supercritical CO2 extracts.

## Historical & Cultural Context

No historical or traditional medicinal uses are documented for Corallina officinalis in any traditional medicine systems. Current research focuses exclusively on modern phytochemical screening rather than ethnobotanical applications.

## Synergistic Combinations

Other marine algae, astaxanthin, fucoidan, spirulina, chlorella

## Frequently Asked Questions

### What is Coral Seaweed (Corallina officinalis) used for?

Corallina officinalis is studied primarily for its antioxidant, antimicrobial, and potential anticancer properties derived from its sulfated polysaccharides and phlorotannin content. In laboratory settings, its extracts have demonstrated up to 78.26% ABTS radical inhibition and cytotoxicity against HCT-15 colon cancer cells, though no approved therapeutic uses in humans currently exist.

### Is Coral Seaweed safe to take as a supplement?

No formal human safety trials for Corallina officinalis supplements have been conducted, so definitive safety conclusions cannot be drawn. Its naturally high calcium carbonate content poses a theoretical hypercalcemia risk at high doses, and its iodine load may interfere with thyroid function or medications like levothyroxine, making medical consultation essential before use.

### What are the active compounds in Corallina officinalis?

The primary bioactive compounds in Corallina officinalis include sulfated polysaccharides, phlorotannins, carotenoids such as fucoxanthin analogs, and phenolic acids. These compounds collectively contribute to its measured antioxidant activity, cytotoxicity against cancer cell lines, and antimicrobial properties observed in laboratory extracts.

### Does Coral Seaweed have anticancer properties?

In vitro studies show that acetone extracts of Corallina officinalis inhibit HCT-15 colon cancer cell viability with an IC50 of 25.895 µg/mL, suggesting cytotoxic potential. However, these are cell-culture findings only, and no animal models or human clinical trials have validated anticancer efficacy or established safe dosing protocols for this purpose.

### How does Coral Seaweed compare to other seaweed supplements like spirulina or kelp?

Unlike spirulina, which is a freshwater cyanobacterium rich in phycocyanin and studied in multiple human trials, Corallina officinalis is a calcified marine red alga with a research base confined to in vitro studies and no clinical trial data. Compared to kelp, which is widely used for iodine supplementation with established dosing guidelines, Coral Seaweed lacks standardized extract preparations, known bioavailability data, and regulatory approval as a dietary supplement.

### What does the research evidence show about Coral Seaweed's antioxidant effectiveness?

In vitro laboratory studies demonstrate that Corallina officinalis exhibits dose-dependent antioxidant activity, with some extracts achieving up to 78.26% ABTS radical scavenging inhibition. However, this preliminary evidence is limited to test-tube studies and has not yet been validated in human clinical trials, so real-world antioxidant benefits remain unconfirmed. The gap between in vitro potency and actual bioavailability in humans means current claims should be considered exploratory rather than established.

### Are there any natural food sources of Coral Seaweed, or is supplementation the only option?

Corallina officinalis is a calcareous red seaweed found naturally in rocky coastal waters, particularly in temperate and subtropical regions, and can be harvested directly from ocean environments. However, it is not a commonly consumed food in most Western diets and is primarily available through specialized supplement products rather than conventional grocery sources. Those seeking whole-food seaweed options with more established consumption history may consider more widely available varieties like nori or wakame.

### Who should avoid Coral Seaweed supplementation, or are there specific populations at higher risk?

Individuals with iodine sensitivity, thyroid conditions, or those taking thyroid medications should exercise caution, as seaweeds can accumulate iodine and potentially interfere with thyroid function. People with shellfish or seafood allergies may experience cross-reactivity to seaweed supplements due to shared marine proteins and should consult a healthcare provider before use. Additionally, those on anticoagulant medications should discuss seaweed supplementation with their doctor, as some seaweed compounds may have mild blood-thinning properties.

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