Apium prostratum (Apiaceae) Sea Celery, Tutae Koau

Apium prostratum, commonly known as sea celery, is a halophytic herb native to the coastal regions of Australia, New Zealand, and South America. Long valued as a vital source of vitamin C for explorers and colonists, it is now gaining recognition as a potent functional food. Modern scientific research reveals that this humble coastal plant is exceptionally rich in phenolic compounds, particularly the flavone glycoside apiin, and exhibits remarkable antioxidant capacity alongside significant inhibitory activity against enzymes linked to diabetes, obesity, and inflammation.

---

1. Taxonomic Insights

Species: Apium prostratum Labill. ex Vent.

Family: Apiaceae (Umbelliferae)

The Apiaceae family comprises approximately 3,700 species of aromatic plants with hollow stems and compound umbels of small flowers. It includes economically important vegetables and spices such as celery, carrot, parsley, and fennel. Members of this family are characteristically rich in essential oils, flavonoids, and coumarins.

Taxonomic Note: The species was first described by Jacques Labillardière in 1804. It has a complex taxonomic history, having been formerly known as Apium australe in some classifications. Two principal varieties are recognized:

· Apium prostratum var. prostratum (mangrove sea celery): Upright habit with fine linear leaves, leaf segments 6-15 times longer than wide, growing in swamps and salt marshes

· Apium prostratum var. filiforme (headland sea celery): Prostrate habit with broader leaves, leaf segments 2-3 times longer than wide, growing on coastal dunes and headlands

Related Herbs from the Same Family:

· Apium graveolens (Celery): The cultivated relative, valued for its stalks, seeds, and medicinal properties as a diuretic, anti-inflammatory, and mild sedative.

· Petroselinum crispum (Parsley): A culinary and medicinal herb renowned for its diuretic, antioxidant, and nutrient-dense properties.

· Foeniculum vulgare (Fennel): A classic carminative and digestive aid with estrogenic properties.

· Coriandrum sativum (Coriander): A digestive stimulant, carminative, and antioxidant-rich culinary herb.

---

2. Common Names

Scientific Name: Apium prostratum Labill. ex Vent. | English: Sea Celery, Prostrate Marshwort, Coastal Celery | Maori (New Zealand): Tutae Koau | Spanish (Chile): Apio Silvestre, Apio de Mar | Australian Indigenous: Various regional names, though less documented | French: Céleri de mer |

---

3. Medicinal Uses

Primary Actions: Antiscorbutic (prevents scurvy), Antioxidant, Antidiabetic (α-glucosidase, α-amylase inhibition), Anti-obesity (pancreatic lipase inhibition), Anti-inflammatory.

Secondary Actions: Diuretic, Digestive tonic, Mild sedative, Antimicrobial.

Medicinal Parts:

The whole plant is used, though leaves and stems are the primary parts for both culinary and medicinal applications.

· Leaves and Stems: The most commonly used parts, rich in phenolic compounds, flavonoids, and vitamin C. Consumed fresh, dried, or as an infusion.

· Roots: Edible raw, boiled, or roasted in ashes; used traditionally in Chile to flavor mate and as a refreshing beverage base.

· Seeds: Used as a flavoring agent in soups and culinary preparations.

---

4. Phytochemicals Specific to the Plant and Their Action

Phenolic Compounds (Quantified via HPLC-LC-HRMS): Seven phenolic compounds have been identified and quantified, representing a significant bioactive matrix.

· Apiin (Apigenin-7-O-apiosylglucoside): The dominant compound, constituting 48.2% of the phenolic profile. It is a flavone glycoside with documented Antioxidant, Anti-inflammatory, and Anxiolytic properties.

· Apigenin: A flavone aglycone comprising 24.8% of the phenolic content. It exhibits potent Antioxidant, Anti-inflammatory, and Anticancer activities, with documented effects on reducing oxidative stress and modulating immune function.

· Caffeic Acid: A hydroxycinnamic acid constituting 6% of the phenolic profile. It is a powerful Antioxidant with Anti-inflammatory and Immunomodulatory effects.

· Ferulic Acid: Another hydroxycinnamic acid at 2% concentration, known for its Antioxidant, Anti-inflammatory, and Neuroprotective properties.

· ρ-Coumaric Acid, Luteolin, Catechin: Present at trace levels (<1%). Notably, catechin was identified for the first time in the Apium genus, expanding the known phytochemical diversity of this species.

Nutrients:

· Vitamin C (Ascorbic Acid): Historically significant as an antiscorbutic agent, this vitamin is a powerful antioxidant essential for collagen synthesis and immune function.

· Minerals: As a coastal halophyte, sea celery accumulates minerals including potassium, sodium, magnesium, and calcium.

· Essential Oils: The characteristic celery-like aroma comes from volatile oils including limonene and other terpenes, contributing to its digestive and mild sedative properties.

---

5. Traditional and Ethnobotanical Uses Covering the Medicinal Uses

Antiscorbutic (Scurvy Prevention) & Nutritional Support

Formulation: Fresh leaves and stems consumed raw or cooked.

Preparation & Use: Sea celery was a critical food source for early explorers and colonists in Australia and New Zealand. Captain Cook collected the plant in bulk at Botany Bay and Poverty Bay in 1769 specifically to protect his crew from scurvy. It was commonly eaten by colonists as a survival food in the early days of the Sydney colony and cultivated as a vegetable around Albany, Western Australia.

Reasoning: The plant is naturally rich in vitamin C, a nutrient essential for preventing scurvy. The identification of significant phenolic compounds with antioxidant activity further supports its role as a nutritional tonic.

Digestive Aid & Culinary Herb

Formulation: Fresh leaves in salads, dried leaves in spice mixes, stems blanched like celery.

Preparation & Use: Both leaves and stems are eaten fresh or cooked. The leaves have a salty, celery-like flavor and are used to flavor soups, as a garnish similar to parsley, or dried in native Australian spice mixes. The var. filiforme is considered more palatable. Stems can be blanched and used like celery, though they are somewhat fibrous. Seeds are used as a flavoring.

Reasoning: The aromatic essential oils provide mild carminative and digestive-stimulating properties. The salty flavor also makes it a valuable seasoning.

Refreshing Beverage & Traditional Drink

Formulation: Root infusion or decoction.

Preparation & Use: In Chilean traditional medicine, the roots are used to prepare a refreshing beverage. Leaves and roots are also used to flavor mate, the traditional herbal infusion.

Reasoning: The plant's mild diuretic and mineral-rich properties make it a suitable base for refreshing drinks, particularly in coastal regions.

Topical & Dermatological Considerations

Formulation: Contact with fresh sap.

Preparation & Use: The plant is primarily used internally or as a flavoring, though caution is noted regarding external contact.

Reasoning: The sap has been reported to cause photosensitivity and dermatitis in some individuals, likely due to the presence of furanocoumarins, compounds common in the Apiaceae family.

---

6. Healing Recipes, Decoctions, and Preparations

Antioxidant Sea Celery Infusion

Purpose: A gentle, antioxidant-rich beverage for daily wellness.

Preparation & Use:

1. Take 1-2 teaspoons of dried sea celery leaves or 3-4 fresh leaves.

2. Pour 250 ml of boiling water over the leaves.

3. Steep for 10-15 minutes.

4. Strain and drink warm. May be enjoyed 1-2 times daily.

Digestive Fresh Salad

Purpose: A nutrient-dense, carminative addition to meals.

Preparation & Use:

1. Harvest tender young leaves and stems of sea celery (var. filiforme preferred).

2. Wash thoroughly.

3. Add fresh to salads, combine with other greens, lemon juice, and olive oil.

4. The salty, celery-like flavor requires minimal additional seasoning.

Culinary Seasoning (Dried Sea Celery)

Purpose: A flavorful, antioxidant-rich seasoning for soups and dishes.

Preparation & Use:

1. Harvest fresh leaves and stems, rinse, and pat dry.

2. Dry in a dehydrator or in a cool, airy space away from direct sunlight.

3. Crumble or grind into a coarse powder.

4. Use as a celery-salt alternative in soups, stews, and savory dishes.

Root Infusion (Refreshing Beverage)

Purpose: A mild, mineral-rich beverage.

Preparation & Use:

1. Clean fresh roots thoroughly.

2. Simmer 1-2 teaspoons of chopped fresh root in 250 ml water for 10 minutes.

3. Strain, cool, and serve chilled or at room temperature.

---

7. In-Depth Phytochemical Profile and Clinical Significance of Apium prostratum (Sea Celery)

Introduction

Apium prostratum, the coastal celery of the Southern Hemisphere, represents a compelling convergence of historical nutrition and modern pharmacological science. For centuries, this unassuming halophyte served as a vital antiscorbutic for explorers navigating the vast Pacific, a testament to its vitamin C content. Yet only recently has the full depth of its phytochemical richness been illuminated. A landmark 2019 study by Norchai and colleagues at the University of New South Wales has transformed our understanding of sea celery from a simple wild food to a complex functional food with validated bioactivities. The identification of seven phenolic compounds, the discovery of catechin in the Apium genus for the first time, and the quantification of its potent enzyme-inhibitory activities position A. prostratum alongside the most promising of Australia's native edible plants. Its profile of apiin and apigenin, combined with its ability to inhibit key metabolic enzymes, suggests significant potential in managing the global burdens of diabetes, obesity, and inflammatory conditions.

1. Phenolic Compounds: The Signature Bioactive Profile

Key Compounds: Apiin (48.2%), Apigenin (24.8%), Caffeic acid (6%), Ferulic acid (2%), ρ-Coumaric acid (trace), Luteolin (trace), Catechin (trace, first report in genus).

Quantitative Profile: Total phenolic content is notably high, with purification concentrating these compounds 1.43-2.67 times compared to crude extracts. Sea celery exhibited the highest total phenolic content among the three Australian native plants studied (compared to samphire and saltbush).

Actions and Clinical Relevance:

· Antioxidant (Potent and Clinically Relevant): Sea celery demonstrated the largest ABTS and DPPH free-radical scavenging capacities among the three plants evaluated. The ABTS and DPPH assays are standard measures of antioxidant capacity, and the plant's superior performance indicates a robust ability to neutralize harmful free radicals. This antioxidant protection is fundamental to preventing cellular damage implicated in aging, cardiovascular disease, neurodegeneration, and cancer. The dominant compounds apiin and apigenin are well-documented antioxidants, with apigenin particularly noted for its ability to reduce oxidative stress.

· Enzyme Inhibition (Antidiabetic and Anti-obesity Mechanisms): The most striking finding of the 2019 research was the potent inhibitory activity of sea celery extract against key metabolic enzymes:

· α-Glucosidase and α-Amylase Inhibition: These enzymes are responsible for breaking down complex carbohydrates into simple sugars for absorption. Inhibiting them slows carbohydrate digestion, reducing postprandial (after-meal) blood glucose spikes. This is a primary therapeutic strategy for managing type 2 diabetes. Sea celery was the most potent inhibitor of both α-glucosidase and α-amylase among the three plants tested, suggesting significant potential as a dietary aid for blood sugar management.

· Pancreatic Lipase Inhibition: This enzyme breaks down dietary fats into absorbable fatty acids. Its inhibition reduces fat absorption, a strategy employed in obesity management. Sea celery again exhibited the strongest pancreatic lipase inhibition among the studied plants, indicating potential as a supportive agent for weight management.

· Hyaluronidase Inhibition: This enzyme breaks down hyaluronic acid, a key component of the extracellular matrix. Excessive hyaluronidase activity is associated with inflammation, venom spread, and certain cancers. While samphire showed the highest hyaluronidase inhibition, sea celery's moderate activity contributes to its overall anti-inflammatory potential.

2. The Significance of Apiin and Apigenin

Key Compounds: Apiin (apigenin-7-O-apiosylglucoside) and its aglycone, apigenin.

Actions and Clinical Relevance:

· Anti-inflammatory: Both apiin and apigenin inhibit pro-inflammatory mediators including COX-2 and various cytokines. Apigenin, in particular, has been extensively studied for its ability to modulate inflammatory pathways, providing a molecular basis for the traditional use of Apium species in inflammatory conditions.

· Neuroprotective and Anxiolytic: Apigenin has documented neuroprotective properties and binds to GABA receptors, contributing to mild anxiolytic (anti-anxiety) effects. This aligns with the traditional use of celery relatives as mild sedatives.

· Anticancer Potential: Apigenin is one of the most studied flavonoids for its anticancer properties, with research demonstrating its ability to induce apoptosis (programmed cell death) and inhibit proliferation in various cancer cell lines. While the concentration in sea celery is significant (24.8% of phenolic content), dietary consumption rather than therapeutic extraction is the relevant context.

3. Catechin: A Novel Discovery in the Apium Genus

Key Compound: Catechin (identified for the first time in the Apium genus).

Actions and Clinical Relevance:

· Significance of Discovery: The identification of catechin in A. prostratum expands the known phytochemical diversity of the genus. Catechin is a well-researched flavan-3-ol, best known as a major component of green tea. It possesses potent antioxidant, anti-inflammatory, and cardioprotective properties.

· Potential Implications: The presence of catechin, even at trace levels, adds another dimension to sea celery's bioactivity, particularly in cardiovascular health, where catechins are associated with improved endothelial function and reduced LDL oxidation.

4. Nutrient and Mineral Profile

Key Nutrients: Vitamin C, potassium, sodium, magnesium.

Actions and Clinical Relevance:

· Antiscorbutic (Historical and Ongoing): The vitamin C content, while variable, was sufficient to prevent scurvy in historical contexts. This remains relevant for individuals with limited access to fresh produce.

· Electrolyte Balance: As a coastal halophyte, sea celery naturally accumulates electrolytes. This makes it a valuable dietary addition for individuals requiring electrolyte replenishment, such as athletes or those in hot climates.

5. Varietal Differences and Palatability

Observations: The var. filiforme (headland sea celery) is widely considered more palatable than var. prostratum (mangrove sea celery).

Implications: Varietal differences may extend beyond palatability to phytochemical composition and bioactivity. Further research comparing the two varieties could reveal distinct applications for each.

An Integrated View of Healing in Apium prostratum

· For Metabolic Health (Diabetes and Obesity): Sea celery offers a dual-mechanism approach to metabolic disorders. Its potent α-glucosidase and α-amylase inhibition slows carbohydrate digestion, moderating postprandial glucose spikes a key factor in managing type 2 diabetes. Simultaneously, its pancreatic lipase inhibition reduces dietary fat absorption, supporting weight management efforts. This combination of activities positions sea celery as a valuable functional food for individuals at risk of or managing metabolic syndrome.

· For Antioxidant Protection and Chronic Disease Prevention: The superior free-radical scavenging capacity, driven by its rich phenolic profile (particularly apiin, apigenin, caffeic acid, and ferulic acid), provides systemic antioxidant protection. This helps prevent the oxidative damage that underlies cardiovascular disease, neurodegeneration, and certain cancers. Regular consumption as a culinary herb or infusion offers a practical means of enhancing dietary antioxidant intake.

· As a Nutritional and Culinary Herb: Sea celery serves as a nutrient-dense, low-calorie flavoring agent. Its naturally salty, celery-like flavor reduces the need for added salt in dishes, while its fiber and phenolic content contribute to overall health. Its historical role as an antiscorbutic underscores its nutritional value, and its contemporary use in native spice mixes reflects its enduring culinary relevance.

· For Anti-inflammatory Support: The combined action of apigenin, apiin, caffeic acid, and other phenolic compounds provides anti-inflammatory support. By inhibiting COX-2 and other inflammatory mediators, sea celery may help manage low-grade chronic inflammation, a contributing factor to numerous age-related diseases.

Toxicological Profile and Safety Considerations

Apium prostratum is generally recognized as safe for culinary use based on its long history of consumption. However, specific considerations apply:

Photosensitivity and Dermatitis: The sap of sea celery, like that of many Apiaceae members, contains furanocoumarins that can cause photosensitivity and contact dermatitis in susceptible individuals. Handling the plant, particularly in large quantities and under direct sunlight, may trigger skin reactions. This is noted in traditional references and contemporary databases.

Pregnancy and Breastfeeding: While culinary use is likely safe, therapeutic quantities or concentrated extracts should be avoided during pregnancy and breastfeeding due to the presence of bioactive compounds and lack of safety data.

Wild Harvesting: As a coastal plant, sea celery may accumulate pollutants from its environment. Only harvest from clean, unpolluted sites away from industrial areas, roads, and contaminated waterways. Proper identification is essential to avoid confusion with toxic Apiaceae look-alikes.

Conclusion: Apium prostratum, the sea celery of the Southern Hemisphere, is a plant whose time has come. Long valued for its culinary versatility and historic role as an antiscorbutic, it has now been revealed as a functional food of considerable scientific interest. The identification of its rich phenolic profile, dominated by apiin and apigenin, and the demonstration of its potent antioxidant and enzyme-inhibitory activities validate its traditional uses and open new avenues for application. Its ability to inhibit α-glucosidase, α-amylase, and pancreatic lipase positions it as a valuable dietary adjunct for managing diabetes and obesity. Its superior antioxidant capacity makes it a meaningful contributor to chronic disease prevention. The discovery of catechin in the Apium genus for the first time expands its phytochemical significance. As interest in native Australian foods grows, sea celery stands out as a species that bridges culinary heritage with evidence-based nutritional science, offering both flavor and functional benefit in a single, unassuming coastal herb.

---

Disclaimer:

Apium prostratum is safe for culinary use. However, the sap may cause photosensitivity and dermatitis in some individuals; handle with care, especially in direct sunlight. Pregnant and breastfeeding women should consume only in culinary amounts. When wild-harvesting, ensure accurate identification to avoid confusion with toxic Apiaceae species. Harvest only from clean, unpolluted environments. This information is for educational purposes only and is not a substitute for professional medical advice.

---

8. Reference Books, Books for In-depth Study:

· Wild Food Plants of Australia by Tim Low

· Edible Wild Plants: An Alternative Approach to Food Security by various authors

· Flora of Australia (relevant volumes on Apiaceae)

· Native Australian Plants: Their Nutritional and Medicinal Potential (research compilations)

· Plants For A Future Database (PFAF.org)

---

9. Further Study: Plants That Might Interest You Due to Similar Medicinal Properties

1. Apium graveolens (Celery)

· Species: Apium graveolens | Family: Apiaceae

· Similarities: The cultivated cousin of sea celery, sharing similar aromatic properties, culinary applications, and a rich flavonoid profile. Celery seeds and extracts are used for their diuretic, anti-inflammatory, and mild sedative properties, while celery stalks are valued as a low-calorie, nutrient-dense vegetable.

2. Petroselinum crispum (Parsley)

· Species: Petroselinum crispum | Family: Apiaceae

· Similarities: Another Apiaceae member with significant antioxidant, anti-inflammatory, and diuretic properties. Parsley is exceptionally rich in apigenin, the same flavone that dominates sea celery's phenolic profile. Both plants share a history of use as nutritional tonics and culinary herbs.

3. Sarcocornia quinqueflora (Samphire)

· Species: Sarcocornia quinqueflora | Family: Amaranthaceae

· Similarities: A fellow Australian native coastal plant evaluated alongside sea celery in the 2019 study. Samphire exhibited the highest FRAP antioxidant activity and hyaluronidase inhibition among the three plants studied. It shares sea celery's halophytic nature and culinary applications as a salty, succulent green.

4. Atriplex nummularia (Old Man Saltbush)

· Species: Atriplex nummularia | Family: Amaranthaceae

· Similarities: The third plant evaluated in the 2019 comparative study. Saltbush is a well-known Australian native edible plant with a salty flavor, used as a seasoning and leafy green. It demonstrates lower but still significant phenolic content and antioxidant activity, representing another valuable native functional food.

---

-x-x-x-End-x-x-x-