Samphire

Other Names

BacileBeach asparagusCachrys maritimaCasse-pierreChicken toeCrest marineCriste marineCrithme maritimeCrithmum canarienseCrithmum maritimumCrithmum maritimum L.Crow's foot greensDail St. PedrFenouil marinGlasswortGolden samphireHerbe de Saint PierreInula crithmoidesKrethmonKrithmoKrithmonKritmoLimbarda crithmoidesMarsh samphireMeerfenchelPasse-pierrePerce-pierrePeter's cressPeter's herbPicklegrassPickleweedPicklewortRock samphireSalicorneSalicornia europaeaSalicornia herbaceaSaltwortSamphire greensSampiereSampkinSaxifrage marinSea asparagusSea beansSea fennelSea pickleSea samphireShamar bahariyaSt. Peter's herbTecticornia

Synopsis

Samphire (Crithmum maritimum L.): A Comprehensive Encyclopedic Reference

1. Identity, Taxonomy, and Botanical Description

Crithmum is a monospecific genus of flowering plant in the carrot family, Apiaceae. The sole species, Crithmum maritimum, is commonly known as rock samphire, sea fennel, or simply samphire. It is a spontaneous aromatic plant and the sole species of the genus Crithmum.

It is a perennial plant growing to 50 centimetres in both height and width. The stems are woody at the base, fleshy elsewhere, and hairless. The leaves are fleshy lobes. The greenish-yellow flowers are borne in umbels. The fruits (seed pods) are yellow or purple and up to 5–6 millimetres.

The plant is one of the widely distributed and studied culinary halophytes. It is found on coastlines throughout much of Europe (north to the British Isles), Macaronesia, parts of West Asia and North Africa in the Atlantic, Mediterranean, and Black Sea coasts. Rock samphire naturally thrives on rocky crevices as a chasmophyte (rock-dweller) and in sandy substrates as a halophyte.

Common synonyms and names by region include:

Crithmum maritimum L. (accepted scientific name)
Rock samphire, sea fennel, sea samphire (English)
The name "samphire" is sometimes applied loosely to other unrelated halophytes, most notably marsh samphire (Salicornia europaea). The major types of samphire include the marsh samphire (Salicornia europaea) and the rock samphire (Crithmum maritimum), with marsh samphire more common in modern culinary use. Marsh samphire was historically used in glassmaking because of its high sodium carbonate content. These two plants are botanically unrelated; the present article concerns Crithmum maritimum exclusively.

2. Common Forms and Preparations

Sea fennel is a facultative halophyte used in salads, soups, and sauces, as well as to prepare medicinal juices and aqueous extracts to treat several ailments. Its essential oil is used as a spice and aromatizing agent.

The plant is encountered in several distinct forms in culinary, medicinal, and cosmetic contexts:

Fresh whole plant: The fleshy leaves of rock samphire are used as a condiment and pickle, or as a salad ingredient.
Pickled/preserved form: Rock samphire was usually cooked in vinegar and made into a pickle, a preparation found in historical recipes from the 1690s to the 1840s.
Essential oil (EO): Obtained by hydrodistillation of the aerial parts; the essential oil of sea fennel is widely used in the food and cosmetic industry.
Aqueous extracts (infusions and decoctions): Water-based preparations are used medicinally and have been analyzed for their polyphenol content and antimicrobial properties.
Hydroethanolic/ethanolic extracts: Used in scientific research and in cosmetic formulations for their rich phenolic content.
Cosmetic preparations including stem-cell biomass: The extract of Crithmum maritimum is widely used in cosmetics. More recently, dedifferentiated plant stem cell fractions have also been incorporated into topical formulations.

3. Traditional and Historical Use

3.1 Ancient Mediterranean World

The halophytic species Crithmum maritimum L. has been used in traditional medicine since antiquity, largely due to its diverse and bioactive phytochemical composition. Although samphire's curative properties were recognized, it was more important as a foodstuff than a medicament. Dioscorides mentions that it was eaten both raw and cooked, and was also preserved in brine; Pliny says it was sometimes boiled with cabbage.

3.2 Medieval European Herbalism

The fifteenth-century herbal Der Gart der Gesundheit classes samphire as warm and dry in the second degree, and recommends it as a diuretic useful in treating dropsy, an old term for edema.

3.3 Seventeenth-Century England

Historically, rock samphire was foraged by coastal communities across Europe and North Africa, where it was valued both as a food source and for its medicinal qualities. In 17th-century England, the plant's popularity inspired a risky cliff foraging industry, where samphire was harvested from steep sea cliffs, making it a rare delicacy. In the 17th century, Shakespeare in King Lear referred to the dangerous practice of collecting rock samphire from cliffs.

3.4 Traditional Medicinal Uses Across Cultures

Traditionally, various parts of this plant have been used as a tonic, antiscorbutic, carminative, vermifuge, and diuretic. The young growing tips are carminative, depurative, digestive, and diuretic. Due to its high vitamin C and mineral content, rock samphire was historically used to prevent scurvy.

Ethnobotanical records document the following traditional applications:

Digestive complaints: Traditionally it was regarded as a good diuretic and was often prescribed as a treatment for obesity. It is considered excellent for curing flatulence and as a digestive remedy.
Urinary tract: A decoction of aerial parts harvested before fructification has been used against inflammations of the urinary tract and prostate.
Kidney stones: It was also used as a treatment for kidney stones.
Antiscorbutic: Sailors historically consumed it for prevention of scurvy, consistent with its documented vitamin C content.
Mediterranean diet: Traditionally, it has been included in the Mediterranean diet, as reported by ethnobotanical studies.

4. Key Constituents and Active Compounds

4.1 Overall Phytochemical Profile

The plant's complex chemical composition includes terpenoids, phenolic acids, flavonoids, tannins, dietary fibers, fatty acids, and essential vitamins. Its leaves are abundant in several bioactive materials, including vitamins like vitamin C, bioflavonoids, and carotenoids, which have been reported for several therapeutic uses.

Samphire is rich in such minerals as sodium, calcium, potassium, and iodine, as well as vitamin C, carotenoids, flavonoids, and such amino acids as glycine and leucine. The aerial parts contained high levels of potassium, calcium, manganese, and iron.

Quantitative analyses have established the nutritional composition in some detail. Plants under field conditions exhibited a nutritionally balanced composition (3.8–6.2 g protein/100 g DW, 4.9–7.5 mg lipids/g WW, 3.9–5.0 g Na/100 g DW), with high phenolic content (30.2–48.0 mg/g DW) regardless of the variability of contrasting habitats. Sea fennel exhibits considerable fiber (34.3 ± 1.92%) and mineral content (23.6 ± 4.8%).

4.2 Phenolic Acids and Flavonoids (Non-Volatile Fraction)

Many studies have revealed a high content of phenolic acids, namely chlorogenic ones, in C. maritimum extracts. Chlorogenic acids have a number of biological activities, including antioxidant, antimicrobial, anti-inflammatory, and anti-carcinogenic effects.

Aqueous extracts contain chlorogenic acid as the major phenolic compound: 49.7 ± 0.8 mg/g in the infusion dry extract and 26.8 ± 0.9 mg/g in the decoction dry extract. Analysis of hydromethanolic extracts of C. maritimum leaves identified 16 compounds in total, including eight phenolic acids, four flavonoids, and four flavanols, while the major compound was chlorogenic acid and its derivatives (neochlorogenic and cryptochlorogenic acid), followed by ferulic acid, kaempferol, and quercetin.

Chlorogenic acid was the most prevalent polyphenol (9.35 mg/g) in C. maritimum leaves. Kaempferol 3-glycoside (1.81 mg/g), naringin (1.24 mg/g), and hesperidin (0.79 mg/g) were also quantified. Total carotenoids (0.32 μg/g) and total chlorophylls (0.62 μg/g) were also measured.

The analyzed organs exhibited different content of total polyphenol (17.11 ± 0.77 to 9.42 ± 0.24 mg GAE g⁻¹ DW), flavonoids (7.06 ± 0.18 to 3.71 ± 0.1 mg EC g⁻¹ DW), and tannins (5.24 ± to 1.06 ± 0.77 mg CE g⁻¹ DW).

4.3 Essential Oil Composition (Volatile Fraction)

The major reported volatile oil constituents have been identified as γ-terpinene, thymyl methyl ether, dillapiole, α- and β-pinene, cymene, limonene, sabinene, thymyl methyl oxide, and β-phellandrene.

The composition of the essential oil is highly variable depending on geographical origin, season, and plant part. The volatile profile of essential oils was evaluated using GC–MS, and 38 compounds were identified. All analyzed samples show a composition characterized essentially by monoterpene hydrocarbons (94.0–97.6%), with limonene, γ-terpinene, β-phellandrene, α-pinene, and p-cymene as the principal compounds.

Specific chemotypic variation has been documented. The main compounds of the EO from Greek cultivated populations (2016) were sabinene (17.6%), γ-terpinene (17.5%), p-cymene (16.7%), β-phellandrene (15.5%), thymol methyl ether (9.3%), terpinen-4-ol (4.8%), and dillapiole (2.0%). In Bulgarian specimens, the phenylpropanoid dillapiole was identified as the major compound in the EO, accounting for 34.09% of the total.

The essential oil contains high amounts of monoterpene hydrocarbons, namely γ-terpinene and sabinene.

4.4 Key Individual Bioactive Compounds and Mechanisms

Chlorogenic acid is consistently the dominant polyphenol in aqueous extracts. According to Ailén et al., the high chlorogenic acids content of both sea fennel extracts—aqueous and ethanolic—determines its anti-inflammatory activity, being a result of a reduced release of TNF-α and increased IL-10 secretion in macrophages.

Dillapiole is a phenylpropanoid present at variable levels. Dillapiol possesses protective effects against ethanol-induced gastric ulcer in animals. However, dillapiole is also a compound of safety concern (see Safety section below). It is identified as a toxic constituent, and its concentration is a key consideration for the dietary safety of the plant.

Limonene is frequently one of the dominant monoterpenes in many geographical chemotypes. Studies concerning the anticancer activity of D-limonene are particularly relevant, and the studies conducted have demonstrated the existence of therapeutic effect in various types of cancer, for instance, lung cancer, breast cancer, gastric cancer, and lymphoma. These effects have been studied in other species and are extrapolated to C. maritimum due to its limonene content; direct clinical evidence from samphire itself is lacking.

β-Pinene contributes to the antibacterial profile. Most studies on this bioactive compound report antibacterial activity, mainly against Gram-positive bacteria such as S. aureus, S. pyogenes, S. pneumoniae, and S. epidermidis. These effects are primarily attributed to its ability to inhibit the synthesis of bacterial biofilms.

5. Scientific Evidence by Area of Use

5.1 Overview of the Evidence Base

It is critical to understand the overall state of evidence before reviewing individual findings. The number of studies investigating C. maritimum L. are limited — in total 24 studies on its biological activity were identified (10 in vitro studies on the essential oil, 14 in vitro studies on C. maritimum extracts, 1 in vivo study involving animals, and 1 study involving humans). Substantial gaps remain in understanding its mechanisms of action, pharmacodynamics, and bioavailability. To date, most studies have been limited to in vitro assays, with a scarcity of in vivo and clinical investigations.

5.2 Antioxidant Activity

Evidence level: In vitro; preliminary.

The traditionally edible aerial parts of rock samphire could be a valuable functional food or feed ingredient due to their high antioxidant capacity, ascorbic acid content, and rich content in secondary metabolites such as phenolics and flavonoids.

Several studies have reported the significant antiradical activities of extracts obtained from C. maritimum plant parts and essential or seed oils, highlighting the presence of a broad spectrum of functional compounds. Antioxidant activity has been reported in hydromethanolic and hydroethanolic extracts using DPPH, ABTS, ORAC, and FRAP assays. The antiradical effects were associated with the high content of chlorogenic acid.

Quantitative antioxidant values from one published study: IC₅₀ values for the infusion and decoction were, respectively: 36.5 ± 1.4 μg/mL and 44.7 ± 4.4 μg/mL in the DPPH assay; 37.3 ± 2.6 μg/mL and 38.4 ± 1.8 μg/mL in the ABTS assay.

Essential oils have low antioxidant activity as compared to acetone extracts; nevertheless, they show best antimicrobial activity. In one early comparative study, the antioxidant activity of the oils was evaluated by two lipid model systems: a modified TBARS assay and a spectrophotometric detection of hydroperoxydienes from linoleic acid in a micellar system. The oils demonstrated antioxidant capacities, comparable in some cases to that of alpha-tocopherol and butylated hydroxytoluene (BHT), used as reference antioxidants.

Published results show great variation due to differences in implemented assays and extraction protocols, as well as in the studied material due to variable genotypic background, environmental conditions, and agronomic conditions. No human clinical trials have evaluated samphire as an antioxidant supplement.

5.3 Antimicrobial Activity

Evidence level: In vitro; preliminary.

Sea fennel's essential oil has a few reports about its antibacterial activity, attributed to the high content of monoterpenic hydrocarbons. Sanchèz-Hernandèz et al. (2021) reported the antibacterial activity against E. coli and S. aureus of EO (100 μL/mL) from sea fennel. The EO rich in γ-terpinene, thymol methyl ether, and dillapiole showed an inhibition halo of 13 mm in S. aureus and no inhibition of E. coli.

Aqueous extracts also show antimicrobial potential. The content of chlorogenic acids determines the antimicrobial activity of the plant against a wide variety of bacteria, including S. aureus, S. pneumoniae, B. subtilis, B. cereus, E. coli, E. faecalis, and S. typhimurium. C. maritimum extract showed a significant content of rutin and quercetin derivatives, which proved to be efficient inhibitors of the growth of E. coli, S. aureus, E. faecalis, and P. (Pseudomonas species). Regarding food-pathogen applications, the essential oil is particularly active against Bacillus cereus and Lactobacillus plantarum.

All antimicrobial findings originate from in vitro experiments. No clinical trials exist testing samphire or its constituents as antimicrobial agents in humans.

5.4 Anti-inflammatory Activity

Evidence level: In vitro and animal; preliminary.

According to Ailén et al., the high chlorogenic acids content of both sea fennel extracts — aqueous and ethanolic — determines its anti-inflammatory activity, being a result of a reduced release of TNF-α and increased IL-10 secretion in macrophages. This mechanism was demonstrated in cell culture models.

One animal study found hepatoprotective effects consistent with anti-inflammatory actions. The study suggested that supplementation with C. maritimum L. to intoxicated rats restored the impaired hepatic markers and reduced induced oxidative stress, GSH, and protein carbonyl levels. The plant was associated with significant hepatoprotection.

No randomized controlled trials or human clinical trials examining anti-inflammatory outcomes from samphire supplementation or administration have been published.

5.5 Anticancer Activity

Evidence level: In vitro and cell-line research only; no human evidence.

Previous studies showed that the wild edible plant Crithmum maritimum L. inhibits the growth of liver cancer cells and promotes liver cell differentiation by reducing lactic acid fermentation (Warburg effect). Researchers aimed to further characterise the effects of C. maritimum on lipid metabolism and markers of cellular metabolic health, such as AMP-activated protein kinase (AMPK), Sirtuin 1 (SIRT1), and Sirtuin 3 (SIRT3), as well as the insulin signalling pathway.

A 2025 systematic literature review identified preclinical activity against gastrointestinal cancers. C. maritimum exhibits preclinical efficacy against GIT cancers via modulation of p53, NRF2, and Wnt/β-catenin pathways. Studies identified chlorogenic acid (30–50% of total polyphenol), gallic acid (15–20% of terpene), limonene, sabinene, α-pinene, γ-terpinene, fatty acids, and vitamin C as key anticancer agents. Standardization, mechanistic validation, and clinical trials are required to advance its therapeutic integration.

All anticancer evidence is preclinical (in vitro or cell-line-based). The absence of human clinical data means that no conclusions about anticancer efficacy in humans can be drawn from current evidence.

5.6 Skin Health and Dermatological Applications

Evidence level: In vitro, ex vivo skin model, one small human pilot study; limited but notable.

This is the area where the most applied human-relevant research has been conducted. Two published investigations are of particular note:

In vitro / skin equivalent model (Caucanas et al.): The aim was to test the influence of dedifferentiated Crithmum maritimum cells (dCMC), totipotent vegetal stem cells, on epidermal regeneration using a skin equivalent (SE) model. Skin equivalents are prepared by seeding fibroblasts on a collagen-glycosaminoglycan-chitosan dermal substrate epidermalized by keratinocytes 3 weeks later. dCMC was administered systemically from the moment when fibroblasts are seeded in the substrate through to the reconstruction of the skin equivalent. The thickness of the epidermis as well as the number of proliferating cells expressing Ki-67 and layers expressing terminal differentiation marker (filaggrin) were compared. dCMC accelerated the complete regeneration and differentiation of the epidermis compared to the negative control (35 days instead of 42 days).

Human pilot study (barrier repair): To assess the recovery rate of the epidermal permeability barrier function following controlled stripping and applications of samphire formulations, 12 healthy subjects older than 50 years were enrolled. Controlled stratum corneum strippings were used to increase transepidermal water loss (TEWL) just above 15 g/m²/h. This procedure followed a 14-day skin preconditioning by daily applications of formulations enriched or not with a samphire (Crithmum maritimum) biomass. An untreated skin site served as control. The epidermal permeability repair kinetics was assessed for 14 days by daily measurements of both TEWL and colorimetric value a*. A rapid (96 h) recovery to lower TEWL values was obtained at each of the samphire-preconditioned sites (0.1% serum, 0.05% cream, the serum-cream association, and 0.5% silicone oil). This small study (n=12, uncontrolled by randomization) represents the only published human evidence. It suggests accelerated epidermal barrier repair but must be interpreted with caution given its small sample size and lack of robust comparators.

Tyrosinase inhibition (anti-hyperpigmentation): A previous study evaluated the anti-tyrosinase activity of essential oils of Crithmum maritimum from France and Croatia. It reported the inactivity of the French sample while the Croatian sample showed an IC₅₀ = 649 µg/mL. Libyan species activity was 12.449 ± 0.68, indicating that geographical variability plays an essential role in oil composition and its activity. These are in vitro enzyme inhibition assays; no clinical evidence supports claims of skin-brightening in humans from samphire use.

UV-damage and epidermal regeneration (in vitro): Through the study of a barrier-weakening 3D full-skin model, it was found that the full-component extract of Crithmum maritimum, rich in chlorogenic acid, could significantly promote the epidermal regeneration of UV-induced skin damage compared to the oil-based extract components.

5.7 Acetylcholinesterase Inhibition and Cognitive Effects

Evidence level: In vitro only; very preliminary.

One study investigated the potential of Crithmum maritimum essential oils as inhibitors for two important therapeutic targets: the tyrosinase and acetylcholinesterase. It was previously reported that EOs from different Croatian sea fennel were highly efficient against cholinesterase enzymes. Acetylcholinesterase inhibition is a known pharmacological strategy in Alzheimer's disease. However, these findings are from in vitro enzymatic assays only; recent evidence suggests additional biofunctional roles such as cognitive enhancement, but no human clinical trials have been conducted to substantiate cognitive effects of samphire.

5.8 Vasodilatory Effects

Evidence level: Preliminary; single reported observation.

The sea fennel flower extract demonstrated a positive vasodilatory effect. The scientific literature notes this as a preliminary finding. Extracts of the plant exhibit significant bioactivity, having shown antiparasitic, hypoglycemic, vasodilatory, and probiotic effects in preliminary studies. No clinical data are available to confirm vasodilatory or blood pressure-lowering effects in humans.

5.9 Hypoglycemic Effects

Evidence level: Preliminary; extrapolated from constituent data.

Hypoglycemic effects have been attributed to the plant primarily on the basis of its constituent profile. The effectiveness of dillapiole in diabetic nephropathy was also investigated. These are preliminary findings based on individual constituents, and no clinical trials of C. maritimum for blood glucose management have been published.

6. Body Systems and Health Areas of Association

Based on the available ethnobotanical and scientific literature, Crithmum maritimum is associated with the following body systems and health areas:

Integumentary system (skin): Epidermal barrier repair, UV-damage recovery, melanogenesis inhibition, wound healing in vitro, and cosmetic skin-brightening applications.
Digestive/gastrointestinal system: Traditionally used for flatulence, digestive complaints, and carminative effects; preclinical anticancer research in gastrointestinal cancers; and historically noted gastroprotective activity of dillapiole in animal models.
Urinary system: Traditional use as a diuretic and for inflammations of the urinary tract.
Cardiovascular system: Preliminary evidence of vasodilatory activity from flower extracts.
Hepatic system: Animal study evidence for hepatoprotection; in vitro evidence against hepatocellular carcinoma cell lines.
Immune/inflammatory system: Anti-inflammatory effects mediated by chlorogenic acid (in vitro, via TNF-α suppression and IL-10 elevation in macrophages).
Neurological system: In vitro acetylcholinesterase inhibition; associated with putative cognitive enhancement effects not yet studied in humans.
Metabolic/endocrine system: Preliminary hypoglycemic and lipid-homeostasis-modulating effects in preclinical contexts.
Antimicrobial/anti-infective: In vitro evidence against a broad spectrum of foodborne and pathogenic bacteria and fungi.

7. Dosage Forms and Dosages Reported in Studies

Very few standardized dosage regimens have been defined. The following dosages and concentrations were reported in specific studies:

Topical skin barrier study (human, n=12): Formulations tested at 0.1% serum, 0.05% cream, the serum-cream association, and 0.5% silicone oil containing samphire biomass, applied daily for 14 days prior to controlled stripping.
Antibacterial in vitro (essential oil): EO was tested at 100 μL/mL against food pathogens.
Anti-tyrosinase in vitro (essential oil): An IC₅₀ of 649 µg/mL was reported for the Croatian essential oil sample in a mushroom tyrosinase enzyme inhibition assay.
Antioxidant (aqueous extracts): IC₅₀ values of 36.5 ± 1.4 μg/mL (infusion) and 44.7 ± 4.4 μg/mL (decoction) were reported in the DPPH assay.
Phenolic content in extracts: Chlorogenic acid content of 49.7 ± 0.8 mg/g in the infusion dry extract and 26.8 ± 0.9 mg/g in the decoction dry extract.

No standardized oral dosing recommendations for C. maritimum as a dietary supplement have been established in the peer-reviewed literature. Dietary intake in the form of food (fresh leaves, pickled preparations) has not been quantified in clinical trials.

8. Safety Considerations and Notable Toxicological Findings

8.1 General Safety Profile

Despite this pharmacological potential, the number of experimental studies (particularly in vivo investigations) remains limited. In the context of dietary use as a food plant (fresh leaves, pickled preparations), no systematic toxicity data are available from controlled clinical trials.

8.2 Dillapiole: A Constituent of Toxicological Concern

The single most substantiated safety concern is the variable content of dillapiole (also spelled dillapiol) in the essential oil. In order to address food value to natural species, it appears necessary to consider the previous safety of the dietary intake of C. maritimum. A matrix plot analysis of the content of dillapiole, a toxic constituent, in the samples was performed.

Regarding dillapiole content, four accessions showed dillapiole values of less than 2%, suggesting the healthiness of sea fennel from those locations, while the highest values were found in samples from France, Portugal, and Tunisia. This finding highlights that dillapiole concentrations are geographically variable and that the origin of the plant material is a relevant safety consideration, particularly for concentrated essential oil preparations.

8.3 Essential Oil vs. Whole-Plant Use

The safety profile of the whole plant (used as food) is distinct from that of the concentrated essential oil. Concerns regarding dillapiole are most relevant to the concentrated EO and high-dose extract preparations. Traditional culinary use involves consumption of small amounts of the fresh plant, where dillapiole exposure is substantially lower.

8.4 High Sodium Content

As a halophyte, plants under field conditions contain 3.9–5.0 g Na/100 g DW. This high sodium content may be a relevant consideration for individuals managing sodium intake, though it is primarily a nutritional rather than toxicological concern under typical culinary use.

8.5 Lack of Drug Interaction Data

No peer-reviewed studies have evaluated the pharmacokinetic interactions between Crithmum maritimum preparations and pharmaceutical drugs. Given its reported vasodilatory and hypoglycemic effects in preliminary studies, caution in the context of antihypertensive or antidiabetic medication would be reasonable, though this has not been formally studied.

8.6 Status of Human Clinical Evidence

Only one study involving humans has been identified in the current literature — the skin barrier repair study described in Section 5.6. This underscores the profound gap in clinical safety data for internal use as a supplement.

References

Health Conditions

Health conditions that Samphire may help support.

No conditions available.

Body Systems

Body systems that Samphire may help support.

No body systems available.