Bells of ireland

Bells of Ireland (Moluccella laevis L.): A Comprehensive Reference

1. Identity and Botanical Classification

1.1 Botanical Name and Taxonomy

Moluccella laevis L., commonly known as Bells of Ireland, Bells-of-Ireland, Molucca balm, shellflower, or shell flower, is a summer-flowering annual native to Turkey, Syria, and the Caucasus. It belongs to the family Lamiaceae (the mint family), which includes many aromatic herbs such as basil, rosemary, oregano, mint, lavender, and sage. The genus Moluccella is sometimes placed in synonymy with Lamium in older literature, and consists of annual or short-lived perennial plants native to Central and Southwest Asia and the Mediterranean.

The genus, which has only eight species worldwide, is represented in Turkey by two species that grow in the Eastern Anatolia and Mediterranean regions. The full native range of M. laevis extends across Turkmenistan, Iran, Iraq, the Caucasus, Cyprus, Syria, Lebanon, Palestine, and Turkey; it has naturalized in scattered locations in Europe, Africa, and North America.

The species epithet laevis is revealing: the species name laevis means smooth, free from hairs or roughness, a reference to the glabrous texture of its leaves and stems. The genus name is spelled as Molucella or as Moluccella; both are equally used in the scientific literature.

1.2 Common Names and Naming History

The "Ireland" part of the common name is in probable reference to the green color of the calyces. Additional common names include lady-in-the-bathtub (for the flower sitting in the calyx), shellflower (for the shell-like calyx), and Molucca balm (referring to the Molucca Islands). In his Species Plantarum, published in 1753, botanist Carl Linnaeus named this plant Moluccella laevis, apparently believing that it originated in the Moluccas, or Maluku Islands, an archipelago in Indonesia that was also called the Spice Islands. This was an error: despite the common name, this plant in the mint family (Lamiaceae) is not from Ireland but is native to western Asia, around Turkey, Syria, and the Caucasus.

1.3 Morphology and Plant Parts Used

Moluccella laevis is a half-hardy annual that produces unusual pale green to emerald green, funnel-shaped "bells" along green stems in summer. The persistent bells are the showy calyx (cup-shaped sepals around the base of the flowers), which surrounds tiny, fragrant, white flowers. The papery ¾ to 1¼ inch bells are densely packed along most of the length of the square stems that reach 2 to 3 feet tall. Clusters of 2½ inch long leaves alternate between the bells, with pairs of small thorns or spines below each calyx.

The rounded leaves are pale green. Fast growing, Moluccella laevis will reach 1 metre (3.28 feet) and spread to 30 centimeters (11.8 inches) with an erect, branching habit. The plant parts studied for biological activity in the scientific literature include the aerial parts (stems, leaves, flowers, and calyces) collected as a whole, as well as separately analyzed flower volatiles and leaf volatiles.

1.4 Common Preparations and Forms

In a research context, extracts of M. laevis have been prepared using a variety of solvents and methods:

• Total ethanolic extract (TEE): Prepared from dried aerial parts; used in the majority of biological activity studies to date.
• Petroleum ether (Pet. ether) fraction: A non-polar fraction used to isolate fatty acids, volatile oils, and lipophilic constituents.
• Ethyl acetate (EtOAc) fraction: A mid-polarity fraction used to isolate phenolic and flavonoid compounds.
• Aqueous fraction: A polar fraction that has shown notable cytotoxic and analgesic activity in preclinical studies.
• Essential oil (EO): Obtained by hydrodistillation or headspace extraction of flowers and leaves, and analyzed by GC-MS.
• Dried plant material: A member of the mint family, the blooming stems can be cut and used in fresh or dried flower arrangements. The dried plant is also known to retain its structural integrity for decorative purposes.

It is a popular ornamental species, but its phytochemical profile remains poorly studied. No standardized supplement monograph, pharmacopeial entry, or established dietary supplement formulation for M. laevis exists in the major official databases (WHO, NIH/ODS, EMA, ESCOP, German Commission E, or USP) as of the current date. Research remains at an early, preclinical stage.

2. Historical and Traditional Use

2.1 Cultivation History and Introduction to Europe

It is believed that the flower was taken to Europe from Syria around 1570, possibly for use in the burgeoning perfume industry, along the established trade routes that linked Europe and the Middle East. Perfumery makes use of the volatile oils of many members of the Lamiaceae family, to which Bells of Ireland belongs, including hyssop, lavender, and patchouli. The plant therefore entered European horticulture not primarily as a medicinal or food plant, but as an aromatic and ornamental novelty.

2.2 Cultural and Symbolic Uses

In the language of flowers, or floriography, Moluccella laevis, commonly known as Bells of Ireland, symbolizes good luck and prosperity, often incorporated into arrangements to convey wishes for fortune and success. The plant was introduced to Europe in the 16th century, around 1570, from its native regions in western Asia, including Turkey and Syria, initially cultivated as a botanical curiosity and possibly for use in perfumes. Despite its Asian origins, the common name "bells of Ireland" emerged due to the striking green coloration reminiscent of Irish landscapes, tying it to folklore where the flower is linked to fairies and mystical guardianship that attracts good fortune.

2.3 Traditional Medicinal Context in the Lamiaceae Family

Bells of Ireland is an alluring ornamental, but since many members of the Lamiaceae family have long been used in traditional medicine, researchers have also begun to investigate whether it might have similar properties. The broader Lamiaceae family, of which M. laevis is a member, has an extensive tradition of ethnopharmacological use. Plants in this family are used in folkloric medicine as antispasmodic, carminative, antiemetic, choleretic, anti-inflammatory, diaphoretic, emmenagogue, and antimicrobial agents. While these uses pertain to related genera within Lamiaceae, no historical record of M. laevis specifically being used as a formal medicinal plant — with documented preparations, dosages, or indications — has been confirmed in the reviewed primary literature.

Related members of the genus, such as species in the closely allied genus Lamium, have documented folk uses. Several Lamium species have been used to relieve pain in arthritic ailments in Turkish folk medicine. Given that Moluccella was historically treated as synonymous with Lamium in some classification schemes, and that both genera share a native range overlapping Turkey and western Asia, ethnobotanical parallels have been drawn — but distinct documentation of M. laevis in traditional healing systems remains sparse and has not been confirmed by formal ethnobotanical surveys.

3. Key Constituents and Active Compounds

3.1 Phenolic Acids and Hydroxycinnamic Acids

Phytochemical analysis using Ultra-Performance Liquid Chromatography–Mass Spectrometry allowed identification of four hydroxycinnamic acids (caffeic, ferulic, rosmarinic, and chlorogenic) and two cyanidin glycosides (cyanidin 3-O-galactoside and cyanidin 3-O-malonylglucoside) in shoot clusters of M. laevis. It is a popular ornamental species, but its phytochemical profile remains poorly studied. UHPLC-DAD analysis showed rosmarinic acid (RA) as the predominant compound in extracts. Culture conditions significantly influenced the RA content, as well as the levels of total phenolics, flavonoids, and DPPH radical scavenging activity. Rosmarinic acid is a well-characterized polyphenol with established antioxidant and anti-inflammatory properties studied across multiple Lamiaceae species.

3.2 Flavonoids

The total ethanolic extract and its fractions have been reported to contain appreciable levels of flavonoidal constituents. The biological activities of extracts obtained from M. laevis using different solvents were investigated, and it was found to exhibit strong anti-inflammatory, antipyretic, and analgesic activities. These activities were attributed to the high levels of phenolic compounds contained in the plant, suggesting that it could play a supportive role in the development of new drugs in the pharmaceutical field. The activities observed could be explained by the presence of the highest amount of phenolic and flavonoidal contents, which are found in both the EtOAc fraction and TEE.

3.3 Stachydrine (Proline Betaine)

One of the most pharmacologically relevant individual compounds identified in M. laevis is stachydrine, a proline-derived betaine alkaloid widely distributed in the Lamiaceae family. The total ethanolic extract (TEE) and its fractions were subjected to LC-HR-ESI-MS metabolic profiling to discover the constituents that possibly underlie cytotoxic activity. Twenty compounds were tentatively identified from metabolic analysis, and eight compounds were isolated. In silico docking study revealed that stachydrine is more likely to account for the antiproliferative activity of both the EtOAc and aqueous fractions, probably via its moderate inhibition of receptor tyrosine kinases.

3.4 Fatty Acids (Saponifiable Matter)

Regarding GC/MS of the saponifiable matters of the petroleum ether fraction of total ethanolic extract of the aerial parts, the main recognized unsaturated fatty acids were methyl linolenate (25.58%) and methyl linoleate (15.87%). The major saturated fatty acids were palmitic acid (25.4%) followed by stearic acid (10.48%). Linolenic and linoleic acid are omega-3 and omega-6 polyunsaturated fatty acids respectively, which are biologically important; however, their presence in the plant extract does not, in itself, constitute evidence for a medicinal or supplement claim.

3.5 Volatile Oil Constituents

A comparative analysis of the volatile constituents of M. laevis flowers and leaves was performed by Headspace GC/MS. The volatile mixtures of both plant parts displayed comparable amounts of hydrocarbons and oxygenated compounds, with a noticeable greater contribution of the latter in the leaves. α-Pinene (40.84%), chrysanthenyl acetate (17.89%), and isobornyl acetate (10.64%) were identified as the major volatile components in the flowers.

A 2025 study conducted GC-MS analysis on the essential oils of Moluccella species growing in Turkey and found that the main components of the EOs of the examined species are α-thujene, β-pinene, β-caryophyllene, and 2-pentadecanone. Significant differences were found in the EO component profiles of Moluccella laevis and Moluccella spinosa. While a total of 33 components were found in M. laevis, 59 components were detected in M. spinosa.

Key volatile compounds identified across studies include monoterpenes (α-pinene, α-thujene, β-pinene), oxygenated monoterpene esters (chrysanthenyl acetate, isobornyl acetate), and sesquiterpenes (β-caryophyllene). β-Caryophyllene is a sesquiterpene with documented CB2 receptor agonist activity and has been studied for anti-inflammatory properties in other botanical contexts, though such mechanisms have not been specifically demonstrated for M. laevis extracts.

3.6 Cyanidin Glycosides

In addition to phenolic acids, tissue culture studies using UPLC-MS identified cyanidin 3-O-galactoside and cyanidin 3-O-malonylglucoside in M. laevis shoot cultures. These are anthocyanin pigments with antioxidant activity well-documented in other plant systems. Their presence at relevant concentrations in whole-plant extracts from field-grown material has not been separately confirmed.

4. Scientific Evidence by Area of Use

All current scientific evidence for Moluccella laevis is derived from preclinical studies — either in vitro (cell-based) or in vivo animal models. No human clinical trials, randomized controlled trials, systematic reviews, or meta-analyses have been published for this species. The evidence base is small, comprising a handful of laboratory studies published between 2020 and 2025. The following sections summarize what has been demonstrated and at what evidentiary level.

4.1 Antimicrobial Activity

Evidence level: Preliminary preclinical (in vitro); no human data.

A study examined its potential antibacterial compounds, concluding that the plant holds promise as a source for discovering new antibacterial agents and warranted further study of its anti-inflammatory properties.

A 2025 study published in Plants (MDPI) examined the essential oils of both M. laevis and M. spinosa from Turkey. This study demonstrates that both plant species, at specific concentrations, possess antibacterial and antidermatophytic properties, and could serve as natural agents that may contribute to the components of anti-inflammatory and wound-healing medications. Additionally, the data obtained reveal the existing antimicrobial susceptibilities of the plant extracts and provide an important reference point for future research. The antimicrobial activity was tested using both disc diffusion and the MIC (minimum inhibitory concentration) methods.

An earlier study by Hamed and colleagues (2020/2021) specifically aimed to evaluate the phytochemical and antibacterial properties of M. laevis aerial parts. The total ethanolic extract and its fractions were investigated against Gram-positive and Gram-negative bacteria. These results, while encouraging at a preliminary level, are limited to in vitro conditions and have not been validated in animal infection models or human subjects. The identity of specific bacterial strains inhibited, the minimum inhibitory concentrations, and the degree of activity relative to clinical antibiotics are parameters that would require access to the full published data beyond what is available in abstract and summary form.

4.2 Anti-inflammatory Activity

Evidence level: Preclinical in vivo (animal model only); no human data.

The biological potential study by Abdelaty, Hamed, Attia, and Desoukey (2021) investigated in vivo biological activities of M. laevis aerial parts in animal models. The study aimed to determine the various in vivo biological activities of Moluccella laevis L. aerial parts. The anti-inflammatory activity demonstrated after 2 hours, for both the total ethanolic extract (TEE) and the petroleum ether fraction, exhibited the same percentage of inhibition (26.24%) as that of indomethacin, whereas the following hour showed results quite higher than that of the positive control.

The anti-inflammatory activity of the TEE and its different fractions of M. laevis aerial parts was assessed using the carrageenan-induced paw edema method, which is a standard rodent model of acute inflammation. While the comparison with indomethacin (a pharmaceutical anti-inflammatory) is notable, this is an animal study and cannot be extrapolated directly to human use without further validation.

4.3 Analgesic and Antipyretic Activity

Evidence level: Preclinical in vivo (animal model only); no human data.

The total ethanolic extract showed higher antipyretic activity compared to the used standard acetylsalicylic acid, with a rapid onset (30 minutes) and a longer duration exhibiting the maximum activity. After 4 hours from the beginning of the experiment, the petroleum ether, ethyl acetate, and aqueous fractions displayed nearly the same effect as that of acetylsalicylic acid, which lasted up to 5 hours. Moreover, the aqueous fraction exhibited the maximum analgesic activity with a rapid onset and a longer duration followed by the petroleum ether fraction.

These findings originate from standard rodent models (typically hot plate, acetic acid-induced writhing for analgesia, and yeast-induced pyrexia for antipyresis). While the results suggest meaningful pharmacological activity relative to established drugs, translation to humans requires dedicated clinical investigation that has not been performed.

4.4 Cytotoxic and Antiproliferative Activity

Evidence level: Preclinical in vitro (cell line studies) supported by in silico docking; no animal or human data.

A 2021 study by Hamed et al., published in Natural Product Research and indexed on PubMed (PMID 33487065), was described as "the current biologically guided study" aimed at the in vitro investigation of cytotoxic activity and phytochemical content of M. laevis aerial parts:

• The aqueous fraction demonstrated the most potent cytotoxic effect against CACO-2 (human colon carcinoma) with IC₅₀ = 0.067 ± 0.01 μg/mL.
• The EtOAc fraction showed a remarkable cytotoxic activity against the MCF-7 cell line (human breast adenocarcinoma) with IC₅₀ = 0.35 ± 0.02 μg/mL.
• In silico docking study revealed that stachydrine is more likely to account for the antiproliferative activity of both the EtOAc and aqueous fractions, probably via its moderate inhibition of receptor tyrosine kinases.

It is critical to note that cell line IC₅₀ values — particularly very low values such as those observed here — do not predict clinical efficacy or safety. Anticancer activity in cell culture is a very early stage of research and the vast majority of compounds active in vitro do not translate to clinically useful treatments without further preclinical and clinical validation.

4.5 Antioxidant Activity

Evidence level: Preliminary preclinical in vitro; no human data.

The inhibition percentages of DPPH radical scavenging activity of methanolic extracts from the above-ground parts of Moluccella species at different concentrations have been determined. It was observed that the DPPH radical scavenging activity of M. laevis was above 50% (56.91 ± 0.06, 81.47 ± 0.53, 84.15 ± 0.59) at concentrations of 500, 750, and 1000 mg/mL, while it was below 50% at other concentrations.

The DPPH radical scavenging assay is a widely used but preliminary measure of antioxidant potential. Activity was concentration-dependent and required relatively high concentrations to exceed 50% scavenging. The phenolic content — particularly rosmarinic acid, caffeic acid, chlorogenic acid, and flavonoids — likely underlies this activity, consistent with known antioxidant mechanisms of hydroxycinnamic acid derivatives. No human bioavailability or in vivo antioxidant studies have been conducted.

4.6 Relationship to Alzheimer's Disease (Related Species)

The strong inhibitory activity of some compounds obtained from M. aucheri (a related species in the same genus) has suggested that this plant could be a good candidate for the treatment of Alzheimer's disease. This finding is from a related, but distinct, species and has not been replicated or extended to M. laevis specifically. It is mentioned here solely for contextual completeness regarding the broader genus.

5. Body Systems and Health Areas Associated with M. laevis

Based on preclinical evidence only, the following body systems and functional areas have been associated with research on Moluccella laevis:

• Immune and inflammatory system: Anti-inflammatory activity demonstrated in the carrageenan-induced rodent paw edema model, attributed to phenolic and flavonoid content.
• Musculoskeletal and pain pathways: Analgesic activity demonstrated in rodent pain models; the aqueous fraction showed the most prominent effect.
• Thermoregulatory system: Antipyretic activity demonstrated in rodent fever models, with the total ethanolic extract surpassing acetylsalicylic acid at early time points.
• Antimicrobial defense: Essential oils and extracts have shown antibacterial and antidermatophytic properties in disc diffusion and MIC assays.
• Oncological research (in vitro only): Cytotoxic activity identified against human colon carcinoma (Caco-2) and breast adenocarcinoma (MCF-7) cell lines in laboratory conditions.
• Antioxidant / free-radical scavenging: Demonstrated in the DPPH assay; linked to rosmarinic acid, caffeic acid, chlorogenic acid, ferulic acid, and flavonoid content.

6. Dosage Forms and Dosages Reported in the Scientific Literature

No human dosage has been established for Moluccella laevis in any clinical trial, monograph, or official guideline. The following represent only the experimental parameters used in preclinical studies, presented exactly as reported in the source literature:

• In vitro cytotoxicity (cell line studies): The aqueous fraction demonstrated cytotoxic effect against CACO-2 at IC₅₀ = 0.067 ± 0.01 μg/mL. The EtOAc fraction showed cytotoxic activity against MCF-7 at IC₅₀ = 0.35 ± 0.02 μg/mL.
• In vitro antioxidant (DPPH) assay: DPPH radical scavenging activity of M. laevis methanolic extracts was above 50% at concentrations of 500, 750, and 1000 mg/mL, while it was below 50% at other concentrations.
• In vivo anti-inflammatory (rodent carrageenan-induced paw edema model): The total ethanolic extract (TEE) and petroleum ether fraction at unspecified doses achieved inhibition of 26.24% at 2 hours — comparable to indomethacin — as reported in the biological potential study (Abdelaty et al., 2021, Journal of Advanced Biomedical and Pharmaceutical Sciences).
• In vivo antipyretic and analgesic (rodent model): The TEE showed higher antipyretic activity compared to the standard acetylsalicylic acid with a rapid onset (30 minutes) and a longer duration. Specific milligram-per-kilogram doses were not recoverable from the available abstract data.

7. Safety Considerations

7.1 General Toxicity Profile

No formal toxicological assessment of Moluccella laevis — including LD₅₀ determination, subchronic or chronic toxicity studies, reproductive toxicity studies, or genotoxicity studies — has been published in the peer-reviewed literature as of the current date. Moluccella laevis is generally considered non-toxic to humans in garden and horticultural contexts, though this characterization is based on the absence of known toxins rather than formal toxicological testing.

7.2 Physical Hazards

However, the plant has tiny thorns on its stems, which can cause minor skin irritation if handled without care. Gloves are advised when handling the plant to avoid any discomfort.

7.3 Pet Safety

Bells of Ireland is not listed as toxic to dogs or cats. While it is always best to keep pets from chewing on plants, this one does not pose a significant risk if ingested in small amounts. However, the thorns could potentially cause mild irritation to the mouth or paws.

7.4 Absence of Human Pharmacological and Interaction Data

Because M. laevis has not been studied in human subjects as a supplement or therapeutic agent, no data exist on:

• Pharmacokinetics (absorption, distribution, metabolism, or excretion) in humans.
• Drug–herb interactions.
• Effects in pregnancy or lactation.
• Dose-related adverse events.
• Contraindications in specific disease states or populations.

This absence of data means that the safety profile in humans is unknown beyond the general non-toxicity observed in garden handling contexts. Due to the pronounced results of M. laevis aerial parts, it can be considered as a potential contribution to natural products in further drug discovery, but this characterization remains aspirational rather than clinically established.

7.5 Absence in Official Supplement Frameworks

Moluccella laevis does not appear in the NIH Office of Dietary Supplements ingredient databases, the NCCIH Herbs at a Glance series, the WHO monograph program, the European Medicines Agency herbal monographs, the ESCOP monographs, the German Commission E monographs, or the USP/NF dietary supplement compendium. It is not recognized as a food ingredient by Codex Alimentarius or the U.S. FDA's GRAS (Generally Recognized as Safe) database. Therefore, no official guidance on acceptable daily intake, safe upper limits, or quality specifications for supplement-grade preparations has been issued by any regulatory body.

8. Current State of the Evidence and Research Gaps

The research on Moluccella laevis as a bioactive plant is genuinely nascent. The key published studies — from Egyptian, Turkish, and Polish research groups working between 2020 and 2025 — have made important first steps in characterizing the plant's chemistry and demonstrating biological activities in laboratory settings. Moluccella laevis L. is an important research plant for chemical and biological investigation due to the presence of very few studies on it.

The following represent the most significant gaps in the existing evidence base:

• No human clinical data of any kind. All efficacy and safety conclusions remain extrapolated from in vitro cell models or in vivo animal models.
• No standardized extract or dose. Different studies have used different solvents, fractions, and concentrations, making comparison across studies difficult.
• Mechanism studies are largely in silico (computational docking), which, while hypothesis-generating, cannot confirm actual biochemical mechanisms in living systems.
• Phytochemical profiling remains incomplete. Its phytochemical profile remains poorly studied. The full complement of bioactive compounds has not been characterized.
• No safety pharmacology or formal toxicology. No LD₅₀, no NOAEL, no organ toxicity assessments, and no genotoxicity studies have been published.
• No established dietary supplement market or formulation. The plant is not currently manufactured, sold, or regulated as a dietary supplement ingredient in major markets.

References

• Hamed ANE et al. (2021). Antiproliferative potential of Moluccella laevis L. aerial parts family Lamiaceae (Labiatae), supported by phytochemical investigation and molecular docking study. Natural Product Research. PubMed PMID 33487065.
• Abdelaty NA, Hamed ANE, Attia EZ, Desoukey SY (2021). Biological Potential of Moluccella laevis L. Aerial Parts, Family Lamiaceae (Labiatae). Journal of Advanced Biomedical and Pharmaceutical Sciences, 4(4):226–230. ResearchGate.
• Hamed A, Abdelaty NA, Attia EZ, Desoukey SY (2020). Phytochemical investigation of saponifiable matter & volatile oils and antibacterial activity of Moluccella laevis L., family Lamiaceae (Labiatae). Journal of Advanced Biomedical and Pharmaceutical Sciences, 3(4):213–220. ResearchGate.
• Biosystematic, Essential Oil, and Biological Activity Studies on Medicinal Plant Moluccella L. (Lamiaceae) Species from Turkey (2025). Plants 14(4):542. PMC11859975.
• Biosystematic, Essential Oil, and Biological Activity Studies on Medicinal Plant Moluccella L. (Lamiaceae) Species from Turkey (2025). Plants (MDPI), 14(4):542.
• Zielińska S et al. (2020). LED illumination and plant growth regulators' effects on growth and phenolic acids accumulation in Moluccella laevis L. in vitro cultures. Acta Physiologiae Plantarum. Springer.
• Zielińska S et al. (2020). LED illumination and plant growth regulators' effects on growth and phenolic acids accumulation in Moluccella laevis L. in vitro cultures. ResearchGate.
• Spathulenol as the most abundant component of essential oil of Moluccella aucheri (Boiss.) Scheen. Natural Volatiles and Essential Oils, 8(2).
• Wikipedia: Moluccella laevis.
• Wikipedia: Moluccella (genus).
• Encyclopædia Britannica: Bells of Ireland (Moluccella laevis).
• University of Wisconsin Horticulture Extension: Bells of Ireland, Molucella laevis.
• Missouri Botanical Garden Plant Finder: Moluccella laevis.
• Baker Creek Heirloom Seeds (RareSeeds): Bells of Ireland – The Garden's Lucky Charm (2025).
• Hamed A et al. (2021). Phytochemical investigation of saponifiable matter & volatile oils and antibacterial activity of Moluccella laevis L. SSRN Preprint.