Lygodium: A Comprehensive Reference on the Climbing Fern Genus as a Dietary Supplement and Medicinal Ingredient
1. Identity and Botanical Classification
Genus and family. Lygodium (commonly called climbing fern) is a genus of about 40 species of ferns, native to tropical regions across the world, with a few temperate species in eastern Asia and eastern North America. It is the sole genus in the family Lygodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed as the only genus in the subfamily Lygodioideae of a more broadly defined family Schizaeaceae, the family placement used in Plants of the World Online as of November 2019.
Etymology. The family name Lygodiaceae derives from the type genus Lygodium, which comes from the Greek lygodes, meaning "flexible," after the flexuous rachis.
Morphological characteristics. Lygodium comprises approximately 40 species of climbing ferns characterized by indeterminate leaves, twining rachises, and dimorphic leaf segments with sori located at the tips of ultimate segments. The stems are rhizomatous, the rhizomes slender, creeping, bearing hairs, and protostelic. The leaves are mostly indeterminate with an elongate, twining and climbing rachis that bears pinnae alternately, the pinnae pseudodichotomously branching, with veins free or anastomosing. Sori are abaxial, on lobes of ultimate leaf segments, with an indusium-like flange covering the sporangium. The fronds may be from 3–12 m (9.8–39.4 ft) long, depending on the species.
Distribution. Lygodium is a wide-ranging genus with native populations existing in Asia, Australasia, Africa, and North and South America. The Lygodiaceae are pantropical in distribution.
Medically and pharmacologically relevant species. Within the genus, several species are studied for their medicinal properties:
- Lygodium japonicum (Thunb.) Sw. (Japanese climbing fern) — the species most widely employed in traditional Chinese medicine, where its spores constitute the official drug material known as Lygodii Spora or Hai Jin Sha (海金砂). It is a terrestrial, herbaceous perennial climber whose origins span Japan, tropical Asia, and Australia.
- Lygodium flexuosum (L.) Sw. — a species native to South and Southeast Asia, widely studied in Indian ethnomedicine and pharmacological research for wound healing, hepatoprotection, and antimicrobial properties.
- Lygodium microphyllum (Cav.) R.Br. — the Old World climbing fern, used medicinally by communities in Southeast Asia, particularly Borneo, and also studied for hepatoprotective and anti-inflammatory activity.
- Lygodium circinnatum (Burm.f.) Sw. — used medicinally and as a craft material across Indonesia, Malaysia, New Guinea, and the Philippines.
Common names and pharmaceutical designations. The TCM drug material known as Hai Jin Sha (Spora Lygodii) is the mature spore of Lygodium japonicum, a climbing and twining perennial vine-like fern. It is a relatively common Chinese herbal medicine, which first appeared in the Jia You Ben Cao (Materia Medica of Jia You Reign) in the Song Dynasty, around 1057–1060 AD.
Part used and preparation of the raw material. In autumn, people harvest the vine leaves of Lygodium japonicum, dry them in the sun, collect the spores, remove impurities, and prepare them as Chinese herbal medicines. The plant is also harvested from the wild for local medicinal use and for its stems, which are used in basketry.
2. Traditional and Historical Use
2.1 Traditional Chinese Medicine (TCM)
Hai Jin Sha (Spora Lygodii), the mature spore of Lygodium japonicum, is a relatively common Chinese herbal medicine whose use was first recorded in the Jia You Ben Cao during the Song Dynasty (approximately 1057–1060 AD). According to traditional Chinese medicine concepts, lygodium has sweet and cold properties, and is associated with the Bladder and Small Intestine meridians; its primary functions are described as clearing heat and regulating urination. It is held to have the action of clearing damp-heat from the bladder and small intestine, being good at inducing diuresis to treat stranguria and alleviating pain in the urinary tract, so it is considered an essential herb for stranguria syndromes.
Among the conditions the lygodium spores were traditionally used to treat are sore throats, turbid urine, dysuria, frequent urination, and stones that develop in the urinary tract. In the TCM literature, Lygodii Spora (spore of Lygodium japonicum) has been prescribed for the treatment of dysuria, male urodynia, nephritis, urinary calculus, and urinary tract infection.
In China, there are 10 species of Lygodium distributed in the southwest and south of the country, and five species have been used in Chinese herbal medicine to treat hepatitis and dysentery. In southern China, the herb is commonly employed for the prevention and treatment of conditions such as hepatitis, urinary tract infections, and kidney stones.
2.2 South and Southeast Asian Ethnomedicine
Lygodium flexuosum (Linn.) Sw. is a climbing fern that commonly grows epiphytically on moss-covered tree trunks and branches as well as lithophytically on shady boulders along with moss. It has been reported as a traditional folkloric medicine for a variety of ailments, particularly useful for carbuncles, inflammation, ulcer, various respiratory diseases, general disorders, muscle sprains, and as a panacea for wounds. Lygodium flexuosum is found nearly throughout India up to an elevation of 1,500 metres, and belongs to the family Lygodiaceae, widely used in treating ailments including jaundice, dysmenorrhoea, wound healing, and eczema.
The Old World Climbing Fern, Lygodium microphyllum (Lygodiaceae), is used by local communities in Sabah (Malaysian Borneo) for skin and dysentery ailments. The native Murut tribe of Sabah used the boiled leaves of Lygodium microphyllum to treat dysentery and skin disorders.
2.3 Traditional Uses in Island Southeast Asia and the Pacific
In Malaysia, the young leaves of Lygodium circinnatum are used as a postpartum medicine, and exudate from the rhizome serves as an insect repellent and to treat aquatic animal and snake bites. In New Guinea, it is used as a birth control drug, and in the Philippines, a tapel (poultice) from crushed leaves is used to cover wounds.
Lygodium circinnatum has traditional uses including as food, boiled feedstuff for hogs, laundry starch to stiffen fabrics and linens, a medicinal remedy for skin problems, and as a live amulet or ritual object.
2.4 Traditional Food Uses
Lygodium microphyllum is one of the ferns often used as raw material for food and traditional medicine. The young leaves of L. microphyllum are used as food ingredients. Ethnobotanical studies have been conducted to review the traditional use of related species and their cultivation.
3. Key Constituents and Active Compounds
3.1 Lygodium japonicum (Lygodii Spora)
The aqueous ethanol extract of Lygodii Spora (spore of Lygodium japonicum) showed in vitro testosterone 5α-reductase inhibitory activity and in vivo anti-androgenic activity. From the lipophilic constituents of Lygodii Spora, oleic acid, linoleic acid, and palmitic acid were identified as the main active principles inhibiting testosterone 5α-reductase.
Research has identified that Lygodium japonicum spores contain multiple components including farnesin, linarin, diisooctyl phthalate, apigenin, protocatechuic acid, and p-coumaric acid, contributing to their activity in treating kidney stones through multiple targets and pathways.
The spores also contain a version of coumaric acid, caffeic acid, and lygodin.
This herb exhibits pharmacological properties such as heat-clearing and dampness-dispelling, strangury relief, antibacterial and anti-inflammatory effects, immune system enhancement, and antioxidant activity. The polysaccharides within the cell matrix are among the key active components of L. japonicum, and their role in stone treatment has been the subject of investigation.
3.2 Lygodium flexuosum
Studies reveal the presence of medicinally active constituents in Lygodium flexuosum, suggesting that this species has potential to synthesize useful secondary metabolites. Both vegetative material and sporophyll-bearing tissue show the presence of secondary metabolites including alkaloids, flavonoids, saponins, tannins, phenols, and glycosides.
Lygodium flexuosum is native to Southeast Asia and is commonly used in traditional medicine in India. It has been found to produce bioactive molecules such as kaempferol, sitosterol, stigmasterol, and lygodinolide. Lygodinolide is a triterpene ester and anthraquinone that has only been identified in the methanolic extract of L. flexuosum; the extent to which it appears in other species is undocumented. The main constituent of the plant is lygodinolide, which is mainly associated with wound-healing activity.
Phytochemical studies of the n-hexane extract of Lygodium flexuosum revealed the presence of saponins, triterpenes, sterols, and bitter principles, which may be responsible for its hepatoprotective action.
3.3 Lygodium microphyllum
Studies report that L. microphyllum contains flavonoids such as kaempferol, quercetin, sitosterol, and acacetin, with acacetin showing the greatest antioxidant activity. The total phenolic content in aqueous extract of L. microphyllum leaves was measured at 206.38 ± 9.62 mg gallic acid equivalent per gram.
Anti-inflammatory components such as quercetin have been identified in Lygodium microphyllum.
4. Scientific Evidence by Area of Use
4.1 Urolithiasis (Kidney and Urinary Tract Stones)
This is the best-studied area in preclinical research on L. japonicum, directly connected to its primary historical use in TCM.
Preclinical (animal) studies: Cho et al. (2014, published in Urolithiasis) investigated the effect of an ethanol extract of Lygodii Spora (LS) as a preventive and therapeutic agent for experimentally induced calcium oxalate nephrolithiasis with ethylene glycol (EG) in rats. Male Wistar rats were randomly divided into preventive (n=18, for 28 days) and therapeutic (n=24, for 42 days) groups. The preventive group was further subdivided into three groups of six rats each: preventive control, preventive lithiatic control (EG), and preventive lithiatic LS (EG + 400 mg/kg LS). In vivo studies with an ethanolic extract of the spores of Lygodium japonicum in an ethylene glycol-induced kidney calculi rat model showed decreased urinary calcium, oxalate, and uric acid; decreased kidney peroxides and the number of oxalate deposits; and increased urinary citrate levels.
Cho et al. (2014) found the extract to be useful as a preventive and therapeutic agent against the formation of oxalate kidney stones, supporting one of the primary traditional uses.
Mechanistic research: A 2025 study published in a peer-reviewed journal examined a polysaccharide (LJP) from Lygodium japonicum, one of the most commonly used herbs in traditional Chinese medicine for treating urinary tract stones. A polysaccharide with a molecular weight of 12.9 kDa was obtained through hot-water extraction and purification, and its role in inhibiting kidney stone formation was investigated. Emerging evidence indicates that the spores of Lygodium japonicum can inhibit the activation of NF-κB and p38 pathways induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Moreover, the ethanol extract of Lygodium japonicum spores has been shown to ameliorate kidney calculi in rats by reducing the release of inflammatory factors.
Evidence strength: The evidence in this area is entirely preclinical (animal and in vitro models). No controlled human clinical trials have been published assessing Lygodium japonicum extracts or Lygodii Spora for kidney stone prevention or treatment in isolation. The results support but do not confirm the traditional use.
4.2 Anti-Androgenic Activity and Hair Growth Promotion
The aqueous ethanol extract of Lygodii Spora (spore of Lygodium japonicum) showed in vitro testosterone 5α-reductase inhibitory activity and in vivo anti-androgenic activity using growth of flank organ in castrated Syrian hamsters and hair regrowth after shaving in testosterone-treated C57Black/6CrSlc mice. From the lipophilic constituents of Lygodii Spora, oleic, linoleic, and palmitic acids were identified as the main active principles inhibiting testosterone 5α-reductase.
Human steroid 5α-reductases (S5αRs) and NADPH irreversibly reduce testosterone to the more potent dihydrotestosterone (DHT). S5αR inhibitors are useful treatments for DHT-dependent diseases, including benign prostatic hyperplasia, androgenic alopecia (pattern hair loss), and acne. There are three S5αR isozymes, and there is a need for safer and more isozyme-selective inhibitors than finasteride and dutasteride currently licensed.
Evidence strength: Evidence is limited to in vitro assays and animal models. No human clinical trials have assessed Lygodii Spora for androgenic alopecia or benign prostatic hyperplasia. The finding that free fatty acids (oleic, linoleic, palmitic acids) are the active 5α-reductase inhibitors in spore extracts is noteworthy but requires human validation.
4.3 Hepatoprotective Activity
Lygodium flexuosum: The preventive and curative effect of Lygodium flexuosum on experimentally induced hepatic fibrosis by carbon tetrachloride (CCl₄) was evaluated in rats. Hepatic fibrosis was induced in male Wistar rats by CCl₄ administration (150 µL/100g rat weight, oral) twice a week for 10 weeks. In preventive treatment, daily doses of L. flexuosum n-hexane extract at 200 mg/kg p.o. were administered for 10 weeks. In curative treatment, the extract at 200 mg/kg p.o. was given for 2 weeks after the establishment of fibrosis over 10 weeks. Treatment with the extract prevented or restored the elevation of serum AST, ALT, and LDH levels. L. flexuosum treatment remarkably prevented or reversed an increase in liver hydroxyproline content in chronically treated rats. These results supported that Lygodium flexuosum exerts effective protection in carbon tetrachloride-induced hepatic fibrosis in rats.
In a related study, treatment with the n-hexane extract of L. flexuosum prior to CCl₄ administration significantly prevented an increase in serum AST, ALT, LDH activity and lipid peroxidation and prevented the depletion of glutathione (GSH).
Lygodium microphyllum: Animal studies were carried out to evaluate hepatoprotection of aqueous extract of L. microphyllum at different doses (200, 400, and 600 mg/kg b.w.) against carbon tetrachloride (CCl₄)-mediated liver injury and histopathological alterations. The extract was able to prevent the increase in levels of serum alanine aminotransferase, serum aspartate aminotransferase, and hepatic malondialdehyde formation in a dose-dependent manner. Immunohistochemical results evidenced the suppression of oxidative stress markers (4-hydroxynonenal, 8-hydroxydeoxyguanosine) and pro-inflammatory cytokines (Tumor Necrosis Factor-α, Interleukin-6, Prostaglandin E2). Histopathological and hepatocyte ultrastructural alterations showed protective effects by L. microphyllum against CCl₄-mediated oxidative stress. The hepatoprotective mechanism was attributed to antioxidative effects through protection of ultrastructural organelles.
Lygodium japonicum (herb, not spore): It is commonly employed in southern China for the prevention and treatment of conditions such as hepatitis, urinary tract infections, and kidney stones. However, there have been limited studies investigating the pharmacological actions of the herb in recent years. Emerging evidence indicates that spores of Lygodium japonicum can inhibit the activation of NF-κB and p38 pathways induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages, suggesting a basis for anti-inflammatory and hepatoprotective effects.
Evidence strength: All hepatoprotective evidence is preclinical, derived from rat and mouse models. The consistent finding across multiple species of the genus — that extracts attenuate CCl₄-induced elevations of liver enzymes and oxidative stress markers — is notable but no human clinical evidence exists.
4.4 Anti-inflammatory, Analgesic, and Antipyretic Activity
Studies using Lygodium microphyllum leaves depicted the role of the plant in pain, inflammation, pyrexia, diarrhea, and helminthic management. The plant extract showed dose-dependent analgesic, anti-inflammatory, antipyretic, antidiarrheal, and anthelmintic activities. These assessments were conducted using in vivo and in vitro approaches, and in silico molecular docking was applied to evaluate binding interactions.
Evidence strength: Evidence is limited to animal model studies and in vitro assays; no human clinical evidence is available for these specific activities.
4.5 Antimicrobial Activity
An investigation of the antibacterial properties of the terrestrial fern Lygodium flexuosum obtained from Kalahandi district, Odisha was conducted against enteric and uro-pathogenic bacteria isolated from clinical samples. Frond-extracts were obtained by the cold percolation method using four solvents (petroleum ether, chloroform, methanol, and water). Antibacterial potencies were tested by the agar-well diffusion method against 7 multidrug resistant (MDR) bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VRE), and five Gram-negative species including Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis.
Separate antimicrobial studies revealed that methanol extracts of the sporophyll type of L. flexuosum exhibited significant antibacterial activity (zone of inhibition: 8.5 mm) against Klebsiella pneumoniae. Chloroform extracts of the sporophyll type showed activity of 8.2 mm against the same bacterium. In antifungal studies, methanol extracts of vegetative material showed the highest inhibitory activity (19.3 mm) against Cladosporium sp.
Antioxidant activity of L. flexuosum using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was documented using frond-extracts in several solvents; only the methanolic extract was recorded to have the maximum activity with an inhibitory concentration 50 (IC₅₀) value of 5 µg/mL.
Evidence strength: All evidence is in vitro; no human clinical trials exist assessing antimicrobial efficacy.
4.6 Wound Healing
A published study explored the protective effect of L. flexuosum against excision, incision, and dead-space wound models in experimental rats. Wistar albino rats of either sex weighing between 180 and 220 g were topically treated with extracts formulated in ointment using simple ointment BP as base. Topical application of L. flexuosum in the excision wound model increased the percentage of wound contraction, and the epithelization time was decreased. In the incision wound model, the breaking strength of wounds increased, and in the dead-space model the weight of dry and wet granuloma and hydroxyproline was increased. These data indicated that the leaf extract of L. flexuosum accelerated wound healing in rats, supporting its traditional use.
Evidence strength: Preclinical animal data only. No human clinical evidence is available.
5. Body Systems and Health Areas of Association
- Urinary/Renal System: In TCM, Lygodium japonicum is traditionally used as a diuretic and to promote urination, related to support of the bladder and urinary tract. Preclinical data support anti-urolithiatic effects in calcium oxalate kidney stone models.
- Hepatic System: Multiple preclinical studies across L. flexuosum and L. microphyllum demonstrate hepatoprotective activity against chemically induced liver injury, with attenuation of liver enzymes and oxidative stress markers in rodent models.
- Endocrine/Androgenic System: Lygodii Spora spore extracts inhibit testosterone 5α-reductase in vitro and in animal models, implicating a potential role in androgen-related conditions such as androgenic alopecia and benign prostatic hyperplasia.
- Integumentary System: Traditional use for wound healing, skin disorders, eczema, and scabies is reported across South and Southeast Asian traditions, with some preclinical wound-healing data.
- Gastrointestinal System: Traditional use for dysentery and gastrointestinal complaints is documented, with preliminary in vivo evidence for antidiarrheal activity.
- Immune / Inflammatory System: Pharmacological properties studied include antibacterial and anti-inflammatory effects, as well as immune system enhancement.
6. Dosage Forms and Reported Dosages in Studies
No standardized human clinical dosages have been established for any Lygodium preparation, as no controlled human trials have been conducted for any of the activities described above. The following dosages are those reported in published preclinical research only:
- Lygodii Spora ethanol extract (anti-urolithiasis in rats): 400 mg/kg administered in drinking water, with the preventive group receiving the extract from day 0 for 28 days and the therapeutic group from day 28 for 42 days.
- Lygodium flexuosum n-hexane extract (hepatic fibrosis in rats): 200 mg/kg p.o. daily for 10 weeks in preventive treatment; 200 mg/kg p.o. for 2 weeks in curative treatment.
- Lygodium flexuosum n-hexane extract (acute hepatotoxicity): n-Hexane extracts at 200 and 100 mg/kg in pre-treatment (48, 24, and 2 hours prior to CCl₄); post-treatment used the same dose levels at 2, 24, and 48 hours after CCl₄ intoxication.
- Lygodium microphyllum aqueous extract (hepatoprotection in rats): 200, 400, and 600 mg/kg b.w.
- L. flexuosum n-hexane extract (cytokine study): 200 mg/kg for 8 days prior to CCl₄ challenge; a negative control group received 200 mg/kg alone for 8 days.
Dosage forms used in research: Preparations described in the literature include aqueous ethanol extracts of spores, n-hexane extracts of fronds or whole plant, aqueous extracts of leaves, methanolic extracts of leaves, and ointment formulations (for topical wound-healing studies). In TCM practice, the spore material is prepared as decoctions for oral administration, but specific preparation details and standardized doses are not established in peer-reviewed pharmacological literature.
7. Safety Considerations and Notable Interactions
General toxicity assessments: Acute toxicity study of Lygodium microphyllum methanol extract found the plant extract to be non-toxic. The inhibitory concentration (IC₅₀) for free radical scavenging activity of L. microphyllum was reached at a concentration of 65 µg/mL, suggesting activity at low concentrations.
Fern class caution: Although no specific reports of toxicity have been found for Lygodium japonicum, a number of ferns contain carcinogens, so some caution is considered advisable. This is a class-level observation reported in botanical reference databases and is not specific to Lygodium itself.
No documented human adverse event reports: The peer-reviewed literature does not contain controlled human data on adverse effects, contraindications, or drug interactions for any Lygodium preparation. The available safety data are limited to acute animal toxicology experiments.
Invasive weed and contamination concern: Lygodium japonicum and L. microphyllum are classified as invasive species in parts of the United States (notably Florida and the southeastern states). Lygodium microphyllum is one of the most invasive (Category I in Florida) weeds in Florida, having invaded more than 50,000 ha of wetlands and moist habitats in southern Florida. Material collected from invasive populations in areas where herbicide control is conducted may carry residues of those herbicides; this is a practical consideration for sourcing.
5α-Reductase inhibition and androgen modulation: Because Lygodii Spora exhibits 5α-reductase inhibitory activity in animal models, individuals taking pharmaceutical 5α-reductase inhibitors (finasteride, dutasteride) should be aware that concurrent use could theoretically produce additive effects, although no human interaction data exist.
Lack of human clinical data as an overarching limitation: Scientific evidence supporting the traditional uses of Lygodium is minimal. The totality of pharmacological research on Lygodium as of 2025–2026 remains at the preclinical stage. The absence of randomized controlled trials in humans means that efficacy and safety in human populations cannot be determined from available evidence.
References
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