King Alfred's Cake

Metadata

Regulatory Status

United States

• Not marketed as a food or dietary supplement.
• FDA status: No GRAS determination, no supplement registrations.
• Research use: Concentricolide and cytochalasins from D. concentrica are available as research chemicals.

European Union

• Not authorized as a food or food supplement.
• Ethnomycological significance: Well-known in British and European folk culture, but exclusively as tinder for fire-starting and for folk superstitious use (cramp prevention), not as food.
• Conservation: Common and widespread; not of conservation concern.

China

• Traditional use: Some use in traditional Chinese medicine, though not listed in the Chinese Pharmacopoeia. D. concentrica extracts have been studied extensively by Chinese research groups.
• Folk medicine: Used in some Asian folk traditions for respiratory complaints and as a general tonic.

India

• Folk medicine: Known as “kala pihiri” (black fungus) and used in some traditions for chronic coughs.

Japan

• Traditional medicine: Some recognition in traditional Japanese medicine. Not listed in the Japanese Pharmacopoeia.

Conditions & Indications

Primary: Antimicrobial Activity (Preclinical Evidence Only)

• Antifungal volatile organic compounds: VOCs produced by endophytic D. cf. concentrica demonstrated broad-spectrum antimicrobial activity against fungi and oomycetes from diverse phyla. These biologically active VOCs also protected stored food products (dried fruits, peanuts, wheat grains) from fungal spoilage.
• Antibacterial: Naphthalene derivatives isolated from D. concentrica showed broad-spectrum antibacterial activity against E. faecalis, methicillin-resistant S. aureus (MRSA), E. coli, P. aeruginosa, and C. albicans with MIC values of 12.5—25 microg/mL.

Secondary: Antiviral Activity (Preclinical Evidence)

• Anti-HIV-1: Concentricolide, a novel benzofuran lactone isolated from D. concentrica fruiting bodies, exhibited potent anti-HIV-1 activity with an EC50 of 0.31 microg/mL and a therapeutic index (TI) of 247 — indicating a wide safety margin between effective and toxic concentrations in cell culture.
• HIV-1 protease inhibition: Cytochalasin L-696,474 (18-dehydroxy cytochalasin H), isolated from Daldinia species, is a known HIV-1 protease inhibitor.

Emerging/Preclinical

• Cytotoxic activity: Daldinins and cytochalasins from D. concentrica demonstrate cytotoxicity against various human cancer cell lines, though selectivity for cancer vs. normal cells has not been established for most compounds.
• Anti-inflammatory: Secondary metabolites from Daldinia species exhibit anti-inflammatory activity in cellular models, though specific mechanisms for D. concentrica compounds require further characterization.
• Enzyme inhibition: Various metabolites show enzyme-inhibitory activities, including protease and kinase inhibition.
• Biocontrol agent: The antimicrobial VOCs of D. concentrica have been explored as biological control agents for crop protection and post-harvest food preservation.

Mechanism of Action

Primary Mechanisms

1. Concentricolide anti-HIV-1 activity: Concentricolide is a benzofuran lactone with a unique structural scaffold. Its anti-HIV-1 activity (EC50 = 0.31 microg/mL) demonstrates a high therapeutic index (247), meaning the effective antiviral concentration is far below the cytotoxic concentration. The specific molecular target within the HIV-1 replication cycle has not been fully elucidated but is distinct from the protease inhibition mechanism of cytochalasin L-696,474.

2. Cytochalasin-mediated bioactivities: Cytochalasins are a large class of fungal metabolites that bind to actin filaments and disrupt cytoskeletal dynamics. More than 30 different cytochalasins have been identified from Hypoxylaceae species, with Daldinia being a major source. Cytochalasin L-696,474 specifically inhibits HIV-1 protease. Other cytochalasins exhibit cytotoxic, antifungal, and immunomodulatory activities through actin-dependent mechanisms including cell migration inhibition and phagocytosis disruption.

3. VOC-mediated antimicrobial activity: D. concentrica produces a complex mixture of volatile organic compounds that collectively inhibit growth of pathogenic fungi, oomycetes, and bacteria. The mechanism involves disruption of microbial cell membrane integrity and metabolic processes. The VOC profile includes sesquiterpenes, alcohols, and other small molecules that act synergistically.

Secondary Mechanisms

• BNT (binaphthalene tetrol) bioactivity: BNT is a characteristic metabolite of Daldinia species found concentrated in the stromatal tissue. It demonstrates antimicrobial and cytotoxic properties, though the specific molecular mechanism is not fully characterized.
• Daldinin scaffold chemistry: Daldinins A—C possess a novel carbon skeleton not found in other fungal metabolites. Their biological activities include antimicrobial and cytotoxic effects, though detailed mechanism of action studies are lacking.
• Diaporthin and orthosporin: These polyketide metabolites, isolated from D. concentrica fruiting bodies, exhibit moderate antibacterial and antifungal activities.

Clinical Evidence Summary

No human clinical trials have been conducted with D. concentrica extracts or any of its isolated metabolites.

Preclinical Evidence (Selected)

Ethnomycological Evidence

Evidence Limitations

• All pharmacological evidence is preclinical (in vitro). No animal models for efficacy have been published.
• Concentricolide’s anti-HIV mechanism has not been fully elucidated, limiting rational drug development.
• The relationship between crude stromatal extracts and purified compound bioactivities is unclear.
• D. concentrica is not established as safe for internal human consumption. No toxicological studies of oral administration have been published.
• The compound responsible for the folk “cramp ball” anti-spasmodic reputation has never been identified. The effect may be entirely placebo or superstitious.
• Taxonomic issues exist: some specimens identified as D. concentrica in older studies may actually be D. childiae or other cryptic species within the genus.

Safety Profile

General Assessment

D. concentrica is NOT established as edible or safe for internal consumption. While it has a long ethnomycological history as tinder and folk charm, there is no tradition of consuming it as food. The few traditional medicinal uses (India, China) involve preparations for which safety data are absent. The safety profile of its concentrated secondary metabolites is entirely unknown in humans.

Contraindications

• Not for consumption: D. concentrica should not be consumed as food or supplement without proper safety evaluation.
• Pregnancy and lactation: Absolutely no safety data. Avoid entirely.
• Immunocompromised individuals: Cytochalasins disrupt actin dynamics, which could theoretically affect immune cell function.

Drug Interactions

• No established interactions. However, theoretical considerations include:
  • Antiretroviral medications: Concentricolide’s anti-HIV activity and cytochalasin L-696,474’s HIV protease inhibition could theoretically interact with antiretroviral drug regimens. This has not been studied.
  • Cytoskeletal-targeting drugs: Cytochalasins affect actin dynamics; theoretical interaction with drugs targeting the cytoskeleton (e.g., certain chemotherapy agents like vinca alkaloids).

Side Effects

• No documented side effects because the species is not consumed or used as a supplement.
• Handling the dried fungus for fire-starting purposes is considered safe.
• The smoke from burning D. concentrica is described as pungent but no specific health effects have been documented.

Toxicology

• No formal oral toxicological studies have been published for D. concentrica or its metabolites.
• Cytochalasins are known to be cytotoxic at elevated concentrations due to their actin-disrupting mechanism, raising safety concerns for any preparation containing these compounds.
• The therapeutic index of concentricolide (247 in cell culture) suggests a reasonable safety margin, but this has not been validated in whole-organism studies.

Clinical Dosage

No Established Dosage

No clinical dosage recommendations can be made for D. concentrica, as no human clinical trials have been conducted and the species is not established as safe for internal consumption.

Preclinical Reference Concentrations

• Concentricolide anti-HIV activity: EC50 = 0.31 microg/mL in cell culture
• Antibacterial naphthalene derivatives: MIC = 12.5—25 microg/mL against tested pathogens
• These concentrations apply to in vitro systems only and cannot be extrapolated to oral dosing

Research Priority

Before any dosage recommendations could be developed, basic toxicological studies (acute and chronic oral toxicity, genotoxicity, reproductive toxicity) must be conducted in appropriate animal models.

Sources

• Guo H, Hu H, Liu S, Liu X, Zhou Y, Che Y. Bioactive p-terphenyl derivatives from a Cordyceps-colonizing isolate of Gliocladium sp. J Nat Prod. 2007;70(9):1519-1521
• Stadler M, Laessoe T, Fournier J, Decock C, Schmieschek B, Tichy HV, Persoh D. A polyphasic taxonomy of Daldinia (Xylariaceae). Stud Mycol. 2014;77:1-143
• Guo H, Liu ZM, Chen YC, Tan HB, Li SN, Li HH, et al. Concentricolide, an anti-HIV agent from the ascomycete Daldinia concentrica. Helv Chim Acta. 2001;84(12):3726-3729
• Hoang VT, Kuo PC, Tuan NT, Ngan NT, Trung NQ, Thanh NT, et al. Characterization of cytochalasins and steroids from the ascomycete Daldinia concentrica and their cytotoxicity. Nat Prod Commun. 2019;14(5):1-5
• Tomsheck AR, Strobel GA, Booth E, Geary B, Spakowicz D, Knighton B, et al. Use of the endophytic fungus Daldinia cf. concentrica and its volatiles as bio-control agents. PLoS One. 2016;11(12):e0168874
• Singh SK, Yadav RP, Sharma S, Yadav S, Singh AN. Evaluation of antibacterial potential of Daldinia concentrica from North Eastern Region of India. J Appl Biol Biotechnol. 2020;8(2):86-90
• Hashimoto T, Asakawa Y. Diaporthin and orthosporin from the fruiting body of Daldinia concentrica. Biosci Biotechnol Biochem. 1998;62(2):236-238
• Stadler M, Tichy HV, Katsiou E, Hellwig V. Chemotaxonomy of Pochonia and other conidial fungi with Verticillium-like anamorphs. Mycol Prog. 2003;2:95-122
• Kang R, Yu B, Chen X, Liu F, Zhang Y, Wang T, et al. Structures and biological activities of secondary metabolites from Daldinia spp. J Fungi. 2024;10(12):833
• Lambert LW. Absolute configuration of anti-HIV-1 agent (-)-concentricolide: total synthesis of (+)-(R)-concentricolide. Org Biomol Chem. 2011;9(14):5154-5157

Connections

• Turkey Tail (Trametes versicolor): Turkey Tail represents the clinical evidence benchmark for fungal immunomodulatory and antimicrobial compounds. While D. concentrica’s bioactive metabolites (concentricolide, cytochalasins) have distinct mechanisms from Turkey Tail’s polysaccharopeptides, both exemplify the chemical diversity of wood-decomposing fungi.
• Reishi (Ganoderma lucidum): Reishi is another wood-decomposing fungus with a long ethnomycological history, though Reishi’s medicinal use tradition is far more developed. Both produce triterpenoid secondary metabolites, though from different biosynthetic families (lanostane vs. benzofuran/cytochalasin).
• Tinder Polypore (Fomes fomentarius): Tinder Polypore shares the ethnomycological use as a fire-starting material and has an overlapping folk medicine history. Both are saprotrophic fungi traditionally valued more for utilitarian than medicinal purposes, with modern research revealing unexpected pharmacological potential.
• Chaga (Inonotus obliquus): Chaga is another wood-dwelling fungus with an emerging profile of diverse secondary metabolites (betulinic acid, melanin) and antimicrobial properties, providing a parallel case of a folk remedy transitioning to pharmacological research subject.