Calycophyllum

Calycophyllum: Botanical Identity, Phytochemistry, Traditional Use, and Scientific Evidence

1. Identity and Botanical Classification

Calycophyllum is a genus of flowering plants in the family Rubiaceae, described by Augustin Pyramus de Candolle in 1830, and found from Mexico, Central America, South America, and the West Indies. The genus encompasses several species of botanical and ethnomedicinal importance, the most scientifically studied of which are Calycophyllum spruceanum and Calycophyllum candidissimum.

1.1 Calycophyllum spruceanum (Benth.) Hook. f. ex K. Schum.

Calycophyllum spruceanum (Benth.) Hook. f. ex K. Schum. (synonyms: Calycophyllum multiflorum and Eukylista spruceana) is an Amazon native species from the family Rubiaceae found in the Amazon basin territory comprising Brazil, Bolivia, Ecuador, and Peru. The tree is popularly known in Brazil by the name Mulateiro or Pau Mulato, and its timber is intensively explored by the wood industry. Additional common names recorded in the ethnobotanical literature include capirona, capirona de bajo, capirona negra, palo mulato, escorrega-macaco, pau-marfim, uhuachaunin, haxo, and huiso asho.

C. spruceanum is a canopy tree found in the Amazon rainforest, notable for its distinctive bark, which naturally sheds completely once or twice a year to prevent the growth of lichens, fungi, epiphytes, and climbing vines. When left to thrive in its rainforest habitat, the capirona grows tall and straight, soaring up to 30 meters (around 100 feet) in height. Because the stem bark sheds completely and regenerates every year, it has high potential for sustainable industrial exploitation.

1.2 Calycophyllum candidissimum (Vahl) DC.

Calycophyllum candidissimum, commonly known as the degami, dagame, or lemonwood, is a species of flowering plant in the family Rubiaceae, native to southern Mexico, Cuba, Central America, Colombia, and Venezuela. It is found in the ecoregion of Central American dry forests and is the national tree of Nicaragua. Its botanical synonyms include Macrocnemum candidissimum Vahl and Mussaenda candida Poir., as recorded in the GBIF Backbone Taxonomy.

1.3 Calycophyllum multiflorum Griseb.

Calycophyllum multiflorum Griseb., 1879, is classified within the order Gentianales, family Rubiaceae, and is recognized by the NCBI Taxonomy system as a distinct eudicot species. Published in the Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen (1879) and classified within the kingdom Plantae, phylum Tracheophyta, class Magnoliopsida, order Gentianales, family Rubiaceae, and genus Calycophyllum.

1.4 Common Dosage Forms and Commercial Preparations

Dried barks of C. spruceanum can be easily found in local traders of medicinal plants, and the cosmetic industry has shown interest in the beneficial effects of C. spruceanum against skin disorders. Preparations encountered in commerce and traditional settings include:

• Bark decoctions (teas): The stem bark is boiled in water and the resulting liquid is consumed internally or applied topically.
• Poultices and skin patches: Preparations of C. spruceanum barks are used in the form of tea, poultice or skin patches to treat stomach diseases, skin inflammation, and uterus tumors.
• Cosmetic extracts: Due to its beneficial effects on the skin, it is appearing as an ingredient in natural cosmetic products in Peru and Brazil.
• Resins: The resin of the tree is used for abscesses and skin tumors.

2. Traditional and Historical Use

2.1 Amazonian Indigenous Traditions (C. spruceanum)

The tree popularly known in Brazil as mulateiro or pau-mulato (Calycophyllum spruceanum (Benth.) K. Schum.) is deeply embedded in the herbal medicine of the Amazon region. Many of the medicinal indications of C. spruceanum are derived from the traditional knowledge of native indigenous populations of the Amazon forests.

Calycophyllum spruceanum DC. (Rubiaceae), a huge endemic tree from the Amazon, has been traditionally used for the treatment of numerous human ailments including mycoses, influenza, diverse infections, cancer and skin diseases throughout "legal Amazonia," which includes Brazil, Peru, Bolivia and Colombia.

Traditional uses documented in the ethnomedical and botanical literature include:

• Skin and dermatological: A bark decoction is used topically for eye infections and infected wounds as well as for skin spots, skin depigmentation, wrinkles, and scars; it stops bleeding quickly and is often applied to bleeding cuts.
• Infectious disease: In the Peruvian Amazon, a decoction of the bark is used against "sarna negra," a subcutaneous infection caused by an arachnid.
• Gastrointestinal and gynecological: In the Brazilian Amazon, this species is known to treat stomach diseases, skin inflammation, and uterus tumors.
• Metabolic and systemic: It is thought to soothe insect bites and reduce bruising and swelling, and the bark is decocted and used internally for diabetes and disorders of the ovaries.
• Anti-aging: In traditional medicine, it is claimed to work as anti-aging (addressing skin wrinkles and aging spots), antimicrobial (antibacterial, antifungal, anti-parasitic), emollient, wound healing, hemostatic, contraceptive, stimulant, and anti-diabetic.

Popularly known as mulateiro, the species is often prescribed in ethnomedicine for healing and vitality, and is also used to control skin patches.

2.2 Traditional Preparations

For internal use, the standard traditional remedy is ½ to 1 cup of standard decoction two to three times daily. This decoction is also a common topical remedy for skin problems, wounds, skin fungus, and overall skin health, applied directly to the affected area several times daily.

In traditional Amazonian medicinal practices, the dried bark of the capirona tree is used to treat fungal infections of the skin. Made into a poultice, the bark is said to be effective in the treatment of cuts, wounds, and burns.

2.3 C. candidissimum in Mesoamerican Traditions

Calycophyllum candidissimum, known as dagame or lemonwood, is native to southern Mexico, Cuba, Central America, Colombia, and Venezuela. The species holds significant cultural status as the national tree of Nicaragua. Its timber has historically been prized for carpentry. The published scientific literature specific to its medicinal use is considerably more limited than that for C. spruceanum.

3. Key Constituents and Active Compounds

3.1 Seco-Iridoids

The most chemically distinctive and pharmacologically studied class of compounds in C. spruceanum are the seco-iridoids. Three seco-iridoids — 7-methoxydiderroside, 6′-O-acetyldiderroside, and 8-O-tigloyldiderroside — were isolated from the wood bark of Calycophyllum spruceanum, together with the known iridoids loganetin and loganin, and the seco-iridoids secoxyloganin, kingiside, and diderroside. In terms of chemistry, there is emphasis on the presence of alkaloids, tannins, and especially secoiridoids; 7-methoxydiderroside, 6′-acetyl-β-D-glucopyranosyldiderroside, and 8-O-tigloyldiderroside are peculiar to the species.

3.2 Flavonoids and Polyphenols

Previous studies on the phytochemical composition of the stem bark of C. spruceanum revealed the presence of iridoid glucosides. In additional characterization by LC-MS/MS, the iridoid gardenoside, the flavonoids 5-hydroxymorin and taxifolin, the anthocyanin cyanidin, and the coumarin 5-hydroxy-6-methoxycoumarin-glucoside were identified. The polyphenols identified correlate with the high phenolic content indicated by Folin-Ciocalteu and the high antioxidant activity demonstrated in vitro.

3.3 Tannins

Mulateiro bark contains a significant quantity of tannin chemicals, which give it an astringent or drying effect. Tannins in the bark are understood to contribute both to its antimicrobial properties and to its topical skin-conditioning effects. The phytochemistry study of C. spruceanum bark extracts showed the presence of phenols and terpenes, possessing respectively antioxidant activity and in vitro activity against trypomastigote forms of Trypanosoma cruzi.

3.4 Alkaloids

In terms of chemistry, there is emphasis on the presence of alkaloids, tannins, and, especially, secoiridoids. The specific alkaloids have not been fully characterized and remain a subject for further phytochemical investigation.

3.5 Summary of Identified Secondary Metabolites

Five secondary metabolites were identified in the water extract of the stem bark by HPLC-MS/MS, namely gardenoside, 5-hydroxymorin, cyanidin, taxifolin, and 5-hydroxy-6-methoxycoumarin-7-glucoside.

• Gardenoside: An iridoid glucoside with documented antioxidant and anti-inflammatory properties in the broader Rubiaceae literature.
• 5-Hydroxymorin and Taxifolin: Flavonoids with established radical-scavenging activity.
• Cyanidin: An anthocyanin pigment associated with antioxidant activity.
• 5-Hydroxy-6-methoxycoumarin-7-glucoside: A coumarin glycoside; coumarins as a class are associated with photoprotective, antimicrobial, and anticoagulant properties.
• 7-Methoxydiderroside, 6′-O-acetyldiderroside, 8-O-tigloyldiderroside: Species-specific seco-iridoids with demonstrated in vitro antiparasitic activity.

4. Mechanisms of Action

4.1 DAF-16/FOXO Pathway and Longevity Signaling

C. spruceanum extract was able to enhance stress resistance and to extend lifespan along with attenuation of aging-associated markers in C. elegans. The demonstrated bioactivities apparently depend on the DAF-16/FOXO pathway.

The extract possibly works through the DAF-16/FOXO molecular pathway to extend lifespan and enhance stress resistance, thus improving survival after induced oxidative stress, decreasing cellular ROS accumulation and expression of hsp-16.2. The lifespan extension was followed by attenuation of the age-related muscle function decline.

Calycophyllum spruceanum water extract has been shown to modulate the DAF-16/FOXO pathway, and five secondary metabolites have been identified via HPLC/Mass Spectrometry analyses, including 5-hydroxy-6-methoxycoumarin-7-glucoside, cyanidin, gardenoside, taxifolin, and 5-hydroxymorin.

4.2 Antioxidant and Free Radical Scavenging

The high polyphenolic and tannin content of the bark is the principal basis for its antioxidant activity. Studies using DPPH, ABTS, superoxide anion radical, singlet oxygen, and β-carotene bleaching assays have been applied to C. spruceanum extracts. The aim of one investigation was to evaluate the in vitro antioxidant and anti-peroxidase potential of ethanol extracts of five plants from the Brazilian Amazon, including Calycophyllum spruceanum.

4.3 Anti-inflammatory and Antinociceptive Mechanisms

The purpose of the 2018 study by da Silva et al. was to investigate in vivo the antinociceptive and anti-inflammatory activities of the hydroalcoholic extract of Calycophyllum spruceanum barks (HECSb) in order to validate its popular usage in inflammatory conditions. Mice were treated per oral with HECSb (5–5000 mg/kg) and evaluated for acute toxicity during 15 days, motor activity (Rota rod test), body weight (up to 72 hours), antinociceptive activity using writhes induced by 0.8% acetic acid, paw licking induced by 2.5% formalin, and paw withdrawal (von Frey test) induced by carrageenan or PGE.

4.4 Antimicrobial Mechanisms

The broad antimicrobial properties are attributed to the combined action of tannins, iridoids, and flavonoids present in the bark extract. The astringent effect of tannins on microbial cell membranes, combined with the direct antifungal and antibacterial activity of specific secondary metabolites, is understood to underlie the clinical indications observed in traditional use and preliminary laboratory studies.

5. Scientific Evidence by Area of Use

5.1 Anti-aging and Longevity

Evidence level: Preliminary — invertebrate model only; no human trials.

A 2018 study (Peixoto et al., published in Molecules) aimed to provide the first step towards science-based evidence of the beneficial effects of C. spruceanum in the promotion of longevity and in the modulation of age-related markers, using the model system Caenorhabditis elegans to evaluate in vivo antioxidant and anti-aging activity of a water extract.

A water extract from the stem bark was investigated regarding its antioxidant and anti-aging properties using the nematode Caenorhabditis elegans. The investigation included the use of several mutant worm strains and uncovered important traits related to the molecular mechanisms triggered by the extract, comprising enhanced resistance against oxidative stress and lifespan extension, followed by attenuation of aging markers.

Wild-type (N2) worms treated with the C. spruceanum extract exhibited an enhanced survival rate after juglone-induced oxidative stress in comparison with untreated worms.

The data might support the popular claims of mulateiro as the "tree of youth," however more studies are needed to clarify its putative benefits to human health. Additional studies are needed to unveil the molecular mechanisms evoked by the extract. Nonetheless, the work supports the indigenous-based anti-aging claims of C. spruceanum. The assessment of its safety profile for human consumption is strongly suggested.

5.2 Antifungal Activity

Evidence level: Preliminary — in vitro studies only; no clinical trials.

Only a few reports exist on the biological activities of C. spruceanum. Portillo et al. reported a broad-spectrum antifungal activity of a dichloromethane extract from the bark against Candida cladosporioides, Cryptococcus neoformans, Fusarium oxysporum var. pinaster, Microsporum gypseum, Penicillium purpurogenum, Saccharomyces cerevisiae, and Trichophyton mentagrophytes, fungi associated with skin and mucosal infections.

Wen et al. studied the activity of an ethanolic bark extract against T. mentagrophytes, one of the most common etiologic agents of tinea unguium and tinea pedis.

A 2023 study published in the Journal of Advances in Biology & Biotechnology evaluated C. spruceanum leaf extract for endodontic applications. The indiscriminate use of antimicrobials has contributed to the selection of multiresistant bacterial strains, mainly Enterococcus faecalis, leading to the search for new strategies, and this study aimed to evaluate the antibacterial activity of C. spruceanum leaf extract against E. faecalis in vitro for endodontic purposes. The C. spruceanum extract showed antibacterial activity against E. faecalis, and its association with calcium hydroxide potentiated its effect.

5.3 Antibacterial Activity

Evidence level: Preliminary — in vitro studies only; no clinical trials.

A Brazilian phytochemical and antimicrobial study evaluated multiple solvent fractions of C. spruceanum bark against several bacterial strains. The hexane extract showed low inhibitory activity only against Aeromonas hydrophila and Pseudomonas aeruginosa. The DCM, AcOEt, and hydromethanolic phases obtained by methanol partition showed inhibition of Acinetobacter baumannii, Aeromonas hydrophilae, and Salmonella enteritidis bacterial strains.

5.4 Anti-inflammatory and Antinociceptive Activity

Evidence level: Preliminary — animal (rodent) studies only; no human trials.

The 2018 study by da Silva et al. published in the Journal of Ethnopharmacology (PMID 29567276) is the primary peer-reviewed source for in vivo anti-inflammatory activity. The study investigated in vivo the antinociceptive and anti-inflammatory activities of the hydroalcoholic extract of Calycophyllum spruceanum barks (HECSb) in order to validate its popular usage in inflammatory conditions. The study employed standard animal models including acetic acid-induced writhing (for antinociception), formalin-induced licking, and carrageenan-induced paw edema (for anti-inflammatory assessment), all conducted in mice. No human clinical data were generated.

5.5 Antiparasitic Activity

Evidence level: In vitro only; no animal or human studies.

7-Methoxydiderroside, 6′-O-acetyldiderroside, and the known secoxyloganin and diderroside showed in vitro activity against trypomastigote forms of Trypanosoma cruzi, with IC50 values of 59.0, 90.2, 74.2, and 84.9 μg/mL, respectively, and were compared to the standard gentian violet (IC50 7.5 μg/mL).

The IC50 values for the C. spruceanum-derived seco-iridoids were substantially higher (i.e., less potent) than the reference compound gentian violet, indicating only moderate antiparasitic potency in vitro. No further animal or human studies on this indication have been reported in the peer-reviewed literature.

5.6 Antioxidant Activity

Evidence level: In vitro and invertebrate (C. elegans) only; no human trials.

One peer-reviewed investigation evaluated the in vitro antioxidant and anti-peroxidase potential of ethanol extracts of five plants from the Brazilian Amazon, including Calycophyllum spruceanum. Multiple assay systems were employed, including DPPH, ABTS, and superoxide anion scavenging. The polyphenols identified correlate with the high phenolic content indicated by Folin-Ciocalteu and the high antioxidant activity demonstrated in vitro.

5.7 Skin Health and Cosmetic Applications

Evidence level: Traditional and preliminary; no controlled human trials.

Dried barks can be easily found in local traders of medicinal plants, and the cosmetic industry has shown interest in the beneficial effects of C. spruceanum against skin disorders. There is emphasis on the presence of alkaloids, tannins, and especially secoiridoids in the chemistry of the plant. Even with proven photoprotective properties, research on C. spruceanum remains limited.

The INCI (International Nomenclature of Cosmetic Ingredients) designation Calycophyllum Spruceanum Bark Extract is recognized in the cosmetics industry, where the ingredient is categorized as a skin-conditioning agent. It appears as a documented ingredient in commercial topical skin supplements and hair-care products.

6. Body Systems and Health Areas

• Integumentary system (skin): Anti-aging, wound healing, hemostatic, antifungal (topical), emollient, and skin-depigmentation uses are the most prominently documented. Traditional claims include anti-aging (skin wrinkles and aging spots), antimicrobial (antibacterial, antifungal, anti-parasitic), emollient, wound healing, and hemostatic properties.
• Immune and infectious disease: Antimicrobial activity (antibacterial, antifungal, antiparasitic) documented in in vitro studies.
• Gastrointestinal system: In the Brazilian Amazon, this species is known to treat stomach diseases.
• Endocrine and metabolic system: The bark is decocted and used internally for diabetes. No clinical studies on glycemic outcomes have been published.
• Reproductive system: Traditional use for disorders of the ovaries and uterus tumors is documented, though no pharmacological studies have validated these claims.
• Aging and cellular longevity: Modulation of the DAF-16/FOXO pathway demonstrated in an invertebrate model, with implications for oxidative stress and cellular aging.
• Musculoskeletal: The lifespan extension elicited by the extract was followed by attenuation of age-related muscle function decline in C. elegans.

7. Dosage Forms and Reported Dosages

No standardized clinical dosage has been established for any species of Calycophyllum. The following dosages appear in the source literature:

• Traditional oral decoction: For internal use, the standard traditional remedy is ½ to 1 cup of standard decoction, taken two to three times daily.
• Topical decoction: This decoction is also a common topical remedy for skin problems, wounds, skin fungus, and overall skin health, applied directly to the affected area several times daily and allowed to dry before covering.
• Animal study — hydroalcoholic extract (HECSb): In the murine anti-inflammatory study, mice were treated per oral with HECSb at doses ranging from 5 to 5000 mg/kg. These are animal doses and cannot be directly extrapolated to human dosing.
• Invertebrate model — aqueous extract (CE): The water extract used in the C. elegans longevity study was obtained from 200 g of stem bark, which was minced and exhaustively extracted with distilled water (5 × 1 L) at room temperature over five days. Specific concentrations used in C. elegans assays were reported in the original publication.
• In vitro antibacterial study: A crude extract of C. spruceanum leaf at 50 mg/mL, diluted in dimethylsulfoxide, was used for in vitro endodontic evaluation.

8. Safety Considerations

Formal toxicological evaluation of Calycophyllum species is very limited in the published literature. The following points are grounded in peer-reviewed sources:

• Acute toxicity assessment in mice: In the 2018 murine study, mice were treated per oral with HECSb at doses of 5–5000 mg/kg and evaluated for acute toxicity during 15 days and motor activity (Rota rod test). No significant acute toxicity findings were highlighted at lower doses in the published abstract, though full toxicological data were reported in the body of the study.
• Safety assessment for human use recommended: The authors of the 2018 C. elegans longevity study explicitly stated that the assessment of its safety profile for human consumption is strongly suggested, reflecting the absence of adequate human safety data.
• Tannin content and drying effect: Mulateiro bark contains a significant quantity of tannin chemicals, which give it an astringent or drying effect. High tannin intake has been associated in the general pharmacological literature with gastrointestinal irritation, interference with iron absorption, and protein binding; these considerations apply to concentrated or prolonged internal use of tannin-rich herbal decoctions.
• No known contraindications or drug interactions are documented in the peer-reviewed literature specific to Calycophyllum species at the time of the available published research.
• Absence of human clinical trials: No controlled human clinical trials have been conducted for any therapeutic indication. All biological activity data are derived from in vitro assays, animal models, or an invertebrate (C. elegans) model. Extrapolation to human health outcomes is not supported by the available evidence.
• Evidence gap noted by researchers: Only few reports exist on the biological activities of C. spruceanum, and the overall evidence base is recognized as preliminary across all areas of claimed use.

9. Overall Evidence Assessment

The published scientific literature on Calycophyllum — primarily centered on C. spruceanum — is limited in volume and depth. The data might support the popular claims of mulateiro as the "tree of youth," however more studies are needed to clarify its putative benefits to human health. Additional studies are needed to unveil the molecular mechanisms evoked by the extract; nonetheless, the presented work supports the indigenous-based anti-aging claims of C. spruceanum.

The strongest current evidence pertains to antifungal and antibacterial activity in cell-free or cell-based in vitro systems, and to longevity/antioxidant modulation in a non-vertebrate animal model. Anti-inflammatory and antinociceptive effects have been demonstrated in murine models only. No human clinical trial data exist for any indication. The entire body of evidence must therefore be characterized as preliminary, and no evidence-based therapeutic claims can be made for Calycophyllum preparations at this stage of research.

References

• Peixoto H, Roxo M, Koolen H, et al. "Calycophyllum spruceanum (Benth.), the Amazonian 'Tree of Youth' Prolongs Longevity and Enhances Stress Resistance in Caenorhabditis elegans." Molecules. 2018;23(3):534. PMC6017494.
• Peixoto H, et al. Molecules 2018, 23, 534. MDPI Open Access version.
• Cardona Zuleta LM, Cavalheiro AJ, et al. "seco-Iridoids from Calycophyllum spruceanum (Rubiaceae)." Phytochemistry. 2003;64(2):549–553. ScienceDirect.
• da Silva APB, et al. "Calycophyllum spruceanum BENTH ameliorates acute inflammation in mice." Journal of Ethnopharmacology. 2018;219:103–109. PubMed PMID 29567276.
• da Silva APB et al. Calycophyllum spruceanum BENTH ameliorates acute inflammation in mice. J Ethnopharmacol. 2018. ScienceDirect.
• De Vargas FS, et al. "Antioxidant activity and peroxidase inhibition of Amazonian plants extracts traditionally used as anti-inflammatory." BMC Complement Altern Med. 2016;16(1):1–8. PMC4769535.
• Silva BBM et al. "Antibacterial Activity of Calycophyllum spruceanum Leaf Extract against Enterococcus faecalis Strains 'In vitro' for Endodontic Purposes." Journal of Advances in Biology & Biotechnology. 2023;26(1):33–41.
• Sobeh M, et al. "Bioactive Phytochemicals with Anti-Aging and Lifespan Extending Potentials in Caenorhabditis elegans." MDPI/PMC. 2021. PMC8658929.
• Wikipedia: Calycophyllum (genus overview, taxonomy, and distribution).
• Wikipedia: Calycophyllum candidissimum.
• GBIF Backbone Taxonomy: Calycophyllum candidissimum (Vahl) DC.
• GBIF Backbone Taxonomy: Calycophyllum multiflorum Griseb.
• NCBI Taxonomy Browser: Calycophyllum multiflorum.
• Taylor L. Technical Data Report for Mulateiro or Capirona (Calycophyllum spruceanum). Rain-Tree Publishing, 2005.
• Caetano et al. "Sobre a botânica, a etnofarmacologia e a química de Calycophyllum spruceanum." Revista Brasileira de Plantas Medicinais (SciELO Brazil).
• PlantPono: Calycophyllum spruceanum species profile.
• Peixoto H et al. Molecules 2018, 23, 534. Semantic Scholar PDF.