The cellular structure of F. betulina contains beneficial polysaccharides, notably α-glucans, which exhibit water insolubility but can be dissolved in alkaline solutions (Grün, 2003; Pleszczyńska et al., 2017). Wiater et al. (2011) isolated and characterized (1→3)-α-d-glucans, with the main chain comprising 84.6% (1→3)-linked α-d-glucopyranose units along with 6% (1→4)-linked units. Piptoporane I was extracted and purified by Olennikov et al. (2012). The α-glucan in F. betulina primarily consists of (1→3)-α-d-glucopyranose units, with occasional branching by β-d-glucopyranose at the C6 position (17.3%). This specific type of fungal α-glucan, present in F. betulina, is known to stimulate the production of microbial mutanases, which have the potential to prevent dental caries. Streptococci mutans produces (1→3), (1→6)-α-d-Glucans (mutans), crucial components of dental plaque matrix, making them a promising target for enzymatic anti-caries strategies (Pleszczyńska et al., 2015). Nonetheless, Streptococcal glucans pose challenges as inducers of mutanases due to their low yield and structural variability. Birch polypore α-glucan, which can constitute up to 44–53% of the dry weight of the cell wall of F. betulina (Grün, 2003), offers a potential alternative to replace S. glucans (Wiater et al., 2008). α-(1 → 3)-Glucooligosaccharides (α-(1 → 3)-GOS), sourced from F. betulina, underwent evaluation for their ability to combat cancer. They demonstrated the capacity to hinder the growth of colon cancer cells by reducing their proliferation and promoting apoptosis, all the while leaving normal colon cells unaffected. These results suggest that α-(1 → 3)-GOS has potential as a valuable dietary or therapeutic substance for restraining cancer cell proliferation, especially in colon carcinoma models (Czerwonka et al., 2019). Fomitopsis betulina was assessed for mycelial growth and exopolysaccharide production across 22 strains. The study found significant variability in growth rates (3.50 ± 0.33 to 8.75 ± 0.50 mm/day) and exopolysaccharide production (0.02 ± 0.00 to 2.20 ± 0.31 g/L), with maltose as the optimal carbon source for growth and dextrose and starch enhancing exopolysaccharide yield. Notably, strain F. betulina 311 demonstrated strong growth and high biopolymer production, highlighting its biotechnological potential (Kizitska et al., 2024).

The fermentation characteristics of exopolysaccharides (EPS) isolated from F. castaneus were studied in simulated human intestinal environments. The purified EPS, containing glucose, galactose, rhamnose, mannose, and arabinose, increased the production of short-chain fatty acids (SCFAs) in fecal extracts from both adults and children, with higher SCFA yields in children. Adding to the microbial flora, such as with Enterococcus fecalis and Lactobacillus rhamnosus, further enhanced SCFA production, highlighting the potential of EPS from F. castaneus to support gut health (Guo and Chi, 2017). FEPS, extracted from Fomitopsis castanea mycelia using ethanol precipitation, exhibited potent inhibition of mushroom tyrosinase with an IC50 of 16.5 mg/ml. It effectively reduced melanin production in human melanoma cells, diminished pigment density in embryos, and hindered NO production in macrophage cells with an IC50 of 42.8 ± 0.64 μg/ml (Jin et al., 2019).

Three types of polygalacturonases, including two endo-type (EndoPG I, II) and one exo-type (ExoPG), were purified from F. cytisina. EndoPG I and II had molecular weights of 38 kDa, while ExoPG ranged from 50-60 kDa, with optimal pH values around 5.0-5.5 and thermal stability up to 45°C. EndoPGs showed varying activity on oligo-galacturonic acids, while ExoPG displayed maximum activity on substrates with 9 GalUA and no activity on unsaturated oligo-galacturonic acids (Miyairi et al., 2001).

Mannofucogalactan, a major polysaccharide from F. officinalis fruiting bodies, was extracted using boiling water and purified, revealing a branched structure with a backbone of partially 3-O-methylated 1,6-O-linked α-D-galactopyranosyl residues. These residues were substituted at O-2 by 3-O-α-D-mannopyranosyl-α-L-fucopyranosyl and β-D-galactopyranosyl units, with α-L-fucopyranosyl units forming part of the side chains (Golovchenko et al., 2018).

Branched β-glucans from F. officinalis showed cytotoxic activity (Golovchenko et al., 2020). Fomitopsis officinalis yielded a purified heteropolysaccharide, FOBP50–1, with a molecular weight of 2.21 × 10⁴ g/mol, composed of 3-O-methylfucose, fucose, mannose, glucose, and galactose in a ratio of 1:6.5:4.4:8.1:18.2. Its structure was elucidated using UV, FT-IR, GC–MS, and NMR analysis. FOBP50–1 demonstrated significant antitumor activity in zebrafish assays by interacting with TLR-4, PD-1, and VEGF, thereby activating immunity and inhibiting angiogenesis. These results highlight its potential as a tumor immunotherapy agent (Shen et al., 2024). A purified heteropolysaccharide, FOBP90-1, was isolated from F. officinalis to explore its anticancer potential. FOBP90-1, with a molecular weight of 2.87 × 10⁴ g/mol, comprises several sugar residues, including α-d-Galp, α-l-Fucp, β-d-Glcp, α-d-Manp, and 3-O-Me-α-l-Fucp, as identified by UV, FT-IR, methylation analysis, and NMR. In zebrafish models, FOBP90-1 demonstrated anticancer activity by promoting immune activation and inhibiting angiogenesis. Mechanistic studies revealed that these effects were mediated through interactions with TLR-2, TLR-4, PD-L1, and VEGFR-2, suggesting FOBP90-1’s potential as a cancer treatment agent (Liu et al., 2024).

An extracellular β-glucosidase was purified from the brown-rot F. palustris, with a molecular mass of approximately 138 kDa and high homology with fungal β-glucosidases from glycosyl hydrolase family 3. The enzyme exhibited optimal activity at pH 4.5 and 70°C, with significant activity against p-nitrophenyl-β-d-glucoside and cellobiose, while being competitively inhibited by glucose and gluconolactone. These findings classify the β-glucosidase as an aryl-β-glucosidase with cellobiase activity, demonstrating notable thermostability (Yoon et al., 2008a).

Fomitopsis pinicola is a traditional medicinal mushroom used in folk medicine in both China and Korea. Polysaccharides are the principal constituents of the fruiting body of F. pinicola. The extract (polysaccharide [FPP]) derived from F. pinicola was observed to lower fasting blood glucose levels while promoting increased body weight. In addition, FPP displayed a restorative impact on insulin levels in the bloodstream. Moreover, FPP demonstrated a noteworthy influence on lipid metabolism by reducing total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol levels while elevating high-density lipoprotein cholesterol levels. Consequently, the FPP extract demonstrated beneficial properties for diabetes management, antioxidant effects, and regulation of lipid levels (Zahid et al., 2020a, 2020b, 2020c).

A heterogalactan was isolated from F. pinicola fruiting bodies and further separated into fucogalactan and mannofucogalactans using chromatography. Structural analysis revealed that all fractions are highly branched polysaccharides with a (1→6)-linked α-D-galactopyranosyl backbone, substituted with L-fucopyranosyl or mannopyranosyl-fucopyranose units (Usui et al., 1981). Polysaccharides from F. pinicola showed no toxicity to endothelial cells and had strong anti-angiogenic and anti-inflammatory effects (Cheng et al., 2008). Fomitopsis pinicola extract effectively lowered blood glucose levels by 77% after 20 days increasing HDL cholesterol by 73% and decreasing LDL cholesterol by 76%. This suggests its potential for atherosclerosis prevention and treatment, though more research is needed to understand the mechanisms involved (Cha et al., 2009). Researchers isolated F. pinicola, a potent ß-1, 4-glucosidase (BGL) producer through morphological and genetic analysis. They purified the BGL using a chromatographic process and found it belongs to glycoside hydrolase family 3, known for efficient enzymes. F. pinicola BGL stands out for its remarkable efficiency and specific substrate preferences (Joo et al., 2009). Fomitopsis pinicola polysaccharides comprise both extracellular and intracellular variants with distinct molecular weights, and both types of polysaccharides exhibited antioxidant properties, as evidenced by their ability to counteract DPPH and hydroxyl radicals in vitro and protect yeast cells from UV and hydrogen peroxide-induced oxidative damage. Importantly, intracellular polysaccharides displayed superior antioxidant activity compared to their extracellular counterparts (Hao et al., 2016).

Fomitopsis pinicola yielded twelve new sesquiterpenoids (fomitopins A–L [1–12]), through bioassay-guided purification. Their structures were determined using spectroscopic analyses and confirmed by ECD simulations. Ten compounds were tested for anti-inflammatory activity, with compound 11 showing the strongest inhibition of superoxide anion generation and elastase release (IC50 values of 0.81 ± 0.15 and 0.74 ± 0.12 μM). These sesquiterpenoids are promising candidates for further anti-inflammatory research (Tai et al., 2019). Fomitopsis pinicola exhibits protective effects against alcohol-induced liver injury through its mycelia polysaccharides (FPMPS). FPMPS improved serum lipid levels, maintained hepatic and cecal morphology, and modulated gut microbiota disrupted by alcohol. Mechanistically, FPMPS-regulated pathways, such as retinol metabolism, bile secretion, TRP channel inflammation, and the PI3K-Akt signaling pathway, play a key role in preventing liver damage. FPMPS shows promise as a potential therapeutic agent for acute alcoholic liver injury and as a functional health food (Wu et al., 2023). Table 1 lists polysaccharides from various species of Fomitopsis, along with their structures and therapeutic applications.

The mycelium of F. betulina was cultured via liquid fermentation, leading to the isolation of seven pimarane-type diterpenes from the fermentation broth. These were pipulinus A–D, pipulinus F, elaeicolasides B, and pipulinus E (Rapior et al., 1996). Twenty sesquiterpene compounds were identified from fresh F. betulina fruiting bodies, including (R)-trans-nerolidol, β-elemene, and α-chamigrene. Four of these—Isobazzanene, (S)-(−)-daucene, (−)-β-barbatene, and (+)-α-barbatene—were reported as fungal components for the first time. Subsequent research identified four additional monoterpenes such as linalool and α-terpineol, further expanding the understanding of F. betulina’s volatile constituents (Rösecke et al., 2000). Schlegel et al. (2000) found piptamine in F. betulina, which exhibited antimicrobial properties against bacteria and yeast, including C. albicans, at low concentrations. This discovery highlights the significance of compounds beyond polysaccharides in mushroom bioactivity. A novel phenolic compound, (E)-2-(4-hydroxy-3-methyl-2-butenyl)-hydroquinone, was isolated from the fresh fruiting bodies of F. betulina (Kawagishi et al., 2002).

Polyporenic acid C and three additional triterpenoids found in F. betulina have been shown to exhibit anti-inflammatory and antibacterial properties by proficiently blocking the activity of 3α hydroxysteroid dehydrogenase and bacterial hyaluronate lyase (Wangun et al., 2004). Two significant tetraterpene compounds, β-carotene, and lycopene, were successfully identified in the dried powder of F. betulina fruiting bodies. These compounds are recognized for their potent antioxidant properties. The known spectrum of phenolics in this species was expanded by detecting four tocopherols—α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol—in a dried powder of F. betulina (Reis et al., 2011). Alresly et al. (2016) isolated one new and ten known triterpenes from fungal fruiting bodies of F. betulina. The new compound had antibacterial activity. Fomitopsis betulina showed high potential for antitumor activities (Sari et al., 2020). In a rich fermentation broth of F. betulina, three sesquiterpenes, including cryptosphaerolide B and two bicyclic sesquiterpenes, rel-(1S,4S,5R,7R,10R)-10-desmethyl-11-euduemene and 10,11-epoxyguaian-13-ol, were identified. In addition, seven pimarane-type diterpenes, pipulinus A–D, pipulinus F, elaeicolasides B, and pipulinus E, were isolated from the mycelium cultured via liquid fermentation. Two phenolic compounds, (3R)-5-carbomethoxymellein and 4-hydroxyphenethyl alcohol, were also identified in the fermentation broth (Sun, 2015). Five previously unreported lanostane-type triterpenoids, named piptolinic acids A–E, were identified from F. betulina, along with five known lanosterol-type triterpenoids: 3-epi-(3′-hydroxy-3′-methylglutaryloxyl)-dehydrotumulosic acid, dehydroeburiconic acid, 6α-hydroxypolyporenic acid C, and 3-epi-dehydropachymic acid (Tohtahon et al., 2017). Previously unreported 24-methyl-lanostane-type triterpenes (piptolinic acid F–J) were isolated from dried F. betulina fruiting bodies, along with seven known lanosterol-type triterpenoids (Khalilov et al., 2018). Eleven triterpenoids and betulin from F. betulina were tested for protective effects against chromosome aberrations in human lymphocytes using the CBMN assay. Most compounds reduced DNA damage more effectively than amifostine, with 2.0 µg/mL being the most effective concentration. D8-lanostanes exhibited better activity than those with a conjugated 7,9 (11)-diene system, while betulin showed the lowest protective activity, comparable to amifostine (Anđelković et al., 2021). Thirteen new 24-methylene lanostane triterpenoids and seventeen previously identified compounds were isolated from F. betulina. Fomitosides L and N exhibited cytotoxic effects on HL60 leukemia cells. Among the known compounds, dehydropachymic acid, pachymic acid, 3-epi-dehydrotumulosic acid, and 12α-hydroxy-3α-(3’-hydroxy-4’-methoxycarbonyl-3’-methylbutyryloxy)-24-methyllanosta-8,24(31)-dien-26-oic acid demonstrated significant cytotoxicity against HL60 leukemia cells while showing selectivity for MRC-5 healthy cells (Sofrenić et al., 2021). Researchers have identified 47 different lanostane-type triterpenoids in F. betulina (Li et al., 2024).

Fomitopsis officinalis fruiting bodies contain abundant triterpenoids, polysaccharides, organic acids, coumarins, and phenolic compounds. Scientific studies have shown that extracts and isolated components from F. officinalis offer diverse therapeutic advantages, encompassing anti-inflammatory, cytotoxic, and antimicrobial properties (Muszyńska et al., 2020). Antiviral effects of F. officinalis could prevent neuropathies associated with infections caused by the herpes viruses or hepatitis C (Stamets, 2011). Two chlorinated coumarins were isolated from the ethanol extract of F. officinalis and characterized. These compounds demonstrated specific antimicrobial activity against M. tuberculosis, including drug-resistant isolates, with minimum inhibitory concentrations (MICs) ranging from 22 to 50 µg/ml (Hwang et al., 2012). Eight compounds were isolated from F. officinalis, including 4, 6, 8 (14), 22 (23)-tetraen-3-one-ergostane, identified for the first time. Fomefficinic acids A and C and 3-keto-dehydrosulfurenic acid inhibited MCF-7 breast cancer cells, while fomefficinic acids A and C also suppressed SMMC-7721 liver cancer cells (Chi et al., 2014). Triterpene lactone, known as fomefficin, and the sesquiterpene extracted from F. officinalis have demonstrated notable anti-cancer effects (Feng and Yang, 2015). Similar properties have been observed in a group of triterpene compounds called the officimalonic acids A – H isolated from the methanol extract of F. officinalis. Their anti-inflammatory and cytotoxic activity in in vitro conditions was confirmed in contact with human cancer cells H460, HepG2, and BGC–823 (Wu et al., 2014). The exploration of the chemical composition of F. officinalis resulted in the isolation of four newly identified lanostane triterpenoids and four previously reported triterpenoids. Their capacity to inhibit Trypanosoma congolense, a pathogenic agent causing severe animal diseases, was assessed. Compounds 2-5 and 8 demonstrated moderate inhibitory activity, with IC50 values ranging from 7.0-27.1 µM (Naranmandakh et al., 2018). Flavonoids in F. officinalis can potentially mitigate oxidative stress in the aging mouse brain (Sha, 2016). Dehydrosulfurenic acid, a lanostane-type triterpenoid derived from F. officinalis, has been patented for its potential use as a pharmaceutical treatment for ischemic stroke (Saba et al., 2015; Simi and Prisco, 2018; Flores et al., 2023),. Moreover, eburicoid acid could further prove to have antidepressant effects (Yang et al., 2019; Muszyńska et al., 2020).

In this study, the fresh fruiting body of F. pinicola was freeze-dried, and 300g of the dried mushroom was extracted sequentially with dichloromethane and methanol. The dichloromethane extract, accounting for 13.7% of the total extract, exhibited antimicrobial activity in a TLC bioassay (Hamburger & Cordell, 1987). Phytochemical analysis of methanol and n-hexane extracts from F. pinicola identified triterpene derivatives and aromatic compounds reduced from lignin. New natural compounds such as pinicolol C and pinicolic acid E were discovered, along with steryl esters such as 3β-linoleyloxyergosta derivatives. HPLC and TLC confirmed that the surface of F. pinicola is rich in lanostane derivatives (Rösecke and König, 2000). Two newly discovered lanostane triterpenoids and ten previously unreported lanostane triterpene glycosides were found in F. pinicola (Yoshikawa et al., 2005). A novel lanostane triterpene, 3α-acetyloxylanosta-8,24-diene-21-ol, was obtained from an active fraction of the fungus F. pinicola extract. In addition, two known triterpenic acids, pinicolic acid A and 3α-acetoxylanosta-8, 24-dien-21-oic acid, were identified. These compounds demonstrate cytotoxic and antimicrobial activities (Petrova et al., 2007). Various lanostane triterpenoids and an ergostane compound obtained from American F. pinicola exhibited antimicrobial activity, particularly against B. cereus, with MIC values ranging from 16 to 128 μg/ml. Compounds A, B, C, and F demonstrated specific antimicrobial effects, while D and E displayed lower specificity (Liu et al., 2010). The effects of F. pinicola, a medicinal fungus with notable anti-tumor activity primarily due to 3α-acetoxylanosta-8,24-dien-21-oic acid, were assessed on immune function in mice. The study found increased phagocytic rate, serum hemolysin levels, lymphocyte conversion rate, and phagocytic index in the F. pinicola group compared to controls. The compound enhanced lymphocyte transformation at low concentrations, but the effect decreased at higher concentrations. Overall, dry mycelia of F. pinicola effectively enhanced immune competence in mice (Bao et al., 2015).

To identify the chemical constituents of the fruiting bodies of F. pinicola, researchers isolated a novel lanostane triterpene glycoside, named fomitoside K, from its methanolic extract (Lee et al., 2012). Three new 24-methyl-lanostane triterpenoids (fomitopsins D-F) and four known compounds were isolated from F. feei. Fomitopsins E and F showed antibacterial activity against B. cereus, while fomitopsin D exhibited antiviral activity against herpes simplex virus type 1 (HSV-1) (Isaka et al., 2017). Seven lanostane-type triterpenes isolated from F. pinicola and F. officinalis showed significant antitumor activity, particularly in MCF-7 cells. Compounds 2 and 4 effectively suppressed tumor growth in mice, influencing VEGF and cytokine expression. Acetyl or carbonyl at C-3 and hydroxy at C-15 enhanced their antitumor effects (Shi et al., 2017). A triterpenoid, 3 acetoxylanosta 8,24 dien 21 oic acid (FPOA), a triterpenoid obtained from the fruiting body of F. pinicola, exhibits cytotoxic properties, particularly targeting HepG2 hepatoma cells (Song et al., 2018). Fomitopsis pinicola yielded twelve new sesquiterpenoids, fomitopins A–L (1–12), through bioassay-guided purification. The structures were determined using spectroscopic analyses and confirmed by ECD simulations. Ten compounds were tested for anti-inflammatory activity, with compound 11 showing the strongest inhibition of superoxide anion generation and elastase release (IC50 values of 0.81 ± 0.15 and 0.74 ± 0.12 μM). These sesquiterpenoids are promising candidates for further anti-inflammatory research (Tai et al., 2019). A methanolic extract of F. pinicola yielded 35 lanostane-type triterpenoids, including 13 newly discovered compounds and 22 previously known ones. These compounds demonstrated cytotoxicity against various human tumor cell lines, such as HL-60, A549, SMMC-7721, MCF-7, and SW480. In addition, certain compounds exhibited selective inhibitory effects against specific cell lines, with some inducing apoptosis in HL-60 cells (Peng et al., 2019). Twelve previously unreported sesquiterpenoids, named fomitopins A–L (1–12), were isolated from F. pinicola, known for its antimicrobial and anti-inflammatory properties. These newly discovered sesquiterpenoids hold promise for further anti-inflammatory research (Tai et al., 2019). Fruiting bodies of F. pinicola yielded 28 lanostane triterpenoids, comprising 11 novel and 17 previously identified compounds. Some of these compounds reduced nitric oxide release, while others demonstrated notable PTP1B inhibitory properties. Kinetic analysis confirmed two compounds as competitive PTP1B inhibitors, and three were observed to enhance glucose uptake in insulin-resistant cells. These findings indicate the potential of F. pinicola as a functional food or medicine for diabetes management (Zhang et al., 2020).

Thirteen novel and nine known lanostane triterpenoids were isolated from F. pinicola fruiting bodies, with their structures confirmed through spectroscopic analysis and X-ray diffraction. Nor-pinicolic acids A−F, featuring unique C-25-C-27 nor-lanostane skeletons, were first identified in this species. Anti-inflammatory assays showed that pinicopsic acid F and 16α-hydroxy-3-oxolanosta-7,9(11),24-trien-21-oic acid exhibited moderate inhibition of LPS-induced NO production in RAW 264.7 cells, with IC50 values of 24.5 and 25.7 μM (Liu et al., 2022).

Twelve previously unreported lanostane-type triterpenes, along with twenty-two known triterpenes, were discovered and characterized in F. pinicola. Thirty-two triterpene compounds were assessed for their anti-inflammatory potential using neutrophils as a model, with pinicolasin J emerging as the most effective inhibitor of superoxide anion generation (Kuo et al., 2021). Volatile compounds from F. pinicola were analyzed, and during sporulation, F. pinicola released (R)- and (S)-oct-1-en-3-ol, octan-3-one, and sesquiterpenes. Chopping up the fruiting bodies released volatiles and they attracted wood-living beetles and moths, with rac-oct-1-en-3-ol being a key attractant (Fäldt et al., 1999). Phytochemical analysis of F. pinicola yielded a new lanostanoid derivative and seven known triterpenes. Five of these compounds showed antimicrobial activity against Bacillus subtilis (Keller et al., 1996).

Chemical analysis of Fomitopsis carnea solid-state cultures led to the discovery of two new triterpenoid glycosides, forpiniosides B and C, and two already known compounds. Structural identification was carried out using HRESIMS and NMR techniques. Among the compounds, forpinioside B showed notable antimicrobial activity against Staphylococcus aureus and B. subtilis, with MIC values comparable to standard antibiotics gentamycin and oxytetracycline (Sum et al., 2023). A new lanostane triterpene glycoside, fomitoside-K, was isolated from Fomitopsis nigra and tested for anticancer activity against human oral squamous cell carcinoma (YD-10B) cells. Fomitoside-K induced apoptosis via mitochondrial dysfunction, increased ROS levels, and activated JNK and ERK pathways. Its effects were reduced by ROS scavengers and MAPK inhibitors. In addition, fomitoside-K showed synergy with adriamycin, suggesting its potential as a treatment for oral cancer through a ROS-dependent mitochondrial apoptosis pathway (Bhattarai et al., 2012). Hypercholesterolemia, a major risk factor for coronary heart disease, can be mitigated by inhibiting NPC1L1-mediated cholesterol absorption. A novel compound, fomiroid A, was discovered in F. nigra mushroom extracts, showing potent inhibition of ezetimibe glucuronide binding to NPC1L1. Fomiroid A, a lanosterone derivative (C₃₀H₄₈O₃), dose-dependently blocked cholesterol uptake in Caco2 cells and acted as a pharmacological chaperone for the L1072T/L1168I mutant of NPC1L1, suggesting a unique mechanism of action compared to ezetimibe (Chiba et al., 2014).

The extract from Fomitopsis rosea yielded two novel lanostane triterpenes—3α-(3′-butylcarboxyacetoxy) oxepanoquercinic acid C 1 and 3α-hydroxy-24-methylene-23-oxolanost-8-en-26-carboxylic acid 2—in addition to three previously identified triterpenes and one epidioxy sterol derivative. While all these triterpenes demonstrated antibacterial effects against S. aureus, none exhibited anti-radical properties against DPPH radicals (Popova et al., 2009). Fomitopsis spraguei was investigated for its methanolic extract, leading to the isolation of five lanostane-type triterpenoids. These included three novel compounds named fomitopsins A–C, along with two known compounds: quercinic acid C and 3α-carboxyacetyl-12β-hydroxyquercinic acid (Quang et al., 2005). Two newly identified 24-methyl-lanostane triterpenoids, named fomitopsins I and J, were detected in Fomitopsis sp. along with seven previously recognized compounds. One known compound exhibited antibacterial effects against B. cereus (with a minimum inhibitory concentration of 6.25 μg/ml) and Enterococcus faecium (with a minimum inhibitory concentration of 12.5 μg/ml) (Isaka et al., 2019). The triterpenoid composition of various Fomitopsis species, highlighting their bioactivities, including anticancer, anti-inflammatory, and antimicrobial properties is summarized in Table 2 .

A novel thermostable endoglucanase has been identified from the brown rot fungus F. meliae CFA 2, which was purified 34.18-fold and has a specific activity of 302.90 U/mg. The enzyme exhibits optimal activity at 70°C and a pH of 4.8, with a molecular weight of 37.87 kDa, making it promising for biomass hydrolysis due to its favorable kinetic properties and stability. Its activity is enhanced by Zn²⁺ and K⁺ ions, with a half-life of 11.36 h at 70°C (Patel and Shah, 2021). The cellulolytic-hemicellulolytic enzyme production of F. meliae CFA 2, a newly isolated brown rot fungus, was studied. Under solid-state fermentation with wheat bran, it produced 1391.12 U/g of endoglucanase. After statistical optimization, the endoglucanase yield increased by 1.83-fold. Enzymatic saccharification of alkali-treated wheat and rice straw released 190.8 and 318.8 mg/g of reducing sugars, respectively, highlighting its potential for biomass degradation (Patel et al., 2021). Cellulose can be broken down by cellulases for biofuel production. Fomitopsis meliae has been cultivated under solid-state fermentation (SSF) on wheat bran, achieving high cellulase yields, particularly CMCase. Using the One-Factor-at-a-Time (OFAT) approach, optimal SSF conditions were determined, including a temperature of 32–36°C, pH 4.0, and a 1:3 moisture ratio. These results highlight F. meliae as a promising cellulase producer for industrial applications (Jini and Singh, 2024). Enzymes and proteins isolated from species of Fomitopsis along with details on their activities, characteristics, and potential biotechnological applications are presented in Table 3 .

Malate synthase, a key enzyme in the glyoxylate cycle, was purified from F. palustris. The enzyme, with a molecular mass of 520 kDa and composed of eight 65-kDa subunits, showed Km values of 45 μM for glyoxylate and 2.2 μM for acetyl-CoA. Its activity was inhibited by oxalate, glycolate, and coenzyme A, with p-chloromercuribenzoate indicating the presence of a sulfhydryl group at the active site. The enzyme required Mg2+ for full activation and stability, becoming inactive without metal ions (Munir et al., 2002). Isocitrate lyase, a key enzyme in the glyoxylate cycle, was purified 76-fold with a 23% yield from F. palustris grown on glucose. The enzyme, with a molecular mass of 186 kDa, consists of three 60-kDa subunits. It has a Km of 1.6 mM for isocitrate at pH 7.0 and requires Mg2+ and sulfhydryl compounds for optimal activity. The enzyme is strongly inhibited by oxalate and itaconate, with Ki values of 37 and 68 μM, respectively. These findings suggest that isocitrate lyase plays a regulatory role in fungal growth (Munir et al., 2002). One study investigated the roles of the glyoxylate and tricarboxylic acid cycles in oxalate biosynthesis during fungal development. Enzyme activities were higher during the vegetative stage, with isocitrate lyase contributing to oxalate synthesis early on, while isocitrate dehydrogenase played a key role in glutamate synthesis during F. palustris fruiting body formation (Yoon et al., 2002). NADP-linked isocitrate dehydrogenase (EC 1.1.1.42) was purified 672-fold from the copper-tolerant fungus F. palustris. The enzyme, with a molecular mass of 115 kDa, consists of two 55-kDa subunits and has Km values of 12.7, 2.9, and 23.9 μM for isocitrate, NADP, and Mg²⁺, respectively, at pH 9.0. Mg²⁺ enhances activity and prevents inactivation. The enzyme is competitively inhibited by 2-oxoglutarate (Ki, 127.0 μM) and strongly inhibited by oxaloacetate and glyoxylate through mixed inhibition (Yoon et al., 2003). Fomitopsis palustris has been shown to degrade crystalline cellulose (Avicel) by producing exoglucanases, endoglucanases, and β-glucosidase. After 14 days, the relative crystallinity of Avicel decreased from 83% to 78.5%. The optimal conditions for exoglucanase activity were pH 4.5 and 70°C. Hydrolysis yielded 1.6 mg/mL of glucose after 43 hours, with a cellulose conversion degree of 3.2%, highlighting F. palustris’ capability to break down crystalline cellulose (Jeong-Jun, 2005).

Fomitopsis palustris produces a 72 kDa extracellular enzyme, identified as a glucoamylase, when grown in cellulose culture with cellobiose. When the enzyme was purified, its amino acid sequence showed high similarity to fungal glycoside hydrolase family 15 glucoamylases. The kinetic activity of the enzyme increased with the substrate’s polymerization, and the glucoamylase gene (gla) was cloned via reverse transcriptase PCR (Yoon et al., 2006). Two endoglucanases produced by F. palustris were purified, with molecular masses of 47 kDa and 35 kDa. The 47-kDa enzyme resembled fungal glycoside hydrolase family 5, while the 35-kDa enzyme exhibited high cellulase activity despite no homology to known glycosylhydrolases. Both enzymes efficiently degraded Avicel, producing cellobiose as the primary product (Yoon et al., 2007a). An extracellular xylanase from the brown-rot fungus F. palustris was purified to a single protein band, showing a molecular mass of approximately 43 kDa on SDS-PAGE. The amino acid sequence of the enzyme indicated significant homology with fungal glycoside hydrolase family 10 xylanases. The optimal activity of the purified xylanase occurred at pH 4.0–5.0 and a temperature of 70^∘C (Yoon et al., 2007b).

When cDNA and FpTRP26 were isolated from F. palustris through yeast transformant screening, they conferred specific resistance to OA. Transformants showed a 65% reduction in OA content when grown with 2 mM OA. FpTRP26 transcript levels increased with OA accumulation and remained high, even in the stationary phase, suggesting that FpTRP26 plays a key role in OA resistance in F. palustris (Watanabe et al., 2007). Two acidic β-glucosidases (βGI and βGII) from Fomitopsis palustris were purified, showing optimal activity at pH 2.5 and 55°C. Both enzymes effectively hydrolyzed cello-oligosaccharides to release glucose, and F. palustris produced high ethanol yields from various sugars, highlighting its potential for bioethanol production (Okamoto et al., 2011). Fomitopsis palustris produces two oxalate-generating enzymes, with oxaloacetate acetylhydrolase (FpOAH) playing a dominant role in oxalate biosynthesis. A cloned 1080-bp cDNA confirmed FpOAH activity, and its gene expression was significantly higher than that of glyoxylate dehydrogenase (FpGLOXDH), suggesting FpOAH’s primary role in oxalate production (Hisamori et al., 2013). Fomitopsis palustris produces cellulases to degrade cellulose, including a newly identified endoglucanase gene, cel12. This gene encodes a protein lacking a cellulose-binding domain but is highly conserved among GH family 12 cellulases. The expression of the gene increases during growth on cellulose, and recombinant cel12 shows endoglucanase activity on carboxymethyl cellulose, but not crystalline cellulose (Song et al., 2018).

The milk-clotting enzyme (BR) from F. pinicola was compared to commercial rennet (HR) for cheese-making. BR had higher activity at 35°C, greater heat stability, and more proteolytic activity than HR. Both enzymes acted similarly on κ-casein, and after 50 minutes, curds produced by BR and HR had the same tension. The study concluded that BR could be a viable substitute for commercial rennet in cheese production (Nakanishi and Itoh, 1969). The solid fermentation product of F. pinicola demonstrated notable anti-tumor and anti-oxidation effects in H22 tumor-bearing mice, with high and moderate doses achieving inhibition rates of 66.66% and 64.70%, respectively. Treatment increased serum levels of IL-2 and IFN-γ, reduced MDA levels, and enhanced antioxidant enzyme activities (SOD, CAT, and GSH-PX), highlighting its potential as a therapeutic agent (Sun et al., 2016).

Laccases from F. pinicola FP58527 SS1 were detected in the secretome when grown on poplar and spruce wood. Two laccases, FpLcc1 and FpLcc2, were produced and purified for testing. Both showed similar low pH-optima and moderate catalytic efficiency. Notably, FpLcc2 was significantly activated by acetic acid, especially at pH 5.0, suggesting a unique regulatory mechanism in brown rot fungi (Csarman et al., 2021). The heterologous expression and characterization of a GH45 endoglucanase from F. pinicola were reported, comparing it with a known GH45 from Phanerochaete chrysosporium. Both enzymes, expressed in Pichia pastoris, demonstrated an acidophilic nature with an optimal pH of 4 and a preference for β-1,4-glucans. No significant differences were observed between the enzymes from the two fungi (Amengual et al., 2022). Fomitopsis pinicola was identified as the wood decay pathogen affecting Korean pine (Pinus koraiensis) in this study through rDNA-ITS analysis and morphological observations (ITS accession number OQ880566.1). The cellulase enzymes, endoglucanase (CMCase) and β-glucosidase, were quantified using the DNS method, and enzyme activity was optimized using a single-factor and orthogonal test. The highest cellulase activity reached 116.94 U/mL under specific conditions, providing a foundation for improving cellulose degradation and advancing biotransformation research by brown-rot fungi (Sun et al., 2024).

Fomitopsis palustris degrades crystalline cellulose (Avicel) and produces cellulases capable of converting it into soluble sugars, with a cellulose conversion degree of 3.2% (Yoon and Kim, 2005). Fomitopsis palustris effectively performs sugar conversion, achieving a 40.6% yield within 72 hours when using rice straw as a substrate (Kim Y. et al., 2010). Fomitopsis palustris secretes oxalic acid during wood decay. Oxalate transport is ATP-dependent and inhibited by various substances. A cDNA, FpOAR, was isolated, and it appears to function as an oxalate transporter. FpOAR-transformants are resistant to oxalic acid, and FpOAR plays a crucial role in oxalate secretion during wood decay (Watanabe et al., 2010). Fomitopsis palustris was optimized for cellulase production from 11 wood rotting fungi. The optimized FPase activity reached 130.45 FPU/mL in an 8-day culture with 4.46 g/L of urea and 27.83 μL/L of Tween 80. The crude cellulase saccharified liquid hot water (LHW)-pretreated Populus tomentosa, released 25.15% reducing sugars after 72 hours, significantly higher than the 14.66% from untreated wood. This demonstrates the potential of F. palustris for cellulase production in woody biomass hydrolysis (Wang et al., 2012). The cost of bioethanol production from lignocellulosic materials is high due to delignification and saccharification processes. Consolidated bioprocessing (CBP) combines these with fermentation in one reactor, potentially reducing costs. The white rot fungus Schizophyllum commune was identified as a strong fermenter. When combined with Bjerkandera adusta and F. palustris, B. adusta enhanced ethanol production from cedar wood, while F. palustris released glucose but did not increase ethanol yield. The results suggest that using multiple fungi in CBP can effectively produce bioethanol from cellulosic materials (Horisawa et al., 2019). Two starch-degrading enzymes, FpAmy13A (α-amylase) and FpGLA15A (glucoamylase), were purified and characterized from F. palustris, and their corresponding genes were cloned. Variations in enzyme characteristics suggest distinct roles in wood starch degradation (Tanaka et al., 2020). Fomitopsis palustris CQ2018 effectively mobilized soil phosphorus, enhancing phosphorus availability in various soil types and promoting root growth in pepper (Capsicum annuum) plants. The fungal inoculation increased phosphorus uptake and fruit yield, improving fruit quality by raising levels of potassium and vitamin C while reducing nitrate content. This fungus shows potential as an environmentally friendly biofertilizer, with further research needed on its applications in different plants and soils (Peng and Huang, 2022).

Incorporating F. pinicola mycelium (CM) in bread dough fermentation improved its bioactive properties and bread quality. Concentrations of 30–40% CM maintained quality, reduced baking loss, and enhanced sensory characteristics, while 50% CM reduced loaf volume and crust brightness. In addition, CM delayed retrogradation and reduced mold growth during storage, with 30–40% CM identified as optimal for maintaining quality and offering potential anti-diabetic benefits (Seung-Hee, 2005). Cellulase from F. pinicola KMJ812, known for its high β-glucosidase activity, was immobilized on various resins, with Duolite A568 yielding the best results: 61.7% cellulase activity and 64.4% β-glucosidase activity. The optimal reaction conditions were 55°C and pH 4.0-4.5, slightly more stable than the unimmobilized enzyme. Notably, the immobilization improved the enzyme’s thermal stability, making it more suitable for industrial applications. The immobilized enzyme retained 98% of its activity after 72 hours at 50°C and 50% after eight uses at the same temperature (Shin et al., 2010b). Fomitopsis pinicola contains 30.11% chitin and yields 71.75% chitosan. The chitin is 72.5% acetylated, with a DTGmax of 341°C. Chitosan has a 73.1% deacetylation rate and a DTGmax of 265°C. Chitin exhibits a CrI of 52%, while chitosan has a CrI of 41%. Both show nano-fiber surface structures. Fomitopsis pinicola could serve as an alternative chitin and chitosan source due to its abundance (Kaya et al., 2015). Endoglucanase, with an apparent molecular weight of 32 kDa, was purified from F. pinicola). The bio-directed synthesis of titanium oxide and silver nanoparticles using F. pinicola was confirmed through various analytical techniques. These nanoparticles exhibited significant antibacterial and anticancer activities, with AgNPs demonstrating enhanced effects, highlighting their potential for biomedical applications (Rehman et al., 2020, Figure 7 ). The methanolic extract of F. pinicola was evaluated as a green corrosion inhibitor for 1018 carbon steel in 0.5 M sulfuric acid. The extract demonstrated 85% inhibition efficiency at 400 ppm, with thermodynamic analysis showing physical adsorption following the Langmuir isotherm. Solid-state fermentation of wheat bran by F. pinicola significantly improved its nutritional and sensory properties, increasing phenol, alkylresorcinol, and antioxidant content. The fermentation also enhanced the flavor, reduced phytic acid, and improved the texture of dough and bread, making it a promising method for enhancing wheat bran as a nutritious food ingredient (Tu et al., 2020). The extract formed a protective film on the steel surface, increasing polarization resistance at higher extract concentrations. GC-MS identified Dehydrergosterol and Phthalic acid as the main inhibitory compounds, supported by theoretical EHOMO and ELUMO values (Martinez-Gonzalez et al., 2024).

Brown rot fungi (G. sepiarium, F. pinicola, and L. sulphureus) filtrate saccharified biomass. Fomitopsis pinicola had high cellobiohydrolase activity, and combining L. sulphureus and F. pinicola enzymes increased sugar yield (Lee J. et al., 2008). Exoglucanase production from Fomitopsis sp. RCK2010 was optimized, resulting in a significant increase. The crude cellulase was then applied to saccharify pretreated Prosopis juliflora, releasing reducing sugars for bioethanol production (Deswal et al., 2012). Table 7 outlines the biotechnological applications of various Fomitopsis species, focusing on their industrial, pharmaceutical, and environmental uses.