**1.5.2 Products of secondary metabolism**

Secondary metabolites produced by a large number of macrofungi have great therapeutic significance. These compounds occur as intermediate products of primary metabolism, but most of them are classified according to the five major metabolic sources (Table 2,3,4). The most productive pathways of synthesis of secondary metabolites are polyketide and mevalonate pathways (Zeidman et al.*,* 2005, from Giovaninni, 2006).

#### **1.5.2.1 Phenolic compounds**

**Phenols** are one of the largest classes of secondary biomolecules, which are characterized by the presence of aromatic rings with hydroxyl group bonded directly to an aromatic hydrocarbon group. Although they are firstly identified in plants (Cowan, 1999), their presence was also observed in fungi (Barros et al., 2008, Mattila et al.*,* 2001, Karaman, 2002, Karaman et al., 2012a). In recent years, there was a causal relationship between the total content of these compounds with biological activities recorded in a large number of macrofungi (Barros et al., 2007), which include anti-inflammatory, antiallergic, anticancer, antihypertensive, antirheumatic and antibacterial activity. Antimicrobial properties of phenolics are explained by the presence of phenol hydroxyl groups, which number is in correlation with their toxicity toward microorganisms (Cowan, 1999). The possible mechanisms of their action include inhibition of extracellular microbial enzymes, deprivation of the substrates required for microbial growth or direct action on microbial metabolism through inhibition of oxidative phosphorylation, by sulfhydryl groups and some non-specific interactions (Cowan, 1999).

It has been shown that the antimicrobial effects of extracts of mushroom *Lactarius deliciosus, Sarcodon imbricatus* and *Tricholoma portentosum* directly correlated with total content of phenols and flavonoids in them (Barros et al., 2007). Extracts of all three fungi showed antibacterial effects on *Bacillus cereus* and antifungal to *Candida neoformans*, while the extract of mushrooms *Lactarius deliciosus* and efficiency demonstrated against *P. aeruginosa* and *Candida albicans*. High content of phenols has been recorded in lignicolous fungi *Meripilus giganteus, G. lucidum* and *Flammulina velutipes* in the form of coumarins and tannins, as well

Antibacterial Agents from Lignicolous Macrofungi 371

membranes of microorganisms (Cowan, 1999), as well as the formation of complexes with metal ions (Biradar et al.*,* 2007). In addition, tannins could form complexes with

The equivalent of tannic acid was detected in extracts of shiitake mushrooms (*Lentinus edodes*), which show the antibiotic effect against bacteria *M. luteus* and *B. cereus* and the fungus *Candida albicans*, while against the strains of *E. coli* and *S. aureus* did not show the same activity (Kitzberger et al., 2007). While the focus of previous mycochemical (gr. myces=fungi) analysis of *Pleurotus ostreatus* was mainly put on the vitamins and minerals content, indicating a high nutritional value of mushrooms (Mattila et al., 2005), recent research revealed its exceptional antimicrobial and antioxidant effects that are associated with the presence of terpene and phenolic compounds (Iwalokun et al., 2007). The presence of phenols in the form of pyrocatechols, and flavonoids in the form of quercetin, was noted in extracts of fungus *Laetiporus sulphureus*, which explains its strong antioxidant properties (Turkoglu et al., 2006). This study also shows that ethanol extract of *L. sulphureus* exhibits strong antibiotic effect against Gram-positive bacteria (*B. subtilis, B. cereus, M. luteus* and *M. flavus*) and the yeast *Candida albicans*, while its activity against Gram-negative bacteria is

**Coumarins** are phenolic compounds of characteristic odor, and, according to the chemical structure, they are lactones built from the benzene and pyrone ring (Cowan, 1999). Despite the antiviral activity of some coumarins and the evidence of their inhibitory effect on the fungus *Candida albicans in vitro* conditions (Cowan, 1999), data on antimicrobial activity of these compounds are scarce. The presence of coumarin in fungi has been established in most genera of Xylariaceae family (Ascomycetes) (Whalley et al.*,* 1999), as well as in certain fungi belonging to lignicolous basidiomycets based on preliminary TLC profiling (Karaman,

Other agents with weak antibacterial effects found in macrofungi are steroids like 5αergosta-7,22-dien-3β-ol or 5,8-epidioxy-5α,8α-ergosta-6,22-dien-3β-ol, isolated from *Ganoderma applanatum* (Pers.) Pat., proved to be weakly active against a number of Grampositive and Gram-negative bacteria and organic acids like oxalic acid proved to be responsible for the antibacterial effect of *Lentinula edodes* (Berk.) Pegler against *S. aureus* and

Other, non-phenolic, compounds including terpenoids (Leon et al., 2004) and polysaccharides (Tseng et al., 2008) have also been designated as mushroom antioxidants or

Terpenes are a broad class of lipophilic secondary metabolites whose general chemical structure is C10H16. In nature they appear as diterpenes, triterpenes and tetraterpens (carotenoids) - C20, C30, C40, as well as the hemiterpens and sesquiterpens - C5, C15. If include additional elements (mostly oxygen within the hydroxyl and carbonyl groups), they are called terpenoids (Cowan, 1999). Terpenoids originate from simple acyclic compounds, isoprene and mevalonic acid, and their structure may be acyclic, monocyclic or bicyclic. Basically, their structure is isopentenyl-pyrophosphate (IPP), whose synthesis is realized in two ways, and pathways of synthesis of higher isoprenoids continue on after the

polysaccharides, affecting microorganisms.

much lower.

2002).

other bacteria.

antimicrobials.

**1.5.2.2 Terpenoid compounds** 

as in *Ganoderma applanatum*, where they were detected in the form of coumarins, flavonoids and tannins (Karaman, 2002, Karaman et al.*,* 2005). Data on the antimicrobial action of these fungi also exist (Karaman et al.*,* 2010). Analyses of extracts of the genus *Ganoderma* species shown the presence of polyphenolic compounds, and antimicrobial properties of these mushrooms explains the activity of compounds of hydrohynon composition - ganomycin A and B (Ofodile et al., 2005 as cited in Mothana et al.*,* 2000).

High concentrations of phenolic acids (> 1.0 mg / g), mainly a high concentration of gallic acid and protocatechuic, could be interpreted as anti-microbial activity of the following species: *L. sulphureus, F. hepatica, P. ostreatus, F. velutipes* and partially *M. giganteus*, which in antimicrobial screening showed moderate activity (Karaman, 2009b). Further studies of mechanisms of antimicrobial components originating from mushrooms could be suggested, including the influence of the protein compounds and organic acids such as oxalic acid, which accumulates in the fruit bodies of brown rot mushrooms, but also malic acid, ellagic acid, or some other compounds.

**Flavonoids** are hydroxylated phenolic compounds (C6-C3 units associated with the aromatic core) and antimicrobial activity can be explained by their ability to create complexes with extracellular soluble proteins and polypeptides that builds cell wall of microorganisms, as well as disruption of the function of cell membrane (Cowan, 1999). There are only few data dealing with detection of flavonoids (rutin, chrysin, naringin, myrcetin and quercetin) in tericolous (Turkoglu, 2007; Baros et al., 2007) lignicolous fungal species (Kim et al., 2008, Jayakumar et al., 2009). Since flavonoids are phenolics that generally occur in plants acting as antioxidants, antimicrobials, photoreceptors, feeding repellants or UV protectors (Pietta, 2000) we assume that the presence of these metabolites in TP of fungi that generally are in tight connection with wood, could have impact on the expressed bioactivity. Recent studies conducted with mushrooms showed a positive correlation between the TP and antioxidant capacity (Turkoglu, 2007, Ribeiro, 2007), possibly due to their ability to chelate metals, inhibit lipoxygenase and scavenge free radicals. Plotting TP content versus antibacterial activity (Karaman et al., 2010), revealed a good positive correlation between these two parameters , showing higher values for MeOH than CHCl3 extracts against most of the bacteria. By comparing different strains of the same bacteria (*S. aureus*) it was concluded that the effect of TP upon the antibacterial activity may be strain specific.

Worthy of note is the antibacterial activity of fungi against the multidrug-resistant strains of bacteria. New sesquiterpenoid hydroquinone from *Ganoderma pfeiefferi* Bres., called ganomycin (Mothana, et al., 2000) inhibit methicillin-resistant strains of *Staphylococcus aureus* and the growth of other, mainly Gram-positive bacteria. In addition, sterol-type compounds, isolated from the species *G. applanatum* such as 5α-ergost-7-en-3β-ol, 5α-ergost-7, 22-dien-3β-ol, 5.8-epidioxy-5α, 8α-ergost-6,22-dien-3β-ol and another new lanostanoid showed weak activity against many Gram + and Gram - bacteria. Oxalic acid is one of the substances responsible for the antimicrobial effects of mushroom *Lentinula edodes* (Berk.). Chloroform extract of mycelium *L. edodes* has bactericidal properties (Hirasawa et al., 1999).

**Tannins** are complex polyphenolic compounds that are devided into the two groups: the hydrolizated (esters of phenolic acids and sugars), and condensed (constructed from flavonoid monomers). Antimicrobial activity of tannins is expressed due to their ability to link amino acids in proteins, inactivating adhesions, enzymes and transport proteins of cell

as in *Ganoderma applanatum*, where they were detected in the form of coumarins, flavonoids and tannins (Karaman, 2002, Karaman et al.*,* 2005). Data on the antimicrobial action of these fungi also exist (Karaman et al.*,* 2010). Analyses of extracts of the genus *Ganoderma* species shown the presence of polyphenolic compounds, and antimicrobial properties of these mushrooms explains the activity of compounds of hydrohynon composition - ganomycin A

High concentrations of phenolic acids (> 1.0 mg / g), mainly a high concentration of gallic acid and protocatechuic, could be interpreted as anti-microbial activity of the following species: *L. sulphureus, F. hepatica, P. ostreatus, F. velutipes* and partially *M. giganteus*, which in antimicrobial screening showed moderate activity (Karaman, 2009b). Further studies of mechanisms of antimicrobial components originating from mushrooms could be suggested, including the influence of the protein compounds and organic acids such as oxalic acid, which accumulates in the fruit bodies of brown rot mushrooms, but also malic acid, ellagic

**Flavonoids** are hydroxylated phenolic compounds (C6-C3 units associated with the aromatic core) and antimicrobial activity can be explained by their ability to create complexes with extracellular soluble proteins and polypeptides that builds cell wall of microorganisms, as well as disruption of the function of cell membrane (Cowan, 1999). There are only few data dealing with detection of flavonoids (rutin, chrysin, naringin, myrcetin and quercetin) in tericolous (Turkoglu, 2007; Baros et al., 2007) lignicolous fungal species (Kim et al., 2008, Jayakumar et al., 2009). Since flavonoids are phenolics that generally occur in plants acting as antioxidants, antimicrobials, photoreceptors, feeding repellants or UV protectors (Pietta, 2000) we assume that the presence of these metabolites in TP of fungi that generally are in tight connection with wood, could have impact on the expressed bioactivity. Recent studies conducted with mushrooms showed a positive correlation between the TP and antioxidant capacity (Turkoglu, 2007, Ribeiro, 2007), possibly due to their ability to chelate metals, inhibit lipoxygenase and scavenge free radicals. Plotting TP content versus antibacterial activity (Karaman et al., 2010), revealed a good positive correlation between these two parameters , showing higher values for MeOH than CHCl3 extracts against most of the bacteria. By comparing different strains of the same bacteria (*S. aureus*) it was concluded that the effect of TP upon the antibacterial activity may

Worthy of note is the antibacterial activity of fungi against the multidrug-resistant strains of bacteria. New sesquiterpenoid hydroquinone from *Ganoderma pfeiefferi* Bres., called ganomycin (Mothana, et al., 2000) inhibit methicillin-resistant strains of *Staphylococcus aureus* and the growth of other, mainly Gram-positive bacteria. In addition, sterol-type compounds, isolated from the species *G. applanatum* such as 5α-ergost-7-en-3β-ol, 5α-ergost-7, 22-dien-3β-ol, 5.8-epidioxy-5α, 8α-ergost-6,22-dien-3β-ol and another new lanostanoid showed weak activity against many Gram + and Gram - bacteria. Oxalic acid is one of the substances responsible for the antimicrobial effects of mushroom *Lentinula edodes* (Berk.). Chloroform

**Tannins** are complex polyphenolic compounds that are devided into the two groups: the hydrolizated (esters of phenolic acids and sugars), and condensed (constructed from flavonoid monomers). Antimicrobial activity of tannins is expressed due to their ability to link amino acids in proteins, inactivating adhesions, enzymes and transport proteins of cell

extract of mycelium *L. edodes* has bactericidal properties (Hirasawa et al., 1999).

and B (Ofodile et al., 2005 as cited in Mothana et al.*,* 2000).

acid, or some other compounds.

be strain specific.

membranes of microorganisms (Cowan, 1999), as well as the formation of complexes with metal ions (Biradar et al.*,* 2007). In addition, tannins could form complexes with polysaccharides, affecting microorganisms.

The equivalent of tannic acid was detected in extracts of shiitake mushrooms (*Lentinus edodes*), which show the antibiotic effect against bacteria *M. luteus* and *B. cereus* and the fungus *Candida albicans*, while against the strains of *E. coli* and *S. aureus* did not show the same activity (Kitzberger et al., 2007). While the focus of previous mycochemical (gr. myces=fungi) analysis of *Pleurotus ostreatus* was mainly put on the vitamins and minerals content, indicating a high nutritional value of mushrooms (Mattila et al., 2005), recent research revealed its exceptional antimicrobial and antioxidant effects that are associated with the presence of terpene and phenolic compounds (Iwalokun et al., 2007). The presence of phenols in the form of pyrocatechols, and flavonoids in the form of quercetin, was noted in extracts of fungus *Laetiporus sulphureus*, which explains its strong antioxidant properties (Turkoglu et al., 2006). This study also shows that ethanol extract of *L. sulphureus* exhibits strong antibiotic effect against Gram-positive bacteria (*B. subtilis, B. cereus, M. luteus* and *M. flavus*) and the yeast *Candida albicans*, while its activity against Gram-negative bacteria is much lower.

**Coumarins** are phenolic compounds of characteristic odor, and, according to the chemical structure, they are lactones built from the benzene and pyrone ring (Cowan, 1999). Despite the antiviral activity of some coumarins and the evidence of their inhibitory effect on the fungus *Candida albicans in vitro* conditions (Cowan, 1999), data on antimicrobial activity of these compounds are scarce. The presence of coumarin in fungi has been established in most genera of Xylariaceae family (Ascomycetes) (Whalley et al.*,* 1999), as well as in certain fungi belonging to lignicolous basidiomycets based on preliminary TLC profiling (Karaman, 2002).

Other agents with weak antibacterial effects found in macrofungi are steroids like 5αergosta-7,22-dien-3β-ol or 5,8-epidioxy-5α,8α-ergosta-6,22-dien-3β-ol, isolated from *Ganoderma applanatum* (Pers.) Pat., proved to be weakly active against a number of Grampositive and Gram-negative bacteria and organic acids like oxalic acid proved to be responsible for the antibacterial effect of *Lentinula edodes* (Berk.) Pegler against *S. aureus* and other bacteria.

Other, non-phenolic, compounds including terpenoids (Leon et al., 2004) and polysaccharides (Tseng et al., 2008) have also been designated as mushroom antioxidants or antimicrobials.

#### **1.5.2.2 Terpenoid compounds**

Terpenes are a broad class of lipophilic secondary metabolites whose general chemical structure is C10H16. In nature they appear as diterpenes, triterpenes and tetraterpens (carotenoids) - C20, C30, C40, as well as the hemiterpens and sesquiterpens - C5, C15. If include additional elements (mostly oxygen within the hydroxyl and carbonyl groups), they are called terpenoids (Cowan, 1999). Terpenoids originate from simple acyclic compounds, isoprene and mevalonic acid, and their structure may be acyclic, monocyclic or bicyclic. Basically, their structure is isopentenyl-pyrophosphate (IPP), whose synthesis is realized in two ways, and pathways of synthesis of higher isoprenoids continue on after the

Antibacterial Agents from Lignicolous Macrofungi 373

*Armillaria mellea* (similar to *A. tabescens) Clitocybe elegans A. novae-zelandiae Radulomyces confluens* 

*Lentinellus* 

**Isovelleral** 

*cucumis* 

*olivascens*

*Fomes annosus Omphalotus olearius Omphalotus nidiformis*.

*Omphalotus olearius Lampteromyces japonicus*, *Omphalotus* 

*Clitocybe subilludens Pleurotus japonicus Omphalotus olearius Omphalotus nidiformis Coprinus atramentarius Agrocybe aegerita*

*Fomes annosus Omphalotus olearius Clitocybe candicans Clavicorona pyxidata Mycena leaiana* 

*Marasmius conigenus* culture – *Flagelloscypha pilatii* contain many Basidiomycota by damage of fruitingbodies, converting to

**CARYOPHYLLENE Naematolin** *Hypholoma fasciculare* weak antibacterial

**ORIGIN EFFECT** (ACTIVITY)

*Collybia confluens* low antifungal, high

antibacterial *(Bacillus* sp.), high antiviral, cytotoxic, nonselective antibiotic

prevent trombocite aggregation, cytotoxic,

antimicrobial **low antifungal, high antibacterial, cytotoxic**  high antifungal , low antibacterial

**antibacterial** 

phytotoxic

cytotoxic

*Clitocybe hydrogramma* antibacterial against

less antifungal, cytotoxic and

*Bacillus* sp., non against *E.* 

**bactericidal,phytotoxic**  antibacterial against Gram + (*Sarcina lutea* and *Bacillus* spp.), non against *E. coli*

weak antibiotic activity on

lower antibiotic and

high antibacterial, antifungal & cytotoxic

*coli* and fungi

antifungal

*B. subtilis*

anticancerogenic properties

cytotoxic, antibiotic (*S. aureus),* antifungal

antiviral (inhibits reverse transcriptase of viruses causing leukemia in rats -weak antibiotic activity (*Acinetobacter*), high cytotoxic, mutagenic

antimicrobial and cytotoxic

**COMPOUND NAME OR CHEMICAL** 

**COLLYBIAL** α**,**β**-unasturated** 

**MARASMANES Marasmic acid** 

**FOMANNOSANES Fomanosin** 

**ILLUDANES Illudin S (lampterol)** 

M

**PROTOILLUDANES**

**HYDROGRAMMANE** (modified marasmic sesquiterpenes)

**ILLUDALANES**  (dicoumaric sesquiterpenes)

**ISOILLUDANES** 

(according to Abraham, 2001)

**(**esters of protoilludanol) **STRUCTURE** 

**Armillyl orselinate** 

(chlorinated derivatives) **Melleolide B, C, D, E, F, G, H** (everniate-armillarin)

hydroxy derivative of marasmic acid **Pilatin** 

**Velutinal and fatty acid** 

**10-hydroxy-isovelleral Hydrogrammic acid** 

**CUCUMANES** culture –*Macrocystidia* 

Hydroxydihydroilludin

**Illudin A, B, C, D i E** 

**Fomajorin D & S Illudalic acid illudinine Candicansol Clavicoronic acid Leaianafulven**

Table 2. Antimicrobial effects of sesquiterpenoids orginated from macrofungi

**esters** 

**Illudosin** 

**Illudin M** 

**Illudalenol, Illudin F, G i H Illudin C2 i C3 Illudinic acid** 

**aldehyde** 

**Arnamiol** 

**Melleolide I, J Radulon A Lentinellic acid**  methyl-estars of lentinellic acid

isomerization of IPP in DMAPP. For all animal and fungal cells characteristic is the mevalonic pathway of isopentenyl-pyrophosphate synthesis, while most plants, bacteria, actinomycetes and protozoa have non-mevalonic mode of its synthesis (Inouye et al., 2004).

One of the many functions of these compounds is their antimicrobial activity, but the mechanism of action of terpenoids on microorganisms is not fully understood (Cowan, 1999). According to their lipophilic nature, it is assumed to act by disrupting membrane functions of microbial cells (Cowan, 1999), and some authors believe that they may cause increasing of non-specific cell membrane permeability for the antibiotic molecule (Byron et al., 2003). Though plant organisms are thought to be the largest source of triterpenoids, in recent years more and more data indicate the presence of these compounds in some representatives of macrofungi (He et al., 2003, Akihisa et al.*,* 2005; de Silva et al., 2006; Abraham, 2001, Deyrup et al., 2007).

**Sesquiterpenes.** One of the many strategies that representatives of the higher fungi use to protect themselves against a number of parasites that feed on their fruit bodies is the production of toxins. It is interesting that many of these toxic chemical suits sesquiterpens (Abraham, 2001). For most basidiomycota fungi the presence of sesquiterpens of protoiludane type is characteristic, which originate from humulene, compounds present in a rare fungus, formed by cyclization of farnesyl-pyrophosphate. Of the few ways of humulene transformation, the most important pathway of synthesis of protoiludane, tricyclic compound which, due to the high reactivity caused by the presence of cyclobutane, is further transformed into a series of compounds. Some of these sesquiterpenes show interesting biological activity, and are considered to be a very interesting object of study in terms of medical chemistry. Several groups of sesquiterpenes originating from higher fungi show a greater or lesser antimicrobial effect (Tables 2, 3). It is interesting to note that some representatives of the genera *Russula* and *Lactarius* synthesize sesquiterpene alcohols that are esterifies with fatty acids. These esters do not show strong antibiotic activity, but in the case of mushroom fruit body injury, leads to cleavage of ester bonds and release of alcohols that are highly reactive and therefore very toxic to microorganisms. Therefore, the mentioned esters may be considered as pro-medicines or precursors of compounds that in metabolic processes are transformed into an active form.

**Triterpenes.** Compounds of triterpene composition are found in many mushroom extracts which showed some antibiotic properties. Genus *Ganoderma* contains about 200 species known for the production of triterpene compounds. Many of these species have found wide application in the prevention and treatment of various diseases due to the numerous biological activities based on the presence of triterpene components (Ofodile et al., 2005). Although thought to be active against bacteria just due to the presence of triterpenes in these fungi, there are data that disagree with such opinions, giving the example of seven different triterpenes isolated from a Vietnamese species *G. collosum*, which showed no antimicrobial effect, but exhibit strong anti-inflammatory activity (Ofodile et al.*,* 2005). Most triterpenes synthesized by species of the genus *Ganoderma* belong to the lanostane type (de Silva et al.*,* 2006). Over 100 compounds from this group have been identified, among them a few newly discovered (Akihisa et al.*,* 2005; de Silva et al.*,* 2006, Jian et al., 2003, Kamo et al., 2003). The review of triterpene compounds isolated from macrofungi is given in Table 3.

Overview of other compounds isolated from macrofungi, which exhibit antimicrobial activity is shown in Tab. 4

isomerization of IPP in DMAPP. For all animal and fungal cells characteristic is the mevalonic pathway of isopentenyl-pyrophosphate synthesis, while most plants, bacteria, actinomycetes and protozoa have non-mevalonic mode of its synthesis (Inouye et al., 2004). One of the many functions of these compounds is their antimicrobial activity, but the mechanism of action of terpenoids on microorganisms is not fully understood (Cowan, 1999). According to their lipophilic nature, it is assumed to act by disrupting membrane functions of microbial cells (Cowan, 1999), and some authors believe that they may cause increasing of non-specific cell membrane permeability for the antibiotic molecule (Byron et al., 2003). Though plant organisms are thought to be the largest source of triterpenoids, in recent years more and more data indicate the presence of these compounds in some representatives of macrofungi (He et al., 2003, Akihisa et al.*,* 2005; de Silva et al., 2006;

**Sesquiterpenes.** One of the many strategies that representatives of the higher fungi use to protect themselves against a number of parasites that feed on their fruit bodies is the production of toxins. It is interesting that many of these toxic chemical suits sesquiterpens (Abraham, 2001). For most basidiomycota fungi the presence of sesquiterpens of protoiludane type is characteristic, which originate from humulene, compounds present in a rare fungus, formed by cyclization of farnesyl-pyrophosphate. Of the few ways of humulene transformation, the most important pathway of synthesis of protoiludane, tricyclic compound which, due to the high reactivity caused by the presence of cyclobutane, is further transformed into a series of compounds. Some of these sesquiterpenes show interesting biological activity, and are considered to be a very interesting object of study in terms of medical chemistry. Several groups of sesquiterpenes originating from higher fungi show a greater or lesser antimicrobial effect (Tables 2, 3). It is interesting to note that some representatives of the genera *Russula* and *Lactarius* synthesize sesquiterpene alcohols that are esterifies with fatty acids. These esters do not show strong antibiotic activity, but in the case of mushroom fruit body injury, leads to cleavage of ester bonds and release of alcohols that are highly reactive and therefore very toxic to microorganisms. Therefore, the mentioned esters may be considered as pro-medicines or precursors of compounds that in

**Triterpenes.** Compounds of triterpene composition are found in many mushroom extracts which showed some antibiotic properties. Genus *Ganoderma* contains about 200 species known for the production of triterpene compounds. Many of these species have found wide application in the prevention and treatment of various diseases due to the numerous biological activities based on the presence of triterpene components (Ofodile et al., 2005). Although thought to be active against bacteria just due to the presence of triterpenes in these fungi, there are data that disagree with such opinions, giving the example of seven different triterpenes isolated from a Vietnamese species *G. collosum*, which showed no antimicrobial effect, but exhibit strong anti-inflammatory activity (Ofodile et al.*,* 2005). Most triterpenes synthesized by species of the genus *Ganoderma* belong to the lanostane type (de Silva et al.*,* 2006). Over 100 compounds from this group have been identified, among them a few newly discovered (Akihisa et al.*,* 2005; de Silva et al.*,* 2006, Jian et al., 2003, Kamo et al., 2003). The review of triterpene compounds isolated from macrofungi is given in Table 3.

Overview of other compounds isolated from macrofungi, which exhibit antimicrobial

Abraham, 2001, Deyrup et al., 2007).

metabolic processes are transformed into an active form.

activity is shown in Tab. 4


Table 2. Antimicrobial effects of sesquiterpenoids orginated from macrofungi (according to Abraham, 2001)

Antibacterial Agents from Lignicolous Macrofungi 375

Extraction procedures are important in assessing good antibacterial activities of extracts. Macrofungi are commonly collected either randomly or by locals in geographical areas or forest habitats where the fruiting bodies are found. Initial screenings of fungi for possible antibacterial activities usually begin by using crude aqueous or alcohol extractions. Since the majority of the identified components of mushrooms are active against microorganisms,

Water-soluble compounds, such as polysaccharides and polypeptides, including lectins, are commonly more effective as inhibitors of virus adsorption and cannot be identified in the screening techniques commonly used. Tannins and terpenoids are occasionally obtained by

For alcoholic extraction, the intact mature fruiting bodies or their segments are brush cleaned, air-dried to constant mass and pulverized, and then soaked in methanol or ethanol for extended periods (24-72h). The resultant filtrated extracts are then filtered and washed, concentrated under reduced pressure at low temperature to avoid destroying of any thermo-labile antimicrobial agents present in the extract and redissolved in the alcohol (or 5% DMSO) to a determined concentration. Water extractions, generally used distilled water, blending of slurry, filtration and centrifugation (approximately 15,000 for 30 min) multiple

**Compounds Origin/Source Biological activity Reference** 




*- in vitro* antifungal activity against some human


antifungal effect

antibacterial *(B. subtilis S. aureus*) antifungal effect

pathogens

Anke et al., 1979; Anke et al., 1983

Negishi et al., 2000;

Kuhnt et al.*,* 1990

Rosa et al.*,* 2003

Hirasawa et al.*,* 1999)

Shitu et al.*,* 2006

Anke et al.*,* 2004

large number of saprotrophic and phytopatogenic fungi, inhibiting the process of

respiration

effect

*Lentinus edodes* antibacterial

cultures of *Oudemansiella mucida*, *Xerula malanotricha* and *Xerula longipes*

*Xerula malanotricha* 

cultures of representatives of the genus *Agrocybe* 

*cinnabarinus*

Table 4. Other compounds from macrofungi with antimicrobial activity

submerged cultures of the genus *Favolaschia* 

they are mostly obtained through initial ethanol or methanol extraction.

**1.6 Extraction methods** 

treatment with less polar solvents.

times for clarification.

**β-methoxyacrylates**

**Polyenes** 

**xerulinic acid** 

**Agrocybolacton** 

disulfide derivate

**Laschiatrion**

skeleton

**Lentionine**  (1,2,3,5,6-

**strobilurins** and **oudemansins** 

**xerulin**, **dihydroxerulin** and

enthatiocyclocheptane) and its

new antibiotic with steroid

**Cinnabarine** *Pycnoporus* 


Table 3. Antimicrobial effects of sesquiterpenoids and triterpenoids from macrofungi (according to Abraham, 2001)
