The increasing prevalence of antimicrobial resistance has created an urgent need to identify biologically active compounds beyond the conventional chemical space explored in modern drug discovery. In this context, lichens represent an unusual and comparatively underexploited source of antimicrobial chemistry. Formed through intimate associations between fungi and photosynthetic partners, lichens occupy exposed and often nutrient-poor environments where survival depends on sophisticated chemical strategies. Their persistence in these challenging habitats suggests that lichen chemistry is not merely a passive collection of metabolites, but part of a functional biological system shaped by competition, environmental stress, and microbial interactions.
Lichen secondary metabolites are particularly intriguing because many are structurally distinct from the major classes of antimicrobial agents currently used in clinical and agricultural applications. Compounds such as usnic acid, atranorin, vulpinic acid, depsides, depsidones, dibenzofurans, and related phenolic molecules possess diverse physicochemical properties that can influence microbial growth in different ways. Rather than acting through a single universal target, these metabolites may interfere with several cellular processes, including membrane integrity, energy metabolism, redox balance, enzyme activity, and intracellular signaling. Such multifaceted activity provides an important basis for investigating lichens as potential reservoirs of antimicrobial molecules.
The antimicrobial potential of lichen metabolites is also closely connected to their ecological function. Lichens are continuously exposed to bacteria, fungi, and other microorganisms that compete for limited resources or interact with the lichen surface. Chemical compounds produced or accumulated within the lichen therefore exist within a biological environment where selective pressure can favor molecules capable of restricting particular microbial populations. This ecological perspective raises an important question: could antimicrobial activity observed in laboratory assays reflect functional properties that evolved in response to natural microbial interactions? Exploring this possibility may reveal relationships between metabolite structure, ecological role, and antimicrobial performance that are difficult to recognize through conventional screening alone.
Despite growing interest in natural antimicrobial agents, the activity of lichen-derived compounds remains highly dependent on factors such as lichen species, geographical origin, environmental conditions, extraction methodology, metabolite concentration, and the susceptibility profile of the test microorganism. These variables make it difficult to treat “lichen extracts” as chemically uniform antimicrobial materials. A more informative approach is to consider individual secondary metabolites and their chemical characteristics alongside their effects on defined microbial systems. Such an approach can help distinguish genuine compound-specific activity from effects arising from complex extract composition.
Investigating the antimicrobial properties of lichen secondary metabolites therefore extends beyond the simple search for new antibiotics. It provides an opportunity to examine how unusual natural products interact with microbial physiology and how ecological chemistry can inform the discovery of biologically relevant molecules. Particular attention to structure-activity relationships, selective microbial inhibition, and possible mechanisms of action may help identify metabolites with distinctive antimicrobial profiles. The study of these compounds could ultimately contribute to the development of new antimicrobial leads while simultaneously expanding our understanding of the chemical strategies that enable lichens to persist within competitive microbial environments.
Lichen-derived metabolites as broad-spectrum antimicrobial agents
The antimicrobial properties of lichens arise from the complex chemical constitution of their thalli and the specialized compounds accumulated during growth. Unlike primary metabolites that are directly associated with basic cellular processes, secondary metabolites can occur in relatively high concentrations within particular lichen species and contribute substantially to their biological activity. Their presence has been associated with inhibitory effects against a diverse range of microorganisms, including Gram-positive and Gram-negative bacteria, yeasts, filamentous fungi, and selected viruses. However, the response of individual microorganisms is not uniform, indicating that susceptibility is closely related to both the chemical characteristics of the metabolite and the physiological properties of the target organism.
Among bacterial microorganisms, lichen-derived substances have frequently demonstrated stronger inhibitory effects against some Gram-positive species than against Gram-negative bacteria. Differences in cell-envelope architecture may contribute to this pattern, since the outer membrane of Gram-negative bacteria can restrict the penetration of certain hydrophobic or phenolic compounds. Nevertheless, activity against Gram-negative organisms has also been reported for particular lichen extracts and purified constituents, demonstrating that resistance to one metabolite does not necessarily predict resistance to another. The antimicrobial response may therefore reflect differences in permeability, intracellular targets, efflux capacity, metabolic state, and the concentration of the active compound reaching the microbial cell.
Fungal microorganisms provide another important target for lichen metabolites. Certain compounds can suppress fungal growth, interfere with spore germination, or reduce the development of hyphae. This activity is significant because fungal pathogens possess cellular structures and metabolic pathways that differ considerably from those of bacteria. Consequently, compounds displaying antifungal effects may provide chemical scaffolds distinct from conventional antibacterial agents. The ability of some lichen substances to influence both bacterial and fungal organisms further demonstrates the breadth of their biological activity, although broad activity should not automatically be interpreted as therapeutic selectivity.
Lichen species from genera such as Ramalina, Parmelia, Umbilicaria, and Cladonia exhibit antibacterial activity against both Gram-positive and Gram-negative bacteria. Their secondary metabolites, particularly usnic acid, salazinic acid, stictic acid, and vulpinic acid, have demonstrated inhibitory effects against pathogenic bacterial strains (Table 1). These bioactive compounds represent promising natural sources for identifying and developing alternative antibacterial agents, especially given the increasing resistance of pathogenic bacteria to several conventional antibiotics.
The antimicrobial performance of a lichen preparation is strongly influenced by its chemical composition. Extracts prepared using different solvents can contain substantially different proportions of phenolic acids, depsides, depsidones, and other constituents. Polar and non-polar extraction systems may consequently produce different antimicrobial profiles from the same lichen material. Extraction temperature, duration, particle size, solvent-to-sample ratio, and post-extraction processing can also affect the quantity of bioactive substances recovered. For this reason, differences between experimental studies may reflect methodological variation as much as genuine differences between lichen species.
Table 1. Synopsis of antimicrobial activities of some lichens
| Lichen | Reported activity | Pathogen |
| Parmelia perlata (L.) Ach. | Antiviral | Yellow fever virus, polio virus |
| Ramalina farinacea | Antiviral | HIV-1, Respiratory synctial virus (RSV) |
| Ramalina farinacea | Antiviral | Adenoviruses, herpes simplex virus (HSV) |
| Ramalina celastri | Antiviral | Arenavirus |
| Caloplaca regalis | Antibacterial | Gram positive bacteria |
| Usnea ghattensis (G.) Awasthi | Antibacterial | Gram positive and Gram-negative bacteria |
| Roccella belangeriana (Awasthi) | Antibacterial | Gram negative bacteria |
| Caloplaca cerina | Antifungal | Fungi |
| Rubia tictorum | Antifungal | Fungi |
| Rhamnus frangula | Antifungal | Fungi |
A further distinction exists between the activity of crude extracts and that of isolated lichen metabolites. A crude extract represents a chemically complex mixture in which several compounds may contribute simultaneously to the observed inhibitory effect. Some constituents may enhance the activity of others, whereas certain combinations may reduce the apparent effect through antagonistic interactions. Purified metabolites, in contrast, allow antimicrobial activity to be associated more directly with a defined chemical structure. Comparing crude preparations with isolated compounds can therefore help determine whether antimicrobial activity is attributable primarily to a dominant constituent or to interactions among multiple metabolites.
The effectiveness of lichen compounds is also dependent on the microorganism being tested and the experimental conditions used to measure inhibition. Minimum inhibitory concentration, minimum bactericidal or fungicidal concentration, inhibition-zone diameter, exposure period, inoculum density, and growth medium can all influence the measured response. These considerations are particularly important when comparing results obtained from different investigations. A large inhibition zone, for example, does not necessarily indicate greater biological potency because diffusion through the test medium depends partly on molecular size, polarity, and solubility.
Beyond direct microbial inhibition, the biological activities associated with lichen metabolites provide additional evidence of their pharmacological versatility. Anti-inflammatory, antioxidant, cytotoxic, and anti-herbivore effects have been described alongside antimicrobial properties, suggesting that some compounds may influence several biological pathways. Such multifunctionality creates opportunities for further investigation but also emphasizes the need to evaluate toxicity and selectivity carefully. An effective antimicrobial substance must ideally inhibit the target microorganism at concentrations that do not produce unacceptable effects on host cells or other beneficial biological systems.
Taken together, the antimicrobial characteristics of lichen secondary metabolites demonstrate a chemically diverse resource with activity extending across multiple microbial groups. The most informative future investigations will require precise identification of active constituents, standardized antimicrobial testing, quantitative assessment of potency, and clarification of compound-specific effects. Establishing these relationships can transform observations of lichen extract activity into reproducible chemical and biological evidence, providing a stronger foundation for evaluating lichen metabolites as sources of antimicrobial leads.
Antibacterial activity of lichens
Lichen-derived metabolites are emerging sources of novel antibacterial compounds. Lichens represent distinctive natural systems in which fungal and photosynthetic partners coexist and generate a chemically diverse array of specialized metabolites. Among these compounds, several lichen-derived substances have attracted attention because of their ability to interfere with bacterial growth and survival. The antibacterial potential of lichens is particularly relevant at a time when the effectiveness of established antibiotics is increasingly compromised by the emergence and dissemination of antimicrobial resistance.
The antibacterial effects associated with lichens are largely attributed to their secondary metabolites, including phenolic acids, depsides, depsidones, dibenzofurans, and related compounds. These substances can interact with bacterial cells through multiple mechanisms rather than relying on a single molecular target. Depending on their chemical structure and concentration, lichen metabolites may compromise bacterial membrane integrity, alter cellular permeability, interfere with essential metabolic processes, or disrupt the synthesis and function of cellular components. Such multiple modes of action may contribute to the broad biological activity observed in several lichen species.
Antibacterial activity has been documented among lichens belonging to genera such as Ramalina, Parmelia, Umbilicaria, and Cladonia. However, the magnitude of activity can vary considerably according to lichen species, metabolite composition, extraction method, concentration, and the bacterial organism tested. Gram-positive bacteria have frequently demonstrated susceptibility to lichen extracts and purified metabolites, although activity against selected Gram-negative organisms has also been reported. Differences in bacterial cell-envelope architecture, particularly the additional outer membrane characteristic of Gram-negative bacteria, may influence their sensitivity to lichen-derived compounds.
Several individual metabolites provide promising examples of this antibacterial potential. Usnic acid, one of the best-characterized lichen substances, has demonstrated inhibitory effects against a range of bacterial organisms and has therefore received considerable attention as a candidate natural antimicrobial compound. Other metabolites, including salazinic acid, stictic acid, and vulpinic acid, have likewise exhibited antibacterial properties under experimental conditions. Their biological effects indicate that lichen chemistry contains structurally diverse molecules capable of interacting with bacterial systems in ways that may differ from conventional antibiotic classes.
The significance of these compounds extends beyond their direct antibacterial effects. Their structural diversity provides opportunities for identifying chemical scaffolds that could be optimized through pharmacological and medicinal-chemistry approaches. Lichen metabolites may consequently serve as starting points for the discovery of new antibacterial molecules, particularly where existing therapeutic options are becoming less reliable because of resistance.
Antibacterial activity demonstrated in laboratory assays does not automatically establish therapeutic effectiveness. Further investigation is required to clarify mechanisms of action, toxicity, pharmacokinetic behavior, stability, selectivity, and activity under physiologically relevant conditions. Isolation and characterization of the most active metabolites may also help distinguish genuinely promising compounds from nonspecific effects associated with crude extracts.
The antibacterial properties of lichens highlight these organisms as valuable reservoirs of chemically distinctive natural products. Systematic exploration of their secondary metabolites could expand the pool of candidate antibacterial scaffolds and contribute to the search for alternative strategies against increasingly difficult bacterial infections.
Antiviral activity of lichens
The antiviral potential of lichens represents an increasingly interesting dimension of their biological activity. Unlike conventional antimicrobial agents that are primarily investigated for their effects on bacteria and fungi, lichen-derived secondary metabolites may interfere with viruses through several distinct stages of the viral life cycle. Lichens produce a chemically diverse array of specialized metabolites, including phenolic compounds, depsides, depsidones, dibenzofurans, anthraquinones, and related molecules. This chemical diversity provides a potentially valuable reservoir of structures for identifying antiviral compounds with mechanisms that differ from those of existing antiviral drugs.
Evidence from experimental investigations indicates that extracts and purified lichen metabolites can exert inhibitory effects against a range of human viral pathogens, including respiratory syncytial virus (RSV), herpes simplex viruses (HSV), human papillomaviruses (HPV), arenaviruses, and adenoviruses. However, the significance of lichen-derived antiviral activity extends beyond demonstrating whether a particular extract suppresses viral replication. Of greater interest is the possibility that individual metabolites may interact with specific viral or host-associated processes responsible for viral attachment, penetration, replication, assembly, or release.
Among the better-known lichen metabolites, usnic acid has attracted considerable attention because of its broad biological activity. Produced by several lichen-forming genera, including Usnea, usnic acid possesses a distinctive dibenzofuran structure that may contribute to its interaction with biological membranes and intracellular targets. Its antiviral effects suggest that lichen metabolites could potentially interfere with early events in viral infection or alter cellular conditions required for efficient viral multiplication. Antiviral potency can vary substantially according to viral species, experimental system, metabolite concentration, and the physiological state of the host cells used in testing.
Parietin, an anthraquinone associated with lichens such as Ramalina, provides another example of the chemical diversity underlying lichen antiviral activity. Its biological properties indicate that anthraquinone-type metabolites deserve further investigation as potential modulators of virus-host interactions. The structural differences between compounds such as usnic acid and parietin are particularly important because they create opportunities for identifying multiple antiviral pharmacophores rather than relying on a single chemical scaffold.
A major research opportunity therefore lies in moving from crude lichen extracts toward the isolation, structural characterization, and mechanistic evaluation of individual metabolites. Advanced approaches combining metabolomics, molecular docking, antiviral screening, and cell-based assays could help identify compounds that selectively inhibit viral processes while minimizing host-cell toxicity. Such investigations may also reveal synergistic interactions between lichen metabolites, suggesting that the antiviral effect of a whole lichen extract could arise from complementary activities among several constituents.
Lichens should not be viewed merely as passive environmental organisms but as chemically sophisticated sources of antiviral molecules. Their secondary metabolites offer diverse molecular frameworks that could inform the discovery of new antiviral agents, particularly against viruses for which therapeutic options remain limited or resistance is emerging. Further investigation of their structure-activity relationships, pharmacological properties, bioavailability, and molecular targets could establish a stronger foundation for translating lichen-derived chemistry into future antiviral drug development.
Anticancer or antiproliferative activity of lichens
Lichens represent a distinctive source of biologically active secondary metabolites with considerable potential for influencing abnormal cellular proliferation. Among these compounds, usnic acid has attracted particular attention because of its ability to interfere with the growth and survival of cancer-associated cells. The biological activity of lichen metabolites appears to extend beyond simple cytotoxicity, suggesting that selected compounds may influence multiple cellular processes involved in tumour development and progression.
The antiproliferative potential of lichen-derived compounds can be associated with their capacity to alter fundamental events required for cancer-cell survival. Rapidly dividing malignant cells depend on tightly regulated mechanisms controlling cell-cycle progression, cellular metabolism, mitochondrial function, and resistance to programmed cell death. Secondary metabolites produced by lichens may disturb these processes, thereby reducing the ability of malignant cells to maintain continuous proliferation. Such effects provide a basis for investigating lichen compounds as potential sources of lead molecules for anticancer drug discovery.
Usnic acid is particularly relevant because experimental studies have demonstrated inhibitory effects against several human cancer cell models, including breast and prostate cancer cell lines. Its activity has been associated with suppression of cellular proliferation and induction of apoptotic responses. Apoptosis is especially important in cancer research because the failure of programmed cell death is a defining characteristic of many malignant cells. A compound capable of restoring or promoting apoptotic signalling may therefore have therapeutic significance. In addition, the interaction of usnic acid with cellular energy metabolism and mitochondrial processes provides a possible mechanistic explanation for its antiproliferative effects.
Other lichen secondary metabolites may contribute complementary biological activities. Phenolic compounds, depsides, depsidones, dibenzofurans, and related metabolites possess diverse chemical structures that can influence oxidative balance, membrane integrity, signalling pathways, and cellular stress responses. Their structural diversity creates opportunities to identify compounds with selective activity against particular cancer-cell phenotypes. Rather than considering individual metabolites in isolation, combinations of chemically related or complementary lichen compounds may also provide an interesting strategy for enhancing antiproliferative activity while potentially reducing the concentration required for individual constituents.
The reported antimutagenic and apoptosis-associated properties of lichen metabolites further strengthen their relevance to cancer research. Prevention of mutation accumulation and interference with uncontrolled cell division represent two interconnected approaches to limiting malignant transformation. However, the biological activity observed in cell-based models should not be interpreted as evidence of clinical efficacy. Important questions concerning selectivity toward cancer cells, molecular targets, bioavailability, metabolism, toxicity, and pharmacological stability remain to be resolved.
Lichen secondary metabolites can be viewed as promising chemical starting points for the development of novel antiproliferative agents. Future investigations combining metabolomic profiling, molecular docking, mechanistic cell biology, and in vivo validation could identify structurally distinct lichen compounds with improved anticancer selectivity. Such an approach may expand the pharmaceutical potential of lichens beyond their ecological significance and establish their secondary metabolites as valuable candidates for future anticancer drug development.
Anti-herbivore activity of lichens
Lichens occupy exposed habitats where they are frequently encountered by small herbivorous invertebrates, including mites, insects, gastropods, and other grazing organisms. Despite their slow growth and limited capacity for rapid tissue replacement, lichens persist under continuous biological pressure partly through chemical defence. Their secondary metabolites form an important component of this defence system, transforming the lichen thallus from a passive food resource into a chemically protected biological structure. These compounds may reduce feeding, interfere with digestion, alter palatability, or discourage repeated grazing, thereby improving the likelihood that the lichen will survive over long periods.
The anti-herbivore effect of lichen chemistry is closely associated with the remarkable diversity of metabolites produced within the thallus. Compounds such as usnic acid, atranorin, fumarprotocetraric acid, vulpinic acid, and related phenolic substances can contribute to the characteristic bitterness, astringency, pigmentation, or unpleasant taste associated with many lichens. Rather than functioning as a single universal defence mechanism, these metabolites may operate collectively, producing a chemical barrier whose effectiveness depends on their concentration, combination, and distribution within the lichen. This chemical complexity can make the thallus less attractive or less nutritionally rewarding to potential consumers.
The protective value of these metabolites is particularly important because lichen tissues are nutritionally unusual. The photobiont supplies photosynthetically derived carbon, while the fungal partner provides structural organization and protection. Herbivory that removes substantial portions of the thallus can therefore disrupt the physical and physiological relationship between these partners. Chemical deterrence may limit such damage before extensive tissue loss occurs. In this sense, secondary metabolites can be viewed as an investment in maintaining the integrity of the lichen symbiosis rather than simply as toxic substances directed against herbivores.
The effectiveness of chemical defence may also depend on the feeding behaviour of the consumer. Generalist grazers encountering an intensely bitter or chemically defended thallus may avoid it and shift to alternative food sources. More specialized consumers, however, may tolerate particular metabolites or even exploit chemically defended lichens as food resources. This creates an ecological interaction in which lichen chemistry does not necessarily eliminate herbivory but can influence which organisms are capable of feeding successfully on the thallus. Secondary metabolites may contribute to shaping the composition of lichen-associated invertebrate communities.
Environmental conditions can further modify the strength of this defence. Light availability, moisture, temperature, nutrient status, and developmental stage may influence metabolite production and accumulation. Chemical defence should therefore be regarded as a dynamic trait that responds to both physiological demands and ecological pressure. A lichen growing under intense environmental stress may alter the allocation of resources between growth, reproduction, and metabolite synthesis, potentially changing its vulnerability to grazing.
Anti-herbivore activity represents an important ecological function of lichen secondary metabolism. These compounds provide a chemical layer of protection that can reduce grazing pressure, preserve thallus structure, and support the long-term persistence of the lichen symbiosis. Their significance extends beyond direct toxicity: lichen metabolites influence feeding choices, consumer specialization, and interactions within the broader lichen-associated ecosystem.
Antifungal activity of lichens
Lichens represent a chemically diverse symbiotic system in which secondary metabolites are continuously produced as part of adaptation to environmental stress. Beyond their ecological functions, these compounds provide a promising source of antifungal molecules with distinct chemical structures and biological activities. The antifungal potential of lichens can be associated with metabolites such as usnic acid, atranorin, vulpinic acid, salazinic acid, and related phenolic compounds, which may interfere with essential cellular processes in susceptible fungi.
A particularly interesting feature of lichen-derived metabolites is their potential to act at multiple cellular targets. Rather than depending exclusively on a single biochemical pathway, some compounds may affect fungal membrane integrity, alter membrane-associated enzymes, disturb mitochondrial function, or interfere with cellular redox balance. Such interactions can reduce fungal growth and, at higher effective concentrations, contribute to cellular damage. This broad mode of action makes lichen metabolites attractive candidates for investigating alternative antifungal mechanisms.
Species belonging to the genus Usnea are of particular interest because their thalli contain substantial quantities of bioactive metabolites, including usnic acid. Extracts and isolated compounds from Usnea may influence the growth and viability of opportunistic and environmental fungi. Similarly, lichens traditionally assigned to genera such as Caloplacaand Parmelia possess chemically diverse profiles that can contribute to antifungal activity. Differences among species, however, may produce markedly different responses, emphasizing the importance of chemical characterization when evaluating biological effects.
The activity of lichen metabolites against fungi such as Candida albicans and Aspergillus species is especially relevant because these organisms include medically and environmentally important fungi. Candida provides a useful model for examining compounds that interfere with yeast growth and cellular membrane function, whereas Aspergillus offers an opportunity to investigate effects on filamentous growth, spore germination, and hyphal development. These contrasting fungal forms can help reveal whether a lichen metabolite possesses a broad-spectrum effect or preferentially targets a particular stage of fungal development.
Other biological activities of lichens
Lichens represent chemically complex symbiotic systems capable of producing a remarkable spectrum of specialized metabolites with biological effects extending beyond direct antimicrobial activity. Although antibacterial and antifungal properties have received considerable attention, the pharmacological significance of lichen-derived compounds is increasingly associated with their ability to influence multiple biological processes. This broader activity profile positions lichens as promising sources of molecules for future therapeutic discovery.
Several lichen secondary metabolites exhibit activities that may be relevant to the regulation of inflammation, oxidative damage, cellular responses, and viral infection. Their anti-inflammatory potential is particularly important because persistent inflammation is implicated in numerous chronic disorders. By modulating inflammatory processes and reducing the production or activity of inflammatory mediators, selected lichen compounds may provide useful chemical templates for the development of new anti-inflammatory agents. Similarly, antioxidant activity demonstrated by certain metabolites suggests a capacity to counteract excessive reactive oxygen species and associated cellular damage. Such properties could contribute to the protection of biological tissues under conditions of oxidative stress.
The biological versatility of lichen metabolites also creates opportunities for investigating antiviral activity. Their interactions with microbial and cellular systems may interfere with different stages of viral infection, including attachment, replication, or intracellular propagation. This possibility is especially relevant in an era characterized by the emergence of infectious diseases and the continuing need for therapeutic agents with alternative mechanisms of action. However, identifying promising compounds is only an initial step; their selectivity, toxicity, bioavailability, molecular targets, and pharmacokinetic behavior must be established before meaningful therapeutic applications can be proposed.
The chemical diversity of lichens further strengthens their value as natural-product resources. Compounds such as depsides, depsidones, dibenzofurans, and related phenolic metabolites provide structurally diverse scaffolds that can serve as starting points for medicinal chemistry and drug optimization. Advances in metabolomics, high-throughput screening, molecular docking, genome-informed discovery, and analytical chemistry now provide opportunities to investigate this chemical diversity more systematically.
Beyond pharmaceutical applications, lichens contribute to human use through their roles as sources of dyes, fragrances, traditional foods, and animal fodder. Their ecological functions also highlight the biological importance of their specialized chemistry. Future research should move beyond documenting activity toward identifying precise mechanisms, optimizing active molecules, and translating promising metabolites into experimentally validated therapeutic candidates. Such an approach could reveal previously underexplored lichen compounds with applications across antimicrobial, anti-inflammatory, antioxidant, antiviral, and other biomedical fields.
References
Odimegwu, D. C., Ngwoke, K., Ejikeugwu, C., & Esimone, C. O. (2019). Latest edition: Lichen secondary metabolites as possible antiviral agents. In Lichen secondary metabolites: Bioactive properties and pharmaceutical potential (pp. 199–214). Springer.
Ahmed, M. Z., Rao, T., Khan, N. A., Aslam, M., & Pane, Y. S. (2024). Antimicrobial activities of lichens. In A. K. Das, A. Sharma, D. Kathuria, M. J. Ansari, & G. Bhardwaj (Eds.), Chemistry, biology and pharmacology of lichen.
Condò, C., Anfelli, I., Forti, L., Sabia, C., Messi, P., & Iseppi, R. (2023). Lichens as a natural source of compounds active on microorganisms of human health interest. Applied Sciences, 13(3), 1976.
Khan, S., Firdous, S. S., Shaheen, H., et al. (2023). Antimicrobial activities of medicinally important lichen extracts against human pathogenic bacteria and fungi. Pharmaceutical Chemistry Journal, 57, 1469–1475.
Odabas, M. N., Kainz, K., Weinberger, I., Schloffer, K., Riedl, S., Chollet-Krugler, M., Zweytick, D., Boustie, J., Madeo, F., & Carmona-Gutierrez, D. (2026). The lichen secondary metabolite lichesterinic acid exhibits antibiofilm activity against fungal pathogens. Frontiers in Cellular and Infection Microbiology, 15, 1730365.
Paguirigan, J. A., Liu, R., Im, S. M., Hur, J. S., & Kim, W. (2022). Evaluation of antimicrobial properties of lichen substances against plant pathogens. The Plant Pathology Journal, 38(1), 25–32.
Poulsen-Silva, E., Otero, M. C., Diaz-Cornejo, S., Atala, C., Fuentes, J. A., & Gordillo-Fuenzalida, F. (2025). Secondary metabolites of lichens: The untapped biomedical and pharmaceutical potential of antimicrobial molecules. Fungal Biology Reviews, 51, 100410.
Shrestha, G., & St. Clair, L. L. (2013). Lichens: A promising source of antibiotic and anticancer drugs. Phytochemistry Reviews, 12, 229–244.
Tian, H., Lu, J., Liang, F., Ding, H., & Xiao, C. (2025). Unassuming lichens: Nature’s hidden antimicrobial warriors. International Journal of Molecular Sciences, 26(7), 3136.
Youness, E.-S., Chouati, T., Aoussar, N., Zalegh, I., Mhand, R. A., Rhallabi, N., & Mellouki, F. (2020). Lichens as sources of antibacterial compounds. In M. Yusuf (Ed.), Lichen-derived products.
Larone D.H (2011). Medically Important Fungi: A Guide to Identification. Fifth edition. American Society of Microbiology Press, USA.
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