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Journal articles on the topic 'Usnic acid concentration'

Author: Grafiati

Published: 3 June 2025

Last updated: 1 August 2025

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1

Yano-Melo, Adriana Mayumi, Carlos Vicente, and Lauro Xavier-Filho. "Influence of Cladonia substellata Vainio extracts and usnic acid on germination and growth of Allium cepa L. seedlings." Bryophyte Diversity and Evolution 16, no. 1 (1999): 11–15. http://dx.doi.org/10.11646/bde.16.1.5.

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The effect of lichen extracts obtained from Cladonia substellata and its main constituent, usnic acid, on the germination and growth of onion (Allium cepa L.) seedlings was investigated. No significant inhibitory effect of the lichen extracts and usnic acid on germination was found, except of usnic acid at the concentration of 726.7 mM. Growth inhibition of the radicle and of the hypocotyl of the seedlings was found for the total extract and for usnic acid in concentrations of 290.6 mM and 726.7 mM.

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Bačkor, M., J. Hudá, M. Repčák, W. Ziegler§, and M. Bačkorová. "The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia 1rregularis." Lichenologist 30, no. 06 (1998): 577–82. http://dx.doi.org/10.1017/s0024282992000574.

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AbstractThe quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiontTrebouxia irregularis, isolated from the lichenCladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth ofT.irregularisand no significant differences were found among samples at different medium pH values.

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3

Bačkor, M., J. Hudá, M. Repčák, W. Ziegler§, and M. Bačkorová. "The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia Irregularis." Lichenologist 30, no. 6 (1992): 577–82. http://dx.doi.org/10.1006/lich.1998.0166.

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AbstractThe quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiont Trebouxia irregularis, isolated from the lichen Cladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth of T.irregularis and no significant differences were found among samples at different medium pH values.

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4

Khramchankova, V., and R. Novikau. "Extraction efficiency analysis of usnic acid from lichens of Belarusian Polesie." Bulletin of Science and Practice 4, no. 6 (2018): 23–32. https://doi.org/10.5281/zenodo.1289323.

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The extraction efficiency of usnic acid by acetone, ethanol and benzene from lichens Evernia prunastri, Ramalina pollinaria and Cladonia arbuscula was investigated. The methods of cold maceration of biomass with the appropriate solvent and extraction in the Soxhlet apparatus — directly and with preliminary cold maceration of the biomass with hexane were used. The extraction efficiency of usnic acid from the biomass Evernia prunastri and Ramalina pollinaria was greatest when using the method of cold maceration with hexane for 7 days, followed by extraction with ethanol in the Soxhlet appa

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5

Fitriani, Lili, Afifah, Friardi Ismed, and Amri Bakhtiar. "Hydrogel Formulation of Usnic Acid and Antibacterial Activity Test Against Propionibacterium acne." Scientia Pharmaceutica 87, no. 1 (2018): 1. http://dx.doi.org/10.3390/scipharm87010001.

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Usnic acid is known for its remarkable antimicrobial activity. The aim of this research was to formulate hydrogel of usnic acid and evaluate the antibacterial activity against Propionibacterium acne. Due to low solubility of usnic acid, solid dispersion was prepared using PVP K-30. In this study, intact usnic acid (UA) and usnic acid-solid dispersion (UA-SD) was formulated in hydrogel using several gelling agents: Aqupec HV-505, sodium alginate and HPMC K 100M. Concentration of each gelling agent was optimized for hydrogel base. All of hydrogel base showed homogenous gel, pH at range 5.37–6.33

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SMEDS, Annika I., and Minna-Maarit KYTÖVIITA. "Determination of usnic and perlatolic acids and identification of olivetoric acids in Northern reindeer lichen (Cladonia stellaris) extracts." Lichenologist 42, no. 6 (2010): 739–49. http://dx.doi.org/10.1017/s002428291000037x.

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AbstractThe ecologically important lichen Cladonia stellaris forms thick carpets in boreal forest floors. In addition to affecting temperature and water conditions in the soil underneath, the secondary metabolites formed by the lichen layer are of ecological interest. In this paper, we investigated the distribution of lichen acids in C. stellaris collected at different latitudes in Finland and developed methods to quantify the two optical enantiomers of usnic acid separately. The lichen extracts were analysed by high-performance liquid chromatography (HPLC) with UV and mass spectrometric (MS)

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7

Araújo, Hallysson Douglas Andrade de, Hianna Arely Milca Fagundes Silva, José Guedes da Silva Júnior, Mônica Camelo Pessoa de Azevedo Albuquerque, Luana Cassandra Breitenbach Barroso Coelho, and André de Lima Aires. "The Natural Compound Hydrophobic Usnic Acid and Hydrophilic Potassium Usnate Derivative: Applications and Comparisons." Molecules 26, no. 19 (2021): 5995. http://dx.doi.org/10.3390/molecules26195995.

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Usnic acid is the best-studied lichen metabolite, presenting several biological activities, such as antibacterial, immunostimulating, antiviral, antifungal, anti-inflammatory, and antiparasitic agents; despite these relevant properties, it is a hydrophobic and toxic molecule. In this context, scientific research has driven the development of innovative alternatives, considering usnic acid as a source of raw material in obtaining new molecules, allowing structural modifications (syntheses) from it. The purpose is to optimize biological activities and toxicity, with less concentration and/or res

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Pires, Regina Helena, Rodrigo Lucarini, and Maria Jose Soares Mendes-Giannini. "Effect of Usnic Acid on Candida orthopsilosis and C. parapsilosis." Antimicrobial Agents and Chemotherapy 56, no. 1 (2011): 595–97. http://dx.doi.org/10.1128/aac.05348-11.

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ABSTRACTThe activity of usnic acid againstCandida orthopsilosisandCandida parapsilosison planktonic and biofilm conditions was investigated by using a broth microdilution and microplate methods. Potentin vitroactivities against differentCandidaspecies were obtained. The metabolic activity of sessile cells ofC. parapsilosiscomplex was reduced by 80% at four times the 80% inhibitory concentration. Thein vitrostudies support further efforts to determine whether usnic acid can be used clinically to cure patients withCandidainfections.

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9

Kikowska, Małgorzata, Barbara Thiem, Karolina Jafernik, et al. "Effect of Elicitation with (+)-Usnic Acid on Accumulation of Phenolic Acids and Flavonoids in Agitated Microshoots of Eryngium alpinum L." Molecules 26, no. 18 (2021): 5532. http://dx.doi.org/10.3390/molecules26185532.

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The present work was aimed at studying the potential of elicitation on the accumulation of phenolic compounds in in vitro shoot cultures of Eryngium alpinum L., a protected plant from the Apiaceae family. The study examined the influence of (+)-usnic acid on the biomass growth as well as on the biosynthesis of the desired flavonoids and phenolic acids in the cultured microshoots. The phenolic compound content was determined by HPLC-DAD. The flavonoid of the highest concentration was isoquercetin, and the phenolic acids of the highest amount were rosmarinic acid, caffeic acid and 3,4-dihydroxyp

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Petrová, Klaudia, Miriam Bačkorová, Zuzana Demčišáková, et al. "Usnic Acid Isolated from Usnea antarctica (Du Rietz) Reduced In Vitro Angiogenesis in VEGF- and bFGF-Stimulated HUVECs and Ex Ovo in Quail Chorioallantoic Membrane (CAM) Assay." Life 12, no. 9 (2022): 1444. http://dx.doi.org/10.3390/life12091444.

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Natural products include a diverse set of compounds of drug discovery that are currently being actively used to target tumor angiogenesis. In the present study, we evaluated the anti-angiogenic activities of secondary metabolite usnic acid isolated from Usena antarctica. We investigated the in vitro effects on proliferation, migration, and tube formation of VEGF- and bFGF-stimulated HUVECs. Ex ovo anti-angiogenic activity was evaluated using the CAM assay. Our findings demonstrated that usnic acid in the concentration of 33.57 µM inhibited VEGF (25 ng/mL) and bFGF (30 ng/mL)-induced HUVECs pro

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Lage, Tiago C. A., Lívia P. Horta, Ricardo M. Montanari, et al. "Structural Elucidation and Free Radical Scavenging Activity of a new o-Orsellinic Acid Derivative Isolated from the Lichen Cladonia rappii." Natural Product Communications 11, no. 9 (2016): 1934578X1601100. http://dx.doi.org/10.1177/1934578x1601100932.

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Rappiidic acid, a new o-orsellinic acid derivative, was isolated from the lichen Cladonia rappii. Its capability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) was investigated and compared with resveratrol and (+)-usnic acid. Usnic acid at 100 μM was the most efficient ROS scavenger, exhibiting activity 3-fold higher than that of resveratrol. At the same concentration, rappidic acid scavenged 23.1% of ROS formed, demonstrating that this compound is twice as active as resveratrol. Both compounds were shown to be poor RNS scavengers.

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Farkas, E., B. Biró, K. Szabó, K. Veres, Zs Csintalan, and R. Engel. "The amount of lichen secondary metabolites in Cladonia foliacea (Cladoniaceae, lichenised Ascomycota)." Acta Botanica Hungarica 62, no. 1-2 (2020): 33–48. http://dx.doi.org/10.1556/034.62.2020.1-2.4.

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The terricolous species Cladonia foliacea (Cladoniaceae, lichenised Ascomycota) widely distributed in open, dry lowland steppe and rocky mountain grassland vegetation in Europe was chosen as a potential test organism for ecological experiments, since their thalli are producing cortical solar radiation-protective and UV screening pigment dibenzofuran usnic acid and medullary secondary substance depsidone fumarprotocetraric acid. Significant seasonal differences were found in the amounts of lichen secondary metabolites analysed by HPTLC and HPLC-PDA between summer and winter collected thalli in

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13

Tanori, Mirella, Michele Pitaro, Emiliano Fratini, et al. "Safety in Rats of a Novel Nasal Spray Formulation for the Prevention of Airborne Viral Infections." Pharmaceutics 15, no. 2 (2023): 591. http://dx.doi.org/10.3390/pharmaceutics15020591.

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Hexedra+® is a nasal spray containing hydroxypropyl methylcellulose, beta-cyclodextrin, and usnic acid. It has been developed with the aim of reducing the risk of transmission of airborne viral infections, with particular reference to influenza and COVID-19. As part of the preclinical development of the product, we carried out a study on thirty male Wistar rats divided into three study groups and treated with Hexedra+, an alternative formulation containing a double concentration of usnic acid (0.015% instead of 0.0075%) or saline solution. Products were administered at the dose of 30 μL into e

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Stojanović, Gordana S., Miroslava Stanković, Igor Ž. Stojanović, Ivan Palić, Vesna Milovanović, and Soflja Rančić. "Clastogenic Effect of Atranorin, Evernic acid, and Usnic Acid on Human Lymphocytes." Natural Product Communications 9, no. 4 (2014): 1934578X1400900. http://dx.doi.org/10.1177/1934578x1400900419.

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Three lichen secondary metabolites atranorin (1), evernic acid (2), and usnic acid (3), were evaluated for their in vitro clastogenic and antiproliferative effects on human lymphocytes using the cytochalasin-B blocked micronucleus (CBMN) assay at concentrations of 2 μg/mL, 4 μg/mL and 6 μg/mL of final culture solution. The frequency of micronucleus (MN) was scored in binucleated cells, and cytokinesis-block proliferation index (CBPI) was calculated. Among the tested compounds, 3 exhibited the most prominent effect decreasing the frequency of MN in the range of 42.5% - 48.9%, that is about doub

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15

ASPLUND, Johan, Andy SIEGENTHALER, and Yngvar GAUSLAA. "Simulated global warming increases usnic acid but reduces perlatolic acid in the mat-forming terricolous lichen Cladonia stellaris." Lichenologist 49, no. 3 (2017): 269–74. http://dx.doi.org/10.1017/s0024282917000159.

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AbstractLichens as sessile and slow-growing symbiotic associations have evolved various carbon-based secondary compounds (CBSCs) to mitigate the effects of some stressors in the extreme environments in which they often grow. The mat-forming lichen Cladonia stellaris, an important fodder for reindeer, produces usnic acid in the outermost layer and perlatolic acid in the medulla. Here, we studied effects of simulated global warming on these CBSCs in C. stellaris cultivated in climate chambers with: 1) ambient conditions as control or 2) ambient conditions +4°C. The chambers simulated, at an hour

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16

Truong, Tuong L., Vo T. Nga, Duong T. Huy, Huynh B. L. Chi, and Nguyen K. P. Phung. "A New Depside from Usnea aciculifera Growing in Vietnam." Natural Product Communications 9, no. 8 (2014): 1934578X1400900. http://dx.doi.org/10.1177/1934578x1400900831.

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From Usnea aciculifera, a new depside aciculiferin A (1) was isolated, together with eleven known compounds, (+)-(12 R)-usnic acid (2), methyl haematommate (3), methyl β-orsellinate (4), methyl orsellinate (5), atranol (6), 7-hydroxy-5-methoxy-6-methylphthalide (7), norstictic acid (8), stictic acid (9), atranorin (10), barbatinic acid (11) and diffractaic acid (12). Their chemical structures were elucidated by 1D and 2D NMR spectroscopic as well as HR-ESI-MS analysis. Usnic acid (2) and depside diffractaic acid (12) presented in high yield of around 1.5% of the dried material. Some lichen sub

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Bankan, Nagaraju, Fathimunnisa Koka, Rajagopalan Vijayaraghavan, Sreekanth Reddy Basireddy, and Selvaraj Jayaraman. "Overexpression of the adeB Efflux Pump Gene in Tigecycline-Resistant Acinetobacter baumannii Clinical Isolates and Its Inhibition by (+)Usnic Acid as an Adjuvant." Antibiotics 10, no. 9 (2021): 1037. http://dx.doi.org/10.3390/antibiotics10091037.

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Acinetobacter species are among the most life-threatening Gram-negative bacilli, causing hospital-acquired infections, and they are associated with high morbidity and mortality. They show multidrug resistance that acts via various mechanisms. In Acinetobacter baumannii, efflux pump-mediated resistance to many antimicrobial compounds, including tigecycline, has been widely reported. Natural compounds have been used for their various pharmacological properties, including anti-efflux pump activity. The present study aimed to evaluate the efflux pump-mediated resistance mechanism of Acinetobacter

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18

A.S., FILIMONOV, ZAKHARENKO A.L., CHEPANOVA A.A., et al. "STUDY OF THE ABILITY OF A NEW USNIC ACID DERIVATIVE TO INHIBIT TDP1 AND TDP2, AND SENSITISE THE EFFECT OF ANTITUMOUR DRUGS." Chemistry for Sustainable Development 31, no. 6 (2023): 707–14. http://dx.doi.org/10.15372/csd2023520.

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A new usnic acid derivative containing cyanoethyl and isoniazid fragments is synthesised. The compound inhibits the activity of DNA repair enzyme Tdp1 with IC50 = 1.2 μM, is inactive against Tdp2 and does not affect cell survival for a panel of passaged cell lines in the concentration range up to 20 μM. It is shown that the compound in combinations with the certain concentrations of antitumour drugs can sensitise the effect of antitumour drugs olaparib and temozolomide on some cell lines.

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Farkas, Edit, Paul M. Kirika, Krisztina Szabó, and Arthur M. Muhoro. "Concentration data of (+)-usnic acid enantiomer from some European and African samples of Flavoparmelia caperata (L.) Hale (Parmeliaceae, lichenised Ascomycota) - results of a preliminary study." Cryptogamie, Mycologie 20, no. 7 (2024): 71–82. https://doi.org/10.5252/cryptogamie-mycologie2024v45a7.

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Farkas, Edit, Kirika, Paul M., Szabó, Krisztina, Muhoro, Arthur M. (2024): Concentration data of (+)-usnic acid enantiomer from some European and African samples of Flavoparmelia caperata (L.) Hale (Parmeliaceae, lichenised Ascomycota) - results of a preliminary study. Cryptogamie, Mycologie 20 (7): 71-82, DOI: 10.5252/cryptogamie-mycologie2024v45a7, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/mycologie2024v45a7.pdf

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Darmawan, Akhmad, Maulidiyah Maulidiyah, Megawati Megawati, et al. "Cytotoxic of Usnic Acid Isolated from Ramalina sp." Journal of Tropical Life Science 14, no. 02 (2024): 349–56. http://dx.doi.org/10.11594/jtls.14.02.14.

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Ramalina sp. (Ramalinaceae) is a type of lichen known to contain many active secondary metabolite compounds that have the potential to be used as medicine or medicinal raw materials. One of the biological activities possessed by Ramalina sp. lichen is its anticancer activity. This research aims to isolate and identify active secondary metabolite compounds from the methanol extract of the Ramalina sp. lichen and to find out the cytotoxic activity of the isolated compound against MCF7 breast cancer cells. Compound 1 (usnic acid) was successfully isolated from fraction A. The isolation and purifi

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de Oliveira, Djalma M., Cristiane B. Pereira, Graziele Mendes, et al. "Two new usnic acid derivatives from the endophytic fungus Mycosphaerella sp." Zeitschrift für Naturforschung C 73, no. 11-12 (2018): 449–55. http://dx.doi.org/10.1515/znc-2017-0162.

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Abstract The endophytic fungus Mycosphaerella sp. (UFMGCB2032) was isolated from the healthy leaves of Eugenia bimarginata, a plant from the Brazilian savanna. Two novel usnic acid derivatives, mycousfuranine (1) and mycousnicdiol (2), were isolated from the ethyl acetate extract, and their structure was elucidated by NMR and MS analyses. Compounds 1 and 2 exhibited moderate antifungal activities against Cryptococcus neoformans and Cryptococcus gattii, each with minimum inhibitory concentration values of 50.0 μg/mL and 250.0 μg/mL, respectively.

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22

Paudel, Babita, Hari Datta Bhattarai, Hong Kum Lee, Hyuncheol Oh, Hyun Woung Shin, and Joung Han Yim. "Antibacterial Activities of Ramalin, Usnic Acid and its Three Derivatives Isolated from the Antarctic Lichen Ramalina terebrata." Zeitschrift für Naturforschung C 65, no. 1-2 (2010): 34–38. http://dx.doi.org/10.1515/znc-2010-1-206.

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The development of new antibacterial compounds is an urgent issue to meet the evolution of resistivity of pathogenic bacteria against the available drugs. The objective of this study was to investigate the antibacterial compounds from the Antarctic lichen species Ramalina terebrata. A total of fi ve compounds, usnic acid, usimine A, usimine B, usimine C, and ramalin, were isolated by bioactivity guided-fractionation of the methanol extract of R. terebrata after several chromatographic procedures. The qualitative antibacterial activities of the crude extract and isolated compounds were determin

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Douglas A. Araújo, Hallysson, José G. Silva Júnior, João R. Saturnino Oliveira, et al. "Usnic Acid Potassium Salt: Evaluation of the Acute Toxicity and Antinociceptive Effect in Murine Model." Molecules 24, no. 11 (2019): 2042. http://dx.doi.org/10.3390/molecules24112042.

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To obtain usnic acid potassium salt (PS-UA), the usnic acid (UA) was extracted and purified from the lichen Cladonia substellata, and modified to produce PS-UA. The structure was determined by 1H-NMR, IR and elemental analysis, ratified through computational models, as well as identification the site of K+ insertion in the molecule. Antinociceptive activity was detected through contortions in mice induced by acetic acid and formalin (phases I and II) after treatments with 10 and 20 mg/kg of PS-UA, indicating interference in both non-inflammatory and inflammatory pain. After oral administration

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Wu, Wei, Bing Hou, Changli Tang, et al. "(+)-Usnic Acid Inhibits Migration of c-KIT Positive Cells in Human Colorectal Cancer." Evidence-Based Complementary and Alternative Medicine 2018 (September 12, 2018): 1–13. http://dx.doi.org/10.1155/2018/5149436.

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Inhibition of tumor cell migration is a treatment strategy for patients with colorectal cancer (CRC). SCF-dependent activation of c-KIT is responsible for migration of c-KIT positive [c-KIT(+)] cells of CRC. Drug resistance to Imatinib Mesylate (c-KIT inhibitor) has emerged. Inhibition of mTOR can induce autophagic degradation of c-KIT. (+)-usnic acid [(+)-UA], isolated from lichens, has two major functions including induction of proton shuttle and targeting inhibition of mTOR. To reduce hepatotoxicity, the treatment concentration of (+)-UA should be lower than 10μM. HCT116 cells and LS174 cel

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Kiliç, Nil, Yasemin Ö. Islakoğlu, İlker Büyük, Bala Gür-Dedeoğlu, and Demet Cansaran-Duman. "Determination of Usnic Acid Responsive miRNAs in Breast Cancer Cell Lines." Anti-Cancer Agents in Medicinal Chemistry 19, no. 12 (2019): 1463–72. http://dx.doi.org/10.2174/1871520618666181112120142.

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Objective: Breast Cancer (BC) is the most common type of cancer diagnosed in women. A common treatment strategy for BC is still not available because of its molecular heterogeneity and resistance is developed in most of the patients through the course of treatment. Therefore, alternative medicine resources as being novel treatment options are needed to be used for the treatment of BC. Usnic Acid (UA) that is one of the secondary metabolites of lichens used for different purposes in the field of medicine and its anti-proliferative effect has been shown in certain cancer types, suggesting its po

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BIDUSSI, Massimo, Knut Asbjørn SOLHAUG, and Yngvar GAUSLAA. "Increased snow accumulation reduces survival and growth in dominant mat-forming arctic-alpine lichens." Lichenologist 48, no. 3 (2016): 237–47. http://dx.doi.org/10.1017/s0024282916000086.

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AbstractRelative growth rates (RGR) and carbon-based secondary compounds (CBSCs) were quantified in four dominant terricolous arctic-alpine mat-forming lichens with different preferences for snow cover. The aim was to evaluate the effects of snow depth, and thus snow cover duration, on lichen growth and performance. The species,Alectoria ochroleuca,Flavocetraria nivalis,Cladonia mitisandCetrariella delisei, are associated with increasing snow depth, respectively. They were transplanted for one year at five snow depths (0, 60, 120, 160 and 200 cm measured in early May) along each of four natura

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А.С., ФИЛИМОНОВ, ЗАХАРЕНКО А.Л., ЧЕПАНОВА А.А. та ін. "ИЗУЧЕНИЕ ИНГИБИРУЮЩЕЙ TDP1 И TDP2 СПОСОБНОСТИ И СЕНСИБИЛИЗИРУЮЩИХ ДЕЙСТВИЕ ПРОТИВООПУХОЛЕВЫХ ПРЕПАРАТОВ СВОЙСТВ НОВОГО ПРОИЗВОДНОГО УСНИНОВОЙ КИСЛОТЫ". Химия в интересах устойчивого развития 31, № 6 (2023): 728–36. http://dx.doi.org/10.15372/khur2023520.

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Синтезировано новое производное усниновой кислоты, содержащее цианэтильный и изониазидный фрагменты. Соединение ингибирует активность фермента репарации ДНК Tdp1 со значением IC50 = 1.2 мкмоль/л, неактивно в отношении Tdp2 и не влияет на выживаемость клеток для панели пассируемых клеточных линий в диапазоне концентраций до 20 мкмоль/л. Показано, что соединение в комбинациях с определенными концентрациями противоопухолевых препаратов способно сенсибилизировать действие противоопухолевых препаратов олапариба и темозоломида на некоторых клеточных линиях. A new usnic acid derivative containing cya

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Filimonov, Aleksandr S., Marina A. Mikhailova, Nadezhda S. Dyrkheeva, et al. "Sulfide, Sulfoxide, and Sulfone Derivatives of Usnic Acid as Inhibitors of Human TDP1 and TDP2 Enzymes." Chemistry 6, no. 6 (2024): 1658–79. https://doi.org/10.3390/chemistry6060101.

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Tyrosyl-DNA phosphodiesterases 1 and 2 (TDP1 and TDP2) are important DNA repair enzymes that remove various adducts from the 3′- and 5′-ends of DNA, respectively. The suppression of the activity of these enzymes is considered as a promising adjuvant therapy for oncological diseases in combination with topoisomerase inhibitors. The simultaneous inhibition of TDP1 and TDP2 may result in greater antitumor effects, as these enzymes can mimic each other’s functions. We have previously shown that usnic acid-based sulfides can act as dual inhibitors, with TDP1 activity in the low micromolar range and

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Kumari, Madhuree, Siya Kamat, Sandeep Kumar Singh, Ajay Kumar, and C. Jayabaskaran. "Inhibition of Autophagy Increases Cell Death in HeLa Cells through Usnic Acid Isolated from Lichens." Plants 12, no. 3 (2023): 519. http://dx.doi.org/10.3390/plants12030519.

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The Western Ghats, India, is a hotspot for lichen diversity. However, the pharmacological importance of lichen-associated metabolites remains untapped. This study aimed to evaluate the cytotoxic potential of lichens of this region. For this, sixteen macrolichens were collected and identified from two locations in the Western Ghats. The acetone extract of Usnea cornuta (UC2A) showed significant cytotoxicity towards multiple human cancer cell lines. Interestingly, co-treatment with chloroquine (CQ), an autophagy inhibitor, increased the cytotoxic potential of the UC2A extract. A gas chromatograp

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Vasarri, Marzia, Linda Ponti, Donatella Degl’Innocenti, and Maria Camilla Bergonzi. "Usnic Acid-Loaded Polymeric Micelles: An Optimal Migrastatic-Acting Formulation in Human SH-SY5Y Neuroblastoma Cells." Pharmaceuticals 15, no. 10 (2022): 1207. http://dx.doi.org/10.3390/ph15101207.

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Usnic acid (UA) is one of the most abundant and common metabolites of lichens, known for its numerous pharmacological properties. Nevertheless, it presents some criticalities that severely limit its use in therapy: poor solubility in water and significant hepatotoxicity. Soluplus and Solutol HS15 and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) were employed to develop polymeric micelles (UA–PM). The chemical and physical properties of the system were characterized, including the size, homogeneity, zeta potential, critical micellar concentration (CMC), encapsulation efficiency (EE%

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Değirmenci, Banu Ceren, Mustafa Kocakaya, Selen İlgün, Gökçe Şeker Karatoprak, Zekiye Kocakaya, and Ahmet Ceylan. "Investigation of Biological Activity of Squamarina cartilaginea (With.) P. James Species Distributed in Türkiye." Cumhuriyet Science Journal 45, no. 3 (2024): 478–85. http://dx.doi.org/10.17776/csj.1424202.

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In this study, the methanol extract of Squamarina cartilaginea, a species distributed in Türkiye, was investigated for its antimicrobial, antioxidant, cytotoxic, and DNA protective effects. The chemical composition of the extract was elucidated through spectroscopic determination of total phenols, total flavonoids, and chromatographic quantification of usnic acid. Antimicrobial activity was assessed using the disk diffusion method, revealing a significant zone of inhibition with a diameter of 17.5 mm against M. luteus and S. aureus. The antioxidant activity was evaluated through scavenging act

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Ozkan, Kubra, Hatice Bekiroglu, Nur Cebi, et al. "Optimizing the Extraction of Polyphenols from Different Edible Lichens Using Response Surface Methodology and the Determination of Their Mineral and Antibacterial Properties." Foods 14, no. 15 (2025): 2562. https://doi.org/10.3390/foods14152562.

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This study employed response surface methodology for the first-time optimization of the ultrasound-assisted extraction (UAE) of the total phenolic content (TPC) and ABTS from edible lichens, including Evernia divaricata, Evernia prunastri, Pseudevernia furfuracea, Bryoria fuscescens, and Lobaria pulmonaria. Fourteen experimental points were generated using Design Expert Software, with the extraction temperature (25–40 °C), extraction time (5–20 min), and ethanol concentration (0–80%) as independent variables, and TPC and ABTS as dependent variables. The phenolic profile and mineral and antibac

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de Souza, Jaqueline Barbosa, Davi de Lacerda Coriolano, Rayza Camila dos Santos Silva, et al. "Ceftazidime and Usnic Acid Encapsulated in Chitosan-Coated Liposomes for Oral Administration against Colorectal Cancer-Inducing Escherichia coli." Pharmaceuticals 17, no. 6 (2024): 802. http://dx.doi.org/10.3390/ph17060802.

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Escherichia coli has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ), co-encapsulated in liposomes, could be an alternative. Coating the liposomes with chitosan (Chi) could facilitate the oral administration of this nanocarrier. Liposomes were prepared using the lipid film hydration method, followed by sonication and chitosan coating via the drip technique. Characterization included particle size, polydispersity index, zeta potential, pH, encapsulation efficiency, and physicochemical a

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Stoica (Oprea), Alexandra Elena, Delia Albuleț, Alexandra Cătălina Bîrcă, et al. "Electrospun Nanofibrous Mesh Based on PVA, Chitosan, and Usnic Acid for Applications in Wound Healing." International Journal of Molecular Sciences 24, no. 13 (2023): 11037. http://dx.doi.org/10.3390/ijms241311037.

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Injuries and diseases of the skin require accurate treatment using nontoxic and noninvasive biomaterials, which aim to mimic the natural structures of the body. There is a strong need to develop biodevices capable of accommodating nutrients and bioactive molecules and generating the process of vascularization. Electrospinning is a robust technique, as it can form fibrous structures for tissue engineering and wound dressings. The best way of forming such meshes for wound healing is to choose two polymers that complement each other regarding their properties. On the one hand, PVA is a water-solu

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Chlumsky, Ondrej, Heidi J. Smith, Albert E. Parker, et al. "Evaluation of the Antimicrobial Efficacy of N-Acetyl-l-Cysteine, Rhamnolipids, and Usnic Acid—Novel Approaches to Fight Food-Borne Pathogens." International Journal of Molecular Sciences 22, no. 21 (2021): 11307. http://dx.doi.org/10.3390/ijms222111307.

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In the food industry, the increasing antimicrobial resistance of food-borne pathogens to conventional sanitizers poses the risk of food contamination and a decrease in product quality and safety. Therefore, we explored alternative antimicrobials N-Acetyl-l-cysteine (NAC), rhamnolipids (RLs), and usnic acid (UA) as a novel approach to prevent biofilm formation and reduce existing biofilms formed by important food-borne pathogens (three strains of Salmonella enterica and two strains of Escherichia coli, Listeria monocytogenes, Staphylococcus aureus). Their effectiveness was evaluated by determin

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Kornienko, Tatyana E., Arina A. Chepanova, Alexandra L. Zakharenko, et al. "Enhancement of the Antitumor and Antimetastatic Effect of Topotecan and Normalization of Blood Counts in Mice with Lewis Carcinoma by Tdp1 Inhibitors—New Usnic Acid Derivatives." International Journal of Molecular Sciences 25, no. 2 (2024): 1210. http://dx.doi.org/10.3390/ijms25021210.

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Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is an important DNA repair enzyme and one of the causes of tumor resistance to topoisomerase 1 inhibitors such as topotecan. Inhibitors of this Tdp1 in combination with topotecan may improve the effectiveness of therapy. In this work, we synthesized usnic acid derivatives, which are hybrids of its known derivatives: tumor sensitizers to topotecan. New compounds inhibit Tdp1 in the micromolar and submicromolar concentration range; some of them enhance the effect of topotecan on the metabolic activity of cells of various lines according to the MTT test. One

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Elečko, Ján, Mária Vilková, Richard Frenák, et al. "A Comparative Study of Isolated Secondary Metabolites from Lichens and Their Antioxidative Properties." Plants 11, no. 8 (2022): 1077. http://dx.doi.org/10.3390/plants11081077.

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Free radicals play a critical role in the chemical processes that occur in all cells. Pharmaceutical companies manufacture a variety of synthetically prepared antioxidants, but it is known that many of these can be carcinogenic. As a result, efforts are being made to find natural antioxidants that do not have these side effects. Lichens may be suitable candidates because they contain secondary metabolites with proven antioxidant properties. This could be explained by the presence of compounds with phenolic groups in lichens. The radical scavenging reaction is a chemical reaction governed by st

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Kosanić, Marijana, Svetlana Ristić, Tatjana Stanojković, Nedeljko Manojlović, and Branislav Ranković. "Extracts of five Cladonia lichens as sources of biologically active compounds." Farmacia 66, no. 4 (2018): 644–51. https://doi.org/10.31925/farmacia.2018.4.13.

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Five lichen species of Cladonia genus (C. fimbriata, C. furcata, C. subulata, C. foliacea and C. rangiferina) were examined. We described the chemical composition of the acetone extracts of the mentioned lichens and the antioxidant, antimicrobial and antitumor activities of their extracts. The phytochemical analysis was determined by HPLC-UV method. The depside (atranorin), depsidones (hypoprotocetraric acid and fumarprotocetraric acid) and dibenzofurane (usnic acid) were identified from these lichens. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on

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Basiouni, Shereen, Marwa A. A. Fayed, Reda Tarabees, et al. "Characterization of Sunflower Oil Extracts from the Lichen Usnea barbata." Metabolites 10, no. 9 (2020): 353. http://dx.doi.org/10.3390/metabo10090353.

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The increasing global emergence of multidrug resistant (MDR) pathogens is categorized as one of the most important health problems. Therefore, the discovery of novel antimicrobials is of the utmost importance. Lichens provide a rich source of natural products including unique polyketides and polyphenols. Many of them display pharmaceutical benefits. The aim of this study was directed towards the characterization of sunflower oil extracts from the fruticose lichen, Usnea barbata. The concentration of the major polyketide, usnic acid, was 1.6 mg/mL extract as determined by NMR analysis of the cr

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Paukov, Alexander, Anzhelika Teptina, Maria Morozova, et al. "The Effects of Edaphic and Climatic Factors on Secondary Lichen Chemistry: A Case Study Using Saxicolous Lichens." Diversity 11, no. 6 (2019): 94. http://dx.doi.org/10.3390/d11060094.

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Diversity of secondary lichen metabolites and their relationship to substrate and environmental parameters were studied in saxicolous lichens in the Middle and South Urals of Russia. Atranorin, usnic acid, gyrophoric acid, zeorin, norstictic acid, antraquinones and stictic acid were found in 73, 42, 41, 37, 36, 35 and 32 species, respectively, of 543 taxa collected. One hundred and ninety six species (i.e., 36% of total species documented) contained no secondary metabolites. Spectra of secondary metabolites of crustose lichens varied on different rock types, while in fruticose and foliose grou

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Tabassum, Nazia, Fazlurrahman Khan, Geum-Jae Jeong, Do Kyung Oh, and Young-Mog Kim. "Controlling Oral Polymicrobial Biofilm Using Usnic Acid on the Surface of Titanium in the Artificial Saliva Media." Antibiotics 14, no. 2 (2025): 115. https://doi.org/10.3390/antibiotics14020115.

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Background/Objectives: Titanium dental implants, while highly successful, face challenges due to polymicrobial infections leading to peri-implantitis and implant failure. Biofilm formation on implant surfaces is the primary cause of these infections, with factors such as matrix production and cross-kingdom interactions contributing to the microbial accumulation of bacterial and fungal pathogens species. To combat this issue, naturally derived molecules have been reported to overcome the hurdle of antimicrobial resistance against the application of conventional antibiotics and antifungals. Meth

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Dyrkheeva, Nadezhda S., Aleksandr S. Filimonov, Olga A. Luzina, et al. "New Hybrid Compounds Combining Fragments of Usnic Acid and Thioether Are Inhibitors of Human Enzymes TDP1, TDP2 and PARP1." International Journal of Molecular Sciences 22, no. 21 (2021): 11336. http://dx.doi.org/10.3390/ijms222111336.

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Tyrosyl-DNA phosphodiesterase 1 (TDP1) catalyzes the cleavage of the phosphodiester bond between the tyrosine residue of topoisomerase 1 (TOP1) and the 3′ phosphate of DNA in the single-strand break generated by TOP1. TDP1 promotes the cleavage of the stable DNA–TOP1 complexes with the TOP1 inhibitor topotecan, which is a clinically used anticancer drug. This article reports the synthesis and study of usnic acid thioether and sulfoxide derivatives that efficiently suppress TDP1 activity, with IC50 values in the 1.4–25.2 μM range. The structure of the heterocyclic substituent introduced into th

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Khramchankova, Volga, and Roman Novikau. "Usnic acid concentration in different thallus parts of Evernia prunastri (L.) Ach., Ramalina pollinaria (Westr.) Ach. and Cladonia arbuscula lichens (Wallr.) Flot." Bulletin of Bryansk department of Russian botanical society 3 (15) (November 19, 2018): 49–53. http://dx.doi.org/10.22281/2307-4353-2018-3-49-53.

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Srivastava, Priya, D. K. Upreti, T. N. Dhole, Apurva K. Srivastava, and Meghanand T. Nayak. "Antimicrobial Property of Extracts of Indian Lichen against Human Pathogenic Bacteria." Interdisciplinary Perspectives on Infectious Diseases 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/709348.

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Context.Usnea ghattensisG. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria.Objective. To explore antimicrobial properties ofUsnea ghattensisagainst some human pathogenic bacteria.Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol.In vitroantimicrobial activity was tested initially byKirby-Bauertechnique of disc diffusion method and was confirmed by minimum inhibitory concentration using Broth microdilution me

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Kasyanova, Anastasia Pavlovna, and Evgeniy Sergeevich Korchikov. "Microcrystallization method use for assessing the content of secondary metabolites of lichens." Samara Journal of Science 11, no. 4 (2022): 47–51. http://dx.doi.org/10.55355/snv2022114106.

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The paper presents photographs of crystals of fumarprotocetraric, evernic, usninic, solorinic, olivetoric, perlatolinic, physodalic, salazinic, tamnolic acids and atranorin obtained from their acetone extracts of lichens. The shape of the crystals is specific to each substance, and their number, size and degree of aggregation depend on the concentration in the solution. Stellate crystals have atranorine, salazinic and evernic acids, with atranorine having the largest and salacic acid having the smallest; rodshaped branched crystals form solorinic and fumarprotocetraric acids, wider in the firs

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Aoussar, Noura, Fatima Ezzahra Laasri, Mohammed Bourhia, et al. "Phytochemical Analysis, Cytotoxic, Antioxidant, and Antibacterial Activities of Lichens." Evidence-Based Complementary and Alternative Medicine 2020 (December 4, 2020): 1–11. http://dx.doi.org/10.1155/2020/8104538.

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Background. Lichens present a complex symbiotic relationship between a filamentous fungus, photoautotrophic partner (algae or cyanobacteria), and bacterial community. The Objective of the Study. This study aimed at investigating the chemical composition and cytotoxic, antioxidant, and antimicrobial activities of acetone extracts of Moroccan Evernia prunastri (E. prunastri), Ramalina farinacea (R. farinacea), and Pseudevernia furfuracea (P. furfuracea). Materials and Methods. The phytochemical analysis was carried out by HPLC-UV. The cytotoxic effect was assessed on human prostate cancer (22RV1

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McCune, Bruce, Wilmer H. Perera, Xinhui Yu, and Kerry McPhail. "Visualizing usnic acid with anisaldehyde reagent." Lichenologist 56, no. 5 (2024): 193–200. https://doi.org/10.1017/s002428292400015x.

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AbstractThe pale yellowish tint of usnic acid in a lichen thallus itself is a commonly used character in identification keys, particularly in the genus Cladonia. Furthermore, the presence of usnic acid is phylogenetically significant in numerous groups of lichens. While the distinctive colour of usnic acid is readily visible when present in high concentrations, it is commonly problematic to discern when in low to moderate concentrations. We explored the use of an anisaldehyde reagent for visualizing usnic acid. Using both usnic acid-containing Cladonia samples and pure usnic acid, this reactio

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GAUSLAA, Yngvar, and Knut Asbjørn SOLHAUG. "Photoinhibition in lichens depends on cortical characteristics and hydration." Lichenologist 36, no. 2 (2004): 133–43. http://dx.doi.org/10.1017/s0024282904014045.

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Two shade-adapted (Lobaria pulmonaria and Cetraria islandica) and two sun-adapted lichen populations (Xanthoria parietina and Cetraria nivalis) were exposed to three irradiance regimes (1: photosynthetic radiation—PAR, 2: PAR+UV-A, 3: PAR+UV-A+UV-B) and two hydration regimes (1: no hydration, 2: daily hydration) in a growth cabinet for three weeks. Shade-adapted thalli had transparent upper cortices without coloured pigments, whereas sun-adapted thalli had coloured UV-B absorbing cortical pigments masking the photobiont. Manipulation of pigment concentration was the third factor used in the fa

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Krajka-Kuźniak, Violetta, Jarosław Paluszczak, Robert Kleszcz, and Wanda Baer-Dubowska. "(+)-Usnic acid modulates the Nrf2-ARE pathway in FaDu hypopharyngeal carcinoma cells." Molecular and Cellular Biochemistry 476, no. 6 (2021): 2539–49. http://dx.doi.org/10.1007/s11010-021-04092-7.

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AbstractNaturally occurring phytochemicals of different origin and structure, arctigenin, bergenin, usnic acid and xanthohumol, were shown to affect Nrf2 pathway in the context of various diseases, but their effect on this pathway in cancer cells was not extensively investigated. This study aimed to evaluate the effect of these compounds on Nrf2 expression and activation in hypopharyngeal FaDu squamous cell carcinoma cells. FaDu cells were treated with 2 or 10 μM arctigenin, bergenin, (+)-usnic acid or xanthohumol for 24 h. While arctigenin, bergenin, and xanthohumol did not affect either Nrf2

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Aslan Engin, Tubanur. "Exploring the antioxidant and protective effects of usnic acid: Opportunities and challenges." Frontiers in Life Sciences and Related Technologies 6, no. 1 (2025): 53–59. https://doi.org/10.51753/flsrt.1572004.

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Lichens are symbiotic organisms that produce a variety of secondary metabolites, including the well-known usnic acid (C18H16O7), which has garnered attention for its diverse biological activities and potential applications. Usnic acid, primarily found in lichen species such as Usnea and Cladonia, is a yellowish-green compound with notable antimicrobial, antiviral, and anti-inflammatory properties. Its antioxidant activity is particularly significant, with the ability to neutralize free radicals, inhibit lipid peroxidation, and stabilize cell membranes. Usnic acid, a secondary metabolite found

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