Synthesis, characterization, and biological evaluation of novel cobalt(II) complexes with ß-diketonates: crystal structure determination, BSA binding properties and molecular docking study.

In order to discover a new antibiotic drug with better or similar activity of the already existing drugs, a series of novel cobalt(II) complexes with ß-diketonate as ligands is synthesized and tested on four strains of bacteria and four species of fungi. All compounds showed notable antimicrobial activity against all tested strains. More importantly, some cobalt(II) complexes displayed greater activity than ketoconazole. It is important to notice that on the tested strains Mucor mucedo and Penicillium italicum complex 2B showed five times better activity compared to ketoconazole, while complex 2D had two times better activity on Penicillium italicum strain compared to ketoconazole. Moreover, investigations with bovine serum albumin were performed. Investigations showed that the tested complexes have an appropriate affinity for binding to bovine serum albumin. In addition, the molecular docking study was performed to investigate more specifically the sites and binding mode of the tested cobalt(II) complexes with ß-diketonate as ligands to bovine serum albumin, tyrosyl-tRNA synthetase, topoisomerase II DNA gyrase, and cytochrome P450 14 alpha-sterol demethylase. In conclusion, all the results indicated the great prospective of the novel cobalt complexes for some potential clinical applications in the future.

Synthesis, characterization, and biological activity of some 2,4-diketo esters containing dehydrozingerone fragment: DNA and protein binding study.

Due to the increased resistance to antibiotics, in recent years there has been a growing interest in the discovery of new antimicrobial agents from different sources. Bacteria that are resistant to most antibiotics are a global public health concern. In order to find a new antimicrobial drug, we synthesized a small series of 2,4-diketo esters and tested them on some gram-positive and gram-negative bacterial strains. Two compounds showed very good antibacterial activity against Staphylococcus aureus and Bacillus subtilis, respectively. Trichophyton mentagrophytes proved to be the most sensitive of the tested species regarding antifungal activity. Also, research was conducted on the biomolecule of bovine serum albumin. Examining these interactions, we concluded that all compounds have the appropriate binding affinity for bovine serum albumin, which is vital. Furthermore, to investigate the potential antitumor activity, interactions with DNA were carried out. Examining the interactions between our compounds and DNA using fluorescence, we concluded that all but one of the compounds interacts with the DNA molecule by intercalation. In addition, a molecular docking study was performed to investigate the binding mode of the tested compounds to DNA and bovine serum albumin. In conclusion, all the results indicate a great potential for the future application of these compounds in clinical practice in the future.

Searching for lichen indicator species: the application of self-organizing maps in air quality assessment-a case study from Balkan area (Serbia).

The subject of this paper is the possibility of using self-organizing map (SOM) in the biomonitoring studies. We used lichens as biomonitors to indicate different degrees of air quality. This research included all of 88 lichen species that was collected at 75 investigated points. These lichen species showed the different responses to air pollution. The air quality was assessed by IAP (index of atmospheric pollution) values. The IAP values were calculated for all of investigated points on the territory of four natural and one urban ecosystem. Calculated IAP values were in range of 10 to 75. On the basis of the lichen data and IAP values, we have employed SOM analysis that distinguished three clusters (A, B, and C). It presented lichen indicator species for each cluster: 16 species for cluster A, 18 species for cluster B, and two species for cluster C. This paper presents a useful method to find indicator species.

Cytotoxic and Antimicrobial Activity of Dehydrozingerone based Cyclopropyl Derivatives.

A small series of 1-acetyl-2-(4-alkoxy-3-methoxyphenyl)cyclopropanes was prepared, starting from dehydrozingerone (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one) and its O-alkyl derivatives. Their microbiological activities toward some strains of bacteria and fungi were tested, as well as their in vitro cytotoxic activity against some cancer cell lines (HeLa, LS174 and A549). All synthesized compounds showed significant antimicrobial activity and expressed cytotoxic activity against tested carcinoma cell lines, but they showed no significant influence on normal cell line (MRC5). Butyl derivative is the most active on HeLa cells (IC50 = 8.63 µm), while benzyl one is active against LS174 and A549 cell lines (IC50 = 10.17 and 12.15 µm, respectively).

Phytochemical study and antioxidant, antimicrobial and anticancer activities of Melanelia subaurifera and Melanelia fuliginosa lichens.

The aim of this study was to investigate antioxidant, antimicrobial and anticancerous activity of Melanelia subaurifera and Melanelia fuliginosa. The phytochemical analysis was determined by HPLC-UV method. Antioxidant activity was evaluated by DPPH and reducing power assay while antimicrobial activity was determined by minimal inhibitory concentration. The cytotoxic activity was tested using MTT method. The method for quantification of 2'-O-methyl anziaic acid and lecanoric acid in these lichens using RF-HPLC was also developed and validated. The depsides (lecanoric acid, gyrophoric acid, atranorin, anziaic acid and 2'-O-methyl anziaic acid), and dibenzofurane (usnic acid) were identified in these lichens. The antioxidant activity (IC50) of lichens extracts ranged from 121.52 to 424.51 µg/ml. 2'-O-Methyl anziaic acid showed the highest antimicrobial activity with MIC ranging from 0.0625 to 1 mg/ml. M. subaurifera extract showed the highest cytotoxic activity against the tested cell lines (IC50 = 9.88 to 31.64 µg/ml).

Biological potential of marine macroalgae of the genus Cystoseira.

In the present investigation the acetone extracts of three macroalgae, Cystoseira amentacea, Cystoseira barbata and Cystoseira compressa, were tested for antioxidant, antimicrobial and cytotoxic potential. As a result of the study, C. amentacea extract had more potent free radical scavenging activity (IC50 = 409.81 µg/mL) than C. barbata and C. compressa extracts. For reducing power, measured values of absorbance varied from 0.0352 to 0.8873. The IC50 values for superoxide anion scavenging activity for different extracts were 521.45-976.62 µg/mL. Total phenol and flavonoid contents in extracts were 39.96-81.28 µg PE/mg and 20.85-64.58 µg RE/mg respectively. Further, all three Cystoseira species exhibited a similar antimicrobial activity. The lowest MIC value (0.312 mg/mL) was shown in the extract obtained from C. compressa against Bacillus subtilis. Finally, extract of C. amentacea expressed the strongest cytotoxic activity toward tested cell lines with IC50 values ranging from 94.72 to 186.55 µg/mL. Based on these results, it can be stated that the tested macroalgae can be used as potential natural antioxidants and antimicrobial and cytotoxic agents.

Bioactivities and Medicinal Value of the Fruiting Body Extracts of Laetiporus sulphureus and Meripilus giganteus Polypore Mushrooms (Agaricomycetes).

In the present investigation methanol and acetone extracts of basidiocarps of mushrooms Laetiporus sulphureus and Meripilus giganteus were evaluated for their antimicrobial, cytotoxic and antioxidant/prooxidant effects. The antimicrobial potential was determined by the microdilution method against ten microorganisms. Cytotoxic effects were evaluated by MTT test, while changes of the redox status parameters (superoxide anion radical, nitrites and reduced glutathione) were determined spectrophotometrically on a human colorectal cancer cell line and human health fibroblasts cells. The results were measured 24 and 72 h after the treatment. Tested extracts exhibited moderate antimicrobial activity with MIC values from 0.004 to 20 mg/mL. The maximum antimicrobial activity was found in the methanol extracts of the M. giganteus against Bacillus subtilis, which was better than positive control. The acetone extract of M. giganteus with IC5072h = 13.36 µg/mL showed significant cytotoxic effect with strong cell selectivity (selectivity index = 37.42) against cancer human colorectal cancer cells. The tested extracts, especially M. giganteus acetone extract, induced an increase in oxidative stress parameters in tested cell lines, but significantly heightened it in human colorectal cancer cells. The obtained results suggest that these extracts, especially M. giganteus acetone extract, can be proposed as a novel source of nutraceuticals and pharmaceuticals.

Analysis of the Chemical and Medicinal Properties of Armillaria ostoyae (Agaricomycetes) Extracts and the Presence of Heavy Metals in Dry Basidiocarps.

We investigated the chemical and medicinal properties of methanolic and acetonic extracts of Armillaria ostoyae and the presence of heavy metals in its dry basidiocarps. The chemical content of extracts was analyzed with the HPLC-DAD-MS/MS method. According to our results, the most abundant mineral was potassium; the most abundant organic acid was malic acid; the most abundant carbohydrate was fructose, and the most abundant polyphenol was chlorogenic acid. The antimicrobial potential was evaluated using the microdilution assay, and the results ranged from 0.62 to 20 mg/mL. Antioxidant potential was studied by DPPH [half-maximal inhibitory concentration (IC50) of the methanolic extract was 619.67 µg/mL and of the acetonic extract was 533.65 µg/mL] and reducing power assays (the results ranged from 0.025 to 0.078 µg/mL). Total phenolic content was presented as gallic acid equivalent (methanolic extract, 6.12 mg GAE/g; acetonic extract, 3.99 mg GAE/g). The antidiabetic potential was explored by applying the α-amylase (the results ranged from 39.62 to 44.33%) and α-glucosidase assays (the results were in the range of 0.27-2.51%). The neuroprotective activity was asserted by the acetylcholinesterase inhibition assay (the results were in the range of 3.06-6.09%). The cytotoxic potential was investigated using the microtetrazolium assay, and the IC50 values ranged from 221.96 to > 400 µg/mL. Heavy metal content of the dry basidiocarps was evaluated using the AAS method and iron was the most abundant metal. A. ostoyae is a conditionally edible mushroom, which was not studied thoroughly before, thus this research will provide valuable knowledge about this species.

From Synthesis to Functionality: Tailored Ionic Liquid-Based Electrospun Fibers with Superior Antimicrobial Properties.

Herein, we report an efficient and facile strategy for the preparation of imidazolium-based ionic liquid (IL) monomers ([CnVIm][Br], n = 2, 4, 6, 8, 10, and 12) and their corresponding polymeric ionic liquids (PILs) with potent antimicrobial activities against Gram-negative and Gram-positive bacteria and fungi. The electrospinning technique was utilized to tailor the polymers with the highest antimicrobial potency into porous membranes that can be easily implemented into diverse systems and extend their practical bactericidal application. The antimicrobial mechanism of obtained ILs, polymers, and nanomaterials is considered concerning the bearing chain length, polymerization process, and applied processing technique that provides a unique fibrous structure. The structure composition was selected due to the well-established inherent amphiphilicity that 1-alkylimidazolium ILs possess, coupled with proven antimicrobial, antiseptic, and antifungal behavior. The customizable nature of ILs and PILs complemented with electrospinning is exploited for the development of innovative antimicrobial performances born from the intrinsic polymer itself, offering solutions to the increasing challenge of bacterial resistance. This study opens up new prospects toward designer membranes providing a complete route in their designing and revolutionizing the approach of fabricating multi-functional systems with tunable physicochemical, surface properties, and interesting morphology.

Chemical Characterization and Bioactive Properties of the Edible and Medicinal Honey Mushroom Armillaria mellea (Agaricomycetes) from Serbia.

Honey mushroom, Armillaria mellea, is an edible and medicinal lignicolous basidiomycete. In this study, we investigated the chemical composition and bioactive properties of its methanolic and acetonic extracts. The chemical characterization of extracts was done with the HPLC-DAD-MS/MS method. The results showed that potassium was the most abundant mineral; chlorogenic acid was the most abundant polyphenol; malic acid was the most abundant organic acid; and among carbohydrates, the most abundant were sorbitol, glucose, fructose, and saccharose. Antioxidative activity was assessed by DPPH (IC50 of the methanolic extract was 608.32 µg/mL and of the acetonic extract 595.71 µg/mL) and reducing power assays (the results ranged between 0.034 and 0.102 µg/mL). Total phenolic content was determined as gallic acid equivalent (methanolic extract: 4.74 mg GAE/g; acetonic extract: 5.68 mg GAE/g). The microdilution assay was used to evaluate the antimicrobial activity of the extracts, and the results ranged from 1.25 to 20 mg/mL. The antidiabetic effect of the extracts was tested by the α-amylase (the results ranged from 34.90% to 41.98%) and α-glucosidase assays (the results were in the range of 0.55-2.79%). The neuroprotective activity was explored by the acetylcholinesterase inhibition assay (the results were in the range of 1.94-7.76%). The microtetrazolium assay was used to investigate the cytotoxic activity of the extracts (the IC50 values ranged from 212.06 to > 400 µg/mL). Although some results suggest that some activities of the extracts are relatively moderate, the honey mushroom can still be considered an excellent source of food and bioactive compounds with medicinal value.

Phytochemical composition, biological activity and anti-inflammatory potential of acetone extract from the lichen Platismatia glauca (L.) W.L. Culb. & C.F. Culb.

This investigation examined the antioxidant, antimicrobial, cytotoxic, and anti-inflammatory activities of the acetone extract of the lichen Platismatia glauca (L.) W.L. Culb. & C.F. Culb. (PGAE). The phytochemical study of PGAE showed presence of seven compounds: salazinic acid, ß-orcinol carboxylic acid, 3-hydroxyphysodalic acid, physodalic acid, physodic acid, atranorin, and chloroatranorin. The antimicrobial potential was determined by microdilution which showed that S. aureus was most sensitive to the effect of PGAE with MIC value 0.312 mg/ml. Antioxidant activity was evaluated by using DPPH method. The obtained IC50 value for PGAE was 194.30 ± 3.32 µg/ml. The cytotoxic effect of the extract was evaluated by MTT test and the strongest activity was towards human epithelial carcinoma cells with IC50 value of 59.10 ± 0.46 µg/ml. The findings revealed that the application of lichen extracts decreased the paw edoema in a dose-dependent manner at 1, 2, 3, and 4 h following carrageenan administration.

Biological activities of Toninia candida and Usnea barbata together with their norstictic acid and usnic acid constituents.

The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC(50) values of 12.72 and 15.66 µg/mL.

Antioxidant, antimicrobial and anticancer activities of three Parmelia species.

BACKGROUND: Lichens are symbiotic organisms consisting of algae and fungi. They are used for human and animal nutrition and in the production of colours, perfumes and alcohol. Lichens have also been used in traditional medicine to treat diseases such as jaundice, pulmonary, stomach and cranial diseases. In this study the acetone extracts of three lichens, Parmelia caperata, Parmelia sulcata and Parmelia saxatilis, were tested for their antioxidant, antimicrobial and anticancer potential. RESULTS: Of the lichens tested, P. saxatilis had the highest free radical-scavenging activity (55.3% inhibition). Moreover, all tested extracts showed effective reducing power and superoxide anion radical scavenging. Strong relationships between total phenolic and flavonoid contents and antioxidant effects of the tested extracts were observed. The extract of P. sulcata was most active in terms of antimicrobial ability, with minimum inhibitory concentration values ranging from 0.78 to 12.5 mg L⁻¹. All extracts were found to have strong anticancer activity, with IC50 values ranging from 9.55 to 22.95 µg mL⁻¹. CONCLUSION: The present study showed that the tested lichen extracts exhibited strong antioxidant, antimicrobial and anticancer effects. This suggests that lichens may be used as possible natural antioxidant, antimicrobial and anticancer agents.

Chemical Composition and Bioctivity of the Giant Polypore or Black-Staining Mushroom, Meripilus giganteus (Agaricomycetes), from Serbia.

In this study, we tested the methanolic and acetonic extracts of the edible species Meripilus giganteus for their medicinal properties. Here, we present the chemical composition, as well as the antimicrobial, antioxidant, antidiabetic, neuroprotective, and cytotoxic activities, of the aforementioned extracts. The chemical composition of the extracts was analyzed with high-performance liquid chromatography coupled with diode-array detection and tandem mass spectrometry. The studied extracts contained 13 minerals, 23 polyphenols, 11 organic acids, and 22 carbohydrates. Antimicrobial activity was tested by applying the microdilution assay, and the results ranged from 0.002 to 20 mg/mL. Antioxidant activity was studied with the DPPH assay (half-maximal inhibitory concentration = 673.42 and 712.31 µg/mL for the methanolic and acetonic extracts, respectively) and the reducing power assay (range, 0.042-0.099 µg/mL). Total phenolic content was determined as 4.86 mg gallic acid equivalents (GAE)/g for the methanolic extract and 5.06 mg GAE/g for the acetonic extract. The antidiabetic effect of the extracts was explored with the α-amylase and α-glucosidase assays, and the results ranged from 30.66% to 38.67% and from 11.06% to 17.08%, respectively. The neuroprotective properties of M. giganteus extracts were studied using the acetylcholinesterase inhibition assay, with results ranging from 4.54% to 9.31%. Cytotoxic activity was tested by applying the microtetrazolium assay, with results ranging from 196.24 to 322.83 µg/mL. Although some assays proved relatively limited activities of the M. giganteus extracts studied, they can still be considered as natural sources of bioactive compounds without side effects.

Antioxidant and Antimicrobial Potential, BSA and DNA Binding Properties of Some 3-Hydroxy-3-Pyrrolin-2-Ones Bearing Thenoyl Fragment.

BACKGROUND: It is known that pyrrolidinone derivates belong to a class of biologically active compounds with a broad spectrum of biological actions. Nowadays, many scientists are making an effort in the discovery of more effective ways to eliminate reactive oxygen species (ROS) that cause oxidative stress or to eliminate the harmful microorganisms from the organism in humans. Therefore, pyrrolidinones seem to be great candidates for the research of this field. METHODS: The antimicrobial activity of tested compounds was estimated by the determination of the minimal inhibitory concentration by the broth micro-dilution method against four species of bacteria and five species of fungi. The antioxidant activity was evaluated by free radical scavenging and reducing power. RESULTS: Among the tested compounds, P22 showed marked antibacterial activity on Staphylococcus aureus with a MIC value of 0.312 mg/mL. Maximum antifungal activity with MIC value 0.625 mg/mL was shown by P23 and P25 compounds against Trichophyton mentagrophytes. Tested samples showed a relatively strong scavenging activity on DPPH radical (IC50 ranged from 166.75- 727.17 µg/mL). The strongest DPPH radical scavenging activity was shown by P3 compound with an IC50 value of 166.75 µg/mL. Moreover, the tested compounds had effective reducing power. Compounds P3, P10, and P13 showed the highest reducing power than those from the other samples. Results of the interactions between DNA and P3 indicated that P3 had the affinity to displace EB from the EB-DNA complex through intercalation [Ksv = (1.4 ± 0.1) × 105 M-1], while Ka values obtained via titration of BSA with P23 or P25 [Ka = (6.2 ± 0.2) and (5.0 ± 0.2) × 105 M-1] indicate that the notable quantity of the drug can be transmitted to the cells. CONCLUSION: Achieved results indicate that our compounds are potential candidates for use as medicaments.

Synthesis, Characterization, and Biological Evaluation of Tetrahydropyrimidines: Dual-Activity and Mechanism of Action.

In this paper, the synthesis, characterization, and biological evaluation of the novel tetrahydropyrimidines-THPMs are described. THPMs are well-known for wide pharmacological activities such as antimicrobial, anticancer, antiviral, etc. This research includes obtained results of in vitro antimicrobial, anticancer, and α-glucosidase inhibitory activities of the eleven novel THPMs. An antibiotic assessment was done against five bacteria (two Gram-positive and three Gram-negative) and five fungi by determining the minimal inhibitory concentration (MIC), using the broth tube dilution method. The most active antibacterial compounds were 4a, 4b, and 4d, while the best antifungal activity was shown by 4e, 4f, and 4k. The lowest MIC value (0.20 mg/mL) was measured for 4e, 4f, and 4k against the Trichophyton mentagrophytes. Moreover, examining the α-glucosidase inhibitory activity revealed the compound 4g as the one with the best activity. The cytotoxic activity was performed on the tumor cell lines (HeLa, K562, and MDA-MB-231) and normal cells (MRC-5). The best antitumor activity was shown by compounds 4b and 4k against HeLa cell lines. The influence on cell cycle and mechanism of action of the most active compounds were examined too. Compound 4b had good antibacterial and anticancer activities, while 4k showed promising antifungal and anticancer activities.

Synthesis, antitumor activity and QSAR studies of some 4-aminomethylidene derivatives of edaravone.

A series of aminomethylidene derivatives obtained from 4-formyledaravone were synthesized and characterized by IR, NMR and elemental analysis. All the compounds were screened for their antitumor activity. The compound containing 5-phenylpyrazole moiety (3q) exhibited remarkable antitumor activity in in vitro assays, especially against human breast cancer MDA-MB-361 and MDA-MB-453 cell lines. The most important whole-molecule descriptors for antitumor activity on MDA-MB-453 cells belong to the group of quantum-chemical descriptors.

Antioxidant, antimicrobial and anticancer activity of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis.

BACKGROUND: The aim of this study is to investigate in vitro antioxidant, antimicrobial and anticancer activity of the acetone extracts of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis. METHODS: Antioxidant activity was evaluated by five separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method against six species of bacteria and ten species of fungi. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. RESULTS: Of the lichens tested, Lecanora atra had largest free radical scavenging activity (94.7% inhibition), which was greater than the standard antioxidants. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. Extract of Cladonia furcata was the most active antimicrobial agent with minimum inhibitory concentration values ranging from 0.78 to 25 mg/mL. All extracts were found to be strong anticancer activity toward both cell lines with IC(50) values ranging from 8.51 to 40.22 µg/mL. CONCLUSIONS: The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial and anticancer effects. That suggest that lichens may be used as as possible natural antioxidant, antimicrobial and anticancer agents to control various human, animal and plant diseases.

Antioxidant properties of some lichen species.

Antioxidant activity of the acetone, methanol and aqueous extracts of the lichens Cladonia furcata, Hypogymnia physodes, Lasallia pustulata, Parmelia caperata and Parmelia sulcata has been screened in vitro by using different methods (DPPH radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content). Of the lichens tested, Lasallia pustulata had powerful antioxidant activities. Acetone, methanol and aqueous extracts of this lichen showed 90.93, 69.87 and 65.08% DPPH radical scavenging activities. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Those various antioxidant activities were compared to standard antioxidants such as ascorbic acid, butylated hydroxyanisole (BHA) and α-tocopherol. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidative activities of tested extracts suggest that these compounds play important role in antioxidant activity. The present stady shows that tested lichen species demonstrated a strong antioxidant activity and can be considered as good sources of natural antioxidants.

Lichens as possible sources of antioxidants.

Acetone, methanol and aqueous extracts of the lichen Cetraria islandica, Lecanora atra, Parmelia pertusa, Pseudoevernia furfuraceae and Umbilicaria cylindrica were investigated for antioxidant activity by five different methods: DPPH radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. Different antioxidant activities of the tested extracts were studied in comparison to known antioxidants such as ascorbic acid, butylated hydroxyanisole (BHA) and α-tocopherol. The tested extracts had strong antioxidant activity. The DPPH radical scavenging activity ranging from 32.68-94.70%. For reducing power, measured values of absorbance varied from 0.016 to 0.109. The superoxide anion scavenging activity for different extracts was 7.31-84.51%. In addition, the high contents of total phenolic compounds (12-76.42 µg of pyrocatechol equivalent) and total flavonoids (1.37-54.77 µg of rutin equivalent) suggests that phenols and flavonoids might be the major antioxidant compounds in studied extracts. Tested lichen species were found to possess effective antioxidant activities and can be used as good natural sources of antioxidants.