The phytochemical analysis of methanol and chloroform extracts of Umbilicaria cylindrica was determined by HPLC-UV method. The predominant phenolic compound in both extracts was depsidone, salazinic ...acid (1). Besides salazinic acid, the tested extracts of U. cylindrica contain norstictic acid (2), methyl-β-orcinol carboxylate (3), ethyl haematommate (4), atranorin (5), and usnic acid (6), in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity, and inhibitory activity towards lipid peroxidation. The lichen extracts demonstrated important antimicrobial activity against eight strains with MIC values from 15.62 to 62.50 μg/mL. This is the first report of the detail chemical composition and antioxidant activity of the lichen Umbilicaria cylindrica, and the results suggest that this lichen can be used as a new source of the natural antioxidants and the substances with antimicrobial features.
The aim of this study was to identify some of the secondary metabolites present in acetonic, methanolic, and hexanic extracts of lichen Xanthoparmelia stenophylla and to examine their antioxidant, ...antimicrobial, and cytotoxic activity. Compounds of the depsid structure of lecanoric acid, obtusic acid, and atranorin as well as usnic acid with a dibenzofuran structure were identified in the extracts by HPLC. The acetone extract was shown to have the highest total phenolic (167.03 ± 1.12 mg GAE/g) and total flavonoid content (178.84 ± 0.93 mg QE/g) as well as the best antioxidant activity (DPPH IC50 = 81.22 ± 0.54). However, the antimicrobial and antibiofilm tests showed the best activity of hexanic extract, especially against strains of B. cereus, B. subtilis, and S. aureus (MIC < 0.08, and 0.3125 mg/mL, respectively). Additionally, by using the MTT method, the acetonic extract was reported to exhibit a strong cytotoxic effect on the HeLa and HCT-116 cell lines, especially after 72 h (IC50 = 21.17 ± 1.85 and IC50 = 21.48 ± 3.55, respectively). The promising antioxidant, antimicrobial, and cytotoxic effects of Xanthoparmelia stenophylla extracts shown in the current study should be further investigated in vivo and under clinical conditions.
The aim of this study was to investigate metabolites of the lichen Laurera benguelensis. A high-performance liquid chromatographic (HPLC) method has been developed for the characterization of ...xanthones and anthraquinones in extracts of this lichen. Lichexanthone, secalonic acid D, norlichexanthon, parietin, emodin, teloschistin and citreorosein were detected in the lichen samples, which were collected from two places in Thailand. Components of the lichen were identified by relative retention time and spectral data. This is the first time that a detailed phytochemical analysis of the lichen L. benguelensis was reported and this paper has chemotaxonomic significance because very little has been published on the secondary metabolites present in Laurera species. Some of the metabolites were detected for the first time in the family Trypetheliaceae. The results of preliminary testing of benzene extract and its chloroform and methanol fractions showed that all samples showed a weak radical scavenging activity. The chloroform extract showed the highest antioxidant activity.
► We investigated chemical composition of acetone extracts of two lichens species. ► Antioxidant, antimicrobial, and anticancer activities of extracts were tested. ► Antioxidant, antimicrobial, and ...anticancer activities of metabolites were tested. ► Tested lichen extracts and compounds demonstrated strong biological effects. ► Lichens may be used as natural antioxidant, antimicrobial and anticancer agents.
The aim of this study is to investigate chemical composition of acetone extracts of the lichens Evernia prunastri and Pseudoevernia furfuraceae and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and some their major metabolites. HPLC–UV method was used for identification of secondary metabolites. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. As a result of the study physodic acid had largest antioxidant activities. Total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also physodic acid. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method.
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.
The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activities of the acetone extracts of the lichens Cladonia furcata, Cladonia pyxidata and Cladonia ...rangiferina and their atranorin and fumarprotocetraric acid constituents. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power, and determination of total phenolic and flavonoid compounds. As a result of the study atranorin had largest free radical scavenging activity with IC50 values 131.48 μg/mL. Moreover, the tested samples had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was fumarprotocetraric acid with minimum inhibitory concentration values ranging from 0.031 to 0.125 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All samples were found to be strong anticancer activity toward both cell lines with IC50 values ranging from 10.97 to 41.23 μg/mL.
•Antioxidant, antimicrobial, and anticancer effects for three lichens were studied.•Two secondary metabolites were isolated from the tested lichens.•Tested lichen extracts and compounds demonstrated a strong biological effect.•Lichens may be used as natural antioxidant, antimicrobial and anticancer agents.
Density functional theory (DFT) calculations were performed to estimate the antioxidant activity of purpurin (1,2,4-trihydroxyanthraquinone-9,10-dione), a naturally occurring anthraquinone pigment. ...All conformations of purpurin and corresponding radicals, anions, and radical cation were analyzed using the M052X/6-311+G(2df,p) level of theory. The most stable rotamer of purpurin involves three internal hydrogen bonds. The most stable rotamers of purpurin radical and anion were obtained by dehydrogenating hydroxyl groups at C1 and C2, in gaseous and aqueous phases. The antioxidant activity of purpurin was elucidated by its bond dissociation enthalpy and ionization potential. Proton dissociation enthalpies were also computed. On the basis of these values, a one-step hydrogen atom transfer mechanism was invoked, rather than sequential proton loss–electron transfer or electron transfer–proton transfer, to explain the antioxidant activity of purpurin in the gas phase and in nonpolar solvents. In aqueous solution, the sequential proton loss–electron transfer mechanism plays a significant role.
Graphical abstract
The purpose of this work was to assess chemical composition, antibacterial activity against
Staphylococcus aureus
isolates from catheter-associated infections and antioxidant activity of methanol ...extracts of three lichens collected from Morocco. The phytochemical analysis of the methanol extracts of these lichens was performed by HPLC–UV method, the predominant phenolic compounds were evernic acid, physodalic acid and usnic acid for
Evernia prunastri, Pseudevernia furfuracea
and
Ramalina farinacea,
respectively. Total phenolic compounds and total flavonoid content of all extracts were also determined. As a result,
Pseudevernia furfuracea
extract had the strongest effect and the highest phenolic compounds content. All extracts showed antibacterial activity against all tested strains (MIC values ranging from 0.078 to 0.625 mg/mL), the strongest inhibition was obtained with the extract of
Evernia prunastri.
In the past years, the chemical behaviour of flavonoids and some anthraquinones as antioxidants has become the subject of intense experimental and theoretical research. In this paper, we used a ...quantum-chemical approach to shed light on the reactivity of the anthraquinone emodin. The structural and electronic features of emodin were investigated at the B3LYP/6-311++G** level of theory. We particularly focused on the 3-OH site and the role played by double bonds of benzene ring B in the reactivity of this site. The analysis of the theoretical bond dissociation enthalpy (BDE) values for all OH sites of emodin clearly shows the importance of the B ring and 3-OH group. The importance of keto-enol tautomerism has also been considered. Our analysis also includes the Mulliken spin density distribution for the radicals formed after H-removal on each OH site. The results clearly show that the BDE on the 1-OH and 8-OH sites are higher, because H-removal also implies the cleavage of the hydrogen bond.
Graphical Abstract
For the first-time, chemical composition and in vitro antitumor activity was investigated of a newly described lichen Anamylopsora pakistanica Usman & Khalid from the second highest plateau of the ...world (Deosai Plains, Pakistan). HPLC-UV method was used for identification of secondary metabolites and the acetone extract had higher values of TPC (41.90 mg GA/g) and TFC (75.37 mg RE/g) as compared to methanol extract. As chemical constituents 5,7-dihydroxy-6-methylphthalide, haematommic acid and alectorialic acid, were identified as major compounds. Atranol, alectorialin, gyrophoric acid and usnic acid were detected as minor substances. Acetone and methanol extracts induced a dose-dependent and time-dependent decrease in the viability of three types of tumour cells HeLa, HCT116 and MDA-MB-231. This lichen extract can induce S phase arrest in HeLa as compared to the untreated cells. Extract of this unique lichen, A. pakistanica, can be used safely as a significant source of biologically active compounds.For the first-time, chemical composition and in vitro antitumor activity was investigated of a newly described lichen Anamylopsora pakistanica Usman & Khalid from the second highest plateau of the world (Deosai Plains, Pakistan). HPLC-UV method was used for identification of secondary metabolites and the acetone extract had higher values of TPC (41.90 mg GA/g) and TFC (75.37 mg RE/g) as compared to methanol extract. As chemical constituents 5,7-dihydroxy-6-methylphthalide, haematommic acid and alectorialic acid, were identified as major compounds. Atranol, alectorialin, gyrophoric acid and usnic acid were detected as minor substances. Acetone and methanol extracts induced a dose-dependent and time-dependent decrease in the viability of three types of tumour cells HeLa, HCT116 and MDA-MB-231. This lichen extract can induce S phase arrest in HeLa as compared to the untreated cells. Extract of this unique lichen, A. pakistanica, can be used safely as a significant source of biologically active compounds.
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