salicylates and lobaric-acid

Parmelia that belongs to the Parmeliaceae Family is a foliose lichen combined with one or two groups of fungi in Phylum Ascomycota or Basidiomycota and algae, which might be green algae or blue-green algae (cyanobacteria). It is generally called "Stone Flower," "Charila," "Pattharphool," or "Shilaaapushpa" in India. Lichen can be generally found growing on walls, old trees and spread largely across India, especially in the mountain area. It is a source of edible organisms for people residing in some regions of Nepal and it is also cultivated in hillsides of Kashmir. It has been found that lichen contains a lot of distinctive chemical compounds such as evernic acid, lecanoric acid, lobaric acid, norstictic acid, physodic acid, and salazinic acid. Some species of this lichen are recommended traditionally for controlling diseases such as boils, bronchitis, inflammations, excessive salivation, toothache, vomiting, etc. It has also applied as an indicator for biomonitoring, astringent, carminative, demulcent, bitter, resolvent, emollient, laxative, sporofic, sedative, diuretic and considered for treating sores, bronchitis, excessive salivation, vomiting, tooth-ache, boils and inflammations. It has been utilized for preparing traditional food and acts as a bioindicator for air pollution and radiation. It shows antibacterial, antioxidant, antimycobacterial and antifungal activities, including haemolytic, anaesthetic, spasmolytic and antispasmodic and antitumour activities. It also has several unique phytoconstituents that could be in charge of different therapeutic activities, but the majority of them are still unexplored. The review mainly focuses on various facets, such as common names, synonyms, traditional uses, botanical descriptions, and pharmacological activities of seven species of Parmelia.

Topics: Depsides; Humans; Hydroxybenzoates; Lactones; Medicine, Traditional; Parmeliaceae; Salicylates

Tetramethrin (Tm) is a commonly used pesticide that has been reported to exert estrogen-antagonistic effects selectively on female rats. The present study was undertaken to assess the protective role of lobaric acid (La) on estrous cycle in Tm-treated female Wistar rats. Female rats were exposed to Tm (50 mg/kg b.w/day) only or in combination with La at low (50 mg/kg b.w/day) or high (100 mg/kg b.w/day) dose for 30 days. The results showed that Tm altered the estrous cycle of female rats by decreasing the levels of luteinizing hormone, follicular-stimulating hormone, progesterone, estrone, and estradiol while increasing testosterone level. The morphology of vaginal smears of Tm-treated female rats showed the presence of abnormal cells and/or structures at different phases of estrus cycle. Strikingly, in (Tm + La)-treated rats, all the observed adverse effects of Tm on the hormonal parameters, cell morphology, and the length of each phase of estrous cycle were significantly diminished in a dose-dependent manner. The docking results showed that La competes with Tm for Gonadotropin-Releasing Hormone (GnRH) receptor, thereby reducing the toxicity of Tm but did not cancel the response of GnRH receptor completely. In conclusion, our results designated that La could be used as a potential candidate in the management of insecticide-induced alterations of the reproductive cycle of rodents.

Topics: Animals; Depsides; Estrous Cycle; Female; Lactones; Pyrethrins; Rats; Rats, Wistar; Salicylates

SARS-CoV-2 is the cause of the ongoing Coronavirus disease 19 (COVID-19) pandemic around the world causing pneumonia and lower respiratory tract infections. In understanding the SARS-CoV-2 pathogenicity and mechanism of action, it is essential to depict the full repertoire of expressed viral proteins. The recent biological studies have highlighted the leader protein Nsp1 of SARS-CoV-2 importance in shutting down the host protein production. Besides, it still enigmatic how Nsp1 regulates for translation. Here we report the novel structure of Nsp1 from SARS-CoV-2 in complex with the SL1 region of 5'UTR of SARS-CoV-2, and its factual interaction is corroborated with enzyme kinetics and experimental binding affinity studies. The studies also address how leader protein Nsp1 of SARS-CoV-2 recognizes its self RNA toward translational regulation by further recruitment of the 40S ribosome. With the aid of molecular dynamics and simulations, we also demonstrated the real-time stability and functional dynamics of the Nsp1/SL1 complex. The studies also report the potential inhibitors and their mode of action to block viral protein/RNA complex formation. This enhance our understanding of the mechanism of the first viral protein Nsp1 synthesized in the human cell to regulate the translation of self and host. Understanding the structure and mechanism of SARS-CoV-2 Nsp1 and its interplay with the viral RNA and ribosome will open the arena for exploring the development of live attenuated vaccines and effective therapeutic targets for this disease.

Topics: 5' Untranslated Regions; COVID-19 Vaccines; Depsides; Glycyrrhizic Acid; Lactones; Molecular Dynamics Simulation; Pregnatrienes; Protein Binding; Ribosome Subunits, Small, Eukaryotic; RNA, Viral; Salicylates; SARS-CoV-2; Viral Nonstructural Proteins; Virulence

Stereocaulon sorediiferum is expected to be a Cu-hyperaccumulator lichen and has fluorescent substances. To clarify the relationship between the fluorescence (FL) of the lichen and its Cu concentration, we collected S. sorediiferum samples at Cu-contaminated and uncontaminated sites in Japan, determined the concentration of Cu, K, Mg, Al, Ca, Mn, Fe, Zn, chlorophyll a,b, and total carotenoids in them, analyzed lichen secondary metabolites and fluorescent substances extracted from them, and measured the FL of them and their extracts. We found that the FL intensity of S. sorediiferum samples is significantly negatively correlated with their Cu concentration. The application of its FL for Cu monitoring may allow a new nondestructive quantitative method for assessing Cu contamination. The spectroscopic and chromatographic analysis shows that the fluorescent substances negatively correlated with Cu concentration are not major lichen secondary metabolites (lobaric acid and atranorin) and remain after immersion in acetone. The correlation analysis and the comparison with the causal relationship between Cu concentration and the chlorophyll a/b ratio suggest that the reason for the decrease in FL intensity with increasing Cu concentration is a structural change of the fluorescent substances by accumulated Cu. These findings lead to a better understanding of the relationship between the FL of S. sorediiferum and its Cu concentration and provide new insights into fluorescent lichen substances.

Topics: Air Pollutants; Ascomycota; Chlorophyll; Chlorophyll A; Copper; Depsides; Fluorescence; Hydroxybenzoates; Japan; Lactones; Lichens; Salicylates

Topics: Antineoplastic Agents; Benzofurans; Cell Cycle Checkpoints; Cell Proliferation; Cell Survival; Colonic Neoplasms; Depsides; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Gene Expression Regulation, Neoplastic; HCT116 Cells; HeLa Cells; Humans; Hydroxybenzoates; Lactones; Lichens; Molecular Structure; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Salicylates; Uterine Cervical Neoplasms

Chikungunya virus (CHIKV) is an arthropod-borne alphavirus. Alphaviruses are positive strand RNA viruses that require a 5' cap structure to direct translation of the viral polyprotein and prevent degradation of the viral RNA genome by host cell nucleases. Formation of the 5' RNA cap is orchestrated by the viral protein nsP1, which binds GTP and provides the N-7 methyltransferase and guanylyltransferase activities that are necessary for cap formation. Viruses with aberrant nsP1 activity are unable to replicate effectively suggesting that nsP1 is a promising target for antiviral drug discovery. Given the absence of commercially available antiviral therapies for CHIKV, it is imperative to identify compounds that could be developed as potential therapeutics. This study details a high-throughput screen of 3051 compounds from libraries containing FDA-approved drugs, natural products, and known bioactives against CHIKV nsP1 using a fluorescence polarization-based GTP competition assay. Several small molecule hits from this screen were able to compete with GTP for the CHIKV nsP1 GTP binding site at low molar concentrations. Compounds were also evaluated with an orthogonal assay that measured the ability of nsP1 to perform the guanylation step of the capping reaction in the presence of inhibitor. In addition, live virus assays with CHIKV and closely related alphavirus, Sindbis virus, were used in conjunction with cell toxicity assays to determine the antiviral activity of compounds in cell culture. The naturally derived compound lobaric acid was found to inhibit CHIKV nsP1 GTP binding and guanylation as well as attenuate viral growth in vitro at both 24 hpi and 48 hpi in hamster BHK21 and human Huh 7 cell lines. These data indicate that development of lobaric acid and further exploration of CHIKV nsP1 as a drug target may aid in the progress of anti-alphaviral drug development strategies.

Topics: Animals; Antiviral Agents; Cell Line; Chikungunya virus; Chlorocebus aethiops; Cricetinae; Depsides; Drug Discovery; Fluorescence; High-Throughput Screening Assays; Humans; Lactones; RNA Caps; Salicylates; Vero Cells; Viral Nonstructural Proteins; Virus Replication

Thioredoxin reductase (E.C 1.6.4.5.; TrxR) is a widely distributed flavoprotein that catalyzes the NADPH-dependent reduction of thioredoxin (Trx) in many cellular events such as DNA synthesis, DNA repair, angiogenesis, antioxidative defense, and regulating apoptosis. Although TrxR is indispensible in protecting cells against oxidative stress, the overexpression of TrxR is seen in many aggressive tumors. Therefore, targeted inhibition of TrxR has been accepted as a new approach for chemotherapy.. In this study, in vitro inhibition effect of the lichen acids (diffractaic, evernic, lobaric, lecanoric, and vulpinic acid) on mitochondrial TrxR purified from rat lung was investigated.. It was the first time the enzyme was purified from rat lungs by using 2', 5'-ADP Sepharose 4B affinity chromatography. The purity of the enzyme was checked with SDS-PAGE. In vitro inhibition effect of the lichen acids was investigated spectrophotometrically. To emphasize the importance of the obtained data, the commercial anticancer drugs cisplatin and doxorubicin were used as positive controls.. Molecular mass of the enzyme was calculated as approximately 52.4 kDa. The enzyme was purified with a 63.6% yield, 208.3 fold, and 0.5 EU/mg proteins specific activity. The IC50 values of five lichen acids were significantly lower than IC50 values of anticancer drugs.. All of the lichen acids, especially lecanoric and vulpinic acid, exhibited much stronger inhibitory effect on TrxR than the anticancer drugs cisplatin and doxorubicin. These lichen acids have pharmacological potential as effective natural antioxidants, antimicrobials, and anticancer agents.

Topics: Animals; Anisoles; Antineoplastic Agents; Cisplatin; Depsides; Dose-Response Relationship, Drug; Doxorubicin; Enzyme Inhibitors; Furans; Hydroxybenzoates; Lactones; Lichens; Lung; Male; Mitochondria; Molecular Structure; Phenylacetates; Rats; Rats, Sprague-Dawley; Salicylates; Structure-Activity Relationship; Thioredoxin-Disulfide Reductase

The first total syntheses of the natural products lobaric acid (1) and its derivatives isolated from the Antarctic lichen Stereocaulon alpinum are reported in this study. Lobarin (3), with a pseudodepsidone structure, was synthesized first in 11 steps by utilizing an Ullmann aryl ether coupling reaction, and lobaric acid was synthesized in an additional three steps by a seven-membered lactonization reaction. Various derivatives were also obtained from the prepared lobaric acid, and the synthetic compounds exhibited significant PTP1B inhibitory activities.

Topics: Antarctic Regions; Ascomycota; Depsides; Lactones; Lichens; Phenyl Ethers; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Salicylates

Herein we report the anti-inflammatory activity of lobaric acid and pseudodepsidones isolated from the nordic lichen Stereocaulon paschale. Lobaric acid (1) and three compounds (2, 7 and 9) were found to inhibit the NF-κB activation and the secretion of pro-inflammatory cytokines (IL-1β and TNF-α) in LPS-stimulated macrophages. Inhibition and docking simulation experiments provided evidence that lobaric acid and pseudodepsidones bind to PPAR-γ between helix H3 and the beta sheet, similarly to partial PPAR-γ agonists. These findings suggest that lobaric acid and pseudodepsidones reduce the expression of pro-inflammatory cytokines by blocking the NF-κB pathway via the activation of PPAR-γ.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Cell Survival; Depsides; Dose-Response Relationship, Drug; Humans; Lactones; Lichens; Lipopolysaccharides; Macrophages; Molecular Docking Simulation; Molecular Structure; NF-kappa B; PPAR gamma; Salicylates; Signal Transduction; Structure-Activity Relationship; U937 Cells

The purpose of this study was to investigate the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on proliferation, viability and reactive oxygen species (ROS) level towards three human cancer cell lines, MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT-116 (colon carcinoma). Cells were treated with different concentrations (2.5-100 μM) of these compounds for 48 h. In this comparative study, our lichen metabolites showed various cytotoxic effects in a concentration-dependent manner, and usnic acid was the most potent cytotoxic agent, while variolaric acid did not inhibit the proliferation of any of the three cell lines used. All tested lichen compounds did not exhibit free radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The lichen metabolites did not significantly increase the intracellular ROS level and did not prevent oxidative injury induced by t-butylhydroperoxide in HeLa cells. To better clarify the mechanism(s) of cytotoxic effect induced by protolichesterinic acid in HeLa cells, we investigated apoptotic markers such as condensation and fragmentation of nuclear chromatin and activation of caspase-3, 8 and 9. Our results revealed that the antiproliferative activity of 40 μM protolichesterinic acid in HeLa cells is related to its ability to induce programmed cell death involving caspase-3, 8 and 9 activation.

Topics: 4-Butyrolactone; Anisoles; Antioxidants; Apoptosis; Benzofurans; Caspases; Cell Line, Tumor; Cell Proliferation; Cell Survival; Depsides; Free Radical Scavengers; Humans; Hydroxybenzoates; Lactones; Lichens; Oxidative Stress; Reactive Oxygen Species; Salicylates

Capturing a coactivator, naturally: the natural products sekikaic acid and lobaric acid, isolated after a high-throughput screen of a structurally diverse extract collection, effectively target the dynamic binding interfaces of the GACKIX domain of the coactivator CBP/p300. These molecules are the most effective inhibitors of the GACKIX domain yet described and are uniquely selective for this domain.

Topics: Depsides; Lactones; Models, Molecular; Molecular Dynamics Simulation; p300-CBP Transcription Factors; Protein Structure, Tertiary; Salicylates

Antioxidant activity of several classes of lichen metabolites were assessed in the in vitro superoxide radical (SOR), nitric oxide radical and 2,2-diphenyl-1-picrylhydrazil radical scavenging assays. The despsides sekikaic acid and lecanoric acid showed promising antioxidant activity in SOR assay with IC₅₀ values of 82.0 ± 0.3 µmol and 91.5 ± 2.1 µmol, respectively, while the depsidone lobaric acid exhibited an IC₅₀ value of 97.9 ± 1.6 µmol, all relative to the standard, propyl gallate (IC₅₀ = 106.0 ± 1.7 µmol). One of the most abundant mononuclear phenolic compounds, methyl-β-orcinol carboxylate was found to be a potent NO scavenger (IC₅₀ = 84.7 ± 0.1 µmol), compared to the standard rutin (IC₅₀ = 86.8 ± 1.9 µmol).

Topics: Antioxidants; Biphenyl Compounds; Chemical Fractionation; Complex Mixtures; Depsides; Enzyme-Linked Immunosorbent Assay; Free Radical Scavengers; In Vitro Techniques; Inhibitory Concentration 50; Lactones; Lichens; Molecular Structure; Nitric Oxide; Picrates; Salicylates; Species Specificity; Superoxides

Seven phenolic lichen metabolites (1-7) have been isolated from a methanol extract of the Antarctic lichen Stereocaulon alpinum by various chromatographic methods. The structures of these compounds were determined mainly by analysis of NMR spectroscopic data. A depsidone-type compound, lobaric acid (1) and two pseudodepsidone-type compounds, 2 and 3, exhibited potent inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with IC(50) values of 0.87microM, 6.86microM, and 2.48microM, respectively. Kinetic analyses of PTP1B inhibition by compounds 1 and 2 suggested that these compounds inhibited PTP1B activity in a non-competitive manner.

Topics: Depsides; Enzyme Inhibitors; Kinetics; Lactones; Lichens; Plant Extracts; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Salicylates

Lobaric acid (1) has been isolated from lichen, Stereocaulon sasakii together with a new benzofuran, sakisacaulon A (2). Lobaric acid (1) inhibited the polymerization of tubulin. Structure-activity relationship of lobaric acid and its derivatives on inhibitory activity of tubulin polymerization was discussed.

Topics: Antimitotic Agents; Benzofurans; Depsides; Lactones; Lichens; Salicylates; Structure-Activity Relationship; Tubulin; Tubulin Modulators

Several lichen compounds, i.e. lobaric acid (1), a beta-orcinol depsidone from Stereocaulon alpinum L., (+)-protolichesterinic acid (2), an aliphatic alpha-methylene-gamma-lactone from Cetraria islandica Laur. (Parmeliaceae), (+)-usnic acid (3), a dibenzofuran from Cladonia arbuscula (Wallr.) Rabenh. (Cladoniaceae), parietin (4), an anthraquinone from Xanthoria elegans (Link) Th. Fr. (Calaplacaceae) and baeomycesic acid (5), a beta-orcinol depside isolated from Thamnolia vermicularis (Sw.) Schaer. var. subuliformis (Ehrh.) Schaer. were tested for inhibitory activity on platelet-type 12(S)-lipoxygenase using a cell-based in vitro system in human platelets. Lobaric acid (1) and (+)-protolichesterinic acid (2) proved to be pronounced inhibitors of platelet-type 12(S)-lipoxygenase, whereas baeomycesic acid (5) showed only weak activity (inhibitory activity at a concentration of 100 microg/ml: (1) 93.4+/-6.62%, (2) 98,5+/-1.19%, 5 14.7+/-2.76%). Usnic acid (3) and parietin (4) were not active at this concentration. 1 and 2 showed a clear dose-response relationship in the range of 3.33-100 microg/ml. According to the calculated IC50 values the highest inhibitory activity was observed for the depsidone 1 (IC50 = 28.5 microM) followed by 2 (IC50 = 77.0 microM). The activity of 1 was comparable to that of the flavone baicalein, which is known as a selective 12(S)-lipoxygenase inhibitor (IC50 = 24.6 microM).

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 4-Butyrolactone; Benzoates; Benzofurans; Blood Platelets; Depsides; Emodin; Humans; In Vitro Techniques; Lactones; Lichens; Lipoxygenase; Lipoxygenase Inhibitors; Molecular Structure; Resorcinols; Salicylates

Several lichen species have been used traditionally as medicinal plants. It has previously been shown that two low-molecular-weight lichen metabolites, lobaric acid isolated from Stereocaulon alpinum Laur. and protolichesterinic acid isolated from Cetraria islandica L. (Ach.), have in-vitro inhibitory effects on arachidonate 5-lipoxygenase. We have studied the effects of these compounds on cultured cells from man, including three malignant cell-lines (T-47D and ZR-75-1 from breast carcinomas and K-562 from erythro-leukaemia), as well as normal skin fibroblasts and peripheral blood lymphocytes. Both test substances caused a significant reduction in DNA synthesis, as measured by thymidine uptake, in all three malignant cell-lines; the dose inducing 50% of maximum inhibition (ED50) was between 1.1 and 24.6 microg mL(-1) for protolichesterinic acid and between 14.5 and 44.7 microg mL(-1) for lobaric acid. The breast-cancer cell-lines were more sensitive than K-562. The proliferative response of mitogen-stimulated lymphocytes was inhibited with a mean ED50 of 8.4 microg mL(-1) and 24.5 microg mL(-1) for protolichesterinic acid and lobaric acid, respectively. These concentrations are of the same order of magnitude as the IC50 values in the 5-lipoxygenase assay. Significant cell death (assessed by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-( 4-sulfophenyl)-2H-tetrazolium) assay and trypan blue exclusion) occurred in the three malignant cell-lines at protolichesterinic acid and lobaric acid concentrations above 20 and 30 microg mL(-1), respectively. In K-562 morphological changes consistent with apoptosis were detected. Up to 38% cell death was observed at 20 microg mL(-1) for protolichesterinic acid and 15 microg mL(-1) for lobaric acid in mitogen-stimulated lymphocytes but unstimulated lymphocytes were clearly less sensitive. In contrast, the DNA synthesis, proliferation and survival of normal skin fibroblasts were not affected at doses up to 20 microg mL(-1) for protolichesterinic acid and 30 microg mL(-1) for lobaric acid. We conclude that the anti-proliferative and cytotoxic effects observed might be related to the 5-lipoxygenase inhibitory activity of protolichesterinic acid and lobaric acid. These results open up the opportunity for future studies of these lichen metabolites with regard to their anti-tumour and anti-inflammatory properties.

Topics: 4-Butyrolactone; Depsides; Ethanol; Fibroblasts; Humans; Lactones; Lichens; Lipoxygenase Inhibitors; Lymphocyte Activation; Lymphocytes; Salicylates; Tumor Cells, Cultured

Several compounds, whose structures represent the most common chemical classes of lichen metabolites, were screened for in vitro activity against Mycobacterium aurum, a non-pathogenic organism with a similar sensitivity profile to M. tuberculosis. Of the compounds tested, usnic acid from Cladonia arbuscula exhibited the highest activity with an MIC value of 32 microg/ml. Atranorin and lobaric acid, both isolated from Stereocaulon alpinum, salazinic acid from Parmelia saxatilis and protolichesterinic acid from Cetraria islandica all showed MIC values >/=125 microg/ml.

Topics: 4-Butyrolactone; Anti-Bacterial Agents; Benzofurans; Depsides; Hydroxybenzoates; Lactones; Lichens; Microbial Sensitivity Tests; Mycobacterium; Salicylates

Lobaric acid, a constituent of the lichen Stereocaulon alpinum, was investigated for effects on the smooth muscle taenia coli from guinea pigs. Inhibitory effects of lobaric acid on spontaneous contractile activity and on contractile activity stimulated by ionophore A23187 were studied. In addition, the activity of lobaric acid on ionophore-induced generation of cysteinyl-leukotrienes in taenia coli was determined by enzyme immunoassay. Lobaric acid significantly reduced spontaneous contractile activity of the muscle and inhibited contractions caused by ionophore A23187 with an effective dose of 5.8 microM. Increased contractility caused by leukotriene D4 was not influenced by lobaric acid. Lobaric acid inhibited the formation of cysteinyl-leukotrienes as determined by enzyme immunoassay with an effective dose of 5.5 microM.

Topics: Animals; Calcimycin; Colon; Depsides; Electric Stimulation; Female; Guinea Pigs; Immunoenzyme Techniques; In Vitro Techniques; Lactones; Leukotriene C4; Leukotriene D4; Leukotriene E4; Lichens; Muscle Contraction; Muscle, Smooth; Salicylates