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ABSTRACT: At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer's disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman's reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor (IC50 = 27.1 microg/ml) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and 1H- and 13C-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the H2O2- and beta-amyloid-injured PC12 cells at 1 to 25 microg/ml. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.
Journal of Microbiology and Biotechnology 02/2013; 23(2):161-6. · 1.38 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the antioxidant properties of an edible lichen Ramalina conduplicans. The extract exhibited potent anti-linoleic acid peroxidation activity, free radical-scavenging activity, and reducing power.
The total phenolic contents were found to be high in the extract. Activity-guided bioautographic thin layer chromatography
(TLC) and HPLC identified sekikaic acid and homosekikaic acid as the main free radical-scavenging compounds in R. conduplicans extract (IC50 [50% inhibition concentration]=0.082 and 0.276mg/ml, respectively). The results suggested that this edible lichen species
have the potential to be utilized as food additives or as protective drugs.
KeywordsBioautographic TLC-Homosekikaic acid-In vitro-Sekikaic acid-Total phenolic contents
Mycoscience 04/2012; 51(5):391-395. · 1.21 Impact Factor
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ABSTRACT: Eight lichen species, Cetraria aculeata, Cladonia furcata, Pseudephebe pubescens, Sphaerophorus globosus, Stereocaulon alpinum, Umbilicaria antarctica, Usnea antarctica and Usnea aurantiacoatra, were collected from King George Island, maritime Antarctica, for the evaluation of antioxidant activities. Anti-linoleic
acid peroxidation activity, free radical scavenging activity, reducing power and superoxide anion scavenging activity were
assessed of methanol and acetone extract of the lichens invitro. Extract of Umbilicaria antarctica, Cladonia furcata, Sphaerophorus globosus and Usnea antarctica were found to have strong invitro antioxidant properties. In general, acetone extract exhibited stronger activities than
methanol extract. The activity-guided bioautographic TLC and HPLC analysis demonstrated that lecanoric acid was the main antioxidant
compound in the acetone extract of Umbilicaria antarctica, the most potent antioxidant lichen species among the test species. The results suggested that several Antarctic lichens and their substances can be used as novel bioresources of natural antioxidants.
Polar Biology 04/2012; 32(7):1033-1040. · 1.66 Impact Factor
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ABSTRACT: The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF. The extract of Nephromopsis pallescens (KOLRI-040516) exhibited the strongest anti-ff. pylori activity. Bioautograghic TLC and HPLC analysis identified usnic acid as the main antibacterial substance produced by JV. pallescens. The growth of JV. pallescens and production of antibacterial substances produced by the fungus were then investigated under several culture conditions including the culture media, initial medium pHs, incubation temperatures, and the degree of aeration. The results indicated that culture in MY medium with an initial pH of 6.0, a temperature of 15°C and a low degree of aeration supported the largest usnic acid production of the fungus (16.4 ug usnic acid/g dry biomass). Especially, aeration was found to be an important factor that affect both growth and usnic acid production of N. pallescens.
The Journal of Microbiology 02/2011; 49(1):66-70. · 1.10 Impact Factor
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ABSTRACT: Antioxidant properties of 46 lichen species collected from high-UV exposed alpine areas of southwestern China were evaluated for their therapeutic utilization. Anti-linoleic acid peroxidation activity, 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity, reducing power and the total phenolic contents were assessed in methanol extract of the lichens in vitro. Extracts of Peltigera praetextata and Sticta nylanderiana exhibited potent activity in all antioxidant tests. Especially, extracts of S. nylanderiana exhibited 1.37 times higher anti-linoleic acid peroxidation activity than ascorbic acid used as a positive control. It also showed the strongest free radical scavenging activity among all the tested species with an inhibition of 90.4% at the concentration of 330microgram/ml. Potent reducing power was also detected in the lichen extract compared with BHA. Generally, the antioxidant lichens contained large amount of phenolic contents. The activity-guided bioautographic TLC and HPLC analysis are used to find out the compounds responsible for the potent antioxidant activities of S. nylanderiana extract. The analysis demonstrated that lecanoric acid is one of the effective antioxidant compounds in S. nylanderiana. The results suggested that several highland lichens can be used as a novel bioresource for natural antioxidants.
Journal of Microbiology and Biotechnology 11/2010; 20(11):1524-8. · 1.38 Impact Factor
