• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.887-896
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• 2015

To develop environment-friendly agricultural products with anti-microbial activity against Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Usnea longissima was extracted by methanol and its extract was fractionated into several solvent fractions. The chloroform fraction, which showed the highest antimicrobial activity, was separated by silica gel-column chromatography and obtained into nine group subfractions. The nine group fractions were searched the antifungal activities by bioassay. The most active No. 3 subfraction was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to database of Wiley library. As a result, Usnic acid was identified as main compounds. In conclusion, Usnic acid isolated from Usnea longissima was antimicrobial chemical against Sclerotinia sclerotiorum as a pathogen of sclerotium disease.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1684-1688
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• 2013

A rapid and sensitive method for determining usnic acid of Lethariella cladonioides in rat was established using high performance liquid chromatography (HPLC) quadrupole time-of-flight (QTOF) tandem mass (MS/MS). Rat plasma was pretreated by mixture of acetonitrile and chloroform to precipitate plasma proteins. Chromatographic separation was achieved on a column ($50{\times}2.1$ mm, $5{\mu}m$) with a mobile phase consisting of water (containing $5{\times}10^{-3}$ M ammonium formate, pH was adjusted to 3.0 with formic acid) and acetonitrile (20:80, v/v) at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via collision induced dissociation (CID) under negative ionization mode. The MS/MS transitions monitored were m/z 343.0448 ${\rightarrow}$ m/z 313.2017 for usnic acid and m/z 153.1024 ${\rightarrow}$ m/z 136.2136 for protocatechuic acid (internal standard). The linear range was calculated to be 2.0-160.0 ng/mL with a detection limit of 3.0 pg/mL. The inter- and intra-day accuracy and precision were within ${\pm}7.0%$. Pharmacokinetic study showed that the apartment of usnic acid in vivo confirmed to be a two compartment open model. The method was fully valid and will probably be an alternative for pharmacokinetic study of usnic acid.

• The Plant Pathology Journal
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• v.38 no.1
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• pp.25-32
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• 2022

Plant pathogens pose major threats on agriculture and horticulture, causing significant economic loss worldwide. Due to the continuous and excessive use of synthetic pesticides, emergence of pesticide resistant pathogens has become more frequent. Thus, there is a growing needs for environmentally-friendly and selective antimicrobial agents with a novel mode of action, which may be used in combination with conventional pesticides to delay development of pesticide resistance. In this study, we evaluated the potentials of lichen substances as novel biopesticides against eight bacterial and twelve fungal plant pathogens that have historically caused significant phytopathological problems in South Korea. Eight lichen substances of diverse chemical origins were extracted from axenic culture or dried specimen, and further purified for comparative analysis of their antimicrobial properties. Usnic acid and vulpinic acid exhibited strong antibacterial activities against Clavibacter michiganensis subsp. michiganensis. In addition, usnic acid and vulpinic acid were highly effective in the growth inhibition of fungal pathogens, such as Diaporthe eres, D. actinidiae, and Sclerotinia sclerotiorum. Intriguingly, the growth of Rhizoctonia solani was specifically inhibited by lecanoric acid, indicating that lichen substances exhibit some degrees of selectivity to plant pathogens. These results suggested that lichen substance can be used as a selective biopesticide for controlling plant disease of agricultural and horticultural significance, minimizing possible emergence of pesticide resistant pathogens in fields.

• BMB Reports
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• v.34 no.3
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• pp.194-200
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• 2001

Secreted arginase from Evernia prunastri thallus has been purified 616-fold from the incubation medium. Purified arginase was resolved as only one peak in a capillary electrophoresis with a pI value of 5.35. The protein contained high amounts of acidic amino acids, such as Asx and Glx, and a relatively high quantity of Ser and Gly. The molecular mass of native, purified arginase was estimated as about 26 kDa by SE-HPLC. Substrate saturated kinetic showed a typical Michaelis-Menten relationship with a K_m value of 3.3 mM L-arginine. Atranorin behaved as a mixed activator of the enzyme (apparent $K_m$ = 0.96 mM); whereas evernic and usnic acid were revealed as non competitive inhibitors (apparent $K_m$ values were 3.16 mM and 3.05 mM, respectively). Kinetics of atranorin binding indicated that saturation was reached from 0.18 ${\mu}mol$ of the total atranorin and the occurrence of multiple sites for the ligand. This agrees with a possible aggregation of several enzyme subunits during the interaction process. A value of binding sites of about 12 was obtained. The binding of evernic acid was saturated from 23 nmol of total phenol. The number of binding sites was about 5. The loss of the binding ability of evernic acid could be interpreted as a single negative cooperatively. Usnic acid behaves in a similar way to evernic acid, although the binding saturation occurs at $0.14\;{\mu}moles$ of the ligand. This binding appears to be unspecific, and has 28 usnic acid binding sites to the protein.

• Mycobiology
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• v.35 no.2
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• pp.45-46
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• 2007

Lecanora muralis was found on the rock along coastal line during the field trip in Jeju island in 2006. Thallus crustose, placodioid, closely adnate, forming orbicular patches; upper surface grayish green, glossy; central lobes areolate, marginal parts plane, edges thin pruinose; lower surface ecorticate; apothecia sessile, lecanorine type, exciple dense and intact when young, and disc plane, but when mature, exciple laciniate, disc protrudent, yellowish brown to orange, $0.5{\sim}1.5$ mm in diameter; ascospores ellipsoid, simple, colorless, $12.5{\sim}15.0{\times}5.0{\sim}7.5\;{\mu}m$. Usnic acid and zeorin contained in thallus. This is the first record of this species in South Korea.

• Analytical Science and Technology
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• v.36 no.2
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• pp.89-98
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• 2023

Analytical methods for detecting atranol, chloroatranol, evernic acid, (+)-usnic acid, and atranorin in sanitary napkins and mouthwashes were developed using ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). UHPLC-MS/MS conditions were optimized for rapid, sensitive, and simultaneous analysis of the five allergenic compounds. The methods were validated by assessing their specificity, matrix effects, limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, and precision. Good linearity was achieved with a determination coefficient of ≥0.99. The LOD and LOQ were 2.1-9.8 and 6.4-29.6 ng/g for sanitary napkins and 0.29-0.48 and 0.87-1.45 ng/mL for mouthwashes, respectively. The accuracy and precision were within an acceptable range according to the criteria reported in the European SANTE/11813/2017 guidelines (70-120 % recovery, <20 % relative standard deviation). Therefore, these methods can be used to analyze atranol, chloroatranol, evernic acid, (+)-usnic acid, and atranorin in sanitary napkins and mouthwashes.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.122-127
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• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.356-357
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• 2011

• Mycobiology
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• v.34 no.3
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• pp.148-150
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• 2006

Karoowia saxeti was recorded during the lichen field expedition in southern part of Korea in 2006. The lichen was found on the rock surface along coastal line. This species was easily recognized by chemistry (K+ yellow) and the presence of isidia. Thallus was saxicolous, subcrustose, more or less lobate at the center with clearly lobed margins, $2{\sim}6\;cm$ broad and pale yellowish green. Thalli lobes were irregular, variable, up to 1.0mm wide, not branched, flat to more or less convex and contiguous to subimbricate. Upper surface of the thalli was continuous, emaculate, moderately isidiate. The isidia was subglobose to cynlindrical, darkening at the tips and unbranched. Low surface of the thalii was black with a spongy rhizoidal and lamellar layer. HPLC analysis proved the presence of stictic acid (K+ yellow), norstictic acid and usnic acid. This is the first record of the species in South Korea.

• Microbiology and Biotechnology Letters
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• v.40 no.1
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• pp.23-29
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• 2012

To isolate a novel antifungal compound, we obtained 100 kinds of endolichenic fungi from Korean Lichen & Allied Bioresources Center and examined their antifungal capability. Three fungi Usnea rigidula (2326), Parmotrema pseudotinctorum (2202) and Myelochroa sp. (2292) showed high antifungal activity against Candida albicans when they grew in both liquid and solid media. We extracted the culture supernatants of these three fungi with chloroform and then with ethyl acetate. Chloroform fraction exhibited the highest antifungal activities when those fractions were examined for the growth inhibition of Candida albicans with disc diffusion method. The chloroform faction was on further analysis with $C_{18}$ column chromatography to see whether the inhibitors are already known or not. Two peak fractions were collected from 4-day culture extract for Usnea rigidula and from 6-day culture extract for Parmotrema pseudotinctorum on the HPLC. A peak fraction from chloroform extracts of 4-day culture filtrate of Parmotrema pseudotinctorum showed higher antifungal activities against C. albicans and C. glabrata than another peak fraction. It appears that the antifungal materials are relatively nonpolar as usnic acid often found in lichenic fungi.