• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1524-1528
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• 2010

The antioxidant properties of 46 lichen species, collected from the highly UV-exposed alpine areas of southwestern China, were evaluated for their potential therapeutic utilization. The anti-linoleic acid peroxidation activity, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity, reducing power, and total phenolic contents were all assessed in vitro in the methanol extract of the lichens. A potent reducing power was detected in a number of the lichen extracts, when compared with butylated hydroxyanisole (BHA). In general, it was found that many of the lichens, with antioxidant properties, contained large quantities of phenolic content. Extracts of Peltigera praetextata and Sticta nylanderiana were found to exhibit the most potent activity in all of the antioxidant tests. In particular, extracts of S. nylanderiana displayed a 1.37 times greater anti-linoleic acid peroxidation activity, when compared with the ascorbic acid used as the positive control. S. nylanderiana also possessed the strongest free radical scavenging activity amongst all the tested species, with an inhibition rate of 90.4% at concentration of $330{\mu}g/ml$. Activity-guided bioautographic TLC and HPLC analyses were used to establish which compounds were responsible for the potent antioxidant activities of the S. nylanderiana extract. These analyses revealed lecanoric acid to be primarily responsible for the effective antioxidant properties of S. nylanderiana. Overall, these results have indicated that several highland lichens have the potential of being utilized as novel bioresources for naturally occurring antioxidant therapies.

• Korean Journal of Veterinary Research
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• v.24 no.2
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• pp.149-162
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• 1984

The research was conducted(1) to confirm the agent(s) responsible for the antimicrobial activity contained in the fermented tomato juice with L. acidophilus(2) to extract and purify the antimicrobial agent(s)(3) to find the biological, physical and chemical properties of the agent(s). The following results were obtained and summarized as followings; 1. The agent responsible for the inhibitory activity was confirmed by both well assay method using fermented tomato juice with L. acidophilus and turbidimetric technique using the cell-free filtrate or neutralized filtrate of tomato acidohilus culture and found exerted antimicrobial agent other than lactic acid. 2. The procedures of purification : The isolation and purification of antimicrobial agent from the lyophilized acidophilus tomato culture were carried out by (1) methanol extraction (2) acetone extraction, (3) Sephadex G-50 gel filtration (4) paper chromatography and (5) thin layer chromatography. 3. The biological, physical and chemical properties of antimicrobial agent: The biological, physical, chemical properties of the purified antimicrobial agent were: (1) The antimicrobial activity was strong against test organisms; Bacillus subtilis(ATCC 6633), Escheichia coli(ATCC 25922), Staphylococcus aureus(ATCC 167), Pseudomonas fluorescens(KFCC 32394), Proteus vulgaris and Shigella dysenteriae. (2) The pH value of the agent was 2.0 and the inhibitory activity was lost when it was neutralized at 7.0 of pH and the agent was heat stable at $121^{\circ}C$ for 60 minutes. (3) The ultraviolet light absorption spectra of methanol-acetone extract and TLC fraction exhibited a maximum absorption at 260nm and 224nm respectively. (4) The most purified agent from TLC plate increased about 130-fold in activity. (5) The agent isolated from TLC plate was free from $H_2O_2$ or lactic acid. 4. Bioautographic assy: By means of bioautography of the agent on silica gel of TLC plate a strong inhibitory activity against B. subtilis was demonstrated. 5. Mass spectrometry: The agent obtained from TLC plate was analyzed by mass spectrometry which show the parent peak at m/e 264 suggesting the molecular weight of the compound and molecular group such as [$C_2H{^+}_4$], [CO], [CH=NH], [$C_3{H^}4_7$], [$\begin{array}{rcl}O\\{\parallel}\\CH_3-C\\\end{array}$], [$C_6-H{^+}_{11}$], [$C_5H{^+}_{11}$], [$\begin{array}{rcl}O\\{\parallel}\\C_5H_7-C^+\\\end{array}$] were suggested.