• KSBB Journal
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• v.25 no.2
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• pp.173-178
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• 2010

Antifungal effect of Ginkgo biloba leaves extracts conducted for Pityrosporum ovale. Antifungal effect verified by diffusion test, optical density test and colony counting test under various concentration. Extract of ginkgo biloba leaves performed with 40% ethanol and 60% water solution at $60^{\circ}C$ and major components analyzed by HPLC. The concentrated extract have bilobalide and ginkgolide A and ginkgolide B and their concentration were 153.0 mg/L, 8403.5 mg/L and 2723.0 mg/L respectively. Ginkgo biloba leaves extracts gave 99.1% of antifungal effect for Pityrosporum ovale examined by colony counting method.

• Korean Journal of Pharmacognosy
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• v.26 no.1
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• pp.23-26
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• 1995

6-Hydroxykynurenic acid and ginkgolide B together with flavonol glycosides and biflavonoids were isolated from the yellow leaves of Ginkgo biloba and identified by means of spectroscopic methods. The correctness of $H{\"{o}}lzl's$ ${13}^C-NMR$ assignments for 6-hydroxykynurenic acid was confirmed by HMQC and HMBC techniques. Based on our present findings, it may be considered that the yellow Ginkgo leaves may contribute to be a source of high medicinal values.

• KSBB Journal
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• v.21 no.4
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• pp.312-316
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• 2006

A optimal condition for the Ginkgo biloba extraction in ethanol and water binary solvent system has been proposed based on concentration of bilobalide and ginkgolide known as having a antimicrobial components in the range 5% to 70% ethanol in water at $80^{\circ}C$. Concentration of bilobalide as a single component of Ginkgo biloba leaves extract is the highest at the 60% ethanol and ginkgolide A and B is highest at 50% ethanol. Antimicrobial effect of Ginkgo biloba leaves extracts on the S. aureus was also examined by disc diffusion test and optical density test. In case of the disc diffusion test, the clean zone diameter was increased from 0.95 cm to 1.70 cm as ethanol concentration increased from 5 to 70%. However, over the 40% of ethanol concentration the antimicrobial effect was almost flat. Based on these results, we propose that the 40% of ethanol and 60% water solvent is most desirable for Ginkgo biloba extract considering vapor pressure problem in concentrating process after extraction. We introduced SEM and TEM to figure out the morphological change on the surface and inside body of S. aureus when Ginkgo biloba leaves extract was treated. After mixed with Ginkgo biloba leaves extract blast like blebs appeared on the surface of S. aureus cells and cell wall was not observed. From the these results, it seems that the Ginkgo biloba leaves extract including bilobalide and ginkgolide A, B prevent cell wall synthesis.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.46-50
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• 1998

This study was conducted with pot experiment to find out the effect of ginkgo leaf wastes application produced from the pharmaceutical process on the growth and yield of red pepper. Four kinds of ginkgo leaf wastes, the natural dried leaves, the leaves produced from the pharmaceutical process, the dried leaves to remove methanol after the pharmaceutical process, and the leaves washed with water to removal methanol and some activated materials after pharmaceutical process, were treated with two levels of application rates. The growth responses and yield were measured throughout the experimented period. Shoot growth of red pepper was inhibited by all treatment of ginkgo leaf wastes compared to the treatment of NPK and NPK+compost. Red pepper yields were also significantly reduced by treatment of the ginkgo leaf wastes except for the treatment of the water washed ginkgo leaf wastes, 1,000 kg/10a, which showed similar yield to NPK treatment. The major reseon to reduce the growth and yield seemed to be originated from the allelopathic substances of the ginkgo leaves. The organic matter contents of the soil after experiment were slightly increased with the treatment of the ginkgo leaf wastes and compost than that of NPK treatment. Based on these results, this study for using the ginkgo leaf wastes should be done more to utilize the wastes of the pharmaceutical process as a organic fertilizer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.7-13
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• 2011

This study was conducted to investigate the antimicrobial activity of Ginkgo biloba L. leaves, seed and outer seedcoat against bacteria. Antimicrobial effects of Ginkgo biloba L. leaves (GBL), seed (GBS) and outer seedcoat (GBO) were examined by paper disc method and optical density method to determine minimum inhibition concentration (MIC), and observed by scanning electron microscope (SEM) to figure out the morphological change on the surface when Ginkgo biloba leaves extract was treated. The extracts of GBL, GBS and GBO were extracted by solvents such as methanol, ethanol, water. The methanol extract of GBL and GBO showed the highest antimicrobial activity against Bacillus cereus, Bacillus subtilis, Klebsiella pneumoniae, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, Yersinia enterocolitica except Escherichia coli and thus was further fractionated. The MICs of the chloroform fraction of GBL methanol extract were $125{\mu}g$/mL against B. subtilis, and L. monocytogenes; GBO methanol extract were $62.5{\mu}g$/mL against B. cereus and $125{\mu}g$/mL against B. subtilis, and L. monocytogenes. The microorganisms were treated with chloroform extracts ($2000{\mu}g$/mL) of GBL and GBO methanol extracts. It was observed by scanning electron microscope (SEM). The cells were expanded and a part of cell wall was completely destructed by GBL and GBO. Thus Ginkgo biloba L. leaves and outer seedcoat could be further developed into a natural antimicrobial agent.

• Environmental Analysis Health and Toxicology
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• v.4 no.1_2
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• pp.35-45
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• 1989

Studies on the heavy metal content of ginkgo leaves growing in all around Seoul. This study was carried out to investigate the concentration of heavy metals and soluble sulfur in ginkgo leaves. These leaves are found growing in park, residential, commercial and industrial areas all around Seoul. These analyzed the quantity of Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn, Hg and soluble surfur in separate samples of washed and unwashed leaves. The results were as follows: 1. This order of heavey metal concentration was found in Seoul area,: Fe＞Mn＞Zn＞Ni＞Pb＞Cu＞Co＞Cd＞Hg. 2. Pb concentration was higher in the commercial area than in the other areas, and it concentration in washed leaves was higher 96～100% and unwashed leaves 85～170%. 3. In the residential area Ni concentration was significantly higer where about seven times more Ni as found on the top part of the leaves. 4. Water soluble surfur was higest in the inudstrial area, but the percentage on top of the leaves was only 0.04～0.05% simillar with other area. 5. Fe, Zn and Ni were almost positively correlated to each component but negatively correlated between Mn and souble sulfer. All of content except Mn and Ni were significance between each area in washed and unwashed leaves.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.207-210
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• 1990

The position of interglycosidic linkages of two acylated flavonol glucorhamnosides from Ginkgo biloba leaves was unambiguously determined as 1 $\longrightarrow$ 2 linkages rather than 1 $\longrightarrow$ 4 ones on the basis of spectroscopic and chemical evidence.

• KSBB Journal
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• v.22 no.1
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• pp.58-61
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• 2007

A Insecticidal effect of Ginkgo biloba leaves extract was conducted for Dermatophagoides pteronyssinus as a predominant species in korea. D. pteronyssinus has been cultured in constant temperature and humidity chamber at the 25$^{\circ}C$ and 75% of relative humidity. The mortality of mites was determined by counting the dead bodies for every hour within 48 hours with pin hall microscope after treated by Ginkgo biloba leaves extract spreaded on 0.1 g of mass cultured media. The sequence of mortality for D. pteronyssinus are as follows, bilobalide was 91.6%, 80$^{\circ}C$ water extract was 82.8%, second water fraction was 75%, ethyl acetate fraction from 80$^{\circ}C$ water fraction was 73%, first ethyl acetate fraction from 80$^{\circ}C$ water extract was 69.4%, putaltrin was 65%, distilled water was 58%, methanol extract was 57.8%, Ginkgolide-A was 57.1 %, ethyl acetate fraction of 80$^{\circ}C$ water extract was 55%, respectively. From the these results we conclude that the bilobalide is the most effective component in the Ginkgo biloba leaves extract having insecticidal effect on house dust mite.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.897-905
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• 2019

To compare the composting characteristics of food waste supplemented with various bulking agents, aerated composting was performed by mixing sawdust, ginkgo leaves, insect feces, and mushroom waste at ratios of 6 : 4 (w/w). The initial temperatures (day after treatment [DAT] 3) of the sawdust, ginkgo leaves, insect feces and the mushroom waste mixtures were 39, 58, 65, and 51℃, respectively. The DAT 3 temperature was the highest in the food waste-insect feces mixture (65℃) and the lowest in the sawdust one (39℃). However, the insect feces treatment was terminated at DAT 21 because of a high water content (70.92%). The water content (DAT 56) of the composted food waste supplemented with sawdust, mushroom waste, and ginkgo leaves stood at 51.28, 39.81, and 44.92%, respectively. Therefore, the fully mature composts satisfied the water content requirement of less than 55% as recommended in the fertilizer standards of the RDA of Korea. The results of the CoMMe-101, Solvita and seed germination index methods indicate that the mushroom waste and ginkgo leaves treatments matured relatively quicker than that of the sawdust one. Based on the above observations, it is concluded that the mushroom waste and ginkgo leaves are more effective bulking agents compared to sawdust and as such, are recommended as suitable replacements for sawdust in food waste composting.

• YAKHAK HOEJI
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• v.38 no.1
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• pp.20-23
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• 1994

The contents of ginkgolides were determined in the leaves of male and female Ginkgo biloba from late spring until mid-autumn. Ginkgolides were detected during the whole growing season in the leaves of each tree. Ginkgolides content was low in late spring, gradually increased to reach a maximum in august and decreased thereafter. The male trees have two or three times higher ginkgolides content than the female trees. Comparing our results with that of previously reported values, the sexual variation of ginkgolides content seemed not to be genetic.