• The Journal of Korean Medicine
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• v.24 no.1
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• pp.141-154
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• 2003

Objectives : This study was undertaken to define the effect of Diospyros kaki L. Radix or Diospyros kaki L. Folium on phenylephrine-induced arterial contraction and the mechanism of Diospyros kaki L. Radix or Diospyros kaki L. Foliuminduced relaxation. Methods : In order to investigate the effect of Diospyros kaki L. Radix or Diospyros kaki L. Folium on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. Diospyros kaki L. Radix or Diospyros kaki L. Folium extract was infused into contracted arterial strips induced by phenylephrine. To analyze the mechanism of Diospyros kaki L. Radix or Diospyros kaki L. Folium-induced relaxation, Diospyros kaki L. Radix or Diospyros kaki L. Folium extract was infused into contracted arterial strips induced by phenylephrine after treatment with indomethacin, $N{\omega}-nitro-L-arginine$, methylene blue or tetraethylammonium chloride, and $Ca^{2+}$ was infused into contracted arterial strips induced by phenylephrine after treatment of Diospyros kaki L. Radix or Diospyros kaki L. Folium in a $Ca^{2+}$-free solution. Results : Diospyros kaki L. Radix or Diospyros kaki L. Folium showed relaxation effect on arterial strip with endothelium contracted by phenylephrine, but in the strips without endothelium, Diospyros kaki L. Radix or Diospyros kaki L. Folium-induced relaxation was significantly inhibited. The endothelium-dependent relaxation induced by Diospyros kaki L. Radix or Diospyros kaki L. Folium was decreased by pretreatment with $N{\omega}-nitro-L-arginine$ or methylene blue but it was not observed in the strips pretreated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied to the strips which were contracted by phenylephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. However, pretreatment with Diospyros kaki L. Radix or Diospyros kaki L. Folium inhibited contractile response to $Ca^{2+}$. Conclusions : Diospyros kaki L. Radix or Diospyros kaki L. Folium may suppress influx of extra- cellular $Ca^{2+}$ through the formation of nitric oxide in the vascular endothelial cells.

• Herbal Formula Science
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• v.29 no.4
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• pp.181-189
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• 2021

Objectives : The calyx of Diospyros kaki Thunb. has usually been used to treat obstinate hiccup. This study investigated the protective effects of Diospyros kaki using C2C12 myoblasts of H₂O₂-induced oxidative stress. Methods : Cell viability and cytotoxicity were determined by MTT assay. The level of reactive oxygen species (ROS), malondialdehyde (MDA), and reduced glutathione (GSH) were measured by using optical properties. Results : The calyx of Diospyros kaki Thunb. extract showed no toxicity to C2C12 myoblasts until 20 ㎍/mL concentration and increased cell viability compared to the H₂O₂ treated group. The calyx of Diospyros kaki Thunb. extract inhibited the production of ROS and MDA at all concentrations. In addition, the calyx of Diospyros kaki Thunb. extract increased the concentration of GSH. Conclusion : This study provides that the calyx of Diospyros kaki Thunb. can be used as a potential material that exhibit antioxidative and protective effects on H₂O₂-induced oxidative stress in C2C12 Myoblasts.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.314-321
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• 2008

Acaricidal effects of materials derived from Diospyros kaki roots against Dermatophagoides farinae and D. pteronyssinus were assessed using impregnated fabric disk bioassay and compared with that of the commercial benzyl benzoate. The observed responses varied according to dosage and mite species. The $LD_{50}$ values of the chloroform extract of Diospyros kaki roots were 1.66 and $0.96{\mu}g/cm^2$ against D. farinae and D. pteronyssinus. The chloroform extract of Diospyros kaki roots was approximately 15.2 more toxic than benzyl benzoate against D. farinae, and 7.6 times more toxic against D. pteronyssinus. Purification of the biologically active constituent from D. kaki roots was done by using silica gel chromatography and high-performance liquid chromatography. The structure of the acaricidal component was analyzed by GC-MS, $^1H-NMR,\;^{13}C-NMR,\;^1H-^{13}C$ COSY-NMR, and DEPT-NMR spectra, and identified as plumbagin. The acaricidal activity of plumbagin and its derivatives (naphthazarin, dichlon, 2,3-dibromo-1,4-naphthoquinone, and 2-bromo-1,4-naphthoquinone) was examined. On the basis of $LD_{50}$ values, the most toxic compound against D. farinae was naphthazarin $(0.011{\mu}g/cm^2)$ followed by plumbagin $(0.019{\mu}g/cm^2),$ 2-bromo-1,4-naphthoquinone $(0.079{\mu}g/cm^2)$, dichlon $(0.422{\mu}g/cm^2)$, and benzyl benzoate $(9.14{\mu}g/cm^2)$. Additionally, the skin color of the dust mites was changed from colorless-transparent to dark brown-black by the treatment of plumbagin. Similar results have been exhibited in its derivatives (naphthazarin, dichlon, and 2-bromo-1,4-naphthoquinone). In contrast, little or no discoloration was observed for benzyl benzoate. From this point of view, plumbagin and its derivatives can be very useful for the potential control agents, lead compounds, and indicator of house dust mites.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.51-55
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• 2000

To investigate the effect of media and growth regulators in micropropagation of persimmon (Diospyros kaki Thunb.), dormant axillary buds taken from trees of persimmon cultivars such as Ichikikeijiro, Tonawase and Hiratenenashi were used. Shoot tips were successfully cultured in full or half of nitrogen strength of MS medium. The most effective cytokinins for shoot proliferation and elongation of persimmon cv. Ichikikeijiro were 5 mg/L and 2 mg/L zeatin, respectively. Shoots were successfully rooted in 1/2N-MS medium with 1 mg/L IBA.

• Korean Journal of Pharmacognosy
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• v.45 no.2
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• pp.181-185
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• 2014

This study was carried out to investigate the acute toxicity of the bark of Diospyros kaki (Ebenaceae) in mice. The aqueous extract of the bark of Diospyros kaki (AEDK) was administered orally at a doses of 5 mg/kg, 50 mg/kg, 300 mg/kg and 2,000 mg/kg. In this study, number of deaths, clinical signs, body weights and pathological examinations were investigated after administration of AEDK. There were neither dead animals nor significant changes of body weights during the experimental period. In addition, no differences were found between control and AEDK treated groups in clinical signs, organ weights and gross pathological findings. AEDK did not show any toxic effect in mice.

• Korean Journal of Pharmacognosy
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• v.51 no.2
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• pp.139-145
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• 2020

The leaves of Diospyros kaki Thunb. were used to treat heart disease and hypotension in traditionally East Asia. The purpose of this study is to simultaneously quantitiative analyze the content of flavonoids in leaves of D. kaki. The isolated flavonoids from the leaves of D. kaki, and the structure of the isolated flavonoids were analyzed based on ¹H and ¹³C NMR spectrum compared to literature data. Simultaneous quantitative analysis of the isolated flavonoids was validated using high performance liquid chromatography (HPLC). Results showed that the calibration curves of the flavonoid compounds were confirmed that they have a large linearity with a correlation coefficient (R²) of 0.99. In the intra-day and inter-day analysis, accuracy and precision of five compounds were measured that accuracy was 94.39 to 114.47% and precision was less than 3.00%. Content analysis showed hyperoside (1.30 ± 0.09%), astragalin (0.81 ± 0.06%), trifoline (1.58 ± 0.07%), quercetin (0.13 ± 0.02%) and kaempferol (1.33 ± 0.25%).

• Journal of Life Science
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• v.23 no.3
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• pp.383-388
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• 2013

This study was performed to determine the whitening effect of several solvent fractions of Diospyros kaki extracts. Fractions from ethanol extracts of D. kaki were prepared by a systematic fractionation procedure using hexane, ethyl acetate, butanol, and $H_2O$. The ethyl acetate fractions were used to evaluate the inhibitory effects on tyrosinase activity and melanin synthesis in B16F10 melanoma cells. Ethyl acetate fractions suppressed the expression of tyrosinase, TRP-1 and TRP-2 in B16F10 melanoma cells. These results showed that ethyl acetate fractions of D. kaki could be developed as a skin whitening material in cosmetics.

• Mycobiology
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• v.49 no.1
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• pp.54-60
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• 2021

During the screening of Korean microflora, a fungal strain (KNU-PT-1804) belonging to the genus Pestalotiopsis was isolated from persimmon tree (Diospyros kaki) bark collected from North Gyeongsang Province, Korea. The strain, KNU-PT-1804, produced smaller conidia compared with related species P. kenyana, P. neglecta, and P. telopeae. The novelty of the strain was confirmed based on phylogenetic analysis using molecular datasets of internal transcribed spacer (ITS) regions, β-tubulin (TUB2), and translation elongation factor 1-alpha (TEF1α) genes. Molecular phylogeny strongly supports that the strain is distinct from previously known Pestalotiopsis species, and we proposed the novel species, Pestalotiopsis kaki sp. nov., and provide a detailed description and illustration.

• Korean Journal of Pharmacognosy
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• v.44 no.2
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• pp.182-187
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• 2013

This study was conducted to investigate glutathione S-transferase(GST) activity, tyrosinase inhibitory effect and elastase inhibitory effect in persimmon calyx(calyx of Diospyros kaki Thunberg) for screening of functional materials from natural products. As a result, EtOAc extract of persimmon calyx turned out to be having tyrosinase inhibitory effect and elastase inhibitory effect. The active constituents of tyrosinase and elastase inhibitory effect were isolated from EtOAc extract of persimmon calyx. Their structure of compounds were identified as ursolic acid and (-)-daucosterol by spectroscopic evidence, respectively.

• The Korean Journal of Mycology
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• v.44 no.2
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• pp.118-121
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• 2016

An unrecorded fungus was isolated from the leaf mold of Diospyros kaki in Sangju, Korea. Morphological and phylogenetic analyses were performed for the isolated fungus, which was ultimately identified as Phialophora sessilis. This is the first report of P. sessilis in Korea.