• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.478-483
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• 1998

For the enhanced production of a cardiac glycoside, digoxin, using in situ adsorption by biotransformation from digitoxin in plant cell suspension cultures, selection of proper resins was attempted and the culture conditions were optimized. Among various kinds of resins tested, Amberlite XAD-8 was found to be the best for digoxin production in considering adsorption characteristics as well as the effect on cell growth. Adequate time for resin addition was determined to be 36 h from the beginning of biotransformation and the presence of resins should be as short as possible to increase the productivity. In addition, to prevent the cells from direct contact with resin particles, immobilized systems were designed and examined. Immobilization further improved the advantages of in situ adsorption. It was confirmed that the increase of the contact area for mass transfer was an important factor in utilizing an immobilized system to enhance digoxin production.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.583-587
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• 1997

The MeOH extracts obtained from the tuber of Ipomoea batatas Lam. were solvent-fractionated with EtOAc, n-BuOH, and $H_2O$, respectively. From EtOAc fraction four different compounds were isolated through the repeated silica gel column chromatographies. From not only the results of NMR and MS data but also the adaptation of hydrolysis, methylation, and acetylation, the chemical structures of compounds were elucidated as resin glycoside, simonin I, ${\beta}-sitosterol$, and two kinds of unsaturated fatty acids.

• Proceedings of the Botanical Society of Korea Conference
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• 1995.06a
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• pp.79-90
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• 1995

Production of a cardiac glycoside, digoxin, by 12$\beta$-hydroxylation from digitoxin was studied in plant cell suspension cultures of Digitalis lanata. In order to increase the conversion yield, various culture conditions including immobilization were investigated and optimized. Since digoxin was released in the medium temporarily and converted further into a glucosylated product, deacetyllanatoside C, in situ adsorption of digoxin was employed to recover the product continuously. Amberlite resin XAD-8 showed the best adsorption characteristics for digoxin among the examined resins, and an integrated process was developed to increase the productivity. In addition, it was found that the utilization of $\beta$-cyclodextrin to entrap digoxin during the culture enhanced the biotransformation yield significantly.

• Journal of the Korean Society of Tobacco Science
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• v.14 no.1
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• pp.79-86
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• 1992

Free and glycosidically bound volatiles from three green tobacco leaves(NC 82, KF 109 and Br-21) were separated by nonionic resin Amberlite XAD-2 adsorption column chromatography and election by selective solvents. Aglycones from the glycosidically bound fractions were released by enzymatic hydrolysis with almond B-glucosidase. A total of 20 components identified from free and glycosidically bound fractions, the major components were benzaldehyde, benzyl alcohol, 2-phenylethyl alcohol, 3-oxo- -ionol, 3-hydroxy-B-ionone, 3-oxo-7, 8-dihydro-n-ionol and scopoletin. Six Cl.B norisoprenoids identified in this study, which have been described to possess a characteristic tobacco aroma-enhancing effect, were not presented in free forms but rather bound glycosidic forms.

• Korean Journal of Pharmacognosy
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• v.1 no.2
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• pp.23-28
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• 1970

One of the indigeneous plants to this country, Syringa dilatata $N_{AKAI}$ (Oleaceae) is known in commerce as 'Ya-Jung-Hyang' (野丁香) and has been known to be of effect as bitter stomachics. Seasonal variations in the content of polyalcohols and free reducing sugars in leaves of this plant which contains syringin glycoside, mannitol and free reducing sugars etc. were studied. Application of chromotropic acid to formaldehyde which was obtained from polyalcohols and reducing sugars by treatment with periodic acid results in reddish violet coloration and the solution has absorption maximum at wave length $570m\;{\mu}$. By the use of ionic exchange resin chromatography, poyalcohols were separated from the above mixture. The content of polyalcohols of this plant was plentiful in the growing season while that of free reducing sugars was decreasing vice versa.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1763-1772
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• 2017

This study aimed to isolate and characterize antibacterial metabolites from Pharbitis nil seeds and investigate their antibacterial activity against various plant pathogenic bacteria. The methanol extract of P. nil seeds showed the strongest activity against Xanthomonas arboricola pv. pruni (Xap) with a minimum inhibition concentration (MIC) value of $250{\mu}g/ml$. Among the three solvent layers obtained from the methanol extract of P. nil seeds, only the butanol layer displayed the activity with an MIC value of $125{\mu}g/ml$ against Xap. An antibacterial fraction was obtained from P. nil seeds by repeated column chromatography and identified as pharbitin, a crude resin glycoside, by instrumental analysis. The antibacterial activity of pharbitin was tested in vitro against 14 phytopathogenic bacteria, and it was found to inhibit Ralstonia solanacearum and four Xanthomonas species. The minimum inhibitory concentration values against the five bacteria were $125-500{\mu}g/ml$ for the n-butanol layer and $31.25-125{\mu}g/ml$ for pharbitin. In a detached peach leaf assay, it effectively suppressed the development of bacterial leaf spot, with a control value of 87.5% at $500{\mu}g/ml$. In addition, pharbitin strongly reduced the development of bacterial wilt on tomato seedlings by 97.4% at $250{\mu}g/ml$, 7 days after inoculation. These findings suggest that the crude extract of P. nil seeds can be used as an alternative biopesticide for the control of plant diseases caused by R. solanacearum and Xanthomonas spp. This is the first report on the antibacterial activity of pharbitin against phytopathogenic bacteria.