• Journal of Plant Biology
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• v.16 no.1_2
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• pp.12-16
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• 1973

The inhibitory effect of Inula sesquiterpene lactones on the growth of Phaseolus vulgaris was tested and the abnormality of the stem organization caused by the lactones was also examined. The longitudinal growth of the young stem and the expansion of the young leaf were stopped by the application of the lactones. However, this inhibitory effect was appeared and strictly restricted within the treated area. So the young shoot was observed for possible bending as a result of the unilateral application of the lactones. When the application of the lactones into the medium, the growth of the plant was entirely repressed. However, the growth of shoot and re-initiation of root were started after the plant was transfered to the lactone free medium. And partial reversal of inhibition of the stem growth was achieved by the additions of gibberelline and the lactones.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.269-272
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• 1995

Antibacterial activity test of solvent fractions, sesquiterpenoid lactones, and Compound I and II extracted from Chrysanthemum boreale M. and Chrysanthemum indium L. were performed against four microorganisms. Among the tested substances, antibacterial activities were appeared against B. subtilis and V. parahaemolyticus at the chloroform fraction, sesquiterpenoid lactones and Compound I extracted from C. boreale. But chloroform fraction and sesquiterpenoid lactones extracted from C. indicum were showed weakly than those of C. boreale. Compound II and all fractions extracted from C. indicum were not appeared against the all tested microorganisms.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.327-330
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• 1994

Bromolactonization of 2-substituted-1-cyclohexenyl-1-acetic acids with 1, 3-dibromo-5, 5-dime-thylhydantoin 9DBH) and potsssium tertiary butoxide (t-BuOK0 in anhydrous DMF was found to proceed in a highly regioselective manner. The reaction predominantly resulted in the formation of ${\betha}-lactones$ (greater than 96%).

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.369.1-369.1
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• 2002

In our previous study, the leaves of Ixeris sonchifolia afforded two new and two known guaiane type sesquiterpene lactones by activity-guided fractionation. Now we report additional isolation of sesquiterpene lactones from the roots of Ixeris sanchi!a!ia. They are glucozaluzanin C and ixerin H. Ixerin H is germacranolide type sesquiterpene glucuside. Theil structures were determined by 1 D and 2D NMR spectroscopy. (omitted)

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.365-366
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• 2002

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1375-1376
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• 2002

• Molecules and Cells
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• v.28 no.5
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• pp.447-453
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• 2009

The quorum sensing (QS) inhibitors that antagonize TraR, a receptor protein for N-3-oxo-octanoyl-L-homoserine lactones (3-oxo-C8-HSL), a QS signal of Agrobacterium tumefaciens were developed. The structural analogues of 3-oxo-C8-HSL were designed by in silico molecular modeling using SYBYL packages, and synthesized by the solid phase organic synthesis (SPOS) method, where the carboxamide bond of 3-oxo-C8-HSL was replaced with a nicotinamide or a sulfonamide bond to make derivatives of N-nicotinyl-L-homoserine lactones or N-sulfonyl-L-homoserine lactones. The in vivo inhibitory activities of these compounds against QS signaling were assayed using reporter systems and compared with the estimated binding energies from the modeling study. This comparison showed fairly good correlation, suggesting that the in silico interpretation of ligand-receptor structures can be a valuable tool for the pre-design of better competitive inhibitors. In addition, these inhibitors also showed anti-biofilm activities against Pseudomonas aeruginosa.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.136-138
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• 2004

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1729-1732
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• 2004

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1142-1149
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• 2009

Several bioactive metabolites, including pyrrolnitrin, N-acylhomoserine lactones, and polyhydroxyalkanoates were isolated from Burkholderia sp. O33. Effects of various nutrients, including sugars, gluconolactone, glycerol, tryptophan, chloride, and zinc were investigated in relation to the production of these metabolites. Logarithmic increase of pyrrolnitrin was observed between 2-5 days and reached a maximum at 7-10 days. Tryptophan concentration reached the maximum at 3 days, whereas 7-chlorotryptophan was gradually increased throughout the studies. Among various carbon sources, gluconolactone, trehalose, and glycerol enhanced pyrrolnitrin production, whereas strong inhibitory effects were found with glucose. Relative concentrations of pyrrolnitrin and its precursors were in the order of pyrrolnitrin$\gg$dechloroaminopyrrolnitrin or aminopyrrolnitrin throughout the experiments. Among three N-acylhomoserine lactones, the N-octanoyl analog was the most abundant quorum sensing signal, of which the concentrations reached the maximum in 2-3 days, followed by a rapid dissipation to trace level. No significant changes in pyrrolnitrin biosynthesis were observed by external addition of N-acylhomoserine lactones. Polyhydroxyalkanoates accumulated up to 3-4 days and decreased slowly thereafter. According to the kinetic analyses, no strong correlations were found between the levels of pyrrolnitrin, N-acylhomoserine lactones, and polyhydroxyalkanoates.