• Natural Product Sciences
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• v.18 no.3
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• pp.183-189
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• 2012

It is well known that inflammation is associated with neurodegenerative disorders, including Alzheimer' disease, Parkinson's disease and ischemia. Nitric oxide (NO), a pro-inflammatory mediator, is produced by inducible NO synthase (iNOS) in microglia as well as macrophages and appears to account for neurodegeneration. In this study, we aimed to isolate NO inhibitors from Pyrus pyrifolia by activity guided purification. As a result, we identified daucosterol and ${\beta}$-sitosterol, which have not been isolated from this plant before. This article also describes NO inhibitory activities of the methanol extract of Pyrus pyrifolia fruit and the isolated compounds from this, which are lupeol, betulin, betulinic acid, ${\beta}$-sitosterol and daucosterol, in LPS-activated RAW 264.7 and BV2 cell lines. Western blot analysis was performed to clarify the underlying mechanism of NO inhibition in the two cell lines.

• Natural Product Sciences
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• v.13 no.4
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• pp.328-331
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• 2007

The methanolic extract of the roots of Lithospermum erythrorhizon (Boraginaceae) was found to show inhibitory activity towards farnesyl protein transferase (FPTase). Bioassay-guided fractionation of the methanolic extract resulted in the isolation of three naphthoquinone compounds, as inhibitors of FPTase. These compounds inhibited the FPTase activity in a dose-dependent manner.

• Natural Product Sciences
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• v.13 no.2
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• pp.164-168
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• 2007

To investigate natural antibiotics from plant essential oils and to evaluate their synergism with current antimicrobial drugs in inhibiting antibiotic-resistant strains of Streptococcus pneumoniae. The minimal inhibitory concentrations (MICs) of eleven plant essential oils and their main components were established for two antibiotic-susceptible and two antibiotic-resistant strains of S. pneumoniae, using broth microdilution tests. Potential synergism with oxacillin, norfloxacin, or erythromycin was evaluated using a checkerboard microtitre assay. Among the tested oils, Mentha piperita oil and its main component, menthol, exhibited the strongest inhibitory activities against all of the tested strains. The activity of antibiotics against antibiotic-resistant strains of S. pneumoniae was enhanced significantly by combination with Mentha piperita oils and its main component, menthol. In conclusion, the combination Mentha piperita essential oil or menthol with antibiotics could be used to reduce the effective dose of antibiotic and to modulate the resistance of S. pneumoniae strains.

• Natural Product Sciences
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• v.13 no.4
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• pp.373-377
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• 2007

Antiscratching behavioral effects of the water extract of two black colored rice (BCR) varieties [Oryza sativa L. cv. Heugjinjubyeo (HJ) and Josaengheugchalbyeo (JH)], major pigment of which is cyanindin 3-glucoside, were investigated. Orally administered BCRs' extracts exhibited potent inhibitory activity against scratching behaviors which were induced by compound 48/80 and histamine. The inhibitory effect of Josaengheugchalbyeo in vivo and in vitro were more potent than those of Heugjinjubyeo. These finding suggest that black colored rice, especially Josaengheugchalbyeo, may inhibit scratching behaviors and anaphylaxis reaction by stabilizing membrane.

• Korean Journal of Pharmacognosy
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• v.19 no.1
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• pp.19-27
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• 1988

The hexane and ether extracts from the roots of Angelica dahurica caused a significant inhibition of hepatic drug-metabolizing enzyme (DME) activity. Through systematic fractionation by $SiO_2\;column$ and vacuum liquid chromatography monitoring by bioassays, three furanocoumarins, phellopterin, byakangelicin and tert-O-methylbyakangelicin were isolated as active principles. These components have biphasic responses, both inhibitory and inducing effects on DME system. Tert-O-methyl byakangelicin was found to have the strongest enzyme inhibitory potency.

• Biomolecules & Therapeutics
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• v.4 no.2
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• pp.122-126
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• 1996

In vitro inhibitory effect of aspalatone ((3-(2-methyl-4-pyronyl)]-2-acetyloxybenzoate) on collagen-, ADP-, and epinephrine-induced platelet aggregation in human platelet rich plasma (PRP) was compared with the effects of reference drugs (acetylsalicylic acid, cilostazol and ticlopidine). Aspalatone inhibited time and dose dependently human platelet aggregation induced by collagen; relative potency was in the order of cilostazol>acetylsalicylic acid>aspalatone>ticlopidine. Aspalatone, like acetylsalicylic acid, potently inhibited only the secondary phase of ADP-and epinephrine-induced aggregation. Thromboxane $B^2$ production evoked by collagen in human PRP was inhibited significantly and concentration-dependently by aspalatone and acetylsalicylic acid. These results were in agreement with the earlier studies in which the antiplatelet action of aspalatone was indicated to be due to the inhibition of platelet cyclooxygenase activity (Han et al., Arzneim. Forsch./Drug Res. 44(II), 1122, 1994; Suh and Han, Yakhak Hoeji 39, 565, 1995). In addition, the inhibitory activity of aspalatone on the platelet aggregation appears to be inversely related to the rate of nonspecific deacetylation of the drug in plasma.

• Natural Product Sciences
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• v.4 no.4
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• pp.263-267
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• 1998

From the dried flower-buds of Syzygium aromaticum Merr. et Perry (Myrtaceae), seven compounds, i.e., eugenol (1), oleanolic acid (2), kaempferol 7-O-metylether (3), 3,3',4-tri-O-methylellagic acid (4), maslinic acid (5), ${\beta}-sitosterol-3-O-glucoside$ (6), and isorhamnetin 3-O-glucoside (7) were isolated. Compound 1 showed cyclooxygenase-2 (COX-2) inhibitory activity.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.587-590
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• 2006

Three naphthopyrone glucosides, cassiaside (1), $rubrofusarin-6-O-{\beta}-D-gentiobioside$ (2), and $toralactone-9-O-{\beta}-D-gentiobioside$ (3), were isolated from the BuOH-soluble extract of the seeds of Cassia tora as active constituents, using an in vitro bioassay based on the inhibition of advanced glycation end products (AGEs) to monitor chromatographic fractionation. The structures of 1-3 were determined by spectroscopic data interpretation, particularly by extensive 1D and 2D NMR studies. All the isolates (1-3) were evaluated for the inhibitory activity on AGEs formation in vitro.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.178-188
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• 2019

Licorice, which has an extensive history of use as an herbal medicine, has been suggested to have oral health benefits. However, to date, no systematic study has been conducted on the preparation method of licorice extracts for oral health. In this study, licorice extracts prepared using water and ethanol were investigated for its ability to inhibit the biofilm formation of Streptococcus mutans. The licorice extract prepared with around 60% ethanol effectively inhibited the biofilm formation of S. mutans. Licorice extracted with 50% ethanol almost completely inhibited the biofilm formation at 1.5 g/L of licorice extract. This inhibitory activity was confirmed in a microplate assay and a flow cell system. Glycyrrhetic acid was extracted from licorice effectively with 60% ethanol concentration. The strong inhibitory activity of glycyrrhetic acid and the synergistic inhibition with glycyrrhizin on biofilm formation were suggested as major reasons for a concentration-specific extraction. These results suggest that licorice extract prepared using around 60% ethanol effectively inhibits the biofilm formation of S. mutans.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.96-104
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• 2019

Beauveria bassiana, one of the most common entomopathogenic fungi, has been isolated, pre defined and characterized in-house from soil of tea cultivation area. Experiments have been performed to verify the presence of chitinase as intracellular metabolite and its release as extracellular product rendering the spores with biopesticide activity. Although there are many responsible enzymes for the pest killer action of B. bassiana, binding property of chitinase depending on presence as well as absence of serine supplemented in the media has been studied with respect to the production and kinetics. A programmed investigation conclusively indicates that the isolated spore (hyphae) of B. bassiana has been metabolically enriched with the enzyme chitinase in presence of an externally added amino acid serine with its inhibitory kinetics.