• International Journal of Oral Biology
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• v.45 no.2
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• pp.33-41
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• 2020

Neuroinflammation is known as the main mechanism implicated in the advancement of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. The main feature of neuroinflammation is associated with the activation of microglia. The activated microglia increase proinflammatory cytokine production and induce progressive neuronal cell death. Citrus flavonoids show neuroprotective effects that are associated with the anti-inflammatory action of flavonoids in neurodegenerative diseases. Among these citrus flavonoids, kaempferol, naringin, and nobiletin show inhibitory effects on nuclear factor-κB and mitogen-activated protein kinase signaling pathways that can modulate inflammatory conditions in microglial cells. In the present review, we present the anti-inflammatory activities of citrus flavonoids and therapeutic potential of flavonoids as neuroprotective agents.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.413-419
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• 2011

The antimicrobial effects of the natural flavonoids kaempferol, quercetin, apigenin, and naringenin as well as a novel flavonoid 7-O-butyl naringenin against the growth of four meat-born Staphylococcus aureus strains were evaluated. First, the flavonoids were screened for inhibitory effects against the growth of each strain using the paper disc diffusion method. Second, the growth inhibitory effects of flavonoids that showed antimicrobial activity were measured using the microplate method. Third, the bactericidal effects of flavonoids were evaluated in a 0.8% (w/v) NaCl solution. All flavonoids showed bacteriostatic effects at >20 mM. Among the flavonoids studied, quercetin was more effective than the others tested. However, the inhibitory effect of 7-O-butyl naringenin on growth of S. aureus KCCM 32395 was greater than that of quercetin at the same concentration. Additionally, 7-O-butyl naringenin exhibited significant bactericidal effects at >25 ${\mu}M$. When bacterial cells were examined using scanning electron microscopy, it appeared that the S. aureus membranes were damaged or morphologically changed when treated with quercetin and 7-O-butyl naringenin at 200 ${\mu}M$.

• Korean Journal of Pharmacognosy
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• v.19 no.2
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• pp.93-96
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• 1988

Three flavonoids were isolated from Epimedium koreanum and identified as quercetin(1), $anhydroicaritin-3-O-{\alpha}-rhamnoside(2)$ and icariin(3) by spectroscopic methods. The former two compounds are the first isolation from this plant.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.151.2-151.2
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• 2003

For the purpose of the development of a skin-whitening agent, Sophora flavescens was evaluated for tyrosinase inhibitory activity and its active principles were identified followed activity-guided isolation. The ethanol extract and dichloromethane fraction from S. flavescens showed significant inhibition of mushroom tyrosinase. From the dichloromethane fraction, three known prenylated flavonoids, sophoraflavanone G, kuraridin, and kurarinone, were isolated. Compared with kojic acid ($IC_50$=20.5 $\mu$M), these compounds possessed more potent tyrosinase inhibitory activity. (omitted)

• Natural Product Sciences
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• v.4 no.1
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• pp.38-41
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• 1998

From the dried leaves of Isodon eriocalyx (Labiatae) six flavonoids were isolated and two of them were elucidated to be novel ones named 5,7,8,4'-tetrahydroxy-6-methoxyflavone (1), and $isothymusin-8-O-{\beta}-D-glucoside$ (2).

• Natural Product Sciences
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• v.8 no.1
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• pp.16-17
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• 2002

The flavonoids kaempferol, quercetin, myrecetin, kaempferol-3-O-rhamnoside and quercetrin has been isolated from the leaves of C. tamala and their structures were established by spectral analysis and direct comparison with authentic samples. This is the first report of occurrence of these compounds from C. tamala.

• Natural Product Sciences
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• v.21 no.3
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• pp.170-175
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• 2015

The present study aims to detect the rare flavonoids isolated from the leaves of Persicaria glabra. The known flavonoids: quercetin (1), isorhamnetin (2), avicularin (3) and new one isorhamnetin-3-O-α-L-(6''-E-p-coumaroyl)-rhamnoside (4) were identified by HPLC, UV, IR and NMR. P. glabra has used traditionally for its analgesic, anti-inflammatory and anti-rheumatic properties. To find out the ingredients responsible for the efficiency of this plant, we have used to study the anti-microbial and anti-inflammatory activities of different extracts.

• Natural Product Sciences
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• v.16 no.2
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• pp.59-67
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• 2010

Flavonoids are well-known anti-inflammatory agents that exert their effects via a variety of mechanisms including antioxidative action, inhibition of eicosanoid metabolizing enzymes and regulation of theexpression of proinflammatory molecules. In this review, synthetic approaches to obtain more useful flavonoid derivatives are summarized. Human clinical trials of flavonoid therapy are discussed. Through continual investigation to identify more potent and comparable flavonoids, new anti-inflammatory flavonoid therapy will be successfully launched, especially for the treatment of chronic inflammatory disorders.

• Food Science and Preservation
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• v.7 no.2
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• pp.211-217
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• 2000

The effects of Citrus flavonoids, hesperetin, hesderidin, naringenin, and naringin, on nonenzymatic lipid peroxidation were studied in three different in vitro experimental models. Hesperetin showed the most antioxidant effect in this experimental condition by measuring the malondialdehyde production using the thiobarbiturate and thiocyanate methods, the lipid peroxidation of microsomal membranes, and DPPH (${\alpha},{\alpha}'-diphenyl-{\beta}-picrylhydrazyl$) method. The antioxidative activity of the flavonoid aglycone forms, hesperetin, Citrus aglycone flavonoid, suggest the most antioxidant effect in this experimental condition, and this effect indicate more potent in the aglycones than their corresponding glycosides.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.367.1-367.1
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• 2002

Flavo.no.ids are a diverse group of phytqchemicals that are produced by various plants in high quantities. Dietary flavonoids in edible plants can be further subdivided into. several structural groups. The large number of compounds arises from various combinations of multiple hydroxyl and methoxyl groups substituting the basic flavonoid skeleton. The chemopreentive activity of flavonoids is dependent on their structural features. (omitted)