• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.1
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• pp.42-47
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• 2002

The major free sugars of buckwheat plants were fructose, glucose, and maltose but their contents and compositions were influenced by the different wavelength of light. Free sugar contents of Clfa 39 (Fagopyrum tataricum) were higher than those of Yangjul-maemil (Fagopyrum esculentum) regardless of the light sources. As treated with red and blue light, the free sugar contents in the leaves of buckwheat plants were slightly increased, but their contents in the stems and flowers were lower than those of natural light condition. Under the natural light condition, maltose was detected in every tissues of buckwheat plants, but as treated with blue and red light, it was not detected in the flowers of buckwheat plants. Citric, malic and acetic acid were detected as major organic acids in buckwheat plants. Red and blue lights decreased the total organic acid contents in buckwheat plants as compared with natural light condition. It was considered that blue light are less active than red light for the accumulation of organic acids. Tataric acid was detected only in the leaves of buckwheat plants, however, as treated with red and blue light, it was not detected in the leaves of Clfa 39. Flowers of Yangjul-maemil contained a considerable amount of rutin and quercitrin. Only small amount of quercitrin was detected in leaves, but it was not detected in stems. On the other hand, Clfa 39 leaves contained a considerable amount of rutin, quercetin and small amount of quercitrin, but quercitrin and quercetin were detected only in the stems of Clfa 39. Red and blue lights significantly decreased the contents of rutin, quercitrin, and quercetin in buckwheat plants as comparing with natural light condition. Rutin content in the flowers of Clfa 39 was increased under the red and blue light conditions.

• Korean Journal of Pharmacognosy
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• v.23 no.4
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• pp.280-282
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• 1992

Quercitrin and hyperin were isolated from the leaves of Kalopanax pictum and these structures were characterized on the basis of chemical and spectral data.

• Natural Product Sciences
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• v.10 no.1
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• pp.35-39
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• 2004

Aldose reductase (AR), the key enzyme of the polyol pathway, is known to play important roles in the diabetic complications. The inhibitors of AR, therefore, would be potential agents for the prevention of diabetic complications. In order to clarify the structural requirements of flavonoids for aldose reductase inhibitory activity, thirty flavonoids were examined. Among the thirty flavonoids, flavonols such as quercetin (5), reyneutrin (7), quercitrin (9), isoquercitrin (11), and avicularin (14) were found to exhibit much stronger AR inhibition. Lonicerin (10), amentoflavone (27) and sophoraflavanone B (30) were also showed strong inhibitory activity. Especially, quercitrin and reyneutrin exhibited the most inhibitory potency on rat lens (RL) AR. The results suggested that flavonol having the 7-hydroxyl and/or catechol moiety at the B ring exhibit strong activity. In addition, flavonols having 3-O-monosaccharide also showed stronger inhibition than free flavonols at the 3-position. These results suggested that quercitrin and reyneutrin are attributed to be the promising compounds for the prevention and/or treatment of diabetic complications.

• Natural Product Sciences
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• v.25 no.3
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• pp.248-254
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• 2019

In the present study, we investigated whether quercitrin, quercetin and afzelin derived from Houttuynia cordata affect the production and gene expression of MUC5AC mucin from airway epithelial cells. Confluent NCI-H292 cells were pretreated with quercitrin, quercetin or afzelin for 30 min and then stimulated with epidermal growth factor (EGF) or phorbol 12-myristate 13-acetate (PMA) for 24 h. The MUC5AC mucin gene expression and production were measured by RT-PCR and ELISA, respectively. The results were as follows: (1) Quercitrin, quercetin and afzelin inhibited EGF- and PMA-induced MUC5AC mucin production from NCI-H292 cells; (2) The three natural products also decreased EGF- and PMA-induced MUC5AC mucin gene expression in NCI-H292 cells. These results suggest that quercitrin, quercetin and afzelin showed the regulatory effect on the steps of gene expression and production of mucin, by directly acting on airway epithelial cells.

• Korean Journal of Medicinal Crop Science
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• v.9 no.3
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• pp.220-224
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• 2001

To obtain the basic information for commercial process and high quality production of Saururus chinensis, the yield and the contents of available component were determined at different compost application amounts and cultural methods. Fresh weight of aerial part was increased by increasing of the compost application amounts. The contents of quercetin, quercitrin and tannin were the highest in the compost 2,000kg/10a. Fresh weight of aerial part at different cutting times was no difference between one harvesting/year and two harvesting/year in S. chinensis. On occasion of two harvesting/year, the contents of component was more collected on July 16 than collected on October 16. Fresh weight of aerial part was less in the field than in the greenhouse culture method, but the contents of quercetin, quercitrin and tannin were more in the field than in the greenhouse culture method.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.18-20
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• 2002

Assay-guided fractionation of the methanol extract of the leaves of Albizzia julibrissin has furnished quercitrin (1) and afzelin (2) as the scavengers of DPPH radical. Quercitrin and afzelin showed scavenging activity of DPPH free radical with the $IC_{50}$ values of 17.3 and 71.5 ${\mu}M$, respectively.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.175-178
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• 2003

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.581-585
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• 1993

Five flavonoids isolated from the ethyl acetate fraction of Cedrela sinensis A. Juss. were identified by high performance liquid chromatography. Separation was achieved by reversed phase chromatography on ${\mu}-bondapak$ C18 column with isocratic elution method. The content of the major flavonoid, quercitrin was about 9.48%(w/w) and 37.06%(w/w) for the methanol extract and ethyl acetate fraction, respectively.

• Journal of the Korean Chemical Society
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• v.67 no.2
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• pp.150-155
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• 2023

Eurya emarginata is an evergreen tree growing in the southern regions of Korea including Jeju Island. In this study, antioxidant and anti-photoaging effects were investigated with the extracts of E. emarginata leaves. As comparative studies with the extract and five solvent fractions, the EtOAc fraction showed the most effective DPPH and ABTS⁺ radical scavenging activities. The EtOAc fraction also inhibited matrix metalloproteinase-1 (MMP-1) production most effectively. Phytochemical study on the EtOAC fraction resulted in the isolation of three compounds; eutigoside C (1), eutigoside B (2) and quercitrin (3). Among the isolates (1-3), quercitrin (3) showed excellent antioxidant activities and inhibitory properties on MMP-1 production. Based on these results, it was suggested that extracts of E. emarginata leaves could be developed as natural anti-photoaging agents in cosmetic formulations.

• Archives of Pharmacal Research
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• v.9 no.4
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• pp.233-236
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• 1986

The flavonoids isolated form the leaves of rhododendron brachycarpum were identified as quercetin, avicularin, quercitrin and hyperin.