• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.389-395
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• 2017

A simultaneous determination of 5 phenolic acids (gallic acid, chlorogenic acid, caffeic acid, pcoumaric acid, trans ferulic acid) and 9 flavonoids (procyanidin b1, aspalathin, rutin, vitexin, hyperoside, isoquercitrin, luteolin, quercetin, chrysoeriol) in rooibos tea has been carried out by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). A validated analysis method in this study was applied to rooibos aqueous infusions. Rooibos tea is an antioxidant-rich tea which has anti-cancer, anti-aging, anti-inflammatory, anti-diabetic effect. Extraction yield of phenolics depends on steeping time and temperature of water. Tea infusions were prepared by placing 1 g of tea leaves or 1 tea bag in 100 mL of boiled water, and then at 3, 6 and 30 minutes intervals the infused teas were taken to carry out the analysis of phenolic contents. Another tea infusion was conducted with cold water ($25-30^{\circ}C$) for 30 minuntes. As a result, the total amount of phenolics was highest in rooibos tea steeped with hot water for 30 minutes, followed by 6 minutes, 3 minutes and cold water 30minutes and the result has statistical significance.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.278-282
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• 2010

In this study, the antibacterial activity and component analysis of Persicaria perfoliata extracts were investigated. MIC (Minimum Inhibitory Concentration) values of ethyl acetate fraction from P. perfoliata on Escherichia coli, Propionibacterium acnes, and Staphylococcus aureus were 0.25%, equally. The results showed that the antibacterial activity of the ethyl acetate fraction was the highest in the S. aureus and P. acnes. Ethyl acetate fraction from P. perfoliata extracts showed 5 bands in TLC and 8 peaks in HPLC (320nm). In HPLC chromatogram of ethyl acetate fraction, first main peak 2 (24.99%) and peak 3 (22.65%) were identified as quercetin-3-o-glucuronide and isoquercitrin in the order of elution time. Also, in HPLC chromatogram of deglycosylated fraction, main peak 2 (76.93%) was identified as quercetin in the order of elution time. And these components are very effective as antioxidants. Thus, these results indicate that extract/fractions of P. perfoliata can be applicable to new functional cosmetics for antioxidant, antibacterial activity.

• Journal of Life Science
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• v.33 no.1
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• pp.43-49
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• 2023

Houttuynia cordata belongs to the Saururacease family and its leaves, stems, and roots have been used as oriental medicines to treat pneumonia, acute or chronic bronchitis, enteritis, and abscesses and to remove extravasated blood. Recently, the antioxidant, anti-inflammation, antibacterial, and anti-proliferation activities and protection abilities of H. cordata against liver and neuron cell damage have been reported. In this study, ethanol extract and its solvent fractions (fractions of hexane, ethyl acetate, butanol, and water residue) were prepared, and their antithrombosis, antidiabetes, antioxidant, and hemolysis activities were evaluated. The ethyl-acetate fraction of H. cordata (EF-HC) showed the highest polyphenol and flavonoids contents among the fractions and exhibited strong antithrombosis and antioxidant activities. The EF-HC at 5 mg/ml showed 2.09-folds of thrombin time, 2.19-folds of prothrombin time, and 1.69-folds of activated partial thromboplastin time compared to the their solvent control and 30.9, 19.9, and 49.6 ㎍/ml of RC₅₀ against DPPH, ABTS, and nitrite radicals, respectively. Furthermore, the EF-HC did not show any hemolytic activity up to 1 mg/ml, whereas the hexane fraction of H. cordata showed 55% hemolysis at 1 mg/ml. This is the first report of the antithrombosis activity of H. cordata. Our results suggest that quercitirin, hyperoside, orientin, and isoquercitrin in EF-HC are related to its antithrombosis and antioxidant activities and that the EF-HC could be developed as a promising antithrombosis agent.

• Preventive Nutrition and Food Science
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• v.17 no.4
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• pp.280-285
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• 2012

Six polyphenolic compounds, such as chlorogenic acid (CA), rutin (RT), isoquercitrin (IQT), quercetin-3-O-(6-O-malonyl)-${\beta}$-D-glucoside (QMG), astragalin (AG), kaempferol-3-O-(6-O-malonyl)-${\beta}$-D-glucoside (KMG), were isolated from mulberry leaves by a series of isolation procedures, such as Diaion HP-20, silica-gel, Sephadex LH-20, and ODS-A column chromatographies. The chemical structures of the phenolic compounds were identified by UV and NMR spectral analyses. Levels of polyphenols in mulberry leaves from six different mulberry cultivars ranged from 1,042.16 to 1,871.97 mg% per dry weight; Guksang cultivar showed the highest levels of polyphenols, whereas Gaeryangdaehwa contained the least polyphenol contents. Generally, levels of polyphenols in mulberry leaves decreased with increasing harvest time, except for Yoolmok, but increased with heat processing time, except QMG and KMG. These results suggest that the heat processed mulberry leaves of Guksang cultivar harvested in early May can be potentially useful sources for production of high quality mulberry leaf teas.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.51-60
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• 2006

Juglans mandshurica barks were collected, extracted with acetone-$H_2O$ (7:3, v/v), fractionated with n -hexane, $CH_2Cl_2$, and EtOAc, and freeze dried to give some dark brown powder. The EtOA cand $H_2O$ soluble fractions were chromatographe d on a Sephadex LH-20 column using $H_2O$-MeOH and EtOH-hexane mixture as eluents. Spectrometric analysis such as NMR and MS, including TLC,were performed to characterize the structures of the isolated compounds. From the EtOAc and $H_2O$ soluble fractions, three flavanols (1~3), three flavonols (4~6) and five flavonol glycosides (7~11) were isolated and elucidated.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.183-192
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• 1996

A chemical examination of the phenolic compounds in the leaves of Sapium japonicum(Euphorbiacesae) has led to the isolation of eleven phenolic compounds, containing five hydrolysable tannins and six flavonoids. On the basis of chemical and spectroscopic evidences, the structures of these compounds were confirmed to be gallic acid(1), 5-O-caffeoyl quinic acid(2), 1-O-galloyl-3,6-(R)-HHDP-${\beta}-_D$-glucose(corilagin)(3), 1-O-galloyl-2,4(R)-DHHDP-${\beta}-_D$-glucose(furosin)(4), 1-O-galloyl-2,4-(R)-DHHDP-3,6-(R)-HHDP-${\beta}-_D$-glucose(geraniin )(5), astragalin(6), trifolin(7), afzelin(8), quercetin(9), isoquercitrin(10) and rutin(11). Among them geraniin was the main component.

• Journal of Applied Biological Chemistry
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• v.51 no.1
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• pp.13-16
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• 2008

Five anthraquinones, emodin (1), ${\omega}$-hydroxyemodin (2), chrysophanol-8-O-${\beta}$-D-glucoside (3), emodin-8-O-${\beta}$-D-glucoside (4), and physcion-8-O-${\beta}$-D-glucoside (5), and five flavonoids, kaempferol-3-O-${\beta}$-D-glucoside (6), quercetin (7), quercitrin (8), isoquercitrin (9), and (+)-catechin (10), were isolated from the EtOAc-soluble extract of the fruits of Rumex japonicus. The structures of 1-10 were identified by spectroscopic methods including NMR studies. This is the first report on the isolation of compounds 3-5 from this plant. The isolates were subjected to in vitro bioassays to evaluate their inhibitory activities on the rat lens aldose reductase (RLAR), among which two anthraquinones (1 and 4), and five flavonols (5-9) showed significant activities on RLAR.

• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.46-51
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• 2007

Bioassay-directed chromatographic fractionation of an ethyl acetate extract from leaves of sweet potato (Ipomoea batatas L.) afforded six quinic acid derivatives: 3,5-epi-dicaffeoylquinic acid (1), 3,5-dicaffeoylquinic acid (2), methyl 3,5-O-dicaffeoylquinate (3), methyl 3,4-dicaffeoylquinate (4), methyl 4,5-dicaffeoylquinic acid (5),4,5-dicaffeoylquinate (6), and two phenolic compounds: caffeic acid (7) and caffeic acid methyl ester (8) together with three flavonoids: quercetin 3-O-${\beta}$-D-glucopyranoside (9), quercetin 3-O-${\beta}$-D-glucopyranoside, isoquercitrin (10) and kaempferol 3-O-${\beta}$-D-glucopyranoside (11). The structures of these compounds were elucidated by the aid of spectroscopic methods. These compounds were assessed for antioxidant activities using three different cell-free bioassay systems. All isolates except 11 showed potent DPPH and superoxide anion radicals scavenging, and lipid peroxidation inhibitory activities. 3,5-epi-DCQA (1) and methyl quinates (3-5) along with flavonoide 9 were isolated for the first time from this plant.

• 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.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.260-264
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• 2008

Eight compounds were isolated from the EtOAc soluble fraction of Euphorbia supina MeOH extract as the radical scavengers for antioxidant activity. Their structures were identified as kaempferol (1), quercetin (2), juglanin (3), avicularin (4), astragalin (5), isoquercitrin (6), hyperin (7), and nicotiflorin (8) by spectroscopic analysis. The antioxidant activity was evaluated by the ORAC (oxygen radical absorbance capacity) assay, which measures scavenging activity against peroxy radicals induced by 2,2'-azobis (2-methylpropionamidine) dihydrochloride, and the ORAC value is expressed as relative trolox equivalent. Compounds 4, 6, and 7 exhibited potent antioxidant activity, whereas the other compounds showed weaker activity than trolox.