Major Flavonoid Compounds Research Articles

Frequent generation of mutants with coincidental changes in multiple traits via ion-beam irradiation in soybean.

Ion beams are powerful mutagens that can induce novel mutants in plants. We previously established a system for producing a mutant population of soybean via ion-beam irradiation, isolated plants that had chlorophyll deficiency, and maintained their progeny via self-fertilization. Here we report the characterization of the progeny plants in terms of chlorophyll content, flowering time and isoflavone content in seeds. Chlorophyll deficiency in the leaf tissues was linked with reduced levels of isoflavones, the major flavonoid compounds accumulated in soybean seeds, which suggested the involvement of metabolic changes associated with the chlorophyll deficiency. Intriguingly, flowering time was frequently altered in plants that had a reduced level of chlorophyll in the leaf tissues. Plant lines that flowered either earlier or later than the wild-type plants were detected. The observed coincidental changes were presumed to be attributable to the following origins: structural changes of DNA segments leading to the loss of multiple gene functions, or indirect effects of mutations that affect one of these traits, which were manifested as phenotypic changes in the background of the duplicated composition of the soybean genome.

Inhibitory effect of different fennel (Foeniculum vulgare) samples and their phenolic compounds on formation of advanced glycation products and comparison of antimicrobial and antioxidant activities

In this study, antioxidant, antibacterial and antiglycation properties of methanolic extracts of 23 fennel samples were evaluated and their major compounds were determined using HPLC analysis. The anti-glycative activity of extracts was evaluated in the bovine serum albumin (BSA)/glucose system. The level of glycation, conformational alterations and protein binding to RAGE receptors were assessed by Congo red binding assay and a brown staining method. Among samples, Kh1 from Iran possessed the highest TFC (14.8mgQUEg−1), TPC (262mg/g DW) and antioxidant activity (IC50=76μg/ml). The HPLC results revealed high variation in 23 fennel samples according to their major flavonoid (quercetin, apigenin and rutin) and phenolic (chlorogenic, caffeic and 1,5-dicaffeoylquinic acid) compounds. The antibacterial activity of methanolic extracts against four food-borne pathogens was also assessed. The seed extracts of Kh1 and En samples showed moderate to good inhibitory activities (MICs=62.5–125μg/ml) against three bacteria, as well as high anti-glycative activity.

Dermatologic evaluation of cosmetic formulations containing Chrysanthemum indicum extract

Chrysanthemum indicum, an oriental medicinal plant, has been shown to display a variety of pharmacological activities including antibacterial and anti-inflammatory effects. In this study, we evaluated the ability of C. indicum extracts to inhibit in vitro tyrosinase activity and the skin care effects of cosmetic formulations containing 0.5% C. indicum water extract in human volunteers. The formation of dopachrome from L -dopa by mushroom tyrosinase was observed after treatments with C. indicum extracts. The volunteers received placebo (no extract) or test (0.5% C. indicum water extract) cosmetic cream and applied it on their face three times a day for 6 weeks. Biophysical skin parameters were measured every 2 weeks. Chrysanthemum indicum methanol and water extracts dose dependently inhibited mushroom tyrosinase activity, and the effects of methanol extract were similar to those of kojic acid, a well-known tyrosinase inhibitor. Clinical evaluations revealed that application of cosmetic formulations containing C. indicum water extract time dependently reduced melanin levels over 6 weeks, whereas the placebo group showed no effect. No changes in moisture, elasticity, wrinkles, evenness, and pore size were observed in either group. HPLC-DAD-ESIMS analyses revealed that luteolin and acacetin-7-O-rutinoside are the major flavonoid compounds in C. indicum water extract. These results suggest that C. indicum water extract could be applied as a natural skin-whitening agent for functional cosmetic uses, due to its melanin-reducing efficacy.

Effect of Baking on Stability of Phenolic and Flavonoid Compounds and Quality of Tigernut Enriched Crackers

Tigernut is considered a good source of bioactive compounds as well as its health benefits and nutritivevalue. In the present study, tigernut tubers were dried, milled to produce tiger nut flour (TNF) and incorporated incrackers, replacing 10, 20, 30 and 40% of wheat flour to formulate samples TF1, TF2, TF3 and TF4. Total phenoliccontents, physical, chemical and sensory characteristics of the produced crackers were determined. The phenolic andflavonoid compounds in TNF and TF4 were identified and quantified by HPLC. The results showed that TNF additiongradually increased the total phenolic contents of TF1, TF2, TF3 and TF4 samples to be 1.33, 1.39, 1.44 and 1.51 mgGAE/g, respectively compared to that of control sample (1.29 mg GAE/g). Pyrogallol, ellagic and benzoic were thepredominant phenolic compounds, whereas luteo-6-arbinose-8-glucose and acacetin were the major flavonoidcompounds in the tigernut crackers. The increase in TNF ratio led to an increase in the nutritional value but alsonegatively affected the physical properties of crackers by reducing spread ratio and breaking force. All crackers sampleshad satisfactory sensory acceptance except that contained 40% TNF.

The Gastrointestinal Tract Metabolism and Pharmacological Activities of Grosvenorine, a Major and Characteristic Flavonoid in the Fruits of Siraitia grosvenorii.

Grosvenorine is the major flavonoid compound of the fruits of Siraitia grosvenorii (Swingle) C. Jeffrey, a medical plant endemic to China. In the present study, for the first time, the grosvenorine metabolism in an in vitro simulated human gastrointestinal tract (including artificial gastric juice, artificial intestinal juice and intestinal flora), as well as its pharmacological activities (including anti-complement, antibacterial and antioxidant activities), was investigated. The results showed that grosvenorine was metabolized by human intestinal flora; its four metabolites were isolated by semi-preparative HPLC and identified by NMR as kaempferitrin, afzelin, α-rhamnoisorobin, and kaempferol. Further pharmacological evaluation showed that grosvenorine exhibited good antibacterial and antioxidant activities, with its metabolites possessing more potent activities. Although grosvenorine did not present obvious anticomplement activity, its metabolites showed interesting activities. This study revealed that intestinal bacteria play an important role in the gastrointestinal metabolism of grosvenorine and significantly affect its pharmacological activities.

Vitexin protects brain against ischemia/reperfusion injury via modulating mitogen-activated protein kinase and apoptosis signaling in mice

Vitexin is a major bioactive flavonoid compound derived from the dried leaf of hawthorn (Crataegus pinnatifida), a widely used conventional folk medicine in China. Recent studies have shown that vitexin presents neuroprotective effects in vitro. Whether this protective effect applies to the cerebral ischemia/reperfusion (I/R) injury remains elusive. In the present study, we examined the potential neuroprotective effect of vitexin against cerebral I/R injury and underlying mechanisms. A focal cerebral I/R model in male Kunming mice was induced by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion for 22 h. The neurological function and infarct volume were assessed by using Long's five-point scale system and triphenyl-tetrazolium chloride (TTC) staining technique, respectively. Neuronal damage was evaluated by histological staining. Extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and p38 phosphorylation, and apoptosis were measured via Western blot at 24 h after reperfusion. As a result, systemic vitexin treatment significantly reduced neurological deficit, cerebral infarct volume and neuronal damage when compared with the I/R group. Western blot analyses revealed that vitexin markedly upregulated p-ERK1/2 and downregulated p-JNK and p-p38. Meanwhile, vitexin increased Bcl-2 expression and suppressed the overexpression of Bax in the I/R injury mice. In conclusion, the results indicate that vitexin protects brain against cerebral I/R injury, and this effect may be regulated by mitogen-activated protein kinase (MAPK) and apoptosis signaling pathways.

Intake and major sources of dietary flavonoid in Korean adults: Korean National Health and Nutrition Examination Survey 2010-2012.

With an effort to investigate possible relationship between flavonoids and health, an accurate estimation of flavonoid intake is valuable. We estimated dietary flavonoid intake and identified the major food sources. Subjects were healthy adults aged >=19 y (n=11,474) who completed the 24-h dietary recall of the Korean National Health and Nutritional Examination Survey (2010-2012). The US Department of Agriculture and newly estimated or published values for typical Korean foods were combined into a Korean-targeted flavonoid database. The mean intake of total flavonoid was 107±1.47 mg/d, with a higher intake in women than in men after energy-adjustment. Quercetin, cyanidin, genistein, daidzein, epigallocatechin 3-gallate, epicatechin, hesperetin, and luteolin were identified as major flavonoid compounds. Across the age range studied, flavonols and flavones showed a reversed U-shape curve; flavan-3-ol and flavanones showed a decreasing pattern; and anthocyanidins and isoflavones showed an increasing pattern. Forty-five food items were identified as contributing >2% of at least one flavonoid compound's intake. Kimchi was the major food source of total flavonoids, followed by green tea, persimmons, and soybeans. Single food items accounting for more than 50% of the intake of a specific flavonoid included persimmons (cyanidin), green tea (epigallocatechin, epicatechin-3-gallate, and epigallocatechin 3-gallate), black tea (thearubigin), tangerines (hesperetin and naringenin), and onions (isorhamnetin). This study provides information on Korean flavonoid intake to enable international comparisons, along with insight into how the sources and intake of various flavonoids vary according to age and gender. This work should facilitate future investigations of the association between flavonoid intake and health.

High-performance liquid chromatography analysis of phenolic acid, flavonoid, and phenol contents in various natural Yemeni honeys using multi-walled carbon nanotubes as a solid-phase extraction adsorbent.

A simple method has been described for simultaneous determination of phenolic acid, flavonoid, and other phenol contents in various natural honey samples collected from various regions of Yemen. Multi-walled carbon nanotubes were used as a solid-phase adsorbent for extraction of the polyphenols from honey samples. The total contents of phenolic acids, flavonoids, and phenolic components of the 12 different samples were found in the range of 363-2658, 261-1646, and 224-1355 μg/100 g of honey samples, respectively. The major phenolic acid, flavonoid, and phenolic compound in these samples were found to be 4-hydroxybenzoic acid (1410 μg/100 g), chrysin (850 μg/100 g), and cinnamic acid (1336 μg/100 g), respectively. A total of 25 compounds (10 phenolic acids, 9 flavonoids, and 6 phenols) were analyzed, and a total of 24 were detected, while only 23 compounds were determined quantitatively in the honey samples. The developed method showed potential usefulness for the analysis of honey and was used for the determination of polyphenols in honey extracts.

Polyphenol extraction and characterization of Justicia secunda Vahl leaves for traditional medicinal uses

Water extracts of Justicia secunda leaves are used by village communities in southern countries to prepare traditional medicines at home. The beverage is usually obtained by boiling the plant in water. On a pilot plant scale, water extracts were processed using an extraction–concentration procedure achieved in a three-step process, including ultrasound-assisted water extraction followed by cross-flow microfiltration of the crude extract and its concentration by reverse osmosis. As the processing conditions were milder than for homemade preparations, the extract obtained was enriched in natural leaf flavonoids. At each step of the pilot plant process, the co-products obtained were analyzed for total polyphenol and total flavonoid contents by the UV–vis spectrophotometric method. The process allowed a better leaf water-extraction of polyphenol compounds than the homemade extraction. The crude extract was concentrated 28 times (v/v) at room temperature by membrane volume reduction, and the total content of polyphenol compounds of the concentrated extract was 17 times higher than those of the crude extract. Individual polyphenol compounds were characterized by HPLC-DAD analysis at λmax=325nm. Additional structure characterization was carried out for the two major flavonoid compounds found (65% of total HPLC-DAD peak area of the flavones-type compounds) in the water extracts by tandem mass spectrometry (LC–ESI-MS2) and by nuclear magnetic resonance (1H NMR, 13C NMR). They were identified as luteolin 7-O-[β-glucopyranosyl-(1→2)-β-rhamnosyl-(1→6)] β-glucopyranoside and luteolin 7-O-[β-apiofuranosyl-(1→2)]-β-xylopyranoside.

Quercetin suppresses invasion and migration of H-Ras-transformed MCF10A human epithelial cells by inhibiting phosphatidylinositol 3-kinase

Quercetin is a major flavonoid compound found in red wine at a much higher concentration than the phytoalexin resveratrol. In this study, we examined potential anti-metastatic effects and found that compared to resveratrol, quercetin more potently inhibits H-Ras-induced invasion and migration in MCF10A human epithelial cells, an effect likely mediated by the mitigation of matrix metalloproteinase (MMP)-2 activation. We then measured Akt phosphorylation to investigate whether the decreased MMP-2 activation was attributable to the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt signalling. Quercetin, but not resveratrol at equivalent concentrations, suppressed the phosphorylation of Akt and was a more potent inhibitor of PI3K activity than resveratrol. An ex vivo binding assay further revealed that quercetin directly binds to PI3K. Collectively, these results suggest that PI3K is a molecular target of quercetin for the inhibition of H-Ras-induced invasion and migration of MCF10A cells.

Antioxidant and anti-dermatophytic properties leaf and stem bark of Xylosma longifolium clos.

BackgroundThe present study was carried out to assess the phytochemical and anti-dermatophytic effect of the leaf and bark extracts of Xylosma longifolium Clos. The leaf and stem bark are used by the indigenous people of Manipur, India for treatment of skin diseases.MethodsThe leaves and stem barks of Xylosma longifolium were extracted using petroleum ether, chloroform and methanol respectively. The different extracts of each plant parts were tested for antioxidant activity using DPPH assay. The phenolic content was assayed using Folin-Ciocalteu colorimetric method. Each extracts was further analysed by RP-HPLC to quantify some individual flavonoid components. The anti-dermatophytic activity was evaluated both by agar diffusion method and micro wells dilution method against the Microsporum boullardii MTCC 6059, M. canis (MTCC 2820 and MTCC 32700), M. gypseum MTCC 2819, Trichophyton ajelloi MTCC 4878, T. rubrum (MTCC 296 and MTCC 3272).ResultsThe free radical scavenging activity values were ranged from 0.7 to 1.41 mg/ml and 0.6 to 1.23 mg/ml, respectively for leaf and stem bark extracts. The amount of total phenolic contents of the extracts occurred in both leaf and bark in the range of 12 to 56.6 mg GAE/100 g and 16 to 58 mg GAE/100 g respectively. RP-HPLC analysis for flavonoids revealed the presence of two major flavonoid compounds, rutin and catechin. Kaempferol was in trace or absent. Methanol leaf extract showed significant low inhibitory effect against tested fungus Trichophyton ajelloi MTCC 4878 (0.140625 mg/ml) as the most sensitive. These finding suggest that the methanol leaf extract tested contain compounds with antimicrobial properties.ConclusionThe results of our study may partially justify the folkloric uses on the plant studied and further provide an evidence that the leaf extract of Xylosma longifolium might be indeed a potential sources of antimicrobial agents.

Changes in secondary metabolites of green tea during fermentation by Aspergillus oryzae and its effect on antioxidant potential

Metabolomic differences between green tea (GT) and Aspergillus oryzae-fermented green tea (FGT) were investigated using Liquid Chromatography–Electrospray Ionization-Ion Trap–Tandem Mass Spectrometry (LC-ESI-IT-MS/MS). To identify the metabolomic differences, principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) of GT and FGT were performed. A total of 17 metabolites differed between GT and FGT. The major flavonoid compounds of GT, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), decreased during fermentation, while the levels of phenolic compounds, such as gallic acid, 3-p-coumaroylquinic acid, and other flavonoid metabolites like gallocatechin, epicatechin, and epigallocatechin, increased significantly during fermentation. Notably, caffeine degradation was also observed during fermentation of GT by A. oryzae. Although the total flavonoid content of FGT decreased, the antioxidant activity of FGT increased significantly due to increased levels of other identified and unidentified metabolites. These results show that fermentation-dependent metabolomic changes have the potential to increase the bioactivity of GT.

Phenolic composition and antioxidant activity of white mulberry (Morus alba L.) fruits

SummaryEight major mulberry cultivars [Nakhonratchasima 60 (NS 60), Buriram 60 (BR 60), Chumphon (CP), Wavee (WV), Chaingmai (CM), Pikultong (PT), Kamphaengsaen (KS) and Kamnanchul (KJ)] cultivated in Thailand were assessed for their flavonoid and phenolic acid composition using HPLC and tested for antioxidant potential using 2,2‐diphenyl‐1‐picrylhydrazyl hydrate (DPPH) assay. The total phenolic content (TPC) ranged from 104.78 to 213.53 mg GAE/100 g DW, and total flavonoid content (TFC) ranged from 69.58 to 211.01 mg CE/100 g DW. The major flavonoid compounds in mulberry fruit cultivars were (+)‐catechin (309.26–750.01 mg/100 g DW), procyanidin B1 (62.59–224.41 mg/100 g DW), quercetin (5.36–58.42 mg/100 g DW), rutin (18.73–26.90 mg/100 g DW) and (−)‐epicatechin (8.47–29.21 mg/100 g DW). Gallic acid, cinnamic acid and p‐hydroxybenzoic acid were found to be the major phenolic acids in mulberry fruit cultivars. The gallic acid and cinnamic acid contents ranged from 7.33 to 23.90 mg/100 g DW and from 11.64 to 15.05 mg/100 g DW, respectively. p‐Hydroxybenzoic acid content ranged from 1.77 mg/100 g DW (PT) to 7.13 mg/100 g DW (KJ). DPPH‐scavenging ability was excellent for ethanolic extract of NS 60, and EC50 value of NS 60 (241.83 μg mL−1) was significantly lower than those of the others (P < 0.05). TPC and TFC of the mulberry fruit were positively correlated with the DPPH‐scavenging ability.

Influence of Storage Conditions on Flavonoids Content and Antioxidant Activity of Selected Shallot (Allium Cepa Var. Ascalonicum Backer) Hybrid Cultivars

Summary The aim of this study was to determine changes in the content of flavonoids in fleshy scales of shallot bulbs in relation to different compositions of atmosphere during storage. Also antioxidant activity of the bulbs was determined. Bulbs of shallot cvs. Bonilla F1, Conservor F1 and Matador F1 were stored in two storage seasons at the normal atmosphere (NA) and controlled atmosphere (CA) of the 4 compositions: 5% CO2 + 5% O2, 5% CO2 + 2% O2, 2% CO2 + 5% O2, 2% CO2 + 2% O2. The temperature of storage was 0-1°C and RH 65%. Before and after 7-month storage the bulbs were examined in respect of flavonoids content and antioxidant activity (AA). Flavonoids were identified in methanolic extracts with HPLC, AA was determined with FRAP and DPPH assays. Three flavonoid compounds were identified in the plants extracts. Quercetin 3,4’ di-O-glucoside and quercetin 4’-glucoside (spiraeoside) were present in the highest amounts. CA conditions influenced content of flavonoids in the bulbs. The highest content after storage was observed at gas composition of 5% CO2 + 5% O2. Two major flavonoid compounds, quercetin 3,4’-di-O-glucoside and quercetin 4’-O-glucoside (spiraeoside) showed the increasing tendency, however not all changes were significant. No significant differences were observed between cultivars, but ‘Bonilla’ F1 showed slightly higher flavonoids content than the other ones. Investigated cultivars did not differ in respect of AA, measured both with DPPH and FRAP assay. There was no significant influence of storage conditions on DPPH level, while FRAP level was influenced significantly. Bulbs from 5% CO2 + 2% O2 composition were characterized by the highest FRAP values and the bulbs stored at normal atmosphere - by the lowest.

Pharmacological potential of ampelopsin in Rattan tea

Rattan tea, made from the leaves of Ampelopsis grossedentata, may potentially perform multiple pharmacological roles, including anti-bacterial, anti-cancer, antioxidant, hepatoprotective and anti-hypertension functions. These beneficial functions of Rattan tea are strongly associated with the bioactivity of ampelopsin, a major flavonoid compound in Rattan tea. In this review, we summarize current research related to the bioactivity and pharmacological mechanisms of ampelopsin, which will provide a better reference for its potential application in the prevention of chronic diseases.

Effects of Baicalin on Protease-Activated Receptor-1 Expression and Brain Injury in a Rat Model of Intracerebral Hemorrhage

"Baicalin, a major flavonoid compound isolated from the dry roots of Scutellaria baicalensis Georgi, has been shown to be neuroprotective after ischemic brain injury. However, little is known about its effects on brain injury following intracerebral hemorrhage (ICH). In this study, we evaluated the effects of baicalin on ICH-induced brain injury in an ICH rat model. Male Wistar rats were injected intracerebrally with 0.5 U collagenaseVII to induce ICH, while control rats were injected with an equal volume of saline. After ICH induction, the rats were randomly divided into four groups and treated with baicalin at different doses (0, 25, 50 or 100 mg/kg) through peritoneal injection. The control rats were injected with an equal volume of vehicle. Brain tissues around the hemorrhage areas were collected on day 1, 3, 5 and 10 after treatment. Brain water content was analyzed by desiccation method; mRNA and protein levels of brain protease-activated receptor-1 (PAR-1) were determined by RT-PCR and Western blot, respectively; cell apoptosis was evaluated by terminal transferase dUTP nick end labeling staining. The results showed that baicalin effectively attenuated brain edema and inhibited cell apoptosis following ICH in a dose- and time-dependent manner, with concomitant suppression of PAR-1 expression at both the mRNA and protein levels. These findings indicate that baicalin has protective effects on ICH-induced brain injury. The effects of baicalin may involve a mechanism of inhibition of PAR-1 expression."

Characterization of a Glucosyltransferase Enzyme Involved in the Formation of Kaempferol and Quercetin Sophorosides in Crocus sativus

UGT707B1 is a new glucosyltransferase isolated from saffron (Crocus sativus) that localizes to the cytoplasm and the nucleus of stigma and tepal cells. UGT707B1 transcripts were detected in the stigma tissue of all the Crocus species analyzed, but expression analysis of UGT707B1 in tepals revealed its absence in certain species. The analysis of the glucosylated flavonoids present in Crocus tepals reveals the presence of two major flavonoid compounds in saffron: kaempferol-3-O-β-D-glucopyranosyl-(1-2)-β-D-glucopyranoside and quercetin-3-O-β-D-glucopyranosyl-(1-2)-β-D-glucopyranoside, both of which were absent from the tepals of those Crocus species that did not express UGT707B1. Transgenic Arabidopsis (Arabidopsis thaliana) plants constitutively expressing UGT707B1 under the control of the cauliflower mosaic virus 35S promoter have been constructed and their phenotype analyzed. The transgenic lines displayed a number of changes that resembled those described previously in lines where flavonoid levels had been altered. The plants showed hyponastic leaves, a reduced number of trichomes, thicker stems, and flowering delay. Levels of flavonoids measured in extracts of the transgenic plants showed changes in the composition of flavonols when compared with wild-type plants. The major differences were observed in the extracts from stems and flowers, with an increase in 3-sophoroside flavonol glucosides. Furthermore, a new compound not detected in ecotype Columbia wild-type plants was detected in all the tissues and identified as kaempferol-3-O-sophoroside-7-O-rhamnoside. These data reveal the involvement of UGT707B1 in the biosynthesis of flavonol-3-O-sophorosides and how significant changes in flavonoid homeostasis can be caused by the overproduction of a flavonoid-conjugating enzyme.

Optimization of Extraction Condition for Supercritical Carbon Dioxide (SCCO 2) Extraction of Strobhilantes crispus (Pecah Kaca) Leaves by Response Surface Methodology

Supercritical carbon dioxide (SC-CO2) extraction was used to obtain the bioactive flavonoid compounds of Strobilanthes crispus (Pecah Kaca). Process variables namely pressure, temperature and co-solvent flow rate were studied for optimization of the extraction yield and bioactive flavonoid compound of S. crispus by response surface methodology following a Box Behnken design of experiments. HPLC was performed to determine the major bioactive flavonoid compounds from S. crispus. The optimum value of yield extraction (6.55%) was obtained at pressure 200 bar, 50°C temperature and co-solvent flow rate of 5 g/min. Under the optimum conditions, eight flavonoid compounds were identified namely (+)-catechin, (-) epicatechin, rutin, myricetin, luteolin, apigenin, naringenin and kaempferol. The experimental extraction yield is in good agreement with the predicted one. The response surface methodology used in this study was able to predict the optimal extraction conditions for the extraction yield of bioactive flavonoid compounds from S.crispus leaves extract.

Isolation and identification of an antioxidant flavonoid compound from citrus-processing by-product

Large amounts of citrus by-products are released from juice-processing plants every year. Most bioactive compounds are found in the peel and inner white pulp. Flavonoids are a widely distributed group of bioactive compounds. The methanolic extract of citrus peel powder has been shown to possess strong antioxidant activity. Therefore the aim of this study was to isolate the major antioxidant flavonoid compound from Citrus unshiu (satsuma) peel as citrus by-product and evaluate its antioxidant activity. The major flavonoid isolated from C. unshiu peel was identified as quercetagetin. The structure of the compound was determined by tandem mass spectrometry and ultraviolet spectroscopy. Its antioxidant activity was assessed by assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, hydroxyl radical and intracellular reactive oxygen species (ROS) scavenging and DNA damage inhibition. Quercetagetin showed strong DPPH radical-scavenging activity (IC₅₀ 7.89 µmol L⁻¹) but much lower hydroxyl radical-scavenging activity (IC₅₀ 203.82 µmol L⁻¹). Furthermore, it significantly reduced ROS in Vero cells and showed a strong protective effect against hydrogen peroxide-induced DNA damage. The results of this study suggest that quercetagetin could be used in the functional food, cosmetic and pharmaceutical industries.

Comparative studies on anxiolytic activities and flavonoid compositions of Passiflora edulis ‘edulis’ and Passiflora edulis ‘flavicarpa’

To compare the anxiolytic activities and flavonoid compositions of the two populations of the species Passiflora edulis, Passiflora edulis 'edulis' with purple fruit and Passiflora edulis 'flavicarpa' with yellow fruit. Four samples for each population of Passiflora edulis were collected from different districts of China. Swiss albino mice were used as experimental animals in elevated plus-maze (EPM) test to assay the anxiolytic effects of ethanol extracts of the samples. The conventional parameters and ethological items of the behavior of the mice were recorded and analyzed. Flavonoid compositions of the samples were analyzed by RP-HPLC monitored with diode array detection and the chromatograms were compared. The ethanol extracts of the samples of Passiflora edulis 'flavicarpa' displayed anxiolytic activity at 400 mg/kg, while those of Passiflora edulis 'edulis' exhibited sedative effect at 400 mg/kg. The chromatograms of the samples belonging to similar population of Passiflora edulis were identical, but those belonging to different population were distinct from each other. The series of peaks between 16 and 24 min in the chromatograms of Passiflora edulis 'flavicarpa' did not appear in those of Passiflora edulis 'edulis', either did the peaks between 54 and 90 min in chromatograms of Passiflora edulis 'edulis' not appear in those of Passiflora edulis 'flavicarpa'. The six major flavonoid compounds isolated from the leaves of Passiflora edulis 'flavicarpa', lucenin-2, vicenin-2, isoorientin, isovitexin, luteolin-6-C-chinovoside, and luteolin-6-C-fucoside, had not been detected in Passiflora edulis 'edulis'. Passiflora edulis 'flavicarpa' is extremely different from Passiflora edulis 'edulis' and they should be distinguished when pharmacological studies are performed on them. The aerial part of Passiflora edulis 'flavicarpa' is possible to be utilized as the resource of Passionflower Extract.