The gene encoding flavonol synthase contributes to lesion mimic in wheat

Lesion mimic often exhibits leaf disease-like symptoms even in the absence of pathogen infection,and is characterized by a hypersensitive-response(HR)that closely linked to plant disease resistance.Despite this,only a few lesion mimic genes have been identified in wheat.In this investigation,a lesion mimic wheat mutant named je0297 was discovered,showing no alteration in yield components when compared to the wild type(WT).Segregation ratio analysis of the F_(2)individuals resulting from the cross between the WT and the mutant revealed that the lesion mimic was governed by a single recessive gene in je0297.Using Bulked segregant analysis(BSA)and exome capture sequencing,we mapped the lesion mimic gene designated as lm6 to chromosome 6BL.Further gene fine mapping using 3315 F_(2)individuals delimited the lm6 within a 1.18 Mb region.Within this region,we identified 16 high-confidence genes,with only two displaying mutations in je0297.Notably,one of the two genes,responsible for encoding flavonol synthase,exhibited altered expression levels.Subsequent phenotype analysis of TILLING mutants confirmed that the gene encoding flavonol synthase was indeed the causal gene for lm6.Transcriptome sequencing analysis revealed that the DEGs between the WT and mutant were significantly enriched in KEGG pathways related to flavonoid biosynthesis,including flavone and flavonol biosynthesis,isoflavonoid biosynthesis,and flavonoid biosynthesis pathways.Furthermore,more than 30 pathogen infection-related(PR)genes exhibited upregulation in the mutant.Corresponding to this expression pattern,the flavonoid content in je0297 showed a significant decrease in the 4^(th)leaf,accompanied by a notable accumulation of reactive oxygen,which likely contributed to the development of lesion mimic in the mutant.This investigation enhances our comprehension of cell death signaling pathways and provides a valuable gene resource for the breeding of disease-resistant wheat.

Identification of Pigments from Jujube Fruit Skin

[Objective]The aim was to identify the composition of pigments from Jujube fruit skin.[Method]Pigments were extracted from＇Lubei Dongzao＇,＇Lajiao Zao＇,＇Chengwu Dongzao＇,＇Dabailing＇and identificated by using high performance liquid chromatography-mass spectrometry（HPLC-MS）.[Result]The results showed that eight flavanols and four to five flavonols were detected,no anthocyanins was detected.The contents of flavonoids were differnt in four varieties.The contents of flavanols（11 mg/g） and flavonols（1.78 mg/g） in＇Dabailing＇ were one-time higher than other varieties.Quercetin 3 rutinoside was the major flavonol.[Conclusion]The research provided theoretical basis for further study on mechanism of Jujube pigment turnning into the red.

An Isopropyldioxy Flavonol from Hypericum perforatum L.

Aim Isolation and structural elucidation of the constituents from the aerialpart of Hypericum perforatum L. Methods Column chromatography and TLC were used to isolate chemicalconstituents. Physico-chemical characterization and spectroscopic analysis were employed forstructural identification. Results Three flavonols were isolated and identified. Conclusion Compound1 is a novel natural product and its structure has been characterized to be 3, 5, 7-trihydroxy-3',4'-isopropyldioxy-flavone.

Antidiabetic and in vitro antioxidant potential of Hybanthus enneaspermus(Linn) F.Muell in streptozotocin—induced diabetic rats

Objective:To evaluate antidiabetic and antioxidant potential of Hybanthus enneaspermus in different models.Methods:The oral glucose tolerance test(OGTT) and normoglycemic effect of alcoholic extract of Hybanthus enneaspermus(AHE) were evaluated at a dose of 125,250 and 500mg/kg p.o.while hypoglycemic activity and effect on body weight were tested at 250 and 500 mg/kg p.o.per day for 21 days in Streptozotocin(STZ) induced diabetic rats.Further,glucose uptake by hemidiaphram was also evaluated.The total polyphenolic and flavonoid were determined and their correlation with various antioxidant assays was also determined.Results:The results showed high level of phenolic content in AHE.AHE also exhibited higher total antioxidant capacity,good reducing power and a significant scavenger of reactive oxygen species like DPPH radical,nitric oxide,hydrogen peroxide and deoxyribose.Furthermore there was a significant increase in the body weight and decrease in the blood glucose level on treatment with the AHE.AHE increased glucose uptake on isolated rat hemi-diaphragm compared to control group.Conclusions:AHE reduce blood glucose level in STZ-induced diabetic model.It does not show significant effect in normoglycemic study but showes significant effect in OGT.AHE has significant antioxidant activity,which may be attributed to high phenolic content.

A New Isoprenylated flavonol from the Leaves of Broussonetia kazinoki

A new isoprenylated flavonol, named broussonol A (1) was isolated from the leaves of Broussonetia kazinoki Sieb. The structure of broussonol A was characterized by chemical and spectral methods.

A New Antimicrobial Flavonol Glycoside from Alchornea davidii

A new flavonol glycoside, isorhamnetin-3-O-b-D-xyloside, was isolated from the extract of leaves and twigs of Alchornea davidii (Euphorbiaceae). Its structure was established on the basis of the spectral analysis and chemical degradation. Antimicrobial assay showed that it moderately inhibited the growth of test bacteria (Staphylococcus aureus, Bacillus subtilis and Pseudomonas fluorescens) and fungi (Candida albicans, Aspergillus niger and Trichophyton rubrum) with MICs at 50 g/mL.

Review of anticancer mechanisms of isoquercitin

This review was based on a literature search of PubM ed and Scielo databases using the keywords "quercetin,rutin,isoquercitrin,isoquercitin(IQ),quercetin-3-glucoside,bioavailability,flavonols and favonoids,and cancer" and combinations of all the words.We collected relevant scientific publications from 1990 to 2015 about the absorption,bioavailability,chemoprevention activity,and treatment effects as well as the underlying anticancer mechanisms of isoquercitin.Flavonoids are a group of polyphenolic compounds widely distributed throughout the plant kingdom.The subclass of flavonols receives special attention owing to their health benefits.The main components of this class are quercetin,rutin,and IQ,which is a flavonoid and although mostly found as a glycoside,is an aglycone(lacks a glycoside side chain).This compound presents similar therapeutic profiles to quercetin but with superior bioavailability,resulting in increased efficacy compared to the aglycone form.IQ has therapeutic applications owing to its wide range of pharmacological effects including antioxidant,antiproliferative,anti-inflammatory,anti-hypertensive,and anti-diabetic.The protective effects of IQ in cancer may be due to actions on lipid peroxidation.In addition,the antitumor effect of IQ and its underlying mechanism are related to interactions with Wnt signaling pathway,mixed-lineage protein kinase 3,mitogen-activated protein kinase,apoptotic pathways,as well proinflammatory protein signaling.This review contributed to clarifying the mechanisms of absorption,metabolism,and actions of IQ and isoquercitrin in cancer.

A Flavonol Glycoside from Smilax glabra

A new flavonol glycoside, named neosmitilbin was isolated form the rhizome of Smilax glabra. Its structure and absolute configuration were elucidated on the basis of spectroscopic studies.

Variation in Antioxidants, Bioactive Compounds and Antioxidant Capacity in Germinated and Ungerminated Grains of Ten Rice Cultivars

Present study was conducted to characterise ten rice(Oryza sativa L.) cultivars viz. IET-23466, Dhan-201, IET-23448, MAS-946, IET-23445, IET-23463, IET-23455, PR-123, PR-115 and IET-23449 based on antioxidants(total phenolics, flavonols and tannins), bioactive compounds(phytic acid, gamma amino butyric acid, tocopherol and reduced ascorbate) and antioxidant activity(1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydroxyl radical scavenging activity, free radical antioxidant power and total reducing power) with an aim to identify cultivars containing higher health promoting components after germination. Three cultivars IET-23466, IET-23463 and PR-123 performed better as revealed by higher level of antioxidants, bioactive compounds and antioxidant activity before and after germination. Three cultivars MAS-946, IET-23445 and IET-23449 had moderate level of antioxidants, bioactive compounds and antioxidant activity. Four cultivars Dhan-201, IET-23448, IET-23455 and PR-115 performed intermediately. Strong positive correlation was observed among total phenolics and the antioxidant activity. Phytic acid was found to be negatively correlated to the antioxidant activity. Our results highlighted that cultivars IET-23466, IET-23463 and PR-123 hold great potential after germination and would open up a useful opportunity for the functional food industry, and consumption of these cultivars after germination would afford health benefits to consumers since they contain higher level of antioxidants.

Chemical Components of Helicia nilagirica Beed.I.Structure of Three New Flavonol Glycosides

Three new flavonol glycosides were isolated from the leaves of Helicia nilagirica Beed.. The structures were elucidated as kaempferol-3-O-b-D-xylopyranosyl-(16)-b-D-glyco- pyranosyl-(12)-a-L-rhamnopyranoside, quercetin-3-O-b-D-xylopyranosyl-(16)-b-D-glycopy- ranosyl-(12)-[-b-D-xylopyranosyl-(14)]-a-L-rhamnopyranoside, and quercetin-3-O-b-D- xylopyranosyl-(16)-b-D-glycopyranosyl-(12)-a-L-rhamnopyranoside, named as Helicianeoside A、B and C, respectively.

A systematic summary of natural compounds in Radix Glycyrrhizae

Objective： To accumulate data from studies on the compounds identified from Gancao （Radix Glycyrrhizae, GC）, andthen systematically summarize and classify these compounds according to their structural characteristics. Methods： Fivedatabases （CNKI, VIP, Wanfang data, CBM, and Pubmed） were used to search for studies on the chemical structure ofcompounds from GC. The retrieval time of the respective databases was from their inception to March 2016. Accordingto the inclusion and exclusion criteria, the papers were carefully screened, and the data were extracted. Results： A totalof 653 compounds from GC were collated from 252 articles, including flavonols （n = 201） belonging to 10 subgroups,terpenes and saponins （n = 167）, coumarins （n = 30） belonging to 3 subgroups, aliphatics （n = 206）, aromatics （n = 35）,and others （n = 14）. The flavones, represented by liquiritin and liquiritigenin, were the most reported compounds isolatedfrom GC, followed by terpenes and saponins such as glycyrrhizic acid and glycyrrhetinic acid. Conclusion： The morethan 600 natural compounds in GC may be responsible for GC’s anti-inflammatory, phlegm-expelling, cough- andpain-relieving activities.

Persimmon Leaf Flavonols Enhance the Anti-Cancer Effect of Heavy Ion Radiotherapy on Murine Xenograft Tumors

The cell cycle checkpoint system play a pivotal role in the cellular DNA damage response, and the discovery of checkpoint inhibitors is expected to sensitize current cancer therapies. Checkpoint signaling cascades are critically modulated by ATM (ataxia telangiectasia-mutated) and its related molecules. Generally, ATM primarily responds to ionizing irradiation-induced DNA double-strand breaks. Heavy ions from an accelerated carbon ion beam have been used to cure cancer because they are more effective than ionizing irradiation such as X-ray and γ-radiation in terms of biological damage. In a previous study, we demonstrated that a persimmon leaf flavonol (PLF) promoted the cytotoxic effect of chemotherapeutic agents on cancer cells through inhibition of checkpoint activities, especially in the ATM dependent pathway. The present study investigated whether PLF inhibits checkpoint activity during the DNA damage response induced by heavy ion irradiation. Treatment with PLF significantly increased the cytotoxicity of heavy ion irradiation in A549 adenocarcinoma cells. The phosphorylation of checkpoint proteins such as p53, SMC1, and Chk1 was increased by heavy ions. PLF reduced the phosphorylation of checkpoint proteins. Pre-treatment with PLF significantly prevented the decrease of mitotic cells in heavy ion-exposed cells. We further evaluated tumor volume in SCID mice inoculated with human lung adenocarcinoma A549 cells. The combination treatment of PLF and heavy ion resulted in a decrease of tumor volume compared with controls, although PLF itself did not exhibit any effect. These results indicate that PLF inhibits tumor growth through modulation of the DNA damage response. PLF may be useful for clinical application in combination with heavy ion radiotherapy.

Indigenous Purple Vegetable Extracts Protect against Hydrogen Peroxide-Induced DNA Damage in Human Lymphocytes

The objectives of this study were to identify the antioxidants in acid hydrolysates of six of Taiwan’s indigenous purple-leaved vegetables (IPLV), including purple-leaved sweet potato (Ipomoea batatas L. Lamark), purple-leaved gynura line 1 (Gynura bicolor D.C.), purple-leaved gynura line 2 (Gynura bicolor D.C.), purple-leaved perilla line 1 (Perilla frutescents L. Britton), bicolored-leaved perilla line 2 (Perilla frutescens L. Britton), and heartleaf houttuynia (Houttuynia cordata Thumb.). Their antioxidant activity and ability to protect DNA from oxidative damage was also evaluated. The antioxidants identified included flavonoids, anthocyanidins and flavonols. Both purple-leaved perilla line 1 and bicolored-leaved perilla line 2 were found to be abundant in cynidin, malvidin, and myricetin. Moreover, purple-leaved sweet potato and heartleaf houttuynia were found to be abundant in quercetin. Purple-leaved sweet potato and purple-leaved perilla line 1 contained significantly higher inhibition percentages of conjugated diene formation than other vegetables. Purple-leaved sweet potato, heartleaf houttuynia, purple-leaved perilla line 1, and bicolored-leaved perilla line 2 had better inhibition percentages of tail DNA% and tail moment in the study. In conclusion, the abovementioned four indigenous purple-leaved vegetables abounded in antioxidants had strong antioxidant activity for protecting DNA in lymphocytes from oxidative damages.

ISOLATION, STRUCTURE ELUCIDATION AND SYNTHESIS OF A NEW PRENYLATED FLAVONOL, MAACKIAFLAVONOL, FROM MAACKIA TENUIFOLIA

A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, IR, MS, NMR and 1H-1H COSY) and confirmed by total synthesis.

A new flavonoid glucoside from Cassia angustifolia

A new flavonoid glucoside with a known one was isolated from the leaves of Cassia angustifolia. Based on the spectral analysis, including MS, ^1H NMR, ^13C NMR, DEPT, ^1H-1HCOSY, HMQC, HMBC and NOSEY, their chemical structures were determined as kaempferol-3-O-[（6＇＇＇-O-trans-sinnapoyt）-β-D-glucopyranosyl （1 → 6）]-β-D-glucopyranoside 1 and apigenin-6,8-di-C-glycoside 2.

English and Black Walnut Phenolic Antioxidant Activity <i>in Vitro</i>and Following Human Nut Consumption

Background: Walnut consumption may reduce the risk of cardiovascular disease by providing antioxidant protection to low density lipoproteins (LDL). Aim: This study compared the phenolic profile and antioxidant activity of English ver- sus black walnuts. Methods: Nuts were extracted in methanol or acetone prior to analysis with HPLC/LC-MS-MS for phenolic identification and quantitation. The ability to prevent oxidation of LDL was examined in vitro using walnut extracts and ex vivo after walnut consumption for 28 days. Results: Flavonoids identified/quantified with HPLC/LC- MS-MS included the phenolic acids 5-caffeoylquinic acid, 3-caffeoylquinic acid (black walnut only), 4-caffeoylquinic acid, and the flavonol glycosides quercetin-3-rutinoside, quercetin-3-galactoside, quercetin-3-pentoside, quercetin-3- arabinoside, quercetin-3-rhamnoside, and the aglycone quercetin (English walnut only). Total phenolic yield of acetone extracts were 166.1 and 24.2 μg/g for English and black walnut respectively, and yield for methanol extracts were 147.6 and 4.1 μg/g for English and black walnut respectively. In vitro LDL oxidation by Cu++ with English walnut ex- tracts significantly extended oxidation lag-time (A234) in a dose dependent manner at 1.0 and 0.1 μg/ml and reduced TBARS formation (1.0 μg/ml). Black walnut extracts reduced TBARS significantly but had no effect on A234. Human consumption of English or black walnuts (30 g nuts/day) for 28 days resulted in no differences in LDL antioxidant ca- pacity (A234) between groups or within groups. Conclusion: This study suggests that the English walnuts have a pheno- lic profile and in vitro antioxidant capacity that is better than black walnuts, but that walnut consumption for 28 days does not improve LDL resistance to oxidation.

New Acetylated Flavonol Glycosides from Knoxia corymbosa

Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.

Dietary flavonoid intake and risk of stomach and colorectal cancer

Stomach and colorectal cancers are common cancers and leading causes of cancer deaths.Because the alimentary tract can interact directly with dietary components,stomach and colorectal cancer may be closely related to dietary intake.We systematically searched published literature written in English via PubMed by searching for terms related to stomach and colorectal cancer risk and dietary flavonoids up to June 30,2012.Twenty-three studies out of 209 identified articles were finally selected for the analysis.Log point effect estimates and the corresponding standard errors were calculated using covariate-adjusted point effect estimates and 95%CIs from the selected studies.Total dietary flavonoid intake was not associated with a reduced risk of colorectal or stomach cancer [odds ratio(OR)(95%CI) = 1.00(0.90-1.11) and 1.07(0.70-1.61),respectively].Among flavonoid subclasses,the intake of flavonols,flavan-3-ols,anthocyanidins,and proanthocyanidins showed a significant inverse association with colorectal cancer risk [OR(95%CI) = 0.71(0.63-0.81),0.88(0.79-0.97),0.68(0.56-0.82),and 0.72(0.61-0.85),respectively].A significant association was found only between flavonols and stomach cancer risk based on a limited number of selected studies [OR(95%CI) = 0.68(0.46-0.99)].In the summary estimates from casecontrol studies,all flavonoid subclasses except flavones and flavanones were inversely associated with colorectal cancer risk,whereas neither total flavonoids nor any subclasses of flavonoids were associated with colorectal cancer risk in the summary estimates based on the cohort studies.The significant association between flavonoid subclasses and cancer risk might be closely related to bias derived from the case-control design.There was no clear evidence that dietary flavonoids are associated with reduced risk of stomach and colorectal cancer.

Quercetin-derivatives painting the yellow petals of American lotus(Nelumbo lutea)and enzymatic basis for their accumulation

American lotus(Nelumbo lutea)is one of the two species in Nelumbo and has only yellow flower.Identification of total flavonoids showed wild American lotus contained almost only flavonols with quercetin 3-O-glucuronide to be the dominant pigment.The variation tendency of the total flavonol content was coincident with yellow color variation of petals during flower development.To understand the mechanism of accumulation and constituent of pigments in petals,three pivotal genes,NlFLS1,NlFLS2 and NlFLS3,which were predicted to encode flavonol synthases were isolated and characterized by analyses of basic bioinformatics,temporal and spatial expression patterns and enzymatic activity.Their temporal expression levels showed the same variation tendency,which was also consistent with the development-dependent variation of total flavonol content.Spatial expression patterns indicated the three genes should function in petals.All the three proteins were demonstrated to be bifunctional dioxygenase,possessing both flavonol synthase activity and flavanone 3-hydroxylase activity.Besides,other flavonol biosynthesis related genes were also investigated on their expression levels to give more clues on the mechanism.Substrate preferences of the three FLSs,substrate competitions between the FLSs and other flavonol biosynthesis related enzymes,and the greatly differential expression levels between F3’H(flavonoid 3-hydroxylase)and F3’5’H(flavonoid 3,5-hydroxylase)contributed to the flavonol constituent in the petals of America lotus,namely abundant quercetin-derivatives while very few kaempferol-derivatives and myricetin-derivatives.

Two New Flavonol Glycosides from Bridelia tomentosa

Two new flavonol glycosides, tamarixetin 3-O-β-D-xylopyranosyl-（1-2）-α-L-ribopyranoside （1） and tamarixetin 3-O-α-L-ribopyranoside （2） were isolated from the leaves of Bridelia tomentosa. Their structures were elucidated by 1D and 2D NMR analysis, as well as MS and IR spectra.