Flavonoids Myricetin Research Articles

Effect of the solvent composition on the profile of phenolic compounds extracted from chia seeds

This study investigated the efficiency of the extraction of phenolic compounds from seeds of chia, Salvia hispanica L. utilizing the statistical tool of mixture planning, simplex-lattice design. The solvents used were acetone, ethanol and water and the responses analyzed were total phenolic content (TPC), antioxidant activity by the capture of the free radical DPPH and ferric reduction ability (FRAP). Moderately polar mixtures were highly efficient to extract the antioxidant phenolic compounds. The best results were obtained for the water-acetone (1/3–2/3) binary mixture, presenting TPC, DPPP and FRAP values of 58.44 mg GAE/g, 250.20 μmol TE/g and 720.15 μmol TE/g, respectively. The best ternary mixture was water-ethanol-acetone (1/6–1/6–2/3), with 60.96 mg GAE/g, 380.53 μmol TE/g and 990.15 μmol TE/g, respectively. The phenolic profile showed that the acids rosmarinic, caffeic, salicylic and the flavonoids myricetin and quercetin are the compounds that most contribute to the elevated antioxidant activity.

A Multi-targeted Natural Flavonoid Myricetin Suppresses Lamellipodia and Focal Adhesions Formation and Impedes Glioblastoma Cell Invasiveness and Abnormal Motility.

Glioblastoma multiforme (GBM) is the most aggressive and malignant primary brain tumor characterized by rapid growth and extensive infiltration to neighboring normal brain parenchyma, which contribute to tumor recurrence and poor prognosis. Myricetin is a natural flavonoid with potent anti-oxidant, anti-inflammatory and anti-cancer activities, which may serve as a potential and harmless agent for GBM treatment. To investigate the anti-glioblastoma effects of myricetin, GBM cells were treated with myricetin alone or in combination with temozolomide. Its effects on GBM cell motility and cytoskeletal structures including lamellipodia, focal adhesions and membrane ruffles were also evaluated. We showed that myricetin alone inhibited glioblastoma U-87 MG cell proliferation, migration and invasion, whereas combination of myricetin and temozolomide did not exhibit any synergistic effect. The inhibitory effect on GBM cell proliferation is independent of PTEN status. Moreover, myricetin showed less cytotoxicity to normal astrocytes than GBM cells. Formation of lamellipodia, focal adhesions, membrane ruffles and vasculogenic mimicry were blocked by myricetin, and phosphorylation of ROCK2, paxillin and cortactin was suppressed. In addition, myricetin could inhibit PI3K/Akt and JNK signaling, and bind to a series of kinases and scaffold proteins including PI3K catalytic isoforms (p110α, p110β and p110δ), PDK1, JNK, c-Jun, ROCK2, paxillin, vinculin and VEcadherin. In conclusion, myricetin is a multi-targeted drug that has potent anti-migratory and antiinvasive effects on GBM cells, and suppresses formation of lamellipodia and focal adhesions, suggesting that it may serve as an alternative option for GBM treatment.

Synthesis and Activity Evaluation of Novel Prenylated Flavonoids as Antiproliferative Agents

Twenty prenylated flavonoids 1―20 were synthesized by glycoside hydrolysis, dehydrogenation, selective O-methylation, O-prenylation and Claisen rearrangement reaction, from abundant and inexpensive natural flavonoids naringin, hespiredin, quercetin and myricetin. Among them, 1―7, 10―15 and 17―20 are novel compounds, the natural product 3,3′,4′,7-tetramethoxy-8-prenyl-5-hydroxy flavonoid(16) was synthesized in a high yield. Their antiprolirative activities were evaluated in vitro on a panel of three human cancer cell lines(HeLa, HCC1954 and SK-OV-3). The results show that most of the target compounds displayed moderate to potent antiprolirative activities against the three cancer cells with half maximal inhibitory concentration(IC50) values from 0.49 μmol/L to 95.07 μmol/L. Among them, 3′,4′,7-trimethoxyl-5-hydroxyl-8-prenyl flavonoid(12) exhibited the strongest antiprolirative activity against the three cancer cells mentioned above with IC50 values of 0.91―7.08 μmol/L. 3′,7-Dimethoxy-5-O-prenyl flavone(6) and 3′,4′,7-trimethoxy-5-O-prenyl flavone(10) showed selective antiproliferative activity against HCC1954 cells with IC50 value of 0.49 and 5.32 μmol/L, respectively.

Phenolic compounds profiling in shake flask and bioreactor system cell cultures of Scrophularia striata Boiss

Variation in levels of phenolic acids and flavonoids in Scrophularia striata Boiss. cells cultured in both shake flask and bioreactor in vitro systems, was studied at different growth phases. Four phenolic acids (cinnamic, salicylic, coumaric, and caffeic acid), one stilbenoid (resveratrol), and seven flavonoids (diosmin, rutin, kaempferol, catechin, myricetin, quercetin, and luteolin) were analyzed by high-performance liquid chromatography with photodiode array detection. Production of phenolics in the bioreactor was higher than in shake flasks. Catechin was the most abundant flavonoid in both culture systems, while quercetin, which was detected only in the bioreactor, was the lowest amount represented (32.82 μg g−1 DW). Resveratrol accumulation in bioreactor cultures was 59.84-fold higher than that in shake flasks. Moreover, hierarchical clustering analysis based on Pearson’s correlation coefficient confirmed a positive correlation between the growth phase and some metabolites. The flavonoid accumulation increased with the cells’ physiological age in the bioreactor. Principal component analysis showed that the time course of induction of phenolic acids, flavonoids, and a stilbenoid (resveratrol) was significantly correlated. These findings highlight the capacity of S. striata for large-scale production of desired phenolics using a bioreactor system.

Myricetin-induced oxidative stress suppresses murine T lymphocyte activation.

A number of polyphenolic compounds present in fruits and vegetables have the capacity to modulate immune responses; however, the impact of the common plant-derived flavonoid myricetin on T lymphocyte function has not been investigated. We show that myricetin inhibited mouse T lymphocyte activation by bead-immobilized anti-CD3 and anti-CD28 monoclonal antibodies, as indicated by a dose-dependent reduction in cell proliferation and decreased synthesis of interferon-γ, interleukin (IL)-2, IL-4, and IL-17 associated with different T helper cell subsets. This effect was attributed to myricetin-induced reactive oxygen species (ROS) since myricetin caused hydrogen peroxide (H2 O2 ) to accumulate in cell-free culture medium and H2 O2 inhibited T cell proliferation and cytokine synthesis. In addition, the antioxidant N-acetyl cysteine restored the ability of myricetin-treated T lymphocytes to proliferate in response to a mitogenic stimulus. The presence of dendritic cells or bone marrow-derived macrophages negated the inhibitory effect of myricetin on T cell activation, and H2 O2 in T cell cultures that were treated with exogenous H2 O2 was reduced when antigen-presenting cells were also present. These findings suggest that antioxidant molecules produced by dendritic cells and macrophages protected T cells from myricetin-induced oxidative stress, and underscore the importance of considering immune cell interactions when evaluating the immunomodulatory activity of ROS-generating phytochemicals.

Polyphenolic contents of Teucrium polium L. and Teucrium scordium L. associated with their protective effects against MMC-induced chromosomal damage in cultured human peripheral blood lymphocytes.

Teucrium species have been used in traditional medicine for treatment of different diseases. The aim of this study was to investigate polyphenolic contents by high-performance liquid chromatography (HPLC), and the genotoxic effect of methanolic extracts of Teucrium polium and Teucrium scordium using the cytokinesis-block micronucleus (CBMN) assay on human peripheral blood lymphocytes (PBLs) from healthy donors. The HPLC analysis showed that extracts consist of phenolic acid (gallic, vanillic, caefic, chlorogenic, p-coumaric, sinapic) and flavonoids (catechin, rutin, myricetin, luteolin, quercetin and apigenin). Cultures were treated with extracts of both plants separately and in combinations with mitomycin C (MMC). In separate treatments, both herbal extracts significantly induced micronucleus (MN) frequency only at the highest concentrations. All concentrations of T. scordium , except the lowest, and all concentrations of T. polium extracts in combined treatment with MMC significantly reduced the frequency of MN. The extract of T. polium did not significantly aefct the nuclear division index (NDI), whereas T. scordium in higher concentrations, separately and in combined treatment with MMC, significantly decreased the NDI value. Our results suggest that both herbal extracts in combination with MMC have antimutagenic (T. polium) and proapoptotic effects (T. scordium), which indicates their protective effects in PBLs.

Potential role of nucleoside diphosphate kinase in myricetin-induced selective apoptosis in colon cancer HCT-15 cells

The flavonoid myricetin (MYR) is derived from vegetables and fruits. It has been shown to exert anti-cancer effects in various cell lines; however, the exact mechanism underlying these effects is yet to be elucidated. In this study, we evaluated the anti-cancer effects induced by MYR treatment in colon cancer HCT-15 cells. To detect cell proliferation, we conducted MTT assay and real time-cell electronic sensing (RT-CES). We next performed comet assay and Annexin V and PI staining to detect cellular apoptotic features. After that, we conducted two-dimensional electrophoresis (2-DE) analysis to identify apoptotic proteins. The results of this analysis revealed that eight spots were differentially expressed. Among the spots, we selected nucleoside diphosphate kinase (NDPK) for further investigation, as it has been shown to regulate cancer cell apoptosis and metastasis. After that, we conducted realtime-PCR and western blot to detect the expression of NDPK mRNA and protein and wound-healing assay to detect cell migration and invasion. Finally, we performed NDPK siRNA transfection study and the results showed that NDPK knockdown inhibited apoptosis. Based on these collective results, we suggest that MYR induces apoptosis in human colon cancer HCT-15 cells selectively by increasing the expression of NDPK and other caspase-regulated apoptosis proteins.

Broad spectrum insect resistance and metabolites in close relatives of the cultivated tomato

Wild relatives of tomato possess effective means to deal with several pests, among which are a variety of insects. Here we studied the presence of resistance components against Trialeurodes vaporariorum, Myzus persicae, Frankliniella occidentalis, and Spodoptera exigua in the Lycopersicon group of Solanum section Lycopersicon by means of bioassays and comprehensive metabolite profiling. Broad spectrum resistance was found in Solanum galapagense and a few accessions of S. pimpinellifolium. Resistance to the sap sucking insects may be based on the same mechanism, but different from the caterpillar resistance. Large and highly significant differences in the leaf metabolomes were found between S. galapagense, containing type IV trichomes, and its closest relative S. cheesmaniae, which lacks type IV trichomes. The most evident differences were the relatively high levels of different methylated forms of the flavonoid myricetin and many acyl sucrose structures in S. galapagense. Possible candidate genes regulating the production of these compounds were identified in the Wf-1 QTL region of S. galapagense, which was previously shown to confer resistance to the whitefly B. tabaci. The broad spectrum insect resistance identified in S. galapagense will be very useful to increase resistance in cultivated tomato.

Suppression of the mechanisms of stone formation by a flavonoid-enriched ethyl acetate fraction of aerial and underground parts of Aerva lanata (Linn.) Juss. ex Schult

Background: Aerva lanata (Linn.) Juss. ex Schult.(AL), belonging to family Amaranthaceae, is a popular medicinal herb known for its immense antiurolithic properties. Several researchers have reported the antilithiatic efficaciousness of the extract. However, there does not exist any evidence regarding the bioassay-guided fractionation of the same as a route to identification of potential antiurolithic phytoconstituents. Objective: The present study aims to evaluate the antiurolithic competence of different extract based phytoconstituent enriched fractions (Fr) of the aerial parts and roots of AL under in vitro conditions to screen out the Fr possessing the best activity. Materials and Methods: Different Fr from the extracts of aerial parts and roots were prepared by solvent-solvent partitioning and were subjected to preliminary phytochemical screening to affirm the presence of intended phytometabolites. The Fr were analyzed for their antilithiatic efficacy by in vitro aggregation and growth assay to assess their ability to counteract calcium oxalate (CaOx) aggregation and growth. The phytochemical evaluation was also performed by high-performance thin layer chromatography (HPTLC). Results: Preliminary phytochemical screening ascertained the presence of expected phytochemicals in the Fr. Antiurolithic assays demonstrated that the flavonoid and phenolic enriched Fr III derived from the extract of aerial parts exhibited the maximum hindrance to CaOx aggregation and growth at 1000 μg/ml with a percentage inhibition of 67.14% ± 1.84% and 66.66% ± 1.65%, respectively. HPTLC analysis revealed the presence of flavonoids quercetin, kaempferol, and myricetin in the same. Conclusion: The antiurolithic ability of AL on the overall process of stone formation might be attributed to the presence of potent phenolic and flavonoid compounds in the aerial parts which may act as a source for isolation of powerful antiurolithic leads from the same. Abbreviations used: AL: Aerva lanata; Fr: Fraction(s); CaOx: Calcium oxalate; HPLTC: High-performance thin-layer chromatography

Bioactivity-guided isolation of potent anxiolytic compounds from leaves of Citrus paradisi.

Context:Citrus fragrances have been attributed with mood-enhancing properties by aromatherapists. Leaves of this plant have been reported to exert anti-anxiety activity. Till date, no specific phytoconstituent responsible for this has been identified.Objective:Isolation of anxiolytic constituent of Citrus paradisi using bioactivity-guided fractionation.Materials and Methods:Leaf extracts of four varieties of C. paradisi in petroleum ether, chloroform, methanol and water were evaluated for anti-anxiety activity in mice using elevated plus-maze apparatus. Because of activity in methanol extract, it was used for safety evaluation/acute toxicity studies in animals. Bioactive fraction of methanol extract was subjected to column chromatography and structure of the isolated compound was elucidated by melting point, ultraviolet, infrared, nuclear mass reactor and mass spectroscopy. The isolated constituents were further evaluated for anti-anxiety activity using light/dark model and hole-board model of anxiety.Results:Results showed no mortality at a dose up to 2000 mg/kg body weight that indirectly reflects the safety profile of the leaf extracts. Fractionation of methanol extract led to the isolation of four flavonoids (rutin, quercetin, kaempferol and myricetin). The isolated compounds exhibited significant anxiolytic activity in different animal models.Conclusion:The study confirms the presence of four flavonoids responsible for anti-anxiety activity.

Inhibition of human monoamine oxidase A and B by flavonoids isolated from two Algerian medicinal plants

BackgroundMonoamine oxidases (MAOs) are outer mitochondrial membrane flavoenzymes. They catalyze the oxidative deamination of a variety of neurotransmitters. MAO-A and MAO-B may be considered as targets for inhibitors to treat neurodegenerative diseases and depression and for managing symptoms associated with Parkinson's and Alzheimer's diseases. PurposeThe objective was to evaluate the inhibitory effect of Hypericum afrum and Cytisus villosus against MAO-A and B and to isolate the compounds responsible for the MAO-inhibitory activity. MethodsThe inhibitory effect of extracts and purified constituents of H. afrum and C. villosus were investigated in vitro using recombinant human MAO-A and B, and through bioassay-guided fractionation of ethyl acetate fractions of areal parts of the two plants collected in northeastern Algeria. In addition, computational protein-ligand docking and molecular dynamics simulations were carried out to explain the MAO binding at the molecular level. ResultsThe ethyl acetate (EtOAc) fractions of H. afrum and C. villosus showed the highest MAO inhibition activity against MAO A and B with IC50 values of 3.37 µg/ml and 13.50 µg/ml as well as 5.62 and 1.87 µg/ml, respectively. Bioassay-guided fractionation of the EtOAc fractions resulted in the purification and identification of the known flavonoids quercetin, myricetin, genistein and chrysin as the principal MAO-inhibitory constituents. Their structures were established by extensive 1 and 2D NMR studies and mass spectrometry. Quercetin, myricetin and chrysin showed potent inhibitory activity towards MAO-A with IC50 values of 1.52, 9.93 and 0.25 µM, respectively, while genistein more efficiently inhibited MAO-B (IC50 value: 0.65 µM). The kinetics of the inhibition and the study of dialysis dissociation of the complex of quercetin and myricetin and the isoenzyme MAO-A showed competitive and mixed inhibition, respectively. Both compounds showed reversible binding. Molecular docking experiments and molecular dynamics simulations allowed to estimate the binding poses and to identify the most important residues involved in the selective recognition of molecules in the MAOs enzymatic clefts. ConclusionQuercetin and myricetin isolated from H. afrum together with genistein and chrysin isolated from C. villosus have been identified as potent MAO-A and -B inhibitors. H. afrum and C. villosus have properties indicative of potential neuroprotective ability and may be new candidates for selective MAO-A and B inhibitors.

Oral administration of fisetin promotes the induction of hippocampal long-term potentiation in vivo

To explore memory enhancing effect of the flavonoid fisetin, we investigated the effect of oral administration of flavonoids on the induction of long-term potentiation (LTP) at hippocampal CA1 synapses of anesthetized rats. Among four flavonoids (fisetin, quercetin, luteolin and myricetin) tested, only fisetin significantly facilitated the induction of hippocampal LTP. The effect of oral fisetin was abolished by intracerebroventricular injection of U0126, an agent that was previously found to inhibit its effect in hippocampal slices in vitro. These results suggest that orally administered fisetin crosses the blood–brain barrier and promotes synaptic functions in the hippocampus.

The natural flavonoid myricetin inhibits gastric H+, K+-ATPase

Myricetin (3,3’,4’,5,5’,7-hexahydroxyflavone), a major flavonoid in berries and red wine, has been recently used as a health food supplement based on its antioxidant and antitumor properties. We report here that myricetin preferentially exerts inhibitory effects on gastric H+, K+-ATPase. Myricetin inhibited H+, K+-ATPase with a sub-micromolar IC50 value in an enzyme assay using freeze-dried tubulovesicles prepared from hog stomach. Na+, K+-ATPase and Ca2+-ATPase were also inhibited by myricetin in a dose-dependent manner, but the IC50 values for these enzymes were approximately an order of magnitude higher compared to the H+, K+-ATPase. In structure-inhibitory functional analysis of sixteen myricetin derivatives, several phenolic hydroxy groups attached to the flavonoid backbone were highlighted as essential modifications for the inhibition of P2-type ATPases. Furthermore, oral administration of myricetin significantly attenuated histamine-induced gastric acid secretion in an in vivo mouse assessment. Therefore, myricetin derivatives seem to be useful seed compounds for developing new drugs and supplements to alleviate gastric acid secretion.

Borago officinalis L. flower: a comprehensive study on bioactive compounds and its health-promoting properties

The herbal plant Borago officinalis L. flower were analysed for its bioactive compounds and antioxidant, antibacterial, anti-inflammatory and anticancer activities using different solvent polarities (methanol, ethanol and water). The RP-HPLC analyses of the methanolic extract confirmed the presence of phenolics (gallic acid, pyrogallol, salicylic acid, caffeic acid), flavonoids (myricetin, rutin) and isoflavonoid (daidzein). Besides, the major individual fatty acids of methanolic extract were α-linolenic, stearidonic, palmitic, linoleic and γ-linolenic acids. The methanolic extract possessed the highest antioxidant properties as compared to the ethanolic and water extracts. The flower methanolic, ethanolic and water extracts showed high, moderate and weak antibacterial activities against common human and foodborne pathogenic bacteria, respectively. Furthermore, the flower extracts showed weak anti-inflammatory in murine RAW 264.7 macrophage cells and low anticancer properties against human hepatic, prostate and colon cancer cells. This high-value flower could be considered as a source of putative antioxidant and antibacterial compounds to improve the human health and to be used as biopreservative in food and cosmetic industries.

The Effect of Myricetin Flavonoid on the Expression of Fyn Gene in Melanoma Cells (A375)

Background: Malignant melanoma as one of the most common cancers is currently spreading worldwide. Regarding after-effect of advanced treatments, using natural products has attracted much attention. Flavonoids, polyphenol compounds rich in diet, are being considered for their therapeutic preventive features. Fyn gene, a member of the protein tyrosine kinase oncogene family, has become an important target for therapy goals. Objectives: The aim of this study was to assess Fyn gene expression after treatment of melanoma cells with myricetin. Methods: In this study, the melanoma cells were treated with different concentrations of myricetin (0 to 100 �M) and their viability was determined by the methylthiazolyl diphenyl-tetrazolium bromide (MTT) assay, also the expression of Fyn gene in treated cells with selected concentrations of myricetin (0, 20, 40, 50, and 60 �M) was detected by real time quantitative polymerase chain reaction (qPCR). Results: The current investigation showed that treatment of A375 melanoma cells with the dietary flavonoid myricetin (3, 5, 7- trihydroxy-2-(3, 4, 5,-trihydroxy phenyl)-4- chromenone), resulted in decreased cell viability and increased expression of Fyn gene. The MTT assay analysis of exposed cells with different concentrations of myricetin showed that up to 25 �Mof myricetin had no cytotoxicity effect on A375 cells, also with increasing of myricetin concentration, the repression of cell proliferation developed as well. Conclusions: Real time qPCR analysis of Fyn expression in exposed cells with various concentration of myricetin leads to overexpression of this gene, dose dependently. Through this research, it was determined that myricetin with its anti-proliferative potential could suppress the development of cancer cells. On the other hand, since Fyn kinase could be involved in tumorigenesis of some cancer cells, it could be concluded that myricetin could effect the carcinogenicity of Fyn function in melanoma cells. Keywords: Melanoma, A375, Myricetin, Fyn Gene

Fibroin/dodecanol floating solidification microextraction for the preconcentration of trace levels of flavonoids in complex matrix samples.

A new fibroin/dodecanol floating solidification microextraction, coupled with high performance liquid chromatography, was developed and applied for enrichment and quantification of the trace flavonoids in traditional Chinese medicine and biological samples. Also, fibroin sensibilization mechanism was described, and influence of sample matrix to enrichment factor was investigated. In this method, a homogeneous fibroin/dodecanol of dispersed solution was employed as microextraction phase to flavonoids (myricetin, quercetin, isorhamnetin, chrysin, kaempferide), the several critical parameters affecting the performance, such as organic extractant, amount of fibroin in organic extractant, volume of extraction phase, dispersant, salt concentration, pH of sample phase, stirring rate, extraction time, and volume of sample phase were tested and optimized. Under the optimized conditions, enrichment factor of flavonoids ranged from 42.4 to 238.1 in different samples, excellent linearities with r2≥ 0.9968 for all analytes were achieved, limits of detection were less than or equal to 5.0ng/mL, average recoveries were 92.5% to 115.0% in different samples. The new procedure is simple, fast, low cost, environmentally friendly and high EF, it can also be applied to the concentration and enrichment of the trace flavonoids in other complex matrixes.

Insecticidal effects of aqueous extracts of wild pomegranate peel and seed (Punica granatum L.) against rose aphids, Macrosiphum rosaeformis

Efficacy of wild pomegranate (Punica granatum Linn.) fruit peel and seeds aqueous extract was evaluated for the control of common insect pests aphids (Macrosiphum rosaeformis) and for its influence on useful non-target predators viz., Coccinella septempunctata. Lethal doses of daru peel and seed suggested these became more toxic to aphids after 24 hr of exposure. A significant difference was obtained in percentage aphids reached to untreated leaves over peel extract treated leaves (23:57 and 23:77) and seed extract treated leaves (7:80 and 17:80) at 90 and 180 min time intervals in food choice assays. No significant effect was observed against Coccinella. LC50 values of daru peel and seed extracts along with mixture of three flavonoids (Kaempferol, Quercetin and Myricetin) were assessed at 48 hr values were 34.9, 4.7 and 0.6 mg/ml and at 72 hr these were 16.1, 0.000001 and 0.00001 mg/ml, respectively. In both the cases field bioassays showed affectivity till 7 DAT. Field data indicated that only X1(1 mg/ml) and X2 (0.1 mg/ml) concentrations of mixture were effective till 11 days after treatment. These are the first reports of the toxic effect of wild pomegranate (daru) fruit peel aqueous extract against M. rosaeformis, hence the study suggests possible usage of Punica granatum peel for the control of rose aphids.

Effect of plant secondary metabolites on common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

AbstractThe effect of various flavonoids, lectins and phenyl β‐D‐glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione‐S‐transferase) enzymes of Spodoptera litura larvae at 7 days after treatment was studied through diet incorporation assay. Flavonoids (rutin, chlorogenic acid, quinic acid, caffeic acid, naringenin, quercitin, kaempferol, myricetin, catechin, and ferulic acid) were incorporated in artificial diet at 100, 500 and 1000 ppm, lectins: groundnut leaf lectin (GLL), concavalin A (ConA) and phenyl β‐D‐glucoside at 1, 2 and 5 μg/mL. Flavonoids such as rutin, quercitin and kaempferol at 1000 ppm were more toxic to S. litura larvae than quinic acid, caffeic acid, naringenin, myricetin, catechin, and ferulic acid. Larval growth and development were significantly reduced in S. litura larvae fed on a diet with GLL and ConA at 5 μg/mL compared to the larvae fed at 2 and 1 μg/mL concentrations. The larvae fed on flavonoid‐treated diets showed significant reduction in serine protease, trypsin and esterase activities. The flavonoids such as rutin, chlorogenic acid, quinic acid, naringenin, quercitin, kaempferol and myricetin, and lectins, GLL and ConA can be utilized in insect control programs.

Dynamic changes of flavonoids in Abelmoschus manihot different organs at different growth periods by UPLC-MS/MS.

Abelmoschus manihot (Linn.) Medicus has been clinically used to treat chronic kidney disease, oral ulcers, burns, and dysmenorrhea in China for many centuries. The major pharmacologically-active components of A. manihot are flavonoids. In this study, a rapid and highly sensitive UPLC-MS/MS analysis method was established and successfully applied to the simultaneous determination of five major flavonoids (rutin, hyperoside, isoquercitrin, quercetin, and myricetin) in different parts of A. manihot harvested at ten growth periods. Under the optimized chromatographic conditions, good separation for five target components was obtained on an Acquity UPLC BEH C18 column within 18min. The total contents of the five investigated flavonoids in A. manihot roots, stems, leaves and flowers ranged from 2.86 to 123.7μg/g, 46.39 to 141.0μg/g, 929.4 to 3096μg/g, and 10,150 to 19,390μg/g, respectively, indicating that the total flavonoids in the four parts could be mainly arranged in a decreasing order as flower>leaf>stem>root. The peak of total flavonoids in flowers and leaves appeared at G8 and G9, respectively. These results will be helpful for the determination of the suitable harvest time of A. manihot and the improvement of the utility value of the disused parts.

Correlation of binding efficacies of DNA to flavonoids and their induced cellular damage

Flavonoids are dietary intakes which are bestowed with several health benefits. The most studied property of flavonoids is their antioxidant efficacy. Among the chosen flavonoids Quercetin, Kaempferol and Myricetin is catagorized as flavonols whereas Apigenin and Luteolin belong to the flavone group. In the present study anti-cancer properties of flavonoids are investigated on the basis of their binding efficacy to ct-DNA and their ability to induce cytotoxicity in K562 leukaemic cells. The binding affinities of the flavonoids with calf thymus DNA (ct-DNA) are in the order Quercetin>Myricetin>Luteolin>Kaempferol>Apigenin. Quercetin with fewer OH than myricetin has higher affinity towards DNA suggesting that the number and position of OH influence the binding efficacies of flavonoids to ct-DNA. CD spectra and EtBr displacement studies evidence myricetin and apigenin to be stronger intercalators of DNA compared to quercetin. From comet assay results it is observed that quercetin and myricetin when used in combination induce higher DNA damage in K562 leukemic cells than when tested individually. Higher binding efficacy has been recorded for quercetin to DNA at lower pH, which is the micro environment of cancerous cells, and hence quercetin can act as a potential anti-cancer agent. Presence of Cu also increases cellular damage as recorded by comet assay.