Production Of Quercetin Research Articles

Effects of different postharvest drying processes on flavonoid content and enzymatic activity of Styphnolobium japonicum (L.) Schott flowers for industrial and medicinal use

Traditionally, fresh S. japonicum flowers (SJF) and S. japonicum flowers buds (SJFB) are dried prior to further processing and use. Here, we investigated the ways in which drying techniques, including sun drying (SD), steam drying (STD), microwave drying (MD), hot air drying (HAD, 40 °C, 60 °C, 80 °C, 100 °C), and freeze drying (FD), alter the flavonoid composition of freshly-harvested SJF and SJFB. The flavonoid content of dried samples was determined by Ultra High Performance Liquid Chromatography-Diode Array Detector (UPLC-DAD). Overall, different drying techniques had significantly different effects on the RU content, ranging from 10.63 % (HAD-80 °C) to 34.13 % (HAD-100 °C) in SJF and from 18.91 % (HAD-100 °C) to 29.16 % (HAD-40 °C) and 30.53 % (SD) in SJFB. To clarify the mechanism by which drying affects the RU content of S. japonicum flowers, we studied the activity of a rutin-hydrolyzing enzyme (RHE) isolated from SJF and SJFB using multiple separation and assay methods. According to the Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) results, the apparent molecular weight of the purified RHE was approximately 38 kDa. According to UPLC-DAD, RHE catalyzes the production of quercetin (QU) from rutin (RU), but not from other flavonoid glycosides. Drying fresh SJF and SJFB at low and high temperatures can inhibit RHE activity and prevent RU hydrolysis. Therefore, subjecting freshly-harvest SJF to HAD-100 °C, and freshly-harvest SJFB to SD or HAD-40 °C, can greatly increase the RU content. In particular, HAD is viable for large-scale application due to its simplicity and industrial feasibility.

Overexpression of AtMYB12 transcription factor simultaneously enhances quercetin-dependent metabolites in radish callus

The study aimed to enhance quercetin production in radish by optimizing Agrobacterium tumefaciens-mediated in-planta transformation. This protocol involved infecting radish seed embryo axis with A. tumefaciens EHA105 strain carrying the 35S::AtMYB12. Radish seeds were infected with the Agrobacterium suspension (0.8 OD600) for 30 min, followed by sonication for 60 s and vacuum infiltration for 90 s at 100 mm Hg. A 3-day co-cultivation in Murashige and Skoog medium with 150 μM acetosyringone yielded a transformation efficiency of 59.6% and a transgenic callus induction rate of 32.3%. Transgenic plant and callus lines were confirmed by GUS histochemical assay, PCR, and qRT-PCR. The transgenic lines showed an increased expression of flavonoid pathway genes (AtMYB12, CHS, F3H, and FLS) and antioxidant genes (GPX, APX, CAT, and SOD) compared to WT plants. Overexpression of AtMYB12 in transgenic callus increased enzyme activity of phenylalanine ammonia lyase, catalase, and ascorbate peroxidase. In half-strength MS medium with 116.8 mM sucrose, the highest growth index (7.63) was achieved after 20 days. In AtMYB12 overexpressed callus lines, phenolic content (357.31 mg g−1 dry weight), flavonoid content (463 mg g−1 dry weight), and quercetin content (48.24 mg g−1 dry weight) increased significantly by 9.41-fold. Micro-wounding, sonication, and vacuum infiltration improved in-planta transformation in radishes. These high-quercetin-content transgenic callus lines hold promise as valuable sources of flavonoids.

Reaction Pathways of Oxidative Transformation of the Radioprotector Quercetin

Quercetin is one of the most promising natural polyphenolic radioprotective compounds. This property is based on its radical-scavenging activity and high antioxidant capacity, in the manifestation of which the products of oxidative degradation of quercetin play a significant role. The formation of specific metabolites during the oxidation of quercetin can determine not only its radioprotective properties, but also toxic manifestations. The purpose of this article is to summarize previously obtained data regarding the reaction pathways of oxidative transformation of quercetin. Materials and methods. We used publicly available scientific publications dedicated to the study of quercetin transformation processes. The method of analysis is descriptive. The discussion of the results. A review of scientific works dedicated to oxygen oxidation, radical-initiated oxidation, electrochemical and enzymatic oxidation is presented, possible transformation products of quercetin and the mechanisms of their formation are given. The most characteristic oxidation pathways of quercetin are determined by the chemical structure of the rings, which exhibit specific reactivity. The influence of the solvent composition on the oxidation products during the autoxidation of quercetin was revealed, while the radical and electrochemical models of oxidation differ in the presence of polymer adducts. Once in a living organism, quercetin can bind free radicals, thereby preventing the harmful effects of radiation, that is, it has the properties of a radioprotector. Conclusions. Quercetin can be considered as a potential radioprotector due to its ability to bind free radicals formed in the biological fluids of living organisms exposed to radiation.

Effects of Low-Dose Kinetin, 2,4-D and Monochromatic Light Conditions on Flavonoid Content in Callus Culture of Dioscorea esculenta

The callus culture of Dioscorea esculenta is a potential strategy to produce efficacious bioactive compounds in multiplied production. It can be carried out by applying plant growth regulators (PGR) and environmental modification, including light-emitting diodes (LEDs) exposure. This study aims to investigate the impact of PGR and the stimulatory effect of LEDs on flavonoid profiles in D. esculenta callus culture. The study was conducted using combination variations of 2,4-D (0.5 and 1 ppm), kinetin (0.5 and 1 ppm), and LEDs stimulatory conditions (light and dark). The results showed that flavonoids are the dominant compounds found in lesser yam cultures, which reached more than 78 % in all treatments-specifically, adding 0.5 ppm kinetin and 0.5 ppm 2,4-D to D. esculenta callus cultures significantly increased flavonoids production compared to single PGR treatment. This shows there is a synergistic activity induced by 2,4-D and kinetin. Furthermore, monochromatic light exposure also significantly affects flavonoid production. Analysis of 5 main flavonoids, isoflavones, flavanones, kaempferols, quercetin, and epigallocatechin, proved that monochromatic light significantly increased flavonoids production compared to callus cultures were kept in a growth room under 24 °C temperature in the dark condition. This study confirmed that equally combining 0.5 ppm of 2,4-D and 0.5 ppm of kinetin under monochromatic LEDs increases flavonoid production in D. esculenta callus cultures. Further research must be conducted to describe how the bioactive compound synthesis signaling pathway involving PGR and monochromatic LEDs improves plant quality in the pharmaceuticals’ role. HIGHLIGHTS Kinetin and 2,4-D at the same concentration of 0.5 ppm is an optimal combination to increase secondary metabolite production in esculenta callus culture Combining kinetin and 2,4-D at low concentrations significantly increased flavonoids, especially kaempferol, isoflavone, quercetin, flavanone, and epigallocatechin in esculenta callus culture Light condition significantly affects the production of flavonoids, especially kaempferol, isoflavone, quercetin, flavanone, and epigallocatechin There is evidence that kinetin and 2,4-D under light conditions work in a synergic effect on the biosynthesis of secondary metabolite compounds in esculenta callus cultures GRAPHICAL ABSTRACT

Efficient regeneration of shoots and roots in graphene oxide and carbon nanotubes mediated callus cultures: A qualitative and quantitative study

The applications of nanomaterials have been assessed for the regeneration of plants and secondary metabolite content. The purpose of this study was to investigate the effects of carbon nanotubes and reduced graphene oxide nanosheets on callus cultures of Fagonia indica. We aimed to assess for the first time whether reduced graphene oxide and carbon nanotubes causes plant regeneration in the absence of plant growth regulators. The callus cultures of Fagonia indica were grown in Murashige and Skoog media enriched with different concentrations of nanomaterials to examine their effect on its regeneration, biomass accumulation, and phytochemical content. Morphological and biochemical responses are measured upon interaction with nanomaterials at different time periods. Results show that calli treated with the highest concentration of carbon nanotubes showed regeneration, while the media containing reduced graphene oxide induces regeneration of shoots and roots at all concentrations. Moreover, the callus growth and biomass accumulation were increased upon addition of both nanomaterials, but the significant results are obtained at low concentration (1 mg/L and 2 mg/L). The media containing carbon nanotubes at a concentration of 2 mg/L produced the maximum biomass yield (FW= 0.7914 g, DW= 0.067 g), whereas the media containing reduced graphene oxide at a concentration of 1 mg/L produced the lowest yield (FW= 6.02985 g, DW= 0.3405 g). The highest total phenolic and flavonoid content values are obtained at the highest concentration of nanomaterials. However, the callus treated with reduced graphene oxide showed increased total phenolic content (107.4 µg GAE/mL) and total flavonoid content (8.06 µg QE/mL) as compared to total phenolic content (32.3 µg GAE/mL) and total flavonoid content (7.11 µg Q/mL) observed in callus treated with carbon nanotubes. Further, the data from High-Performance Liquid Chromatography shows that carbon nanotubes alone have the potential to trigger the pathways of secondary metabolism while reduced graphene oxide triggers only the production of Quercetin and Gallic acid. This study gives the first evidence that the use of reduced graphene oxide gives better results than carbon nanotubes as an elicitor for inducing plant regeneration, biomass accumulation, and the in vitro biosynthesis of valuable secondary metabolites.

Dietary antioxidant quercetin overcomes the acquired resistance of Sorafenib in Sorafenib-resistant hepatocellular carcinoma cells through epidermal growth factor receptor signaling inactivation.

Sorafenib (SOR) is a molecular targeting agent commonly utilized as a primary treatment for advanced and inoperable hepatocellular carcinoma (HCC). Regrettably, the effectiveness of SOR is frequently hindered by the resistance of multiple HCC cases. The current investigation endeavors to examine the potential of the natural product quercetin (QUE) in reversing the acquired resistance of SOR-resistant cells, known as Huh7R, to SOR. Moreover, this study aims to elucidate the underlying molecular mechanism that contributes to this phenomenon. The results demonstrated that QUE significantly impeded proliferation and stimulated apoptosis in Huh7R cells, while also suppressing the growth of transplanted tumors. The impact of QUE enhanced the efficacy of SOR treatment for Huh7R. Additionally, bioinformatic and western blot analyses indicated that the underlying mechanisms may be associated with EGFR tyrosine kinase inhibitor resistance, the PI3K-AKT signaling pathway, and HCC. Furthermore, molecular docking and dynamics simulation assays revealed that QUE exhibited strong affinity and stability towards its hub targets, EGFR and AKT1. It is noteworthy that the activation of EGFR by its ligand, EGF, mitigated the effects of co-treatment with QUE and SOR. These findings suggest that QUE might potentially serve as a therapeutic agent in treating as well as facilitating SOR against Huh7R cells, which has substantial clinical and research implications for the treatment of acquired resistance to SOR in HCC.

Structure-specific metabolism of flavonol molecules by Bacillus subtilis var. natto BCRC 80517

Flavonols (3-hydroxy flavones) have been studied for their beneficial bioactivities for human health. Recently, we reported that a flavonoid phosphate synthetase (BsFPS) from Bacillus subtilis BCRC 80517 can transform several flavonoids into their phosphate conjugates, which become more water-soluble and thus increase the oral bioavailability. However, the in vivo metabolism of different flavonols has yet to be determined. Here, we investigated biotransformation of three flavonols (quercetin, kaempferol and fisetin) by B. subtilis BCRC 80517. C-ring cleavage products of quercetin and kaempferol, i.e., 2-protocatechuoyl-phloroglucinol carboxylic acid (2-PCPGCA), were produced, whereas two phosphate derivatives of fisetin (fisetin 4′-O-phosphate and fisetin 3′-O-phosphate) were generated by cultivation with B. subtilis BCRC 80517. Our results indicated that there are structure-specific metabolic pathways in B. subtilis toward different flavonols, where the 5-hydroxy group determines metabolic priority. Our findings provide new insights for developing bioproduction platform to produce flavonol phosphate derivatives for nutraceutical applications.

Optimizing yeast for high-level production of kaempferol and quercetin

BackgroundTwo important flavonoids, kaempferol and quercetin possess remarkably potent biological impacts on human health. However, their structural complexity and low abundance in nature make both bulk chemical synthesis and extraction from native plants difficult. Therefore microbial production via heterologous expression of plant enzymes can be a safe and sustainable route for their production. Despite several attempts reported in microbial hosts, the production levels of kaempferol and quercetin still stay far behind compared to many other microbial-produced flavonoids.ResultsIn this study, Saccharomyces cerevisiae was engineered for high production of kaempferol and quercetin in minimal media from glucose. First, the kaempferol biosynthetic pathway was reconstructed via screening various F3H and FLS enzymes. In addition, we demonstrated that amplification of the rate-limiting enzyme AtFLS could reduce the dihydrokaempferol accumulation and improve kaempferol production. Increasing the availability of precursor malonyl-CoA further improved the production of kaempferol and quercetin. Furthermore, the highest amount of 956 mg L− 1 of kaempferol and 930 mg L− 1 of quercetin in yeast was reached in fed-batch fermentations.ConclusionsDe novo biosynthesis of kaempferol and quercetin in yeast was improved through increasing the upstream naringenin biosynthesis and debugging the flux-limiting enzymes together with fed-batch fermentations, up to gram per liter level. Our work provides a promising platform for sustainable and scalable production of kaempferol, quercetin and compounds derived thereof.

Feasibility study of value-added production from onion peel agricultural wastes for circular economy

BackgroundAs a highly populated and resource-limited Taiwan, material recycling and reuse are of great importance to satisfy net-zero waste accumulation while simultaneously developing value-added production for circular economy. Herein, quercetin-rich onion peel wastes were chosen as a model to consider the technical feasibility of material recycling through fermentation. Pretreatment of onion peels extracts (OPEs) through frozen-preservation methods and serial acclimation via lactose-degrading bacteria was implemented for comparative optimization. MethodsOptimal extraction conditions (e.g., solvent, temperature of extraction, and frozen-preservation time) were first determined. Batch cultures of Lactobacillus sp. and Yogurt mixed consortia were implemented to maximize quercetin product formation using OPEs as sole nutrient sources via fermentation. Comparative assessment was performed by assessing total phenolic content, total quercetin content, and quercetin concentration. Microbial fuel cells were used to investigate time courses of electrochemical characteristics of residual OPEs during fermentation. Significant findingsComparative assessment revealed that OPEs could be optimized under extraction conditions of 50% ethanol as solvent, 75 °C extraction temperature, and frozen-preservation temperature of -20 °C. Yogurt mixed consortia yielded higher quercetin production that Lactobacillus sp. at 9 days fermentation. Phase-plane trajectories also revealed that using extracts frozen for 84 days at -20 °C through 9-day fermentation could achieve maximal quercetin production (ca. 1.5–1.75-fold compared to no fermentation). MFC results suggested that OPE fermentation was electrochemically favorable to enhance quercetin generation. Approximately two or three cycles of bacterial acclimation is sufficient to obtain maximal quercetin productivity and stable power-stimulating characteristics (ca. 1.35–1.5 fold power density amplification). To the best of our knowledge, this study was the first work to quantitatively decipher the most appropriate operation strategy for quercetin production from agricultural wastes (OPEs).

Phototoxic Potential of Different DNA Intercalators for Skin Cancer Therapy: In Vitro Screening.

Photodynamic therapy is a minimally invasive procedure used in the treatment of several diseases, including some types of cancer. It is based on photosensitizer molecules, which, in the presence of oxygen and light, lead to the formation of reactive oxygen species (ROS) and consequent cell death. The selection of the photosensitizer molecule is important for the therapy efficiency; therefore, many molecules such as dyes, natural products and metallic complexes have been investigated regarding their photosensitizing potential. In this work, the phototoxic potential of the DNA-intercalating molecules-the dyes methylene blue (MB), acridine orange (AO) and gentian violet (GV); the natural products curcumin (CUR), quercetin (QT) and epigallocatechin gallate (EGCG); and the chelating compounds neocuproine (NEO), 1,10-phenanthroline (PHE) and 2,2'-bipyridyl (BIPY)-were analyzed. The cytotoxicity of these chemicals was tested in vitro in non-cancer keratinocytes (HaCaT) and squamous cell carcinoma (MET1) cell lines. A phototoxicity assay and the detection of intracellular ROS were performed in MET1 cells. Results revealed that the IC50 values of the dyes and curcumin in MET1 cells were lower than 30 µM, while the values for the natural products QT and EGCG and the chelating agents BIPY and PHE were higher than 100 µM. The IC50 of MB and AO was greatly affected by irradiation when submitted to 640 nm and 457 nm light sources, respectively. ROS detection was more evident for cells treated with AO at low concentrations. In studies with the melanoma cell line WM983b, cells were more resistant to MB and AO and presented slightly higher IC50 values, in line with the results of the phototoxicity assays. This study reveals that many molecules can act as photosensitizers, but the effect depends on the cell line and the concentration of the chemical. Finally, significant photosensitizing activity of acridine orange at low concentrations and moderate light doses was demonstrated.

Production of podophyllotoxin, kaempferol and quercetin in callogenesis of Dysosma versipellis — an endangered medicinal plant

• Dysosma versipellis is an endangered medicinal herb found in southwest regions of China. • Callus initiation was achieved in B5 salts with 2 mg/L 2,4-D, and 0.2 mg/L kinetin under complete darkness. • The maximum callus biomass proliferation was obtained on B5 basal salts supplemented with 2 mg/L 2,4-D. • Leaf callus showed maximum production of podophyllotoxin, kaempferol and quercetin than that of control. • UPLC analysis revealed that roots and rhizomes were the primary source of secondary compounds accumulation. Dysosma versipellis is an endangered medicinal herb found in southwest regions of China. It has long been used in Traditional Chinese Medicine for general remedies in China. This herb is commonly used as an alternative to Podophyllum species. The large-scale removal of D. versipellis rhizomes from natural habitat continues at higher rates than natural regeneration. This study reports the callus induction from D. versipellis explants, callus proliferation and production of tumor inhibitory compounds such as podophyllotoxin, kaempferol and quercetin. The results revealed that tender leaves of D. versipellis exhibited the highest callus induction efficiency of 86% than other explants tested. The best callus initiation was obtained in Gamborg's medium (B5) augmented with 2 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), 0.2 mg/L kinetin, 3% sucrose, 0.1% activated charcoal and 0.7% agar and incubated under complete darkness. The maximum callus biomass proliferation was obtained on B5 basal salts supplemented with 2 mg/L 2, 4-D. The UPLC analysis of leaf callus showed maximum production of podophyllotoxin, kaempferol and quercetin than that of control callus. Furthermore, analysis of whole plant parts for their secondary compounds found roots and rhizomes were the primary source of secondary compounds accumulation. Therefore, this bioactive-enriched callus biomass protocol may be used as a possible technique for sustainable production of podophyllotoxin, kaempferol and quercetin at commercial scale.

Fast and selective production of quercetin and saccharides from rutin using microwave-assisted hydrothermal treatment in the presence of graphene oxide

Rutin is a flavonoid glycoside, well-known for its antioxidant, anticarcinogenic, and cardioprotective properties. However, it exhibits lower bio absorptivity and bioactivity than its aglycon form, quercetin. Although liquid acid catalysts are conventionally utilized to obtain quercetin via rutin hydrolysis, the neutralization procedure is a major disadvantage owing to the added cost. In this study, graphene oxide (GO) was used as an alternative catalyst under microwave (MW) irradiation, owing to its easy separation from the reaction solution and high MW absorptivity, resulting in improved thermal efficiency. Two types of GOs were prepared (GO-HU using Hummer’s method and GO-TO using Tour’s method), and their catalytic performance for rutin hydrolysis was evaluated and compared. The highest rutin conversion (98.8 %) and quercetin yield (81.9 %) were obtained at 180 °C when the reaction was conducted for 15 min using 3 mg of GO-TO and 2400 ppm of initial rutin concentration in 50 mL of water.

Distinctive sensing nanotool for free and nanoencapsulated quercetin discrimination based on S,N co-doped graphene dots

A selective and sensitive fluorescent nanoprobe (sulfur and nitrogen co-doped graphene quantum dots, S,N-GQDs) was designed for both detection and discrimination between free and quercetin-loaded nanoemulsion in food samples of diverse nature. Quercetin nanoemulsions (Q-NEs) were synthesized by a phase inversion temperature (PIT) procedure, while S,N-GQDs were synthesized using a bottom-up methodology by means of simple hydrothermal treatment of citric acid and cysteamine. Both synthetized nanomaterials (analyte and fluorescent probe), were carefully characterized through advanced spectroscopic and high-resolution microscopic techniques. It was observed that fluorescence intensity of S,N-GQDs could be markedly and distinctively quenched by the addition of both quercetin forms through inner filter effect (IFE) mechanisms, exhibiting static quenching events for free quercetin and Q-NEs but with a characteristic 13 nm red-shift spectra in presence of Q-NEs. Linear dynamic ranges between 0.05 and 10 mg L−1 and 0.025–70 mg L−1, with detection limits of 17 and 8 μg L−1 were revealed for free and nanoquercetin, respectively. After nanostructural and physic-chemical optimization, the discrimination strategy was metrologically validated and applied to nutraceutical supplements containing nanoencapsulated quercetin and on diverse free quercetin products such as onion peels and dietary supplements. Accuracy and reliability were proved by means of a statistical comparison with the results obtained by a μHPLC-DAD method (paired Student's t-test at 95% confidence level). The method provides the exciting prospect of analyzing new designed nanoencapsulated bioactives without altering their native nanostructure, as well as being able to accomplish the challenge to distinguish between both forms of quercetin.

Byproduct from Triphala Extraction as Tannin and Rutin Sources for Production of Gallic Acid, Isoquercetin and Quercetin by Solid-State Fermentation

Byproduct from Triphala Extraction as Tannin and Rutin Sources for Production of Gallic Acid, Isoquercetin and Quercetin by Solid-State Fermentation

Effect of Light Quality and Media Components on Shoot Growth, Rutin, and Quercetin Production from Common Buckwheat.

Common buckwheat (Fagopyrum esculentum Moench) seeds are important nutritious grains that are widely spread in several human food products and livestock feed. Their health benefits are mainly due to their bioactive phenolic compounds, especially rutin and quercetin, which have a positive impact on heart health, weight loss, and diabetes management. In this study, we evaluated different media and light treatments for the in vitro cultures of common buckwheat (CB) in order to find the most optimum one producing the highest yield with the highest purity of these compounds. The subcultured treated samples included in this study were shoots, leaves, stems, hairy roots, and calli. From the several treated samples and under different light stress conditions, the best production was achieved by growing the shoots of common buckwheat in hormone-free media containing activated charcoal and exposing to blue light, attaining 4.3 mg and 7.0 mg/g of extracts of rutin and quercetin, respectively, compared to 3.7 mg of rutin/g of extract and traces of quercetin in the seeds of CB. Continuous multiplication of CB shoots in the media containing charcoal and different concentrations of kinetin produced an extract with 161 mg/g of rutin and 26 mg/g of quercetin with an almost 20-fold increase in rutin content. The rutin content under these conditions reached up to 16% w/w of the extract. The hairy root cultures of the leaves exposed to red light showed a significantly high yield of quercetin attaining 10 mg/g of extract. Large-scale production of CB shootlets under the best conditions were carried out, which enabled the isolation of pure quercetin and rutin using a simple chromatographic procedure. The identity and purity of the isolated compounds were confirmed through NMR and HPLC analyses.

Stability of quercetin in DMEM and cell culture with A549 cells

AbstractQuercetin is evidently unstable in Dulbecco's modified Eagle's medium (DMEM) at 37°C. However, the underlying mechanism of this instability is not clear yet. The stability and new degradation products of quercetin in DMEM at 37°C were investigated via in UPLC‐MS‐MS analysis. With increasing incubation time, quercetin formed various degradation products derived from its dimer and there were numerous isomers formed during this process. Ascorbic acid significantly improved the stability of quercetin by protecting quercetin from auto‐oxidation in this medium. Ascorbic acid also remarkably enhanced the stability of quercetin in DMEM in the presence of A549 cells and obviously increased the antiproliferative effect of quercetin toward A549 cells.

Recent advances on the stability of dietary polyphenols

Recent advances on the stability of dietary polyphenols

Hydrolyzed Flavonoids from Cyrtosperma johnstonii with Superior Antioxidant, Antiproliferative, and Anti-Inflammatory Potential for Cancer Prevention.

Cyrtosperma johnstonii is one of the most interesting traditional medicines for cancer treatment. This study aimed to compare and combine the biological activities related to cancer prevention of the flavonoid glycosides rutin (RT) and isorhamnetin-3-o-rutinoside (IRR) and their hydrolysis products quercetin (QT) and isorhamnetin (IR) from C. johnstonii extract. ABTS and MTT assays were used to determine antioxidant activity and cytotoxicity against various cancer cells, as well as normal cells. Anti-inflammatory activities were measured by ELISA. The results showed that the antioxidant activities of the compounds decreased in the order of QT > IR > RT > IRR, while most leukemia cell lines were sensitive to QT and IR with low toxicity towards PBMCs. The reduction of IL-6 and IL-10 secretion by QT and IR was higher than that induced by RT and IRR. The combination of hydrolysis products (QT and IR) possessed a strong synergism in antioxidant, antiproliferative and anti-inflammatory effects, whereas the combination of flavonoid glycosides and their hydrolysis products revealed antagonism. These results suggest that the potential of the combination of hydrolyzed flavonoids from C. johnstonii can be considered as natural compounds for the prevention of cancer.

Gene Expression and Metabolic Analyses of Nontransgenic and AtPAP1 Transgenic Tobacco Infected with Potato Virus X (PVX).

Potato virus X (PVX), a species of the genus Potexvirus, is a plant pathogenic virus that causes severe symptoms such as mild mosaic, crinkling, necrosis, and mottling on leaves. The objectives of the present study were to investigate the effect of PVX virus infection on the metabolic system in nontransgenic and Arabidopsis thaliana production of anthocyanin pigment 1 (AtPAP1) transgenic tobacco using transcript expression analysis and metabolic profiling. Potato virus X inoculation increased the gene expression of phenylpropanoid and flavonoid biosynthesis and the production of chlorogenic acid, p-coumaric acid, benzoic acid, rutin, quercetin, and kaempferol in nontransgenic tobacco leaves. However, in the AtPAP1 transgenic tobacco leaves, PVX inoculation decreased the expression of AtPAP1 and phenylpropanoid and flavonoid biosynthesis genes, and the production of phenolics and anthocyanin also declined. In contrast, the levels of amino acids and tricarboxylic acid (TCA) cycle intermediates increased after infection in the AtPAP1 transgenic plant leaves. To date, these results have not been reported previously. We suggest that PVX infection decreases AtPAP1 expression, leading to the downregulation of phenylpropanoid and flavonoid biosynthesis in transgenic plants.

Polyamine Elicitation of Quercetin and Rutin Production in Callus Cultures of Caper and Impact to Regeneration

Nowadays, efforts to produce high amounts of secondary metabolites with anticancer properties in plants have become remarkable studies of biotechnological approaches. Polyamines are known to have successful roles in plant metabolism and molecular signalling. The important point is to determine the type and concentration of polyamine suitable for the physiology of the plant. This study was carried out to examine the effects of different polyamine applications in callus culture of Caper (Capparis L.) plant on plant regeneration and the production of quercetin and rutin with anticancer properties. For this purpose, different varieties (spermine, spermidine, and putrescine) and concentrations (0.0, 0.5, and 1.0 mg/l) of polyamines and 2.0 mg/l 6-benzylaminopurine (BAP) and 1.0 mg/l α-naphthaleneacetic acid (NAA) of plant growth regulators were added to the Murashige and Skoog (MS) culture medium. According to the results, the highest value in terms of callus induction was determined in 1.0 mg/l spermine, the highest value in plant regeneration was obtained in 0.5 mg/l spermine, and the highest quercetin and rutin accumulation were detected in 0.5 mg/l spermidine application. The regeneration and the amount of quercetin increased approximately 2-fold compared to the control group in the aforementioned polyamine (PA) applications. Our findings showed that spermine and spermidine proved more effective in the callus culture of Caper than putrescine, and the use of low-dose polyamines gave outstanding results. Therefore a particularly valuable finding obtained in this study is that polyamines can be used as an effective elicitor in the tissue culture of Caper plant.