(+)-methyl jasmonate-induced bioformation of myricetin, quercetin and kaempferol in red raspberries

Flavonoids: A treasure house of prospective pharmacological potentials

Flavonoids are organic compounds characterized by a range of phenolic structures, which are abundantly present in various natural sources such as fruits, vegetables, cereals, bark, roots, stems, flowers, tea, and wine. The health advantages of these natural substances are renowned, and initiatives are being taken to extract the flavonoids. Apigenin, galangin, hesperetin, kaempferol, myricetin, naringenin, and quercetin are the seven most common compounds belonging to this class. A thorough analysis of bibliographic records from reliable sources including Google Scholar, Web of Science, PubMed, ScienceDirect, MEDLINE, and others was done to learn more about the biological activities of these flavonoids. These flavonoids appear to have promising anti-diabetic, anti-inflammatory, antibacterial, antioxidant, antiviral, cytotoxic, and lipid-lowering activities, according to evidence from in vitro, in vivo, and clinical research. The review contains recent trends, therapeutical interventions, and futuristic aspects of flavonoids to treat several diseases like diabetes, inflammation, bacterial and viral infections, cancers, and cardiovascular diseases. However, this manuscript should be handy in future drug discovery. Despite these encouraging findings, a notable gap exists in clinical research, hindering a comprehensive understanding of the effects of flavonoids at both high and low concentrations on human health. Future investigations should prioritize exploring bioavailability, given the potential for high inter-individual variation. As a starting point for further study on these flavonoids, this review paper may promote identifying and creating innovative therapeutic uses.

Melatonin enhanced oilseed rape growth and mitigated Cd stress risk: A novel trial for reducing Cd accumulation by bioenergy crops

Melatonin (M) is a pleiotropic molecule that improves plant growth and increases heavy metal tolerance. The role of M for improving plant growth and tolerance under cadmium (Cd) stress, and mitigation of Cd-induced toxicity has not yet been sufficiently examined. Therefore, here we conducted a glasshouse experiment to explore the influence of various M dosages on Cd detoxification and stress-tolerance responses of Brassica napus under high Cd content (30 mg kg^-1). The effects of M on the modulation of Cd tolerance in B. napus plants have been investigated using various growth attributes, Cd accumulation and tolerance indices, and secondary metabolic parameters. We found that Cd stress inhibited root growth (by 11.9%) as well as triggered reactive oxygen species accumulation (by 31.2%) and MDA levels (by 18.7%); however, exogenous M substantially alleviated the adverse effect of oxidative stress by decreasing levels of H₂O₂ (by 38.7%), MDA (by 13.8%) and EL (by 1.8%) in the Cd-stressed plants, as compared to the M-untreated plants (control). Interestingly, exogenous M reduced Cd accumulation in roots (∼48.2-58.3-fold), stem (∼2.9-5.0-fold) and leaves (∼4.7-6.6-fold) compared to control plants, which might be due to an M-induced defense and/or detoxification response involving a battery of antioxidants. Overall, addition of the exogenous M to the Cd-stressed plants profoundly enhanced Cd tolerance in B. napus relative to control plants. These results suggested the biostimulatory role (at the physiological and molecular level) of M in improving growth, Cd tolerance, and Cd detoxification in B. napus, which indicate the potentiality of M for green remediation of Cd contaminated soils. This green trial would provide a reference for producing renewable bioenergy crops under Cd stress in contaminated soils. However, these recommendations should be verified under field conditions and the potential mechanisms for the interaction between Cd and M should be explicitly explored.

Effects of exogenous methyl jasmonate on quality and preservation of postharvest fruits: A review

Methyl jasmonate (MeJA) is a volatile hormone involved in a number of plant processes, acting as a signal in response to external stresses and modulating the biosynthesis of other phytohormones. Here, we are reviewing for the first time all reports related to the effects of exogenous MeJA on postharvest fruits. Application of MeJA during preharvest and postharvest stages has been demonstrated to enhance fruit antioxidant capacity and phenolics content, which in turn extended fruit shelf-life, enhanced fruit quality and reduced chilling injury. The postharvest application of MeJA has been reported to alter volatiles pattern and to enhance the innate disease resistance of postharvest fruits against pathogenic fungi. The results obtained using different treatment conditions, such as temperature, storage time and concentration, have been highlighted and compared along the manuscript in order to provide new insights on the applicability of MeJA for enhancing postharvest fruit quality and preservation.

Cloning and molecular characterization of rutin degrading enzyme from tartary buckwheat (Fagopyrum tataricum Gaertn.)

Rutin and quercetin, abundant in tartary buckwheat, have physiological and pharmacological functions and play roles in abiotic stress tolerance in plant. Rutin degrading enzymes (RDE) are the key enzymes for rutin metabolism. However, the RDE coding sequence information has not been available. In this study, a 1515-bp coding sequence of RDE was cloned from tartary buckwheat (named FtRDE) using 5' and 3' RACE, based on the FtRDE protein sequence. The recombinant RDE (rRDE) expressed in P.pastoris with glycosylation modification degraded rutin into quercetin and the Glu171 and Glu382 were indispensable residues for catalytic activity. FtRDE was highly expressed in seed filling stage and response to ABA and MeJA, confirmed by qRT-PCR and FtRDE promoter activity analysis in mesophyll protoplast. This study provided a new approach for the large-scale preparation of RDE by heterologous expression and production of quercetin by hydrolyzing rutin, and could be helpful for understanding the FtRDE function under stress conditions.

Ornithine decarboxylase is involved in methyl jasmonate-regulated postharvest quality retention in button mushrooms (Agaricus bisporus)

BACKGROUND

In the present study, we investigated the role of ornithine decarboxylase (ODC) in the methyl jasmonate (MeJA)-regulated postharvest quality maintenance of Agaricus bisporus (J. E. Kange) Imbach button mushrooms by pretreating mushrooms with a specific irreversible inhibitor called α-difluoromethylornithine (DFMO) before exposure to MeJA vapor.

RESULTS

Mushrooms were treated with 0 or 100 µmol L^-1 MeJA or a combination of 120 µmol L^-1 DFMO and 100 µmol L^-1 MeJA, respectively, before storage at 4 °C for 21 days. Treatment with MeJA alone induced the increase in ODC activity whereas this effect was greatly suppressed by pretreatment with DFMO. α-Difluoromethylornithine strongly attenuated the effect of MeJA on decreasing cap opening, slowing the decline rate of soluble protein and total sugar, and accumulating total phenolics and flavonoids. α-Difluoromethylornithine pretreatment also counteracted the ability of MeJA to inhibit polyphenol oxidase and lipoxygenase activities, and malondialdehyde production, and to stimulate superoxide dismutase and catalase activities. It also largely downregulated MeJA-induced accumulation of free putrescine (Put).

CONCLUSION

These results reveal that ODC is involved in MeJA-regulated postharvest quality retention of button mushrooms, and this involvement is likely to be associated with Put levels. © 2018 Society of Chemical Industry.

Separating and Identifying the Four Stereoisomers of Methyl Jasmonate by RP-HPLC and using Cyclodextrins in a Novel Way

INTRODUCTION

Several authors have reported on the different bioactivities of methyl jasmonate (MeJA) stereoisomers. However, no simple, precise and cheap method for separating and identifying them using reversed-phase high performance liquid chromatography (RP-HPLC) has been developed.

OBJECTIVE

(1) To create a simple, precise and cheap method for separating and identifying the four stereoisomers present in commercial racemic mixtures of MeJA and (2) to identify the four stereoisomers using molecular docking techniques and coinjection. Materials and Methods - RP-HPLC using a 250 mm C18 column and different proportions of cyclodextrins (CDs) and organic solvents was applied to a commercial sample of racemic MeJA.

RESULTS

The results show that the best conditions for separating the MeJA stereoisomers are: 20% methanol in the mobile phase, a temperature of 45 °C and a 16 mM concentration of methyl-β-cyclodextrin (M-β-CD). A simple C18 250 mm column and a flow rate of 1.25 mL/min were used. The reduction in the retention time of MeJA observed when M-β-CD is added to the mobile phases was used to determine the complexation constants of the guest/CD complex and compared with the obtained when other CDs were used. The K_F for M-β-CD (117.49 ± 5.9 1/M) was obtained with a 1:1 stoichiometry. The four stereoisomers were identified by molecular docking techniques and coinjection of a commercially available rosemary essential oil.

CONCLUSION

The new method identified and classified the four stereoisomers of MeJA in the following ordination: (-)epiMeJA, (-)MeJA; (+)MeJA and (+)epiMeJA. These results could be used to improve the elicitation of cell cultures with only the best isomer. Copyright © 2016 John Wiley & Sons, Ltd.

New Procedure to Obtain Polyphenol-Enriched Grapes Based on the Use of Chemical Elicitors

The effect of the postharvest treatment of methyl jasmonate enantiomers in conjunction with ethanol on bioformation of resveratrol and quercetin glycosides in grapes was evaluated. The antioxidant activity of treated grape extracts as compared with untreated extracts was also assayed. Exogenous (-)-methyl jasmonate in combination with ethanol induced a significant increase in the levels of resveratrol (from 27 to 39 μg g(-1)), quercetin-3-O-glucoside (from 59 to 136 μg g(-1)), quercetin-3-O-galactoside (from 398 to 807 μg g(-1)) and quercetin-3-O-rutinoside (from 23 to 43 μg g(-1)). (+)-Methyl jasmonate with ethanol also resulted in increase of quercetin-3-O-glucoside and quercetin-3-O-rutinoside. However, no (+)-methyl jasmonate effect was observed for resveratrol and quercetin-3-O-galactoside. Both (-)- and (+)-methyl jasmonate treatments provided with extracts with higher antioxidant activity. From the results found in the present work postharvest treatment with (-)-methyl jasmonate in conjunction with ethanol is proposed as a mean to obtain polyphenol-enriched grape extracts with improved antioxidant properties. The procedure here developed is proposed as a mean to obtain functional grapes. Extracts obtained from grapes treated with (-)-methyl jasmonate with ethanol can be particularly useful for industry due to their high antioxidant capacity.

Plant-growth regulators alter phytochemical constituents and pharmaceutical quality in Sweet potato (Ipomoea batatas L.)

Background

Sweet potato (Ipomoea batatas L.) is one of the most important consumed crops in many parts of the world because of its economic importance and content of health-promoting phytochemicals.

Methods

With the sweet potato (Ipomoea batatas L.) as our model, we investigated the exogenous effects of three plant-growth regulators methyl jasmonate (MeJA), salicylic acid (SA), and abscisic acid (ABA) on major phytochemicals in relation to phenylalanine ammonia lyase (PAL) activity. Specifically, we investigated the total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), and total β-carotene content (TCC). Individual phenolic and flavonoid compounds were identified using ultra-high performance liquid chromatography (UHPLC). Antioxidant activities of treated plants were evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and a β-carotene bleaching assay. Anticancer activity of extracts was evaluated against breast cancer cell lines (MCF-7 and MDA-MB-231) using MTT assay.

Results

TPC, TFC, TAC, and TCC and antioxidant activities were substantially increased in MeJA-, SA-, and ABA-treated plants. Among the secondary metabolites identified in this study, MeJA application significantly induced production of quercetin, kaempferol, myricetin, gallic acid, chlorogenic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid. Luteolin synthesis was significantly induced by SA application. Compared with control plants, MeJA-treated sweet potato exhibited the highest PAL activity, followed by SA and ABA treatment. The high DPPH activity was observed in MeJA followed by SA and ABA, with half-maximal inhibitory concentration (IC₅₀) values of 2.40, 3.0, and 3.40 mg/mL compared with α-tocopherol (1.1 mg/mL). Additionally, MeJA-treated sweet potato showed the highest β-carotene bleaching activity, with an IC₅₀ value of 2.90 mg/mL, followed by SA (3.30 mg/mL), ABA (3.70 mg/mL), and control plants (4.5 mg/mL). Extracts of sweet potato root treated with MeJA exhibited potent anticancer activity with IC₅₀ of 0.66 and 0.62 mg/mL against MDA-MB-231 and MCF-7 cell lines respectively, compared to that of extracts of sweet potato treated with SA (MDA-MB-231 = 0.78 mg/mL; MCF-7 = 0.90 mg/mL) and ABA (MDA-MB-231 = 0.94 mg/mL; MCF-7 = 1.40 mg/mL). The results of correlation analysis showed that anthocyanins and flavooids are corresponding compounds in sweet potato root extracts for anticancer activity against breast cancer cell lines.

Conclusions

MeJA has great potential to enhance the production of important health-promoting phytochemicals in sweet potato.

Physicochemical and thermodynamic characterization of the encapsulation of methyl jasmonate by natural and modified cyclodextrins using reversed-phase high-pressure liquid chromatography

Although the combinations of methyl jasmonate (MeJA) and cyclodextrins (CDs) have been used by different authors to stimulate the production of several metabolites, no study has been published about the possible formation of MeJA-CD complexes when these two molecules are added together to the reaction medium as elicitors. For this reason and because knowledge of the possible complexation process of MeJA with CD under different physicochemical conditions is essential if these two molecules are to be used in cell cultures, this paper looks at the complexation of MeJA with natural and modified CDs using a reversed-phase high-pressure liquid chromatography (RP-HPLC) system. The interaction of MeJA with β-CD was more efficient than with α- and γ-CDs. However, a modified CD, HP-β-CD, was the most effective of all of the CDs tested. Moreover, MeJA formed complexes with CD with a 1:1 stoichiometry, and the formation constants of these complexes were strongly dependent upon the temperature of the mobile phase used but not the pH. To obtain information about the mechanism of the affinity of MeJA for CD, the thermodynamic parameters ΔG°, ΔH°, and ΔS° were calculated. Finally, molecular modeling studies were carried out to propose which molecular interactions are established in the complexation process.

Adsorption chromatography separation of the flavonols kaempferol, quercetin and myricetin using cross-linked collagen fibre as the stationary phase

BACKGROUND

Kaempferol, quercetin and myricetin are typical flavonols that are most concentrated in many medicinal herbs. However, the separation of these flavonols is very challenging due to their similar molecular structures. In the present investigation, the chromatographic separation of the flavonols kaempferol, quercetin and myricetin was performed using glutaraldehyde cross-linked collagen fibre (GCF) as the stationary phase.

RESULTS

Kaempferol, quercetin and myricetin could be completely separated from each other by the GCF column by using gradient elution with different solutions of aqueous ethanol (100% to 70%) and 50% acetone. When the chromatographic separation was carried out at a flow rate of 0.75 bed volume h(-1) with a sample loading of 30 mg 7 g(-1) GCF, the purity of kaempferol, quercetin and myricetin was 98.17%, 93.81% and 81.76%, respectively. The separation resolution was influenced by column length, flow rate and sample loading amount. The separation efficiency of GCF was not obviously reduced after applications had been repeated five times. In the fifth repeated application, the purity of the recovered kaempferol, quercetin and myricetin was still higher than 97%, 94% and 78%, respectively.

CONCLUSION

GCF is a promising adsorbent for use as a stationary phase in the chromatographic separation of flavonols from their mixtures.

Enhanced squalene production by wild-type Saccharomyces cerevisiae strains using safe chemical means

Interest is increasing in establishing renewable sources for squalene, a functional lipid, as the conventional ones are limited. In the present study, squalene production was achieved in a wild-type laboratory Saccharomyces cerevisiae strain by two safe chemical means using terbinafine (0.05-0.55 mM) and methyl jasmonate (MJ) (0-1.00 mM). Bioprocess kinetics optimized by response surface methodology and monitored by high-performance liquid chromatography revealed a clear dependence of growth and squalene content (SQC) and yield (SQY) on the above regulators. Maximum SQC (10.02±0.53 mg/g dry biomass) and SQY (20.70±1.00 mg/L) were achieved using 0.442 mM terbinafine plus 0.044 mM MJ after 28 h and 0.300 mM terbinafine after 30 h, respectively. A 10-fold increase in SQY was achieved in comparison to that in the absence of regulator. The ruggedness of optimum conditions for SQY was verified for five industrial strains. The cellular lipid fraction (∼12% of dry biomass) was rich in squalene (12-13%). Results are encouraging toward bioprocess scale up.