A new approach for achievement of inulin accumulation in suspension cultures of Jerusalem artichoke (Helianthus tuberosus) using biotic elicitors

Biotechnological processes to obtain bioactive secondary metabolites from some Mexican medicinal plants

The consumption of medicinal plants has increased in recent decades due to the fact that they biosynthesize compounds with many biological activities; thus, some plant species with biological potential are being utilized as raw material by the industries for preparation of drugs, phytodrugs, or food supplements. This has the consequence of overexploitation and deforestation, which endangers plant species-of-interest. In recent years, alternatives have been sought to eradicate this problem. A solution that was given and is maintained is plant biotechnology, which favors the production of secondary metabolites (SMt) with important biological activity. Plant biotechnology allows us to increase the yield of a compound-of-interest, reduces its production times and costs, and allows constant and controlled production of the raw material, while aiding in the protection of medicinal plants that are found in danger of extinction. In the scientific literature, procuring the SMt by means of biotechnological processes is described, highlighting the study of five species from Mexican traditional medicine (Lopezia racemosa, Galphimia glauca, Cnidoscolus chayamansa, and Buddleja cordata), and the main biological activities are as follows: anti-inflammatory, hepatoprotector, neuroprotector, anxiolytic, antitumoral, antibacterial, and antioxidant, among others. KEY POINTS: • Secondary metabolites produce by biotechnology processes • Active secondary metabolites isolated from Mexican medicinal plants • Recent advances on the production of some bioactive secondary metabolites.

Artichoke extracts in cancer therapy: do the extraction conditions affect the anticancer activity?

Background

Artichoke is an edible plant that is grown in the Mediterranean region and is known for its antimicrobial, antifungal, antibacterial, antioxidant and anticancer activities. Different artichoke extraction methods can impressively affect the nature as well as the yield of the extracted components.

Main body

The different methods of artichoke extraction and the influence of the extraction conditions on the extraction efficiency are summarized herein. In addition, cancer causalities and hallmarks together with the molecular mechanisms of artichoke active molecules in cancer treatment are also discussed. Moreover, a short background is given on the common types of cancer that can be treated with artichoke extracts as well as their pathogenesis. A brief discussion of the previous works devoted to the application of artichoke extracts in the treatment of these cancers is also given.

Conclusion

This review article covers the extraction methods, composition, utilization and applications of artichoke extracts in the treatment of different cancers.

Recent advances in bio-based multi-products of agricultural Jerusalem artichoke resources

The Jerusalem artichoke is a perennial plant that belongs to the sunflower family. As a non-grain crop, Jerusalem artichoke possesses a number of desirable characteristics that make it a valuable feedstock for biorefinery, such as inulin content, rapid growth, strong adaptability, and high yields. This review provides a comprehensive introduction to renewable Jerusalem artichoke-based biomass resources and recent advances in bio-based product conversion. Furthermore, we discuss the latest in the development of inulinase-producing microorganisms and enhanced inulin hydrolysis capacity of microbes by genetic engineering, which lead to a more cost-effective Jerusalem artichoke biorefinery. The review is aimed at promoting Jerusalem artichoke industry and new prospects for higher value-added production.

Simultaneous quantitative determination of 11 sesquiterpene lactones in Jerusalem artichoke (Helianthus tuberosus L.) leaves by ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry

A method of ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was developed for the simultaneous quantification of 11 sesquiterpene lactones in 11 Jerusalem artichoke leaf samples harvested in a number of areas at different periods. The optimal chromatographic conditions were achieved on a ZORBAX Eclipse Plus C₁₈ column (3.0 × 150 mm, 1.8 μm) with linear gradient elution of methanol and water in 8 min. Quantitative analysis was carried out under selective ion monitoring mode. All of the sesquiterpene lactones showed good linearity (R² ≥ 0.9949), repeatability (relative standard deviations < 4.66%), and intra- and interday precisions (relative standard deviations < 4.52%) with an accuracy of 95.24-104.84%. The recoveries measured at three concentration levels varied from 95.07 to 104.87% with relative standard deviations less than 4.9%. The limit of detection and limit of quantitation for this method were 0.89-5.05 and 1.12-44.33 ng/mL, respectively. The results showed that the contents of sesquiterpene lactones varied significantly in the Jerusalem artichoke leaf samples from different areas. Among them, the content of sesquiterpene lactones in the sample collected from Dalian, Liaoning province was the highest and the early flowering period was considered to be the optimal harvest time.

Elicitation of Jerusalem artichoke (Helianthus tuberosus L.) cell suspension culture for enhancement of inulin production and altered degree of polymerisation

BACKGROUND

Plant cell suspension cultures have emerged as a potential source of secondary metabolites for food additives and pharmaceuticals. In this study inulin accumulation and its degree of polymerisation (DP) in the treated cells in the same medium were investigated after treatment with six types of elicitors.

RESULTS

An in vitro cell suspension culture of Jerusalem artichoke (Helianthus tuberosus L.) was optimised by adding an extra nitrogen source. According to the growth kinetics, a maximum biomass of 5.48 g L^-1 was obtained from the optimal cell suspension medium consisted of Murashige and Skoog basic medium (MS) + 1.0 mg L^-1 α-naphthalene acetic acid (NAA) + 1.0 mg L^-1 6-benzylaminopurine (6-BA) + 0.5 mg L^-1 proline + 1.0 mg L^-1 glutamine. Methyl jasmonate (MeJA, 250 µmol L^-1 ) treatment for 15 days led to the highest levels of inulin (2955.27 ± 9.81 mg L^-1 compared to control of 1217.46 ± 0.26 mg L^-1 ). The elicited effect of five elicitors to the suspension cells of Jerusalem artichoke is as follows: AgNO₃ (Ag, 10 µmol L^-1 ), salicylic acid (SA, 75 µmol L^-1 ), chitosan (KJT, 40 mg L^-1 ), Trichoderma viride (Tv, 90 mg L^-1 ), yeast extract (YE, 0.25 mg L^-1 ), and the corresponding content of inulin is increased by 2.05-, 1.93-, 1.76-, 1.44- and 1.18-fold compared to control, respectively. The obvious effect on the percentage of lower DP in inulin was observed in cells treated with 40 mg L^-1 KJT, 0.25 mg L^-1 YE and 10 µmol L^-1 Ag.

CONCLUSIONS

Among the six types of elicitors, the descending order of inulin content is MeJA > Ag > SA > KJT > Tv > YE. For the purpose inulin with lower DP and its application to prebiotic food, three elicitors, including KJT, YE and Ag, can be used for the elicitation. © 2016 Society of Chemical Industry.

Separation and identification of candidate protein elicitors from the cultivation medium of Leptosphaeria maculans inducing resistance in Brassica napus

The Dothideomycete Leptosphaeria maculans, a worldwide fungal pathogen of oilseed rape (Brassica napus), secretes a broad spectrum of molecules into the cultivation medium during growth in vitro. Here, candidate elicitor molecules, which induce resistance in B. napus to L. maculans, were identified in the cultivation medium. The elicitation activity was indicated by increased transcription of pathogenesis-related gene 1 (PR1) and enhanced resistance of B. napus plants to the invasion of L. maculans. The elicitation activity was significantly lowered when the cultivation medium was heated to 80°C. Active components were further characterized by specific cleavage with the proteolytic enzymes trypsin and proteinase K and with glycosidases α-amylase and β-glucanase. The elicitor activity was eliminated by proteolytic digestion while glycosidases had no effect. The filtered medium was fractionated by either ion-exchange chromatography or isoelectric focusing. Mass spectrometry analysis of the most active fractions obtained by both separation procedures revealed predominantly enzymes that can be involved in the degradation of plant cell wall polysaccharides. This is the first study searching for L. maculans-specific secreted elicitors with a potential to be used as defense-activating agents in the protection of B. napus against L. maculans in agriculture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:918-928, 2016.

Effect of inulin on efficient production and regulatory biosynthesis of bacillomycin D in Bacillus subtilis fmbJ

The effect of inulin on the production of bacillomycin D and the levels of mRNA of bacillomycin D synthetase genes: bmyA (BYA), bmyB (BYB), bmyC (BYC), the thioesterase gene (TE) and regulating genes: AbrB, ComA, DegU, PhrC, SigmaH and Spo0A in Bacillus subtilis fmbJ were investigated. The production of bacillomycin D was enhanced with the increase of biomass concentration. The maximum production and productivity of bacillomycin D were found to be 1227.49 mg/L and 10.23 mg/L h. Inulin significantly improved the expression of bacillomycin D synthetase genes: bmyA (BYA), bmyB (BYB), bmyC (BYC) and the thioesterase gene (TE). Also, inulin up-regulated ComA, DegU, SigmaH and Spo0A and therefore promoted the high production of bacillomycin D. Our results provided a practical approach for efficient production of bacillomycin D and a meaningful explanation for regulatory mechanism of bacillomycin D biosynthesis.

RNA-seq analysis and de novo transcriptome assembly of Jerusalem artichoke (Helianthus tuberosus Linne)

Jerusalem artichoke (Helianthus tuberosus L.) has long been cultivated as a vegetable and as a source of fructans (inulin) for pharmaceutical applications in diabetes and obesity prevention. However, transcriptomic and genomic data for Jerusalem artichoke remain scarce. In this study, Illumina RNA sequencing (RNA-Seq) was performed on samples from Jerusalem artichoke leaves, roots, stems and two different tuber tissues (early and late tuber development). Data were used for de novo assembly and characterization of the transcriptome. In total 206,215,632 paired-end reads were generated. These were assembled into 66,322 loci with 272,548 transcripts. Loci were annotated by querying against the NCBI non-redundant, Phytozome and UniProt databases, and 40,215 loci were homologous to existing database sequences. Gene Ontology terms were assigned to 19,848 loci, 15,434 loci were matched to 25 Clusters of Eukaryotic Orthologous Groups classifications, and 11,844 loci were classified into 142 Kyoto Encyclopedia of Genes and Genomes pathways. The assembled loci also contained 10,778 potential simple sequence repeats. The newly assembled transcriptome was used to identify loci with tissue-specific differential expression patterns. In total, 670 loci exhibited tissue-specific expression, and a subset of these were confirmed using RT-PCR and qRT-PCR. Gene expression related to inulin biosynthesis in tuber tissue was also investigated. Exsiting genetic and genomic data for H. tuberosus are scarce. The sequence resources developed in this study will enable the analysis of thousands of transcripts and will thus accelerate marker-assisted breeding studies and studies of inulin biosynthesis in Jerusalem artichoke.

Medicinal plant cell suspension cultures: pharmaceutical applications and high-yielding strategies for the desired secondary metabolites

The development of plant tissue (including organ and cell) cultures for the production of secondary metabolites has been underway for more than three decades. Plant cell cultures with the production of high-value secondary metabolites are promising potential alternative sources for the production of pharmaceutical agents of industrial importance. Medicinal plant cell suspension cultures (MPCSC), which are characterized with the feature of fermentation with plant cell totipotency, could be a promising alternative "chemical factory". However, low productivity becomes an inevitable obstacle limiting further commercialization of MPCSC and the application to large-scale production is still limited to a few processes. This review generalizes and analyzes the recent progress of this bioproduction platform for the provision of medicinal chemicals and outlines a range of trials taken or underway to increase product yields from MPCSC. The scale-up of MPCSC, which could lead to an unlimited supply of pharmaceuticals, including strategies to overcome and solution of the associated challenges, is discussed.

Biotic elicitor enhanced production of psoralen in suspension cultures of Psoralea corylifolia L

Cell cultures of Psoralea corylifolia L. were established from the leaf disk derived callus. The effect of different biotic elicitors prepared from the fungal extract (Aspergillus niger and Penicillium notatum), yeast extract and chitosan with different concentrations was studied. The increased synthesis of psoralen in 16-day old cell cultures under 16 h of light and 8 h of dark period was studied. Elicitation of psoralen in A. niger elicitor treated cells was found 9-fold higher over control cells. Treating the cells with P. notatum, yeast extract and chitosan elicitors lead to four to seven-fold higher psoralen accumulation over control cells. The extract of A. niger at 1.0% v/v increased the significant accumulation of psoralen (9850 μg/g DCW) in the cultured cells. Our study clearly shows that all the elicitors had the potential to increase the accumulation of psoralen but the A. niger elicitor at 1.0% v/v induced maximum accumulation.