Anthraquinone Production Research Articles

Rational Construction of Cyanide-Functionalized D-A-π-D Covalent Organic Framework for Highly Efficient Overall H2O2 Photosynthesis from Air and Water.

Sacrificial-agent-free overall photosynthesis of H2O2 from water and air represents currently a promising route to reform the industrial anthraquinone production manner, but, still blocks by the requirement of pure O2 feedstock, due to the insufficient oxygen supply from water under air. Herein, we report a rational molecule design on COFs (covalent organic frameworks) equiped with cyanide-functionalized D-A-π-D system for highly efficient overall H2O2 production from air and water through photocatalytic oxygen reduction reactions (ORR) and water oxidation reaction (WOR). Without using any sacrificial agent, the as-synthesized D-A-π-D COF is found to enable a H2O2 production rate as high as 4742 μmol h-1 g-1 from water and air and an O2 utilization and conversion rate up to 88 %, exceeding the other D-A-π-A COF by respectively 1.9- and 1.3-fold. Such high performance is attributed to the tuned electronic structure and prolonged charge lifetime facilitated by the unique D-A-π-D structure and cyanide groups. This work highlights a fundamental molecule design on advanced photocatalytic COFs with complicated D-A system for low-cost and massive H2O2 production.

Rational Construction of Cyanide‐Functionalized D‐A‐π‐D Covalent Organic Framework for Highly Efficient Overall H2O2 Photosynthesis from Air and Water

Sacrificial‐agent‐free overall photosynthesis of H2O2 from water and air represents currently a promising route to reform the industrial anthraquinone production manner, but, still blocks by the requirement of pure O2 feedstock, due to the insufficient oxygen supply from water under air. Herein, we report a rational molecule design on COFs (covalent organic frameworks) equiped with cyanide‐functionalized D‐A‐π‐D system for highly efficient overall H2O2 production from air and water through photocatalytic oxygen reduction reactions (ORR) and water oxidation reaction (WOR). Without using any sacrificial agent, the as‐synthesized D‐A‐π‐D COF is found to enable a H2O2 production rate as high as 4742 μmol h‐1 g‐1 from water and air and an O2 utilization and conversion rate up to 88%, exceeding the other D‐A‐π‐A COF by respectively 1.9‐ and 1.3‐fold. Such high performance is attributed to the tuned electronic structure and prolonged charge lifetime facilitated by the unique D‐A‐π‐D structure and cyanide groups. This work highlights a fundamental molecule design on advanced photocatalytic COFs with complicated D‐A system for low‐cost and massive H2O2 production.

In silico prediction of polyketide biosynthetic gene clusters in the genomes of Hypericum-borne endophytic fungi

BackgroundThe search for new bioactive natural compounds with anticancer activity is still of great importance. Even though their potential for diagnostics and treatment of cancer has already been proved, the availability is still limited. Hypericin, a naphthodianthrone isolated essentially from plant source Hypericum perforatum L. along with other related anthraquinones and bisanthraquinones belongs to this group of compounds. Although it has been proven that hypericin is synthesized by the polyketide pathway in plants, none of the candidate genes coding for key enzymes has been experimentally validated yet. Despite the rare occurrence of anthraquinones in plants, their presence in microorganisms, including endophytic fungi, is quite common. Unlike plants, several biosynthetic genes grouped into clusters (BGCs) in fungal endophytes have already been characterized.ResultsThe aim of this work was to predict, identify and characterize the anthraquinone BGCs in de novo assembled and functionally annotated genomes of selected endophytic fungal isolates (Fusarium oxysporum, Plectosphaerella cucumerina, Scedosporium apiospermum, Diaporthe eres, Canariomyces subthermophilus) obtained from different tissues of Hypericum spp. The number of predicted type I polyketide synthase (PKS) BGCs in the studied genomes varied. The non-reducing type I PKS lacking thioesterase domain and adjacent discrete gene encoding protein with product release function were identified only in the genomes of C. subthermophilus and D. eres. A candidate bisanthraquinone BGC was predicted in C. subthermophilus genome and comprised genes coding the enzymes that catalyze formation of the basic anthraquinone skeleton (PKS, metallo-beta-lactamase, decarboxylase, anthrone oxygenase), putative dimerization enzyme (cytochrome P450 monooxygenase), other tailoring enzymes (oxidoreductase, dehydrogenase/reductase), and non-catalytic proteins (fungal transcription factor, transporter protein).ConclusionsThe results provide an insight into genetic background of anthraquinone biosynthesis in Hypericum-borne endophytes. The predicted bisanthraquinone gene cluster represents a basis for functional validation of the candidate biosynthetic genes in a simple eukaryotic system as a prospective biotechnological alternative for production of hypericin and related bioactive anthraquinones.

Optimization of conditions to achieve a high content of alizarin and purpurin in the adventitious roots of Rubia cordifolia L.

Rubia cordifolia L. (Indian madder) is a valuable medicinal plant known for its natural dye content, notably alizarin and purpurin, with applications in textiles and cosmetics. This study aims to optimize the concentrations of auxin, salicylic acid, elicitors, and precursors to maximize the production of alizarin and purpurin in adventitious roots. Various concentrations and combinations of auxins were systematically tested to explore their effects on the yield of adventitious root formation and dye compounds. Nodal explants cultivated in MS media supplemented with IAA + IBA + NAA (1.5 + 0.5 + 0.75 mg/L) at a pH of 5.7 exhibited the highest adventitious root production. Post-establishment of root cultures, the impact of salicylic acid, L-phenylalanine, elicitors (yeast extract, pectin, and Xylan), and the precursor α-ketoglutaric acid on the production of anthraquinones (AQ) was evaluated. High-performance liquid Chromatography (HPLC) analysis revealed enriched alizarin, purpurin, and total AQ content. The maximum amount of AQ (64.65 mg/g), alizarin (17.59 mg/g), and purpurin (19.61 mg/g) was observed when cultured on 30 mg/L of α-ketoglutaric acid, compared to other elicitors and precursors. This optimized condition provides valuable insights for the sustainable cultivation and utilization of R. cordifolia as a prominent source of natural dyes. It offers practical implications for the dye industry and its production.

Neoplaca mirabilis, a new genus and a new epigaeic species containing naphthopyrans from the family Teloschistaceae

AbstractThe production of anthraquinones is a major characteristic of most species in the Teloschistaceae. Other secondary metabolites are quite rare in this family, but some species are known to produce depsides, depsidones, xanthones and usnic acid. A new monotypic genus, Neoplaca, with a new species N. mirabilis, is described from the subfamily Caloplacoideae of the family Teloschistaceae, lacking anthraquinones but containing the naphthopyrans simonyellin and consimonyellin. This is the first time this class of organic compounds has been found in the family Teloschistaceae and the second in the order Teloschistales, where simonyellin has been detected in Brigantiaeaceae. Simonyellin and consimonyellin have also previously been reported in the family Roccellaceae. Neoplaca mirabilis is currently known from the two nearby localities in Yakutia, Russia, where it is common and grows on base-rich soil on exposed south-facing siliceous outcrops. The thallus consists of scattered whitish to greyish, or rarely with pale yellow tinge, squamules 1–4.5 mm diam. and 0.3–1 mm thick with citrine to orange-yellow blastidia produced from their margin; apothecia and pycnidia are unknown. In addition to naphthopyrans, N. mirabilis contains an unidentified brown pigment similar in some features to melanin. The new species is also interesting in that the pigments are apparently located inside the cells of the cortex, not on their surface, where anthraquinones are found in Teloschistaceae.

Investigation of anthraquinone-producing Trichoderma reesei by highperformance liquid chromatography (HPLC)

Objective: To investigate the isolates of Trichoderma that produce anthraquinones by High-performance LiquidChromatography (HPLC).Methods: Trichoderma specimen were collected from Wassit Soil and identified dependent on morphological featuresand tested for production of anthraquinones by HPLC, Trichoderma isolate which produced a high concentration ofanthraquinones diagnosed for the species using PCR-ITS region.Results: Ten isolates were identified as Trichoderma according to morphological and microscopic features. Resultsthree Trichoderma isolates show differences between the concentrations of anthraquinones among the ten isolates.The total concentration of this compound in the extracts of specimens 1, 2 and 3 were (7.765ug/ml), (2.308ug/ml),and (4.977ug/ml) respectively. At the final concentration of Trichoderma isolates, genomic DNA have been extracted(400 to 600 ug) / (2 to 3g) fresh mycelium, and with a concentration of (1.6 to1.8), and the results of amplifyingTrichoderma DNA samples by using ITS-1 and ITS-4 showed a single unique band consistent with T. reesei F48-03, Whichwith other isolates of the Trichoderma were missing, were identified successfully.Conclusion: For identification and phylogenetic classification of Trichoderma, DNA-based methods that provide usefulclassification information are presently used. For several years, most T. spp. is regarded as a single species due to theirmorphological similarity. This research used ITS markers to distinguish genotypes within T. spp. because of amplifyinga distinct, naturally determined locus with a couple of T.reesei -specific oligonucleotide primers. This research wascarried out to provide supporting evidence for the long-standing antimicrobial use of anthraquinone.Keywords: DNA, Primers, Trichoderma, Phylogeny, Soil, Chromatography, Liquid, Polymerase, Reaction,Anthraquinones, Mycelium, Plant, Genomics.

The haplotype-resolved genome assembly of autotetraploid rhubarb Rheum officinale provides insights into its genome evolution and massive accumulation of anthraquinones

Rheum officinale, a member of the Polygonaceae family, is an important medicinal plant that is widely used in traditional Chinese medicine. Here, we report a 7.68-Gb chromosome-scale assembly of R. officinale with a contig N50 of 3.47 Mb, which was clustered into 44 chromosomes across four homologous groups. Comparative genomics analysis revealed that transposable elements have made a significant contribution to its genome evolution, gene copy number variation, and gene regulation and expression, particularly of genes involved in metabolite biosynthesis, stress resistance, and root development. We placed the recent autotetraploidization of R. officinale at ∼0.58 mya and analyzed the genomic features of its homologous chromosomes. Although no dominant monoploid genomes were observed at the overall expression level, numerous allele-differentially-expressed genes were identified, mainly with different transposable element insertions in their regulatory regions, suggesting that they functionally diverged after polyploidization. Combining genomics, transcriptomics, and metabolomics, we explored the contributions of gene family amplification and tetraploidization to the abundant anthraquinone production of R. officinale, as well as gene expression patterns and differences in anthraquinone content among tissues. Our report offers unprecedented genomic resources for fundamental research on the autopolyploid herb R. officinale and guidance for polyploid breeding of herbs.

Exploring characteristics of value-added production of anthraquinones in rhubarb via fermentation: Compartmental modelling and molecular docking analysis

BackgroundRhubarb is an anthraquinone-rich herb with extensive pharmacological properties. The study adopted compartmental modeling, metagenomic analysis, and molecular docking analysis to predict optimal cycles of acclimation and maximal value-added production in fermentation of Rheum palmatum L. The work highlights the importance of fermentation and microbial consortia in value-added production. MethodAccording to transient dynamics of four anthraquinones (i.e., aloe-emodin, rhein, emodin, and chrysophanol) in R. palmatum L. fermentation, compartmental modeling was applied to quantitatively reveal the optimal cycle of acclimation for value-added production. Metagenomic analysis and comparative molecular docking analysis were used to scrutinize the fermentation process for microbial community and metabolic pathway assessment. Significant findingsCompartmental modelling indicated that the third cycle had the lowest k2k1 ratio and the highest bioconversion rates for aloe-emodin, emodin, and chrysophanol in acclimation using S. cerevisiae and microbial consortia. This coincides with the experimental findings, supporting the optimal performance of value-added production. The metabolic pathway of anthraquinone intermediates in R. palmatum L. using different cultures was established. As metagenomic analysis indicated, evolution of biodiversity in microbial community before and after fermentation suggested that Firmicutes and Proteobacteria tended to be the most dominant phyla. The β-glucosidase from Klebsiella spp. seemed to have more affinity than Lactococcus spp. that may explain Klebsiella's dominance after fermentation.

Genome-Wide Mining of the Tandem Duplicated Type III Polyketide Synthases and Their Expression, Structure Analysis of Senna tora

Senna tora is one of the homologous crops used as a medicinal food containing an abundance of anthraquinones. Type III polyketide synthases (PKSs) are key enzymes that catalyze polyketide formation; in particular, the chalcone synthase-like (CHS-L) genes are involved in anthraquinone production. Tandem duplication is a fundamental mechanism for gene family expansion. However, the analysis of the tandem duplicated genes (TDGs) and the identification and characterization of PKSs have not been reported for S. tora. Herein, we identified 3087 TDGs in the S. tora genome; the synonymous substitution rates (Ks) analysis indicated that the TDGs had recently undergone duplication. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the type III PKSs were the most enriched TDGs involved in the biosynthesis of the secondary metabolite pathways, as evidenced by 14 tandem duplicated CHS-L genes. Subsequently, we identified 30 type III PKSs with complete sequences in the S. tora genome. Based on the phylogenetic analysis, the type III PKSs were classified into three groups. The protein conserved motifs and key active residues showed similar patterns in the same group. The transcriptome analysis showed that the chalcone synthase (CHS) genes were more highly expressed in the leaves than in the seeds in S. tora. The transcriptome and qRT-PCR analysis showed that the CHS-L genes had a higher expression in the seeds than in other tissues, particularly seven tandem duplicated CHS-L2/3/5/6/9/10/13 genes. The key active-site residues and three-dimensional models of the CHS-L2/3/5/6/9/10/13 proteins showed slight variation. These results indicated that the rich anthraquinones in S. tora seeds might be ascribed to the PKSs' expansion from tandem duplication, and the seven key CHS-L2/3/5/6/9/10/13 genes provide candidate genes for further research. Our study provides an important basis for further research on the regulation of anthraquinones' biosynthesis in S. tora.

Production of anthraquinones from cell and organ cultures of Morinda species.

Since ancient times, Morinda species, particularly Morinda citrifolia, have been used for their therapeutic benefits. Iridoids, anthraquinones, coumarins, flavonoids, lignans, phytosterols, and carotenoids are examples of natural substances with bioactivity. Anthraquinone derivatives are the most significant of these chemicals since they are utilized as natural coloring agents and have a wide range of medicinal functions. Utilizing cell and organ cultures of Morinda species, various biotechnological methods have been developed for the bioproduction of anthraquinone derivatives. The generation of anthraquinone derivatives in cell and organ cultures is summarized in this article. The methods used to produce these chemicals in bioreactor cultures have also been examined. KEY POINTS: • This review investigates the potential of cell and organ cultures for anthraquinone synthesis. • The overproduction of anthraquinones has been addressed using a variety of techniques. • The use of bioreactor technologies for anthraquinone manufacturing is highlighted.

Metagenomics Shines Light on the Evolution of 'Sunscreen' Pigment Metabolism in the Teloschistales (Lichen-Forming Ascomycota).

Fungi produce a vast number of secondary metabolites that shape their interactions with other organisms and the environment. Characterising the genes underpinning metabolite synthesis is therefore key to understanding fungal evolution and adaptation. Lichenised fungi represent almost one-third of Ascomycota diversity and boast impressive secondary metabolites repertoires. However, most lichen biosynthetic genes have not been linked to their metabolite products. Here we used metagenomic sequencing to survey gene families associated with production of anthraquinones, UV-protectant secondary metabolites present in various fungi, but especially abundant in a diverse order of lichens, the Teloschistales (class Lecanoromycetes, phylum Ascomycota). We successfully assembled 24 new, high-quality lichenised fungal genomes de novo and combined them with publicly available Lecanoromycetes genomes from taxa with diverse secondary chemistry to produce a whole-genome tree. Secondary metabolite biosynthetic gene cluster (BGC) analysis showed that whilst lichen BGCs are numerous and highly dissimilar, core enzyme genes are generally conserved across taxa. This suggests metabolite diversification occurs via re-shuffling existing enzyme genes with novel accessory genes rather than BGC gains/losses or de novo gene evolution. We identified putative anthraquinone BGCs in our lichen dataset that appear homologous to anthraquinone clusters from non-lichenised fungi, suggesting these genes were present in the common ancestor of the subphylum Pezizomycotina. Finally, we identified unique transporter genes in Teloschistales anthraquinone BGCs that may explain why these metabolites are so abundant and ubiquitous in these lichens. Our results support the importance of metagenomics for understanding the secondary metabolism of non-model fungi such as lichens.

Anthraquinone Production from Cell and Organ Cultures of Rubia Species: An Overview.

The Rubia genus includes major groups of medicinal plants such as Rubia cordifolia, Rubia tinctorum, and Rubia akane. They contain anthraquinones (AQs), particularly alizarin and purpurin, which have pharmacological effects that are anti-inflammatory, antioxidant, anticancer, hemostatic, antibacterial, and more. Alizarin and purpurin have been utilized as natural dyes for cotton, silk, and wool fabrics since the dawn of time. These substances have been used in the cosmetics and food industries to color products. The amount of AQs in different Rubia species is minimal. In order to produce these compounds, researchers have established cell and organ cultures. Investigations have been conducted into numerous chemical and physical parameters that affect the biomass and accumulation of secondary metabolites in a cell, callus, hairy root, and adventitious root suspension cultures. This article offers numerous techniques and approaches used to produce biomass and secondary metabolites from the Rubia species. Additionally, it has been emphasized that cells can be grown in bioreactor cultures to produce AQs.

Deciphering biotransformation of anthraquinone electron shuttles in Rheum palmatum L. for value-added production

BackgroundRecent findings indicated that electron mediating characteristics of electrochemical catalysis would enhance disease-treating efficacy of herbal medicine. In particular, biomass energy-amplifying and electron transfer-stimulating medicines could even treat not only brain-associated diseases, but also virus-caused infections. Exploring different electron shuttle (ES)-bearing medicinal herbs for biorefinery should have potentials to develop value-added production (e.g., medicated diet). MethodsMicrobial fuel cells (MFCs) were used as the bioenergy-evaluating platform to select the most promising anthraquinone (AQ) ES-abundant herb. Optimal conditions of water and ethanol extraction were determined to maximize bioenergy content of resultant extract. According to HPLC, MS/MS and TAC analyses, serial acclimation to select effective rhubarb-degrading bacteria was implemented to maximize the product formation. Significant findingsRheum palmatum L. was the most favorable AQ-plentiful medicinal herb to exhibit bioenergy-stimulating activities. Extraction at higher ethanol % could obtain the maximal recovery of AQ content; however, an increased inhibition was resulted as MFC results indicated. With 3-4 cycles of acclimation using appropriate food-originated microbes, the production of aloe-emodin and chrysophanol increased ca. 400% and 270%, respectively. To the best of our knowledge, this first-attempt study provided a novel bioenergy perspective to maximize AQ production of rhubarb fermentation. Moreover, significant reduction of biotoxicity potency should be top-priority concern to guarantee this GRAS production.

Producción de antraquinonas por cultivo in vitro de suspensiones celulares y raíces transformadas de Rubia Tinctorum: un modelo para la enseñanza en el estudio de bioprocesos por cultivo de tejidos de plantas

Plant cell culture bioprocesses constitute an excellent tool for the formation of undergraduate, magister, and Ph.D. students. In fact, students can acquire experience in the field of plant biochemistry and molecular biology; plant primary and secondary metabolism; and biochemical engineering. In the present manuscript, the production of anthraquinones in different plant cell tissue cultures is showed as easy and versatile model to introduce magister students in the field of plant secondary metabolite production. AQs are extracted with ethanol 80% and spectrophotometrically quantified, which also makes it environmentally friendly and easy to manipulate in the laboratory. The students were able to analyse biomass and product formation kinetics in batch suspension and hairy root cultures and evaluate the effect of MeJa elicitation an extended used strategy to trigger secondary metabolite production in plant cell cultures. Moreover, the performance of in situ product removal, which has been extensively used in biocatalyst and microbial fermentations, was evaluated. In summary, an inexpensive, accessible, and robust laboratory work is presented that can be adapted to undergraduate, magister, and/or Ph.D. students' courses in different plant biology, chemistry, and biochemical engineering programs.

Influence of salicylic acid and L-phenylalanine on the accumulation of anthraquinone and phenolic compounds in adventitious root cultures of madder (Rubia tinctorum L.)

Madder (Rubia tinctorum L.) is a perennial plant that its roots and rhizomes have rich anthraquinone (AQ) derivatives including alizarin and purpurin. This study was carried out to determine the effects of salicylic acid (SA) and L-phenylalanine (L-Phe) applications on the root growth parameters and secondary metabolite accumulation in madder adventitious roots derived from internode parts without needing to be collected from nature. For this aim, two different L-Phe (50 and 100 µM) and SA (20 and 40 µM) were added separately and together to the liquid Murashige and Skoog (MS) medium cultured adventitious roots for 7 days. Then roots were evaluated in terms of fresh root weight, root growth index, dry root weight, and contents of total AQ, alizarin, purpurin, total phenolic contents (TPC), and some important phenolic compounds. According to the results, L-Phe stimulated the root growth of madder while the effects of SA on root growth parameters varied depending upon its concentrations. L-Phe had no significant influence on the total AQ, alizarin, and purpurin. Conversely, SA increased the AQs, and 20 µM SA was the most suitable application providing the greatest total AQ, alizarin, and purpurin. TPC and individual phenolic compounds changed according to the applications. Not only L-Phe but also SA had positive effects on the phenolic accumulation in adventitious roots. It was determined that the combinations of 40 µM SA and 100 µM L-Phe were the most effective applications in terms of phenolic accumulation. Madder is a plant whose popularity has increased in food, cosmetics, pharmacy and recently medicine. This research was designed in order to produce high amounts of important secondary metabolites in adventitious root cultures of madder without the need to collect plants from nature. In this study, it has been shown that L-phenylalanine and salicylic acid applied to adventitious roots remarkably increase the production of anthraquinones and phenolics when used in appropriate concentrations and combinations.

Enhanced catalytic oxidation of anthracene by deposition of MoO3 and WO3 nanoparticles on MCM-41

A series of MoW-doped MCM-41 catalysts were prepared for the selective oxidation of anthracene to high value-added anthraquinone. Although anthraquinone production has been progressively industrialized, the anthracene oxidation still faces the problems of poor solubility of reactants and low anthracene conversion, particularly when employing supported catalysts in solution media. We herein reported a challenging but crucial method for anthraquinone production by using anthracene, H2O2 and Mo1W2-MCM-41 catalyst in HOAc under mild reaction conditions. In addition, experimental and theoretical results revealed that the synergistic effect between Mo, W and MCM-41 species contributes to an enchanced cataltic activity with conversion up to 97.6 %. The highly active H2O2-MCM-41 catalyst can be used for several cycles without obvious activity loss and serve as a promising candidate for anthraquinone as well as its derivatives production, making it a good alternative for various oxidation reactions.

Pigment elicitation and sun protection factor of callus induced from Cassia tora seedling explants

Natural pigments are derived from sources such as plant, animal, insects, and fungi. The anthraquinones are natural pigments that have pharmacological activities. They have applications in several domains such as the pharmaceutical, cosmetic and textile industries. Anthraquinones occur naturally in many plants including Cassia tora of the Fabaceae family. The present study focused on the production of pigments (anthraquinones) from callus of Cassia tora cultured on medium supplemented with 6-benzylaminopurine and thidiazuron. The elicitor, salicylic acid, increased anthraquinone production in callus cultures whereas ethrel had minimum effect. Anthraquinone production increased twofold in callus inoculated in medium containing 10 mM salicylate. The yield obtained was 3709 ± 269.65 mg/kg dry weight of callus in Fraction B. The sun protection factor of the callus extracts was also assessed. The maximum sun protection factor observed was 38. Growth analysis of Cassia tora callus, modulating callus growth and pigment (anthraquinones) production with the elicitors Ethrel and salicylic acid. Potential application of callus extract as Sun protectant.

Enhanced production of anthraquinones and phenolic compounds using chitosan from the adventitious roots of Morinda coreia Buck. and Ham.

This report establishes the production and characterization of anthraquinones and phenolic compounds from the adventitious root cultures of Morinda coreia, induced from the leaves on half strength Murashige and Skoog’s (MS) medium fortified with 1.0 mg l−1 of Indole-3 butyric acid (IBA). The in vitro regenerated adventitious roots (AR) were treated with various concentrations of IBA (0.5–5.0 mg l-1) containing half-strength of liquid MS medium with sucrose (1.5 %). The maximum amount of anthraquinones (149.80 mg g−1 dry weight of AR) and phenolic compounds (71.6 mg g−1 dry weight of AR) were detected on 1.0 mg l−1 and 4.0 mg l−1 of IBA respectively. These proliferated AR on IBA contained 2.10 times more anthraquinones and 1.89 times more phenolics as compared with the yield of in vivo grown roots of M. coreia. Other parameters, such as growth ratio (5.082), fresh weight (1.568 g) and dry weight (0.163 g) of AR were recorded maximum with the concentration of 1.0 mg l−1 IBA. These AR were introduced into the two-stage culture system with various concentrations of chitosan (0.2, 0.4 and 0.8 mg ml-1) for elicitation. Among these, 0.4 mg ml-1 chitosan was observed as the best concentration and further used for the production of secondary metabolites (anthraquinones and phenolics) at different time intervals (2–8 days). Growth ratio and biomass (fresh and dry weight) were decreased from second to eighth day of elicitation but the amount of anthraquinones (292.038 mg g-1 dry weight) and phenolics (86.8 mg g-1 dry weight) were increased till 4th day of the elicitation. The methods developed in this study could be used for further proliferation of AR and large scale production of anthraquinones and phenolic compounds using in vitro raised leaves of M. coreia.

Enhanced production of anthraquinones by gamma-irradiated cell cultures of Rubia cordifolia in a bioreactor

The aim of this study was to obtain high-yielding cell cultures of Rubia cordifolia by applying gamma irradiation and subsequently scaling up for anthraquinone production in a bioreactor. Calli cultured on MS medium was irradiated at variable doses between 2 Gy and 30 Gy. The callus cultures that were irradiated at 8 Gy accumulated a maximum alizarin level of 26.86 mg g-1 DW and a purpurin level of 44.85 mg g-1 DW during the M1T4 (fourth sub-cultures after gamma irradiation treatment) subculture, which was 6-fold and 11-fold higher than those of the nonirradiated callus cultures, respectively. Suspension cultures that originated from high-yielding callus cultures irradiated at 8 Gy were scaled up in an 8-L stirred bioreactor equipped with different impellers. The callus cultures in a bioreactor using a helical ribbon for homogenous mixing synthesized 63.58 % more anthraquinones than those in the bioreactor equipped with a Rushton disc turbine. This is the first report on the production of alizarin and purpurin in a bioreactor.

Recycling of Chinese herb residues by endophytic and probiotic fungus Aspergillus cristatus CB10002 for the production of medicinal valuable anthraquinones

BackgroundThe global prevalence of traditional Chinese medicine stimulates the prosperous development of herb medicines, but the annual generation of massive herb residues becomes big issues about environmental pollution and waste of resources. Microbes play important roles in the circulation of substances in nature, and endophytes represent an underexplored microbial resource possessing the unique symbiotic relationship with plants, not only for discovery of secondary metabolites, but also for potential green recycling of herb residues.ResultsThe recycling capacities of several endophytic strains were respectively evaluated via solid state fermentation with herb residues of commercial Huazhenghuisheng oral-liquid (HOL). Among them, Aspergillus cristatus CB10002, a probiotic fungus isolated from Chinese Fu-brick tea, was competent to recycle HOL residues for the production of medicinal valuable anthraquinones, in which four of them, especially citreorosein with significant anti-obesity activity, were first discovered in A. cristatus. Subsequent quantitative analysis showed that about 2.0 mg/g citreorosein and 7.5 mg/g total anthraquinones could be obtained after 35-day fermentation, which was very competitive and economically beneficial. Further nutritional comparisons also revealed that the recycling process indeed ameliorated the nutrients of HOL residues, and thus proposed a possibility to directly dispose the final leftovers as a compost organic fertilizer.ConclusionsThe endophytic and probiotic fungus A. cristatus CB10002 isolated from Chinese Fu-brick tea was screened out to effectively reutilize HOL residues for the production of nine medicinal valuable anthraquinones, whose biosynthesis may be regulated by the induction of HOL residues. The competitive yields of these anthraquinones, as well as the certain composting properties of final leftovers, have made the microbial recycling of HOL residues economically beneficial. Our work demonstrated a promising applied potential of A. cristatus in reutilization of herb residues, and provided a practical strategy for sustainable and value-added microbial recycling of herb residues.