Methyl jasmonate enhanced production of rosmarinic acid in cell cultures ofSatureja khuzistanicain a bioreactor

Trends in plant tissue culture, production, and secondary metabolites enhancement of medicinal plants: a case study of thyme

MAIN CONCLUSION

Thymus plants are greatly threatened by overharvesting and climate change. Plant cell and tissue culture techniques provide effective alternatives for the production and the enhancement of both biomass and bioactive compounds. Medicinal and aromatic plants are rich sources of various bioactive compounds known as secondary metabolites, which are used across a range of fields, including medicinal, cosmetics, pharmaceuticals, perfumes, agrochemicals and agrofood industries. Thyme is considered one of the most popular herbs globally, valued for its significant medicinal, pharmaceutical, and nutritional benefits. However, its natural habitats are rapidly diminishing due to excessive harvesting and climate change. Consequently, several approaches have been developed to find alternatives to harvesting wild thyme. Plant cell and tissue culture techniques offer a superior alternative to traditional propagation methods, such as seeds, cuttings, or tuft division. These techniques enable the production of large quantities of uniform, disease-free plantlets for commercial cultivation and facilitate the development of new genotypes. Additionally, they support the production and enhancement of bioactive compounds from thyme plants. This review explores the application of plant cell, tissue, and organ culture biotechnology in thyme plants, focusing on enhancing production and improving secondary metabolite yields and biomass production.

Integrative effects of phytohormones in the phenolic acids production in Salvia verticillata L. under multi-walled carbon nanotubes and methyl jasmonate elicitation

Salvia verticillata L. is a well-known herb rich in rosmarinic acid (RA) and with therapeutic values. To better understand the possible roles of phytohormones in the production of phenolic acids in S. verticillata, in this work, we investigated some physiological and biochemical responses of the species to methyl jasmonate (MJ) and multi-walled carbon nanotubes (MWCNTs) as two effective elicitors. The leaves were sprayed with aqueous solutions containing 100 mg L-1 MWCNTs and 100 µM MJ and then harvested during interval times of exposure up to 96 h. The level of abscisic acid, as the first effective phytohormone, was altered in the leaves in response to MJ and MWCNTs elicitation (2.26- and 3.06-fold more than the control, respectively), followed by significant increases (P ˂ 0.05) detected in jasmonic acid and salicylic acid contents up to 8 h after exposure. Obtained data revealed that simultaneously with changes in phytohormone profiles, significant (P ˂ 0.05) rises were observed in the content of H2O2 (8.85- and 9.74-folds of control), and the amount of lipid peroxidation (10.18- and 17.01-folds of control) during the initial times after exposure to MJ and MWCNTs, respectively. Later, the content of phenolic acids increased in the elicited leaves due to changes in the transcription levels of key enzymes involved in their biosynthesis pathways, so 2.71- and 11.52-fold enhances observed in the RA content of the leaves after exposure to MJ and MWCNTs, respectively. It is reasonable to conclude that putative linkages between changes in some phytohormone pools lead to the accumulation of phenolic acids in the leaves of S. verticillata under elicitation. Overall, the current findings help us improve our understanding of the signal transduction pathways of the applied stimuli that led to enhanced secondary metabolite production in medicinal plants.

Metabolomics Reveals Rubiadin Accumulation and the Effects of Methyl Jasmonate Elicitation in Damnacanthus major Calli

Callus suspension techniques have been considered attractive for improving bioactive metabolite productivity; methyl jasmonate (MeJA) is a widely used elicitor for stimulating synthetic pathways. In this study, a multivariate analysis-based metabolomics approach was employed to investigate the primary and specialized metabolites in the leaves, unelicited calli, and 100 or 200 μM MeJA elicited calli of Damnacanthus major. Rubiadin, a powerful anthraquinone with various therapeutic properties, was only identified in D. major calli, accumulating in a MeJA elicitation concentration-dependent manner. Callus cultures also contained high levels of amino acids, sugars, and phenolic compounds, indicating energy metabolism and metabolic adaptation responses for proliferation and stabilization. Regarding MeJA application, elicited calli contained higher amounts of quinic acid, kaempferol, and glucose with lower amounts of sucrose and raffinose than those in the unelicited control, which were closely related to protective mechanisms against MeJA. Moreover, excessive elicitation increased the asparagine, fructose, and raffinose levels and decreased the glucose and sucrose levels, which was ascribed to increased activation of the aminoacyl-tRNA biosynthesis pathway and wider utilization of glucose than of fructose after sucrose degradation. These results will be useful for optimizing plant cell culture techniques to achieve high production rates for valuable specialized metabolites.

Disposable Bioreactors Used in Process Development and Production Processes with Plant Cell and Tissue Cultures

The bioreactor is the centerpiece of the upstream processing in any biotechnological production process. Its design, the cultivation parameters, the production cell line, and the culture medium all have a major influence on the efficiency of the process and the result of the cultivation. Disposable bioreactors have been used for the past 20 years, playing a major role in process development and commercial production of high-value substances at medium scales.Our review deals with scalable, disposable bioreactors that have proven to be useful for the cultivation of plant cell and tissue cultures. Based on the definitions of terms and a categorization approach, the most commonly used, commercially available, disposable bioreactor types are presented below. The focus is on wave-mixed, stirred, and orbitally shaken bioreactors. In addition to their instrumentation and bioengineering characteristics, cultivation results are discussed, and emerging trends for the development of disposable bioreactors for plant cell and tissue cultures are also addressed.

Rosmarinic Acid and Related Dietary Supplements: Potential Applications in the Prevention and Treatment of Cancer

Cancer constitutes a severe threat to human health and quality of life and is one of the most significant causes of morbidity and mortality worldwide. Natural dietary products have drawn substantial attention in cancer treatment and prevention due to their availability and absence of toxicity. Rosmarinic acid (RA) is known for its excellent antioxidant properties and is safe and effective in preventing and inhibiting tumors. This review summarizes recent publications on culture techniques, extraction processes, and anti-tumor applications of RA-enriched dietary supplements. We discuss techniques to improve RA bioavailability and provide a mechanistic discussion of RA regarding tumor prevention, treatment, and adjuvant therapy. RA exhibits anticancer activity by regulating oxidative stress, chronic inflammation, cell cycle, apoptosis, and metastasis. These data suggest that daily use of RA-enriched dietary supplements can contribute to tumor prevention and treatment. RA has the potential for application in anti-tumor drug development.

Quantification of rosmarinic acid from different plant species of lower Himalayan region and expression analysis of underlying L-Phenylalanine pathway

This study adopts a very effective high-performance liquid chromatography (HPLC) technique for the quantitative determination of rosmarinic acid (RA) and PCR-based amplification of biosynthetic key regulators in Isodon rugosus, Daphne mucronata, and Viburnum grandiflorum from the lower Himalayan regions. Rosmarinic acid is engaged in a variety of biological processes and has significant industrial significance. In this study, it was identified from crude methanolic extract using thin-layer chromatography with a standard, and its content was quantified using HPLC without interrupting spikes using a mixture of methanol and deionized water containing acetonitrile (70:30 v/v) and acetic acid (0.1% v/v) at UV 310 nm absorption. We used RT-PCR to identify cDNAs encoding PAL, C4H, and RAS, and Image J's semi-quantitative analysis to quantify the expression levels of genes involved in RA production from chosen plant material. The highest levels of PAL, C4H, and RAS were detected, by band intensity, in the leaves and flowers of I. rugosus, which also exhibited a substantial quantity of RA. However, in V. grandiflorum and D. mucronata the transcript of the given genes was low. The concentration of RA ranged from 187.7 to 21.2 mg g^-1 for I. rugosus, 17.42 to 5.42 mg g^-1 for V. grandiflorum, and 15.19 mg g^-1 for D. mucronata. This study demonstrated that the method for quantifying RA from a crude methanolic extract was effective, indicating that I. rugosus might be used as an indigenous alternative source of RA.

Engineering Considerations to Produce Bioactive Compounds from Plant Cell Suspension Culture in Bioreactors

The large-scale production of plant-derived secondary metabolites (PDSM) in bioreactors to meet the increasing demand for bioactive compounds for the treatment and prevention of degenerative diseases is nowadays considered an engineering challenge due to the large number of operational factors that need to be considered during their design and scale-up. The plant cell suspension culture (CSC) has presented numerous benefits over other technologies, such as the conventional whole-plant extraction, not only for avoiding the overexploitation of plant species, but also for achieving better yields and having excellent scaling-up attributes. The selection of the bioreactor configuration depends on intrinsic cell culture properties and engineering considerations related to the effect of operating conditions on thermodynamics, kinetics, and transport phenomena, which together are essential for accomplishing the large-scale production of PDSM. To this end, this review, firstly, provides a comprehensive appraisement of PDSM, essentially those with demonstrated importance and utilization in pharmaceutical industries. Then, special attention is given to PDSM obtained out of CSC. Finally, engineering aspects related to the bioreactor configuration for CSC stating the effect of the operating conditions on kinetics and transport phenomena and, hence, on the cell viability and production of PDSM are presented accordingly. The engineering analysis of the reviewed bioreactor configurations for CSC will pave the way for future research focused on their scaling up, to produce high value-added PDSM.

Gentianella lutescens subsp. carpatica J. Holub.: Shoot Propagation In Vitro and Effect of Sucrose and Elicitors on Xanthones Production

In vitro shoot culture of the endangered medicinal plant Gentianella lutescens was established from epicotyl explants cultured on MS basal medium with 0.2 mg L⁻¹ 6-benzylaminopurine (BA) and evaluated for xanthones content for the first time. Five shoot lines were obtained and no significant variations in multiplication rate, shoot elongation, and xanthones profile were found among them. The highest rooting rate (33.3%) was achieved by shoots treated for 2 days with 5 mg L⁻¹ indole-3-butyric acid (IBA) followed by cultivation in liquid PGR-free ½ MS medium for 60 days. HPLC analysis revealed the lower content of xanthones—mangiferin, bellidifolin, demethylbellidifolin, demethylbellidifolin-8-O-glucoside and bellidifolin-8-O-glucoside—in in vitro cultured shoots compared to wild growing plants. The increasing concentration of sucrose, sorbitol and abiotic elicitors salicylic acid (SA), jasmonic acid (JA) and methyl jasmonate (MeJA) altered shoot growth and xanthone production. Sucrose and sorbitol applied at the highest concentration of 233.6 mM increased dry matter percentage, while SA at 100 μM promoted shoot growth 2-fold. The increased sucrose concentration enhanced accumulation of xanthones in shoot cultures 2–3-fold compared to the control shoots. Elicitors at 100–300 μM increased the accumulation of mangiferin, demethylbellidifolin-8-O-glucoside, and bellidifolin-8-O-glucoside almost equally, while MeJA at the highest concentration of 500 μM enhanced amount of aglycones demethylbellidifolin and bellidifolin 7-fold compared to the control. The obtained results facilitate conservation of G. lutescens and pave the way for further research on large-scale shoot propagation and production of pharmacologically active xanthones.

Bioproduction process of natural products and biopharmaceuticals: Biotechnological aspects

Decades of research have been put in place for developing sustainable routes of bioproduction of high commercial value natural products (NPs) on the global market. In the last few years alone, we have witnessed significant advances in the biotechnological production of NPs. The development of new methodologies has resulted in a better understanding of the metabolic flux within the organisms, which have driven manipulations to improve production of the target product. This was further realised due to the recent advances in the omics technologies such as genomics, transcriptomics, proteomics, metabolomics and secretomics, as well as systems and synthetic biology. Additionally, the combined application of novel engineering strategies has made possible avenues for enhancing the yield of these products in an efficient and economical way. Invention of high-throughput technologies such as next generation sequencing (NGS) and toolkits for genome editing Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9 (CRISPR/Cas9) have been the game changers and provided unprecedented opportunities to generate rationally designed synthetic circuits which can produce complex molecules. This review covers recent advances in the engineering of various hosts for the production of bioactive NPs and biopharmaceuticals. It also highlights general approaches and strategies to improve their biosynthesis with higher yields in a perspective of plants and microbes (bacteria, yeast and filamentous fungi). Although there are numerous reviews covering this topic on a selected species at a time, our approach herein is to give a comprehensive understanding about state-of-art technologies in different platforms of organisms.

Powerful Plant Antioxidants: A New Biosustainable Approach to the Production of Rosmarinic Acid

Modern lifestyle factors, such as physical inactivity, obesity, smoking, and exposure to environmental pollution, induce excessive generation of free radicals and reactive oxygen species (ROS) in the body. These by-products of oxygen metabolism play a key role in the development of various human diseases such as cancer, diabetes, heart failure, brain damage, muscle problems, premature aging, eye injuries, and a weakened immune system. Synthetic and natural antioxidants, which act as free radical scavengers, are widely used in the food and beverage industries. The toxicity and carcinogenic effects of some synthetic antioxidants have generated interest in natural alternatives, especially plant-derived polyphenols (e.g., phenolic acids, flavonoids, stilbenes, tannins, coumarins, lignins, lignans, quinines, curcuminoids, chalcones, and essential oil terpenoids). This review focuses on the well-known phenolic antioxidant rosmarinic acid (RA), an ester of caffeic acid and (R)-(+)-3-(3,4-dihydroxyphenyl) lactic acid, describing its wide distribution in thirty-nine plant families and the potential productivity of plant sources. A botanical and phytochemical description is provided of a new rich source of RA, Satureja khuzistanica Jamzad (Lamiaceae). Recently reported approaches to the biotechnological production of RA are summarized, highlighting the establishment of cell suspension cultures of S. khuzistanica as an RA chemical biofactory.

Fast and cost-effective preparation of plant cells for scanning electron microscopy (SEM) analysis

The analysis of plant cell structure provides valuable information about its morphological, physiological, and biochemical characteristics. Nowadays, scanning electron microscope (SEM) is widely used to provide high-resolution images at the surface of biological samples. However, biological specimens require preparation, including dehydration and coating with conductive materials for imaging by SEM. There are several techniques for providing images with maximum maintenance of cell structure and minimum cellular damage, but each requires the use of expensive and hazardous materials, which can be damaging to the cell in many cases. Therefore, the provision of new and effective preparation methods based on maintaining cell structure for imaging can be very practical. In the present study, a fast and cost-effective protocol was first performed for chemical fixation and preparation of the plant cells for imaging by SEM. Taxus baccata and Zhumeria majdae cells were chemically fixed using glutaraldehyde and then successfully dried with different percentages of ethanol including 70, 80, 90, and 100%. In addition, SEM was performed for imaging the cell surface in different micro-scales. This protocol can be used by plant cell biologists and biotechnologists who are interested in studying structural and biochemical responses of treated or stressed plant cells by SEM.

Green (cell) factories for advanced production of plant secondary metabolites

For centuries plants have been intensively utilized as reliable sources of food, flavoring, agrochemical and pharmaceutical ingredients. However, plant natural habitats are being rapidly lost due to climate change and agriculture. Plant biotechnology offers a sustainable method for the bioproduction of plant secondary metabolites using plant in vitro systems. The unique structural features of plant-derived secondary metabolites, such as their safety profile, multi-target spectrum and "metabolite likeness," have led to the establishment of many plant-derived drugs, comprising approximately a quarter of all drugs approved by the Food and Drug Administration and/or European Medicinal Agency. However, there are still many challenges to overcome to enhance the production of these metabolites from plant in vitro systems and establish a sustainable large-scale biotechnological process. These challenges are due to the peculiarities of plant cell metabolism, the complexity of plant secondary metabolite pathways, and the correct selection of bioreactor systems and bioprocess optimization. In this review, we present an integrated overview of the possible avenues for enhancing the biosynthesis of high-value marketable molecules produced by plant in vitro systems. These include metabolic engineering and CRISPR/Cas9 technology for the regulation of plant metabolism through overexpression/repression of single or multiple structural genes or transcriptional factors. The use of NMR-based metabolomics for monitoring metabolite concentrations and additionally as a tool to study the dynamics of plant cell metabolism and nutritional management is discussed here. Different types of bioreactor systems, their modification and optimal process parameters for the lab- or industrial-scale production of plant secondary metabolites are specified.

In Vitro Study of the Anticancer Effects of Biotechnological Extracts of the Endangered Plant Species Satureja Khuzistanica

Many medicinal plant species are currently threatened in their natural habitats because of the growing demand for phytochemicals worldwide. A sustainable alternative for the production of bioactive plant compounds are plant biofactories based on cell cultures and organs. In addition, plant extracts from biofactories have significant advantages over those obtained from plants, since they are free of contamination by microorganisms, herbicides and pesticides, and they provide more stable levels of active ingredients. In this context, we report the establishment of Satureja khuzistanica cell cultures able to produce high amounts of rosmarinic acid (RA). The production of this phytopharmaceutical was increased when the cultures were elicited with coronatine and scaled up to a benchtop bioreactor. S. khuzistanica extracts enriched in RA were found to reduce the viability of cancer cell lines, increasing the sub-G0/G1 cell population and the activity of caspase-8 in MCF-7 cells, which suggest that S. khuzistanica extracts can induce apoptosis of MCF-7 cells through activation of the extrinsic pathway. In addition, our findings indicate that other compounds in S. khuzistanica extracts may act synergistically to potentiate the anticancer activity of RA.

Anticancer potential of rosmarinic acid and its improved production through biotechnological interventions and functional genomics

Rosmarinic acid (RA) is a highly valued natural phenolic compound that is very commonly found in plants of the families Lamiaceae and Boraginaceae, including Coleus blumei, Heliotropium foertherianum, Rosmarinus officinalis, Perilla frutescens, and Salvia officinalis. RA is also found in other members of higher plant families and in some fern and horned liverwort species. The biosynthesis of RA is catalyzed by the enzymes phenylalanine ammonia lyase and cytochrome P450-dependent hydroxylase using the amino acids tyrosine and phenylalanine. Chemically, RA can be produced via methods involving the esterification of 3,4-dihydroxyphenyllactic acid and caffeic acid. Some of the derivatives of RA include melitric acid, salvianolic acid, lithospermic acid, and yunnaneic acid. In plants, RA is known to have growth-promoting and defensive roles. Studies have elucidated the varied pharmacological potential of RA and its derived molecules, including anticancer, antiangiogenic, anti-inflammatory, antioxidant, and antimicrobial activities. The demand for RA is therefore, very high in the pharmaceutical industry, but this demand cannot be met by plants alone because RA content in plant organs is very low. Further, many plants that synthesize RA are under threat and near extinction owing to biodiversity loss caused by unscientific harvesting, over-collection, environmental changes, and other inherent features. Moreover, the chemical synthesis of RA is complicated and expensive. Alternative approaches using biotechnological methodologies could overcome these problems. This review provides the state of the art information on the chemistry, sources, and biosynthetic pathways of RA, as well as its anticancer properties against different cancer types. Biotechnological methods are also discussed for producing RA using plant cell, tissue, and organ cultures and hairy-root cultures using flasks and bioreactors. The recent developments and applications of the functional genomics approach and heterologous production of RA in microbes are also highlighted. This chapter will be of benefit to readers aiming to design studies on RA and its applicability as an anticancer agent.