Growth and rosmarinic acid production in cell suspension cultures of Salvia officinalis L

Controlled Production of Carnosic Acid and Carnosol in Cell Suspensions of Lepechinia meyenii Treated with Different Elicitors and Biosynthetic Precursors

Lepechinia meyenii is a medicinal plant specialized in the biosynthesis of different types of antioxidants including the diterpenes carnosic (CA) acid and carnosol (CS). Herein we present the results of plant tissue culture approaches performed in this medicinal plant with particular emphasis on the generation and evaluation of a cell suspension system for CA and CS production. The effect of sucrose concentration, temperature, pH, and UV-light exposure was explored. In addition, diverse concentrations of microbial elicitors (salicylic acid, pyocyanin, Glucanex, and chitin), simulators of abiotic elicitors (polyethylene glycol and NaCl), and biosynthetic precursors (mevalonolactone, geranylgeraniol, and miltiradiene/abietatriene) were evaluated on batch cultures for 20 days. Miltiradiene/abietatriene obtainment was achieved through a metabolic engineering approach using a recombinant strain of Saccharomyces cerevisiae. Our results suggested that the maximum accumulation (Acc_max ) of CA and CS was mainly conferred to stimuli associated with oxidative stress such as UV-light exposure (Acc_max , 6.2 mg L^-1 ) polyethylene glycol (Acc_max , 6.5 mg L^-1 ) NaCl (Acc_max , 5.9 mg L^-1 ) which simulated drought and saline stress, respectively. Nevertheless the bacterial elicitor pyocyanin was also effective to increase the production of both diterpenes (Acc_max , 6.4 mg L^-1 ). Outstandingly, the incorporation of upstream biosynthetic precursors such as geranylgeraniol and miltiradiene/abietatriene, generated the best results with Acc_max of 8.6 and 16.7 mg L^-1 , respectively. Optimized batch cultures containing 100 mg L^-1 geranylgeraniol, 50 mg L^-1 miltiradiene/abietatriene (95 : 5 %) and 5 g L^-1 polyethylene glycol treated with 6 min UV light pulse during 30 days resulted in Acc_max of 26.7 mg L^-1 for CA and 17.3 mg L^-1 for CS on days 18-24. This strategy allowed to increase seven folds the amounts of CA and CS in comparison with batch cultures without elicitation (Acc_max , 4.3 mg L^-1 ).

Elicitor-Induced Metabolomics Analysis of Halodule pinifolia Suspension Culture for an Alternative Antifungal Screening Approach against Candida albicans

Elicitors are the agents that stimulate the defense responses of plants, and accumulate specialized metabolites in plant tissue culture. This study investigated the elicitor-feeding response of H. pinifolia suspension cell cultures (SCC) for metabolomics analysis and screening of specialized compounds against Candida albicans. Methyl jasmonate (MeJA) was used as an elicitor, and treatment of SCC at a concentration of 20 µM MeJA resulted in the maximum rosmarinic acid (RA) accumulation (117 mg/g dry weight), with transcript levels of RA biosynthetic genes HpPAL, HpC4H, and Hp4CL being 4.2, 2.5, and 3.7-fold higher, respectively, than the controls. GC-MS-based metabolomics analysis revealed a total of 47 metabolites, including 30 organic acids, six amino acids, six flavonoids, two sugars, two plant growth regulators, and one vitamin, which were significantly different between control and MeJA-treated cells. Furthermore, five phenolic acids were discovered at higher concentrations, including p-anisic acid, p-coumaric acid, caffeic acid, vanillic acid, and rosmarinic acid, and were purified and structurally elucidated for alternative antifungal screening against C. albicans and the evaluation of ADMET properties. The results from antifungal screening revealed that RA at MIC of 31.25 mg/L exhibited the lowest growth percentage of C. albicans (1.99%), with higher inhibition of isocitrate lyase 1 (ICL 1) enzyme (93.1%), followed by p-anisic acid (86.2%) and caffeic acid (85.1%), respectively. The drug likeliness and ADMET properties of RA exhibited promising results, with a bioactivity score of 0.57, 0.15, and 0.24 for nuclear receptor ligand, protease inhibitor, and enzyme inhibitor, respectively. Therefore, MeJA appears to have a significant effect on enhanced RA accumulation in H. pinifoia cells with phenylpropanoid transcript expression, and acts as an ICL1 inhibitor of C. albicans.

Rosmarinic Acid and Ulvan from Terrestrial and Marine Sources in Anti-Microbial Bionanosystems and Biomaterials

In order to increase their sustainability, antimicrobial renewable molecules are fundamental additions to consumer goods. Rosmarinic acid is extracted from several terrestrial plants and represents an effective anti-microbial agent. Ulvan, extracted from algae, is an anti-microbial polysaccharide. The present review is dedicated to discussing the sources and the extraction methodologies for obtaining rosmarinic acid and ulvan. Moreover, the preparation of bioanosystems, integrating the two molecules with organic or inorganic substrates, are reviewed as methodologies to increase their effectiveness and stability. Finally, the possibility of preparing functional biomaterials and anti-microbial final products is discussed, considering scientific literature. The performed analysis indicated that the production of both molecules is not yet performed with mature industrial technologies. Nevertheless, both molecules could potentially be used in the packaging, biomedical, pharmaceutical, cosmetic, sanitary and personal care sectors, despite some research being required for developing functional materials with specific properties to pave the way for many more applications.

Production of bioactive plant secondary metabolites through in vitro technologies-status and outlook

Medicinal plants have been used by mankind since ancient times, and many bioactive plant secondary metabolites are applied nowadays both directly as drugs, and as raw materials for semi-synthetic modifications. However, the structural complexity often thwarts cost-efficient chemical synthesis, and the usually low content in the native plant necessitates the processing of large amounts of field-cultivated raw material. The biotechnological manufacturing of such compounds offers a number of advantages like predictable, stable, and year-round sustainable production, scalability, and easier extraction and purification. Plant cell and tissue culture represents one possible alternative to the extraction of phytochemicals from plant material. Although a broad commercialization of such processes has not yet occurred, ongoing research indicates that plant in vitro systems such as cell suspension cultures, organ cultures, and transgenic hairy roots hold a promising potential as sources for bioactive compounds. Progress in the areas of biosynthetic pathway elucidation and genetic manipulation has expanded the possibilities to utilize plant metabolic engineering and heterologous production in microorganisms. This review aims to summarize recent advances in the in vitro production of high-value plant secondary metabolites of medicinal importance.

Key points

• Bioactive plant secondary metabolites are important for current and future use in medicine

• In vitro production is a sustainable alternative to extraction from plants or costly chemical synthesis

• Current research addresses plant cell and tissue culture, metabolic engineering, and heterologous production

Plant terpenes on treating cardiovascular and metabolic disease: a review

The use of medicinal plants as a therapy alternative is old as human existence itself. Nowadays, the search for effective molecules for chronic diseases treatments has increased. The cardiometabolic disorders still the main cause of death worldwide and plants may offer potential pharmacological innovative approaches to treat and prevent diseases. In the range of plant molecules are inserted the terpenes, which constituent essential elements with several pharmacological characteristics and applications, including cardiovascular and metabolic properties. Thus, the aim of the present review is to update the terpenes use on chronic disorders such as obesity, diabetes, hypertension and vascular conditions. The review includes a brief terpenes description based on the scientific literature in addition to data collected from secondary sources such as books and conference proceedings. We concluded that terpenes could act as adjuvant or main alternative treatment (when started earlier) to improve cardiometabolic diseases, contributing to reduce side effects of conventional drugs, in addition to preserving ethnopharmacological knowledge.

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.

Metabolic Engineering of Saccharomyces cerevisiae for Rosmarinic Acid Production

Rosmarinic acid is a hydroxycinnamic acid ester commonly found in the Boraginaceae and Lamiaceae plant families. It exhibits various biological activities, including antioxidant, anti-inflammatory, antibacterial, antiallergic, and antiviral properties. Rosmarinic acid is used as a food and cosmetic ingredient, and several pharmaceutical applications have been suggested as well. Rosmarinic acid is currently produced by extraction from plants or chemical synthesis; however, due to limited availability of the plant sources and the complexity of the chemical synthesis method, there is an increasing interest in producing this compound by microbial fermentation. In this study, we aimed to produce rosmarinic acid by engineered baker's yeast Saccharomyces cerevisiae. Multiple biosynthetic pathway variants, carrying only plant genes or a combination of plant and Escherichia coli genes, were implemented using a full factorial design of experiment. Through analysis of variances, the effect of each enzyme variant (factors), together with possible interactions between these factors, was assessed. The best pathway variant produced 2.95 ± 0.08 mg/L rosmarinic acid in mineral medium with glucose as the sole carbon source. Increasing the copy number of rosmarinic acid biosynthetic genes increased the titer to 5.93 ± 0.06 mg/L. The study shows the feasibility of producing rosmarinic acid by yeast fermentation.

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.

Comparative metabolomic responses to gibberellic acid and 6-benzylaminopurine in Cunila menthoides Benth. (Lamiaceae): a contribution to understand the metabolic pathways

Gibberellic acid elicited synthesis of many phenols from different classes and enhanced production of sesquiterpenoids, polyterpenoids, steroids and monoterpenoids compared to control and 6-benzylaminopurine. Little is known about the effects of 6-benzylaminopurine (BA) and gibberellic acid (GA3) on the synthesis of secondary metabolites in species of Lamiaceae. In this study, for the first time, the profile of secondary metabolites in plantlets of Cunila menthoides was characterized, using UPLC-ESI-Qq-oaTOF-MS. Ninety metabolites were identified, including polyphenols and terpenes. BA down-regulated most of the identified molecules in relation to GA3 and MS0 (control). The results showed that GA3 elicited synthesis of many phenols from different classes, and seemed to play a major role in the shikimate pathway in relation to BA. GA3 enhanced production of sesquiterpenoids, polyterpenoids, steroids and monoterpenoids compared to MS0 and BA, and also seemed to positively influence the MEP/DOXP and MVA pathways. These data show the most comprehensive metabolomic profile of Cunila menthoides to date, and the effects of BA and GA3 on the synthesis of secondary metabolites, modulating quantitative aspects of metabolism in Lamiaceae.

Enhanced production of phenolic acids in cell suspension culture of Salvia leriifolia Benth. using growth regulators and sucrose

Salvia leriifolia Benth. (Lamiaceae) is an endangered medicinal plant with hypoglycemic, anti-inflammatory and analgesic properties. Many of the beneficial effects of Salvia spp. are attributed to the phenolic compounds. In the present study, an efficient procedure has been developed for establishment of cell suspension culture of S. leriifolia as a strategy to obtain an in vitro phenolic acids producing cell line for the first time. The effect of growth regulators and various concentrations of sucrose have been analyzed, to optimize biomass growth and phenolic acids production. The callus used for this purpose was obtained from leaves of 15-day-old in vitro seedlings, on Murashige and Skoog (MS) basal medium supplemented with different hormone balances including benzylaminopurine (BAP) and indole butyric acid (IBA); 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KIN); naphthaleneacetic acid (NAA) and BAP. Modified MS medium supplemented with 5 mg/L BAP and 5 mg/L NAA was the optimal condition for callus formation with the highest induction rate (100%), the best callus growth and the highest phenolic acids content. No callus induction was observed in combinations of IBA and BAP. Cell suspension cultures were established by transferring 0.5 g of callus to 30 mL liquid MS medium supplemented with 5 mg/L BAP and 5 mg/L NAA. Dynamics of phenolic acids production has been investigated during the growth cycle of the suspension cultures. The maximum content of caffeic acid and salvianolic acid B were observed on the 15th day of the cultivation cycle while the highest amount of rosmarinic acid was observed on the first day. In response to various sucrose concentrations, cell cultures with 40 g/L sucrose not only produced the highest dry biomass but also the highest induction of caffeic acid and salvianolic acid B. The highest amount of rosmarinic acid was observed in media containing 50 g/L sucrose. These prepared cell suspension cultures provided a useful system for further enhanced production of phenolic acids at a large scale.

Production of eurycomanone from cell suspension culture of Eurycoma longifolia

CONTEXT

Eurycomanone is found in the Eurycoma longifolia Jack (Simaroubaceae) tree, exhibits significant antimalarial activity, improves spermatogenesis, suppresses expression of lung cancer cell tumour markers and regulates signalling pathways involved in proliferation, cell death and inflammation.

OBJECTIVES

Establishment of cell suspension culture of E. longifolia to determine the eurycomanone accumulation during cultures.

MATERIALS AND METHODS

Callus of E. longifolia was cultured in MS medium supplemented with 0.8% agar, 30/L sucrose, 1.25 mg/L NAA and 1 mg/L KIN for biomass production. Cell suspension culture was established by transferring friable calli to the same medium without agar. Eurycomanone content during cell culture was determined by HPLC with a C18 column, flow rate of 0.8 mL/min, run time of 17.5 min, detector wavelength of 254 nm. The stationary phase was silica gel and the mobile phase was acetonitric:H₂O. Roots of 5 year-old trees were used as the control.

RESULTS

The cells from 3 g of inoculum increased in biomass with a maximum value of 16 g fresh weight (0.7 g dry weight) at 14th day of culture. The cell growth then decreased from day 14 to day 20. Eurycomanone was produced during culture from the beginning to 20th day, its highest content (1.7 mg/g dry weight) also obtained at 14th day (the control is 2.1 mg/g dry weight).

DISCUSSION AND CONCLUSIONS

Cell suspension culture of E. longifolia is a suitable procedure to produce eurycomanone. The yield of eurycomanone biosynthesis in 14 days-old cells are relatively high, approximately 0.8 times the control.

Establishment and characterization of a Satureja khuzistanica Jamzad (Lamiaceae) cell suspension culture: a new in vitro source of rosmarinic acid

An in vitro approach to the production of rosmarinic acid (RA), a medicinally important caffeic acid ester, in a cell suspension culture (CSC) of Satureja khuzistanica Jamzad (Lamiaceae) has been investigated for the first time. The CSC was established from friable calli derived from shoot tip explants in Gamborg's B5 liquid medium supplemented with 30 g/L sucrose, 20 mg/L L-glutamine, 200 mg/L casein hydrolysate, 5 mg/L benzyladenine (BA) and 1 mg/L indole-3-butyric acid (IBA). The effect of nitrogen source (KNO3 and (NH4)2SO4) and their different concentrations on the fresh and dry weight (g/L), as well as RA content (mg/g dry weight) were measured. CSC growth measurements indicated a maximum specific cell growth rate of 1.5/day, a doubling time of 7.6 days and a high percentage of cell viability (96.4 %) throughout the growth cycle. Maximum cell fresh weight (353.5 g/L), dry weight (19.7 g/L) and RA production (180.0 mg/g) were attained at day 21 of culture. Cell growth and RA content were affected by nitrogen deficiency. Media containing 8.3 mM of total nitrogen (¼ of B5 standard medium) led to a minimum cell fresh weight (243.0 g/L), dry weight (17.4 g/L) and RA content (38.0 mg/g) after 21 days. The established CSC provided useful material for further optimization experiments aimed at a large-scale production of RA.

Production and applications of rosmarinic acid and structurally related compounds

Rosmarinic acid (α-o-caffeoyl-3,4-dihydroxyphenyllactic acid; RA) is a naturally occurring hydroxylated compound commonly found in species of the subfamily Nepetoideae of the Lamiaceae and Boraginaceae, such as Rosmarinus officinalis, Salvia officinalis, and Perilla frutescens. RA is biosynthesized from the amino acids L-phenylalanine and L-tyrosine by eight enzymes that include phenylalanine ammonia lyase and cinnamic acid 4-hydroxylase. RA can also be chemically produced by the esterification of caffeic acid and 3,4-dihydroxyphenyllactic acid. RA and its numerous derivatives containing one or two RA with other aromatic moieties are well known and include lithospermic acid, yunnaneic acid, salvianolic acid, and melitric acid. Recently, RA and its derivatives have attracted interest for their biological activities, which include anti-inflammatory, anti-oxidant, anti-angiogenic, anti-tumor, and anti-microbial functions. Clinically, RA attenuates T cell receptor-mediated signaling, attenuates allergic diseases like allergic rhinitis and asthma, and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like symptoms, protects from neurotoxicity, and slows the development of Alzheimer's disease. These attributes have increased the demand for the biotechnological production and application of RA and its derivatives. The present review discusses the function and application of RA and its derivatives including the molecular mechanisms underlying clinical efficacy.

New trends in biotechnological production of rosmarinic acid

Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyl lactic acid, is widely distributed in the plant kingdom. Interest in it is growing due to its promising biological activities, including cognitive-enhancing effects and slowing the development of Alzheimer's disease, cancer chemoprotection or anti-inflammatory activity, among others. In order to meet the increasing demand for this compound, several biotechnological approaches to its production based on plant cell and hairy root cultures have been developed. Empirical strategies are currently being combined with metabolic engineering tools to increase RA production in plant cell platforms in a more rational way. Discussed here are the latest advances in the field, together with recent trends in plant biotechnology, such as the application of single use technology and the use of biosensors in downstream processes.

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.

Rosmarinic acid and its derivatives: biotechnology and applications

Rosmarinic acid (RA) is one of the first secondary metabolites produced in plant cell cultures in extremely high yields, up to 19% of the cell dry weight. More complex derivatives of RA, such as rabdosiin and lithospermic acid B, later were also obtained in cell cultures at high yields. RA and its derivatives possess promising biological activities, such as improvement of cognitive performance, prevention of the development of Alzheimer's disease, cardioprotective effects, reduction of the severity of kidney diseases and cancer chemoprevention. The TNF-α-induced NF-κB signaling pathway has emerged as a central target for RA. Despite these impressive activities and high yields, the biotechnological production of these metabolites on an industrial scale has not progressed. We summarized data suggesting that external stimuli, the Ca(2+)-dependent NADPH oxidase pathway and processes of protein phosphorylation/dephosphorylation are involved in the regulation of biosynthesis of these substances in cultured plant cells. In spite of growing information about pathways regulating biosynthesis of RA and its derivatives in cultured plant cells, the exact mechanism of regulation remains unknown. We suggest that further progress in the biotechnology of RA and its derivatives can be achieved by using new high-throughput techniques.

Cloning and characterisation of rosmarinic acid synthase from Melissa officinalis L

Lemon balm (Melissa officinalis L.; Lamiaceae) is a well-known medicinal plant mainly due to two groups of compounds, the essential oil and the phenylpropanoid derivatives. The prominent phenolic compound is rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid. RA shows a number of interesting biological activities. Rosmarinic acid synthase (RAS; 4-coumaroyl-CoA:hydroxyphenyllactic acid hydroxycinnamoyltransferase) catalyses the ester formation. Cell cultures of M. officinalis have been established in order to characterise the formation of RA in an important diploid medicinal plant. RAS activity as well as the expression of the RAS gene are closely correlated with the accumulation of RA in suspension cultures of M. officinalis. The RAS cDNA and gene (MoRAS) were isolated. The RAS gene was shown to be intron-free. MoRAS belongs to the BAHD superfamily of acyltransferases. Southern-blot analysis suggests the presence of only one RAS gene copy in the M. officinalis genome. The enzyme was characterised with respect to enzyme properties, substrate preferences and kinetic data in crude plant extracts and as heterologously synthesised protein from Escherichia coli.

Influence of growth regulators and sucrose concentrations on growth and rosmarinic acid production in calli and suspension cultures of Coleus blumei

Rosmarinic acid, which is reported to have adstringent, antibacterial, antiviral and antioxidant activities, is one of the most prominent secondary compounds in Coleus blumei (Lamiaceae). Rosmarinic acid (RA) production in different hybrids of C. blumei was estimated by HPLC. Conditions for HPLC were as follows: column, 150 x 4.6 mm; solvent system, methanol -0.1% phosphate (45 : 55); flow rate, 0.9 mL/min; detection: 325 nm. Two out of four hybrids of C. blumei (hy1; hy2) contain better rosmarinic acid production (0.9 and 1.0% dry weight, respectively) and the leaves have the highest rosmarinic acid production, followed by stems and roots. The hydroxyphenylpyruvate reductase (HPPR) gene expression levels were analysed by semi-quantitative RT-PCR. Hy3 shows highest level of HPPR gene expression out of four hybrids on genotype-specific patterns, and stems represent the highest level of HPPR gene expression among leaves, roots and stems. This was probably a result of the fact that the RA biosynthetic pathway was regulated by interactions of several enzymes necessary for biosynthesis. The explants from the hy1 leaves were used in subsequent studies on the effect of different growth regulators (2.0 mg L(-1) 6-benzyl-aminopurine (6-BA), different 2,4-dichlorophenxyaretic acid (2,4-D) and alpha-naphthaleneacetic (NAA) concentrations) and sucrose contents (1, 2, 3, 4, 5 or 6%) on culture growth and rosmarinic acid accumulation. On the effect of different growth regulators, the best result is obtained when the B5-medium supplemented is with 2.0 mg L(-1) 6-BA, 0.5 mg L(-1) NAA, 0.8 mg L(-1) 2,4-D and 2% sugar, and solidified with 0.8% agar. In this case, both growth index and rosmarinic acid accumulation reach a maximum, which is 49.7 and 25.3% (dry weight), respectively. The optimal medium for suspension culture growth contains 2.0 mg L(-1) 6-BA, 0.5 mg L(-1) NAA, 0.8 mg L(-1) 2,4-D, 600 mg L(-1) inositel and 2% sugar, and the rosmarinic acid production is 1.7% (dry weight). The rosmarinic acid accumulation is enhanced by the sucrose concentrations. When the sucrose content is 6%, the calli and cell culture accumulate 33.7% (dry weight) and 10.1% (dry weight) rosmarinic acid, respectively. Higher sucrose content (>or=5%) has a negative influence on culture growth. B5-medium supplemented with 2.0 mg L(-1) 6-BA, 0.5 mg L(-1) NAA, 0.8 mg L(-1) 2,4-D, 4% sugar and 0.8% agar is best for both culture growth and rosmarinic acid accumulation. On the basis of the above results, we can establish a two-phase culture system by calli of C. blumei for the biosynthesis of RA. In the growth phase, the calli grow well, but with lower RA production in a modified B5-1A medium with 2% sucrose. The calli are then subcultured to B5-1A medium with 6% sucrose where the calli start to accumulate RA, but grow slowly.

Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia virgata (Jacq), Salvia staminea (Montbret & Aucher ex Bentham) and Salvia verbenaca (L.) from Turkey

This study was designed to examine the in vitro antioxidant activities and rosmarinic acid levels of the methanol extracts of Salvia virgata, Salvia staminea and Salvia verbenaca. The extracts were screened for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid systems. In the first case, the most active plant was S. verbenaca (14.30+/-1.42 microg mg(-1)), followed by S. virgata (65.70+/-2.12 microg mg(-1)). S. staminae exhibited the weakest antioxidant activity in this test system of which IC(50) value is 75.40+/-0.57 microg mg(-1). In beta-carotene/linoleic acid test system, S. verbenaca extract was superior to the other extracts studied (inhibition value is 77.03%+/-0.42). Antioxidant activities of BHT, ascorbic acid, curcumin and alpha-tocopherol were determined in parallel experiments. Activity of rosmarinic acid was also screened for better establishing the relationship between rosmarinic acid level and antioxidant activity for the plant extracts. According to the results obtained by spectrophotometric analysis and further supported by HPLC, S. verbenaca has the highest rosmarinic acid level with a value of 29.30+/-0.24 microg mg(-1). Our results showed that the rosmarinic acid and its derivatives are more likely to be responsible for most of the observed antioxidant activities of Salvia species.

Production and optimisation of rosmarinic acid by Satureja hortensis L. callus cultures

In this study, production and optimisation of rosmarinic acid, a phenolic acid and an economically important metabolite, was investigated in the callus cultures established from the mature seeds of Satureja hortensis L. (summer savory) plant. Gamborg's B5 basal medium, supplemented with indol butyric acid (IBA) (1.00 mg L(-1)), N6-benzyl aminopurine (6-BA) (1.00 mg L(-1)) and sucrose (2.5%, w/v), was employed for the establishment and maintenance of the callus cultures. Applications were individually prepared by preparing the media containing different IBA/6-BA combinations and sucrose concentrations. All of the applications were carried out in the continuous dark. In the applications, where the effects of IBA/6-BA combinations on the growth and rosmarinic acid accumulation were assayed (1-15 applications), the highest biomass yield was obtained from the medium supplemented with 1.00 mg L(-1) IBA and 5.00 mg L(-1) 6-BA. In the case of the rosmarinic acid accumulation, an opposite relationship was determined between the growth and rosmarinic acid production. While the highest biomass yield was obtained from the medium containing 1.00 mg L(-1) IBA and 5.00 mg L(-1) 6-BA, the highest rosmarinic acid accumulation was obtained from the medium supported with 1.00 mg L(-1) IBA and 1.00 mg L(-1) 6-BA. In the applications where the effects of sucrose concentrations on the growth and rosmarinic acid accumulation were examined, the highest biomass yield was obtained from the medium which is supplemented with 5.0% (w/v) sucrose. In this category, the highest rosmarinic acid accumulation was obtained from the medium which is supported with 3.0% (w/v) sucrose. According to the experiments carried out with the wild S. hortensis, it is found to have 25.02+/-1.21 mg g(-1) rosmarinic acid. No differentiation was observed in any callus during the course of this study.

Growth optimization of Zataria multiflora Boiss. tissue cultures and rosmarinic acid production improvement

In order to improve the growth of Zataria multiflora tissues in vitro experiments in different hormonal treatments and culture media were carried out. Shoot cultures, established from plantlets shoot apex, were treated by different levels of 6-benzylaminopurine and 1-naphtalen acetic acid added to Murashige and Skoog medium with two conditions of active charcoal. The highest proliferation rate was obtained with 1 mg L(-1) 6-benzylaminopurine, without charcoal. Callus cultures of Zataria multiflora were established from plantlets shoot nodes on MS supplemented with 1 mg L(-1) kinetin and 0.5 mg L(-1) 2, 4-dichlorophenoxyacetic acid. Callus growth rate on three different media (MS salts and vitamins, MS salts with Gamborg vitamins and Gamborg salts and vitamins) was evaluated. The best growth was recorded on Gamborg medium (salts and vitamins) with 0.75 mg L(-1) 6-benzylaminopurine and this medium was retained for rosmarinic acid production optimization experimentation. Sucrose and glucose were tested at different doses to compare the effect of carbohydrates on the growing rate and the production ofrosmarinic acid in shoot cultures and callus cultures. Experiments also were done at two light exposures (total obscurity or 16 h light/8 h dark). Very high level of rosmarinic acid was detected in callus tissues (158.26 mg g(-1) dry weight) as compared with propagated shoots (12.28 mg g(-1) dry weight). The dose of carbohydrate had a direct effect on the production of rosmarinic acid dependent of the type of tissues. The best ratio production/growth was obtained in callus cultures treated with glucose 75 g L(-1) under light exposure. These results indicate that, in Zataria multiflora, the undifferentiated state of tissues appears particularly more efficient for metabolic production in vitro, such as rosmarinic acid, in comparison to differentiated shoots.

Plant cell cultures: Chemical factories of secondary metabolites

This review deals with the production of high-value secondary metabolites including pharmaceuticals and food additives through plant cell cultures, shoot cultures, root cultures and transgenic roots obtained through biotechnological means. Plant cell and transgenic hairy root cultures are promising potential alternative sources for the production of high-value secondary metabolites of industrial importance. Recent developments in transgenic research have opened up the possibility of the metabolic engineering of biosynthetic pathways to produce high-value secondary metabolites. The production of the pungent food additive capsaicin, the natural colour anthocyanin and the natural flavour vanillin is described in detail.

Determination of phenolic antioxidant compounds produced by calli and cell suspensions of sage (Salvia officinalis L.)

Sage (Salvia officinalis L.) calli were established by culturing internodal segments, excised from aseptic seedlings, on MS basal medium gellied with agar and supplemented with 0.05 mg/L dichlorophenoxyacetic acid (2,4-D) in presence of benzyladenine (BA) or zeatin (ZEA) or kinetin (KIN), at 1.5 mg/L. Suspended cells were established by transferring one callus to 50 mL of liquid MS basal medium devoid of agar and containing the same type of hormonal supplementation used in respective calli growth. The highest growth of calli and suspensions occurred with 1.5 mg/L ZEA. However, with this cytokinin supplementation, as well as with 1.5 mg/L KIN, both in presence of 0.05 mg/L 2,4-D, suspensions differentiated small root shaped structures. Well shaped, majority single cell suspensions were formed under the effect of 0.05 mg/L 2,4-D and 0.5 mg/L KIN. Calli grown with 0.05 mg/L 2,4-D and 1.5 mg/L BA and suspended cells grown with 0.05 mg/L 2,4-D and ZEA or KIN at 1.5 mg/L, or KIN at 0.5 mg/L, were searched for phenolics production. Twelve phenolic compounds were identified in calli: gallic acid, 3-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, caffeic acid, rosmarinic acid, hesperetin, epirosmanol, hispidulin, genkwanin, carnosol, carnosic acid, and methyl carnosate. With the exception for genkwanin and epirosmanol all of these phenolic compounds were also produced by the sage suspension cultures grown in the presence of 1.5 or 0.5 mg/L KIN. Genkwanin was the only phenolic absent in the suspensions grown with 1.5 ZEA. Suspended cells, grown with 0.5 mg/L KIN, and calli cultures showed the highest specific accumulation of the total phenolics, with rosmarinic acid representing 94-97%.

Essential oils produced by in vitro shoots of sage (Salvia officinalis L.)

In vitro shoots of sage (Salvia officinalis L.) were established under eight different hormonal supplementations and proliferated by subculture of nodal shoot segments. The respective essential oils, obtained by hydrodistillation, were composed of more than 75 compounds, 65 of which were identified. The 10 major compounds were, by order of retention time, alpha-pinene (4.1-5.4%), camphene (6-7.1%), beta-pinene (9.3-14.5%), limonene (2-2.3%), 1,8-cineole (3.6-5.6%), (-)-thujone (13.2-16.1%), (+)-isothujone (6.6-7.4%), camphor (19.8-24%), alpha-humulene (5.1-6.8%), and manool (4.2-7.7%). Notwithstanding the eight different hormonal supplementations tested, the percentage composition of the shoot essential oils were kept in a narrow range of variation. However, the type and concentration of growth regulators apparently influenced the accumulation of essential oils. The highest accumulation of essential oils and the highest shoot biomass growth were obtained with 2.0 mg/L kinetin and 0.05 mg/L 2,4-dichlorophenoxyacetic acid.

Large-scale cultivation ofSolanum chrysotrichum cells: Production of the antifungal saponin SC-1 in 10-I airlift bioreactors

Cells of two different cell lines:ccvx (cotyledon derived) andccvz (hypocotyl derived) ofSolanum chrysotrichum were cultivated in 10-1 airlift bioreactors for the production of the human antimycotic compound SC-1. When using 3 g l^-1 dry weight inoculum in a batch culture, higher levels of biomass were achieved with theccvx cell line (14.6 g l^-1) than withccvz (7.7 g l^-1), resulting in 23 and 12 mg g^-1 of SC-1 after 17 days in culture forccvx andccvz, respectively. The maximum productivity of SC-1 in bioreactors was 0.025 g l^-1 day^-1 after 9 days in culture. When using a draw-fill mode, the productivity increased by 60% to a value of 0.041 g l^-1 day, 4 days after 50% of the cell suspension was removed and replaced with fresh medium. This latter bioreactor system is a feasible alternative for the production of the antimycotic metabolite ofS. chrysotrichum on a large scale.