Biogenesis of rosmarinic acid in Mentha

Molecular Pathways of Rosmarinic Acid Anticancer Activity in Triple-Negative Breast Cancer Cells: A Literature Review

Breast cancer is the most frequent type of cancer in women. Oncogenic transcription factors promote the overproduction of cellular adhesion molecules and inflammatory cytokines during cancer development. Cancer cells exhibit significant upregulation of antiapoptotic proteins, resulting in increased cell survival, tumor growth, and metastasis. Research on the cell cycle-mediated apoptosis pathway for drug discovery and therapy has shown promising results. In fact, dietary phytoconstituents have been extensively researched for anticancer activity, providing indirect protection by activating endogenous defense systems. The role of polyphenols in key cancer signaling pathways could shed light on the underlying mechanisms of action. For instance, Rosmarinic Acid, a polyphenol constituent of many culinary herbs, has shown potent chemoprotective properties. In this review, we present recent progress in the investigation of natural products as potent anticancer agents, with a focus on the effect of Rosmarinic Acid on triple-negative BC cell lines resistant to hormone therapy. We highlight a variety of integrated chemical biology approaches aimed at utilizing relevant mechanisms of action that could lead to significant clinical advances in BC treatment.

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

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.

Bioactive Secondary Metabolites from Plant Sources: Types, Synthesis, and Their Therapeutic Uses

Plants are the source of various photochemicals; metabolites are used in medicinal and environmental sectors as well as being widely used in commercial and pharmaceutical products. Although they produce a number of medicinal products, either already on the market or under trial, the amounts obtained from plant sources are very minute or difficult to synthesize at an industrial level due to the complex chemical composition and chirality exhibited by these compounds. However, plant cell cultures offer a good alternative for the consistent production of desired secondary metabolites under the influence of precursors and elicitors. In this review, we discuss the various aspects of secondary metabolites, production synthesis, and sources of medical products from plant sources.

Identification and biochemical characterisation of tyrosine aminotransferase from Anthoceros agrestis unveils the conceivable entry point into rosmarinic acid biosynthesis in hornworts

MAIN CONCLUSION

Tyrosine aminotransferase (AaTAT) from the hornwort Anthoceros agrestis Paton (Anthocerotaceae) was amplified and expressed in E. coli. The active enzyme is able to accept a wide range of substrates with distinct preference for L-tyrosine, therefore, possibly catalysing the initial step in rosmarinic acid biosynthesis. The presence of rosmarinic acid (RA) in the hornwort A. agrestis is well known, and some attempts have been made to clarify the biosynthesis of this caffeic acid ester in lower plants. Parallel to the biosynthesis in vascular plants, the involvement of tyrosine aminotransferase (EC 2.6.1.5; TAT) as the initial step was assumed. The amplification of a nucleotide sequence putatively encoding AaTAT (Genbank MN922307) and expression in E. coli were successful. The enzyme proved to have a high acceptance of L-tyrosine (Km 0.53 mM) whilst slightly preferring 2-oxoglutarate over phenylpyruvate as co-substrate. Applying L-phenylalanine as a potential amino donor or using oxaloacetate or pyruvate as a replacement for 2-oxoglutarate as amino acceptor resulted in significantly lower catalytic efficiencies in each of these cases. To facilitate further substrate search, two methods were introduced, one using ninhydrin after thin-layer chromatography and the other using derivatisation with o-phthalaldehyde followed by HPLC or LC-MS analysis. Both methods proved to be well applicable and helped to confirm the acceptance of further aromatic and aliphatic amino acids. This work presents the first description of a heterologously expressed TAT from a hornwort (A. agrestis) and describes the possible entry into the biosynthesis of RA and other specialised compounds in a so far neglected representative of terrestrial plants and upcoming new model organism.

Network Pharmacology and Molecular Docking Suggest the Mechanism for Biological Activity of Rosmarinic Acid

Rosmarinic acid (RosA) is a natural phenolic acid compound, which is mainly extracted from Labiatae and Arnebia. At present, there is no systematic analysis of its mechanism. Therefore, we used the method of network pharmacology to analyze the mechanism of RosA. In our study, PubChem database was used to search for the chemical formula and the Chemical Abstracts Service (CAS) number of RosA. Then, the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) was used to evaluate the pharmacodynamics of RosA, and the Comparative Toxicogenomics Database (CTD) was used to identify the potential target genes of RosA. In addition, the Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of target genes were carried out by using the web-based gene set analysis toolkit (WebGestalt). At the same time, we uploaded the targets to the STRING database to obtain the protein interaction network. Then, we carried out a molecular docking about targets and RosA. Finally, we used Cytoscape to establish a visual protein-protein interaction network and drug-target-pathway network and analyze these networks. Our data showed that RosA has good biological activity and drug utilization. There are 55 target genes that have been identified. Then, the bioinformatics analysis and network analysis found that these target genes are closely related to inflammatory response, tumor occurrence and development, and other biological processes. These results demonstrated that RosA can act on a variety of proteins and pathways to form a systematic pharmacological network, which has good value in drug development and utilization.

Application of 1H-NMR combined with qRT-PCR technology in the exploration of rosmarinic acid biosynthesis in hair roots of Salvia miltiorrhiza Bunge and Salvia castanea f. tomentosa Stib

MAIN CONCLUSION

Methyl jasmonate promotes the synthesis of rosmarinic acid in Salvia miltiorrhiza Bunge and Salvia castanea f. tomentosa Stib, and it promotes the latter more strongly. Salvia miltiorrhiza Bunge (SMB) is a traditional Chinese medicinal material, its water-soluble phenolic acid component rosmarinic acid has very important medicinal value. Salvia castanea f. tomentosa Stib (SCT) mainly distributed in Nyingchi, Tibet. Its pharmacological effects are similar to SMB, but its rosmarinic acid is significantly higher than the former. Methyl jasmonate (MJ) as an inducer can induce the synthesis of phenolic acids in SMB and SCT. However, the role of MJ on rosmarinic acid in SMB is controversial. Therefore, this study used SMB and SCT hair root as an experimental material and MJ as a variable. On one hand, exploring the controversial reports in SMB; on the other hand, comparing the differences in the mechanism of action of MJ on the phenolic acids in SMB and SCT. The content of related metabolites and the expression of key genes in the synthesis pathway of rosmarinic acid was analyzed by 1H-NMR combined with qRT-PCR technology. Our research has reached the following conclusions: first of all, MJ promotes the accumulation of rosmarinic acid and related phenolic acids in the metabolic pathways of SMB and SCT. After MJ treatment, the content of related components and gene expression are increased. Second, compared to SMB, SCT has a stronger response to MJ. It is speculated that the different responses of secondary metabolism-related genes to MJ may lead to different metabolic responses of salvianolic acid between the two.

Polyphenol Profile and Antimicrobial and Cytotoxic Activities of Natural Mentha × piperita and Mentha longifolia Populations in Northern Saudi Arabia

New sources of polyphenols with anticancer, antioxidant, and antimicrobial properties in arid environments are critical for the development of alternative medicines and natural remedies. This study explored the polyphenol profiles and biological activities of methanolic leaf extracts from natural Mentha × piperita and Mentha longifolia populations in northern Saudi Arabia. Chromatographic analyses identified several polyphenols in M. × piperita including phenolic acids: rosmarinic acid (1547.6 mg/100 g DW (dry weight)), cryptochlorogenic acid (91.7 mg/100 g DW), and chlorogenic acid (69.4 mg/100 g DW), as well as flavonoids: naringin (328.8 mg/100 g DW) and cynaroside (162.8 mg/100 g DW). The major polyphenols in M. longifolia were: rosmarinic acid (781.6 mg/100 g DW), cryptochlorogenic acid (191.1 mg/100 g DW), p-coumaric acid (113.0 mg/100 g DW), m-coumaric acid (112.2 mg/100 g DW), and chlorogenic acid (63.8 mg/100 g DW). M. × piperita and M. longifolia leaf extracts had high antioxidant activities due to the major polyphenols (cynaroside, rosmarinic and cryptochlorogenic acids). M. × piperita had higher activities against different cancer cells than M. longifolia. Naringin, cryptochlorogenic acid, and rosmarinic acid had the highest activities against cancer cells. The leaf extracts had antibacterial effects against most bacteria species (Pseudomonas aeruginosa was most sensitive), which was attributed to the polyphenols. Antifungal activities were similarly broad (Aspergillus flavus was most sensitive) and attributed to naringin, cryptochlorogenic acid, and caffeic acid. Populations of M. × piperita and M. longifolia in Northern Riyadh may be a valuable source of natural biologically active compounds.

Induction of Biosynthetic Genes Related to Rosmarinic Acid in Plant Callus Culture and Antiproliferative Activity Against Breast Cancer Cell Line

BACKGROUND AND OBJECTIVE

Rosmarinic acid is considered as one of the most important secondary metabolites in medicinal plants especially of family Lamiaceae. Rosmarinic acid can prevent both the tumor initiation and promotion stages of carcinogenesis. The aim of current study was to evaluate the antiproliferative effects of Hyssopus officinalis and Thymus vulgaris callus crude extracts contained rosmarinic acid on breast cancer cells with correlation to phenylpropanoid biosynthetic pathway genes expression.

MATERIALS AND METHODS

Calli of both plants were maintained on Murashige and Skoog medium supplemented with kinetin and 2,4-D. Rosmarinic acid was determined spectrophotometrically in both seed-germinated plants (control) and callus tissues. Transcriptional profiling of rosmarinic acid pathway genes was performed with RT-PCR system. The human breast cancer cell line MCF-7 was treated with different levels of crude extracts at different time intervals in order to show their effects on the cell proliferation using a cell viability colorimetric assay (MTT).

RESULTS

The results showed a significant increase of rosmarinic acid content up to 6.5% in callus compared to control. The transcriptional profile of the selected rosmarinic acid genes in callus tissues indicated significant effects on the rosmarinic acid content in both genotypes. T. vulgaris (90 μg mL-1) and H. officinalis (150 μg mL-1) callus extracts had exhibited highest reduction in the cell MCF-7 viability after 48 h of exposure.

CONCLUSION

It was concluded that rosmarinic acid production increased in callus tissue, showed the higher gene expression levels and remarkably inhibited growth of human breast cancer cell line.

Chitosan enhances rosmarinic acid production in shoot cultures of Melissa officinalis L. through the induction of methyl jasmonate

BACKGROUND

Chitosan is a polycationic polysaccharide derived from chitin that has been recognized as an effective elicitor in the production of secondary metabolites of many medicinal plants. In this study, the effect of abiotic elicitor (chitosan) at various concentrations on rosmarinic acid (RA) and total phenolic accumulation in shoot cultures of lemon balm was investigated.

RESULTS

Treatment of shoots by chitosan led to a noticeable induction of phenylalanine ammonia-lyase (PAL), catalase (CAT), guaiacol peroxidase (GPX) and lipoxygenase (LOX) activities. Besides, the expression of PAL1, TAT and RAS genes and accumulation of RA and phenolic compound increased in chitosan-treated lemon balm shoots. Chitosan treatment also increased H2O2 accumulation and the expression of RBOH, an essential gene implicated in ROS production. Also, the up-regulation of the OPR gene by exogenous chitosan was associated with the induction of endogenous JA determined by GC-MASS.

CONCLUSION

The present study showed that the induced production of rosmarinic acid by chitosan involves the trigger of defense-related enzymes, up-regulated expression of TAT and RAS genes, and stimulation of JA biosynthesis.

Exogenous application of rosmarinic acid improves saccharification without affecting growth and lignification of maize

Biomimetically incorporated into the lignin structure, rosmarinic acid improves in vitro maize cell wall saccharification; however, no in planta studies have been performed. We hypothesized that rosmarinic acid, itself, could inducer saccharification without disturbing plant growth. Its effects on growth, enzymes of the phenylpropanoid pathway, lignin, monomeric composition, and saccharification of maize were evaluated. In a short-term (24 h) exposure, rosmarinic acid caused deleterious effects on maize roots, inhibiting the first enzymes of the phenylpropanoid pathway, phenylalanine ammonia-lyase and tyrosine ammonia-lyase, altering lignin composition and slightly increasing saccharification. In a long-term (14 d) exposure, rosmarinic acid increased saccharification of maize stems by about 50% without any deleterious effects on plant growth, the phenylpropanoid pathway and lignin formation. This demonstrated that exogenous application of rosmarinic acid on maize plants improved saccharification, and represented an interesting approach in facilitating enzymatic hydrolysis of biomass polysaccharides and increasing bioethanol production.

Identification of a novel S6K1 inhibitor, rosmarinic acid methyl ester, for treating cisplatin-resistant cervical cancer

Background

The mTOR/S6K1 signaling pathway is often activated in cervical cancer, and thus considered a molecular target for cervical cancer therapies. Inhibiting mTOR is cytotoxic to cervical cancer cells and creates a synergistic anti-tumor effect with conventional chemotherapy agents. In this study, we identified a novel S6K1 inhibitor, rosmarinic acid methyl ester (RAME) for the use of therapeutic agent against cervical cancer.

Methods

Combined structure- and ligand-based virtual screening was employed to identify novel S6K1 inhibitors among the in house natural product library. In vitro kinase assay and immunoblot assay was used to examine the effects of RAME on S6K1 signaling pathway. Lipidation of LC3 and mRNA levels of ATG genes were observed to investigate RAME-mediated autophagy. PARP cleavage, mRNA levels of apoptotic genes, and cell survival was measured to examine RAME-mediated apoptosis.

Results

RAME was identified as a novel S6K1 inhibitor through the virtual screening. RAME, not rosmarinic acid, effectively reduced mTOR-mediated S6K1 activation and the kinase activity of S6K1 by blocking the interaction between S6K1 and mTOR. Treatment of cervical cancer cells with RAME promoted autophagy and apoptosis, decreasing cell survival rate. Furthermore, we observed that combination treatment with RAME and cisplatin greatly enhanced the anti-tumor effect in cisplatin-resistant cervical cancer cells, which was likely due to mTOR/S6K1 inhibition-mediated autophagy and apoptosis.

Conclusions

Our findings suggest that inhibition of S6K1 by RAME can induce autophagy and apoptosis in cervical cancer cells, and provide a potential option for cervical cancer treatment, particularly when combined with cisplatin.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5997-2) contains supplementary material, which is available to authorized users.

Recent Advances in the Analysis of Rosmarinic Acid From Herbs in the Lamiaceae Family

Rosmarinic acid (RA) is a phenolic acid found in a variety of plants, especially those in the Lamiaceae family. A number of biological effects are attributed to the compound; so, in recent years, RA has been the focus of many studies. The aim of this review is to provide information on the latest developments on flow chromatography analysis of RA. A reverse-phase high-performance liquid chromatography (HPLC) method with gradient elution and either diode array or mass spectrometric detection is usually used to measure the compound. Factors affecting the performance of HPLC analysis of RA such as sample preparation, column, mobile phase, and detection methods are discussed in detail in this review.

Derivatization of Rosmarinic Acid Enhances its in vitro Antitumor, Antimicrobial and Antiprotozoal Properties

On its own, rosmarinic acid possesses multiple biological activities such as anti-inflammatory, antimicrobial, cardioprotective and antitumor properties, and these are the consequence of its ROS scavenging and inhibitory effect on inflammation. In this study, two quaternary phosphonium salts of rosmarinic acid were prepared for the purpose of increasing its penetration into biological systems with the aim of improving its antimicrobial, antifungal, antiprotozoal and antitumor activity. The synthetized molecules, the triphenylphosphonium and tricyclohexylphosphonium salts of rosmarinic acid, exhibited significantly stronger inhibitory effects on the growth of HCT116 cells with IC50 values of 7.28 or 8.13 μM in comparison to the initial substance, rosmarinic acid (>300 μM). For the synthesized derivatives, we detected a greater than three-fold increase of activity against Acanthamoeba quina, and a greater than eight-fold increase of activity against A. lugdunensis in comparison to rosmarinic acid. Furthermore, we recorded significantly higher antimicrobial activity of the synthetized derivatives when compared to rosmarinic acid itself. Both synthetized quaternary phosphonium salts of rosmarinic acid appear to be promising antitumor and antimicrobial agents, as well as impressive molecules for further research.

Chemical composition and antioxidant activity of phenolic compounds and essential oils from Calamintha nepeta L

Background Essential oils, infusion and decoction extracts of Calamintha nepeta L. were evaluated for their bioactive substances (polyphenols and essential oils) and antioxidant activities. Methods The amounts of phenolic compounds were determined by colorimetric assays and identified by high performance and liquid chromatography coupled with ultraviolet detector (HPLC-UV) method. The chemical composition of essential oils was determined by gas-chromatography coupled with mass spectrometry (GC/MS) method. For the evaluation of the antioxidant activity of essential oils and extracts, two different assays (reducing power and DPPH radical scavenging activity) were used. Results Infusion extract presented the highest phenolic content, followed by the decoction one, while the lowest amount was observed in essential oils. The amount of flavonoids of the decocted extract was higher than that of the infused one. The phenolic profile of C. nepeta infusion and decoction extracts revealed the presence of 28 and 13 peaks, respectively. Four phenolics compounds were identified in infusion (gallic acid (GA), rosmarinic acid (RA), caffeine (C) and caffeic acid (CA)) and two were identified in decoction (GA and RA). The chemical composition of essential oils revealed the presence of 29 compounds, accounting for the 99.7% of the total oils. Major compounds of essential oil (EO) were trans-menthone (50.06%) and pulegone (33.46%). Infusion and decoction extracts revealed an interesting antioxidant activity which correlates positively with their total phenolic contents. Conclusions These results showed that Calamintha nepeta could be considered as a valuable source of phenolics and essential oils with potent antioxidant activity.

Molecular Pharmacology of Rosmarinic and Salvianolic Acids: Potential Seeds for Alzheimer's and Vascular Dementia Drugs

Both caffeic acid and 3,4-dihydroxyphenyllactic acid (danshensu) are synthesized through two distinct routs of the shikimic acid biosynthesis pathway. In many plants, especially the rosemary and sage family of Lamiaceae, these two compounds are joined through an ester linkage to form rosmarinic acid (RA). A further structural diversity of RA derivatives in some plants such as Salvia miltiorrhiza Bunge is a form of RA dimer, salvianolic acid-B (SA-B), that further give rise to diverse salvianolic acid derivatives. This review provides a comprehensive perspective on the chemistry and pharmacology of these compounds related to their potential therapeutic applications to dementia. The two common causes of dementia, Alzheimer's disease (AD) and stroke, are employed to scrutinize the effects of these compounds in vitro and in animal models of dementia. Key pharmacological mechanisms beyond the common antioxidant and anti-inflammatory effects of polyphenols are highlighted with emphasis given to amyloid beta (Aβ) pathologies among others and neuronal regeneration from stem cells.

The cardioprotective effect of rosmarinic acid on acute myocardial infarction and genes involved in Ca2+ homeostasis

Acute myocardial infarction (AMI) is a common cause of hospitalisation and high mortality due to lethal arrhythmias. Sarcoplasmic reticulum Ca2+ ATPase (SERCA2) and ryanodine receptor (RyR2) regulate the cytosolic Ca2+ ion concentration. Rosmarinic acid (RA) is one of the most common caffeic esters in Rosmarinus officinalis. The present study was conducted to test the hypothesis whether RA can protect cardiac function against AMI and arrhythmias induced by isoproterenol through the regulatory effect of SERCA2 and RyR2 gene expression. To this aim, male Sprague-Dawley rats were allocated into in vivo and ex vivo studies and received RA (10, 15, and 30 mg/kg; 14 days). AMI was induced by two consecutive subcutaneous injections of 100 mg/kg isoproterenol. Blood pressure (BP), heart rate, electrocardiography (ECG) parameters, plasma levels of cardiac biomarkers, and antioxidative enzymes were evaluated (in vivo study). Cardiac functions were measured in isolated hearts using Langendorff set up. Gene expressions of SERCA2 and RyR2 were measured in left ventricular heart. Isoproterenol administration showed a significant decline in BP, QRS voltage, activities of antioxidant enzymes, cardiac function, and gene expressions of SERCA2 and RyR2. The results also indicated a significant increase in heart rate, ST-elevation, cardiac biomarkers, and antioxidant enzymes. RA at 30 mg/kg dosage showed the best effect on the improvement of the mentioned factors. This study suggests that RA has potent cardioprotective effects against AMI and arrhythmia, which may be due to its ability to enhance expression of plasma antioxidant enzymes and genes involved in Ca2+ homeostasis SERCA2 and RyR2. The protective role of RA is also possibly related to its antiadrenergic effects.

Rosmarinic acid: modes of action, medicinal values and health benefits

The supplementation of livestock rations with herbs containing bioactive components, such as rosmarinic acid (RA), have shown promising results as a natural feed additive in promoting growth, productive and reproductive performance, feed utilization, fertility, anti-oxidant status and immunologic indices. Furthermore, RA reportedly reduces the risks of various animal diseases and mitigates side effects of chemical and synthetic drugs. RA is a natural polyphenol present in several Lamiaceae herbs like Perilla frutescens, and RA is becoming an integral component of animal nutrition as it counters the effect of reactive oxygen species induced in the body as a consequence of different kinds of stressors. Studies have further ascertained the capability of RA to work as an anti-microbial, immunomodulatory, anti-diabetic, anti-allergic, anti-inflammatory, hepato- and renal-protectant agent, as well as to have beneficial effects during skin afflictions. Additionally, RA is favored in meat industries due to enhancing the quality of meat products by reportedly improving shelf-life and imparting desirable flavor. This review describes the beneficial applications and recent findings with RA, including its natural sources, modes of action and various useful applications in safeguarding livestock health as well as important aspects of human health.

Rosmarinic acid induces rabbit articular chondrocyte differentiation by decreases matrix metalloproteinase-13 and inflammation by upregulating cyclooxygenase-2 expression

BACKGROUND

Matrix metalloproteinases (MMPs) are known to play an important role in the degradation of the extracellular matrix and the pathological progression of osteoarthritis (OA). The natural polyphenolic compound rosmarinic acid (Ros. A) has been shown to suppress the inhibitory activity of matrix metalloproteinases (MMPs). However, the effects of Ros. A on OA have not been investigated.

METHODS

In the current study, primary articular chondrocytes were cultured from rabbit articular cartilage and treated with Ros. A. Phenotypic characterization was performed by western blotting to assess specific markers, prostaglandin E2 (PGE2) assays, and alcian blue staining to measure sulfated-proteoglycan production.

RESULTS

We report that in rabbit articular chondrocytes, Ros. A increased type II collagen, sulfated-proteoglycan, cyclooxygenase-2 (COX-2), and PGE2 production in a dose- and time-dependent manner. Furthermore, Ros. A suppressed the expression of MMP-13. In addition, treatment with Ros A activated extracellular signal-regulated kinase (ERK)-1/2 and p38 kinase signaling pathways. Inhibition of MMP-13 enhanced Ros. A-induced type II collagen expression and sulfated-proteoglycan synthesis but COX-2 and PGE2 production were unchanged. Ros. A-mediated up-regulation of ERK phosphorylation was abolished by the MEK inhibitor, PD98059, which prevented induction of the associated inflammatory response. Inhibition of p38 kinase with SB203580 enhanced the increase in type II collagen expression via Ros. A-mediated down-regulation of MMP-13.

CONCLUSIONS

Results suggest that ERK-1/2 regulates Ros. A-induced inflammation and that p38 regulates differentiation by inhibiting MMP-13 in rabbit articular chondrocytes.

A tyrosine aminotransferase involved in rosmarinic acid biosynthesis in Prunella vulgaris L

Rosmarinic acid (RA) and its derivants are medicinal compounds that comprise the active components of several therapeutics. We isolated and characterised a tyrosine aminotransferase of Prunella vulgaris (PvTAT). Deduced PvTAT was markedly homologous to other known/putative plant TATs. Cytoplasmic localisation of PvTAT was observed in tobacco protoplasts. Recombinantly expressed and purified PvTAT had substrates preference for L-tyrosine and phenylpyruvate, with apparent K m of 0.40 and 0.48 mM, and favoured the conversion of tyrosine to 4-hydroxyphenylpyruvate. In vivo activity was confirmed by functional restoration of the Escherichia coli tyrosine auxotrophic mutant DL39. Agrobacterium rhizogenes-mediated antisense/sense expression of PvTAT in hairy roots was used to evaluate the contribution of PvTAT to RA synthesis. PvTAT were reduced by 46-95% and RA were decreased by 36-91% with low catalytic activity in antisense transgenic hairy root lines; furthermore, PvTAT were increased 0.77-2.6-fold with increased 1.3-1.8-fold RA and strong catalytic activity in sense transgenic hairy root lines compared with wild-type counterparts. The comprehensive physiological and catalytic evidence fills in the gap in RA-producing plants which didn't provide evidence for TAT expression and catalytic activities in vitro and in vivo. That also highlights RA biosynthesis pathway in P. vulgaris and provides useful information to engineer natural products.

Transcriptomic analyses reveal biosynthetic genes related to rosmarinic acid in Dracocephalum tanguticum

Dracocephalum tanguticum Maxim, a Lamiaceae species endemic to the Qinghai-Tibetan Plateau and adjacent regions, is an important ornamental, medicinal and aromatic herb. In this study, a comprehensive transcriptome of 18 libraries from six organs namely, roots, stems, leaves, sepals, flowers and seeds of D. tanguticum were generated. More than 100 Gb of sequence data were obtained and assembled de novo into 187,447 transcripts, including 151,463 unigenes, among which the six organs shared 17.7% (26,841). In addition, all unigenes were assigned to 362 pathways, in which 'biosynthesis of secondary metabolites' is the second enriched pathway. Furthermore, rosmarinic acid (RA) is one of the multifunctional phenolic bioactive compounds produced in some Lamiaceae species. The six organs of D. tanguticum were confirmed to produce RA. A total of 22 predicted biosynthetic genes related to RA from the transcriptome were further isolated. Two of these genes were identified as candidates by evaluating the correlation coefficient between the RA contents and the expression of the predicted biosynthetic genes in the six organs. The new sequence information will improve the knowledge of D. tanguticum, as well as provide a reference tool for future studies of biosynthetic genes related to RA in this species.

Stability of Rosmarinic Acid in Aqueous Extracts from Different Lamiaceae Species after in vitro Digestion with Human Gastrointestinal Enzymes

The present study compares the gastrointestinal stability of rosmarinic acid in aqueous extracts of thyme, winter savory and lemon balm with the stability of pure rosmarinic acid. The stability of rosmarinic acid was detected after two-phase in vitro digestion process (gastric and duodenal) with human gastrointestinal enzymes. The concentration of rosmarinic acid in undigested and digested samples was detected using HPLC-DAD. Results showed that gastrointestinal stability of pure rosmarinic acid was significantly higher than that of rosmarinic acid from plant extracts after both gastric and intestinal phases of digestion. Among plant extracts, rosmarinic acid was the most stable in lemon balm after gastric (14.10%) and intestinal digestion phases (6.5%). The temperature (37 °C) and slightly alkaline medium (pH=7.5) did not affect the stability of rosmarinic acid, while acid medium (pH=2.5) significantly decreased its stability (≥50%). In addition, the stability rate of rosmarinic acid is influenced by the concentration of human gastrointestinal juices.

In vitro propagation and cell cultures of memory tonic herb Evolvulus alsinoides: a best source for elicited production of scopoletin

Evolvulus alsinoides L. is used for preparation of 'Shankhapushpi', an important popular ayurvedic drug that contributes considerably to the improvement of memory power. The improvement is attributed to the presence of furanocoumarin scopoletin, a metabolite with a wide range of biological activities. This report describes, for the first time, an in vitro culture system for propagation and enhanced production of scopoletin. Different concentrations of auxins and cytokinins individually and in combination were used in Murashige and Skoog (MS) medium to induce shoot regeneration in cotyledonary nodal explants and callus formation in leaf explants. The best response was achieved in MS medium fortified with 5.0 μM 6-benzyladenine (BA) in which 96 % of cultures produced 7.6 ± 0.6 shoots per explant. Regenerated shoots were rooted on MS medium with 5.0 μM indole-3-acetic acid (IAA). Plantlets were successfully acclimatized and established in soil. MS medium fortified with 10 μM BA + 5.0 μM IAA showed maximum growth and accumulation of scopoletin in cell cultures. Cell cultures could be maintained over 24 months. The influences of auxins, cytokinins, organic acids, amino acids, and fungal-derived elicitors on production of scopoletin were studied. Presence of either L-arginine, sodium pyruvate, or yeast extract highly promoted scopoletin production as compared with control and achieved 75.02-, 72.13-, and 57.98-fold higher accumulation, respectively. The results presented herein have laid solid foundation for large-scale production of scopoletin and further investigation of its purification and utilization as a novel pharmaceutical drug.

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.

Biosynthesis of Fukinolic Acid Isolated fromPetasites japonicus

The biosynthesis of fukinolic acid, which had been isolated from the Japanese fuki vegetable, Petasites japonicus, was investigated by feeding selected (13)C-labeled compounds to axenic cultures of P. japonicus. [1,2-(13)C(2)] sodium acetate and [1-(13)C] L-tyrosine were incorporated into the fukiic acid sub group, while [3-(13)C] L-phenylalanine was incorporated into the caffeic acid moiety.

Selective responses of enzymes in the two parallel pathways of rosmarinic acid biosynthetic pathway to elicitors in Salvia miltiorrhiza hairy root cultures

Rosmarinic acid and salvianolic acid B are two important phenolic compounds with therapeutic properties in Salvia miltiorrhiza Bunge. The biosynthesis of rosmarinic acid is initiated by two parallel pathways, namely the phenylpropanoid pathway and the tyrosine-derived pathway. Salvianolic acid B is a structural dimer of rosmarinic acid and is believed to be derived from rosmarinic acid. In the current study, methyl jasmonate (MeJA) and hyphal extracts from fungi were used as elicitors to examine the relationship between enzymes in the two parallel pathways and accumulation of phenolic compounds in S. miltiorrhiza hairy root cultures. The results showed that accumulations of rosmarinic acid, salvianolic acid B and total phenolics were enhanced by MeJA while suppressed by fugal extracts. Responses of enzymes in the tyrosine-derived pathway, at both the gene transcript and enzyme activity levels, showed a better consistency with alterations of phenolic compounds content after the two elicitors treated. Our study implied that compared with enzymes in the phenylpropanoid pathway, enzymes in the tyrosine-derived pathway are more correlated to rosmarinic acid and salvianolic acid B biosynthesis in S. miltiorrhiza hairy roots.

Chemical constituents of Plectranthus amboinicus and the synthetic analogs possessing anti-inflammatory activity

This study demonstrates that compounds 1-4 from an extract of Plectranthus amboinicus inhibit the binding of AP-1 to its consensus DNA sequence. Thymoquinone (5) was further identified as a nonpolar ingredient from the hexane extract of P. amboinicus to suppress the expression of lipopolysaccharide-induced tumor necrosis factor-alpha (TNF-α). We then synthesized 2-alkylidenyl-4-cyclopentene-1,3-diones as the designed biomimetics of thymoquinone, and found that compounds 8a, 8b and 8d were more potent TNF-α inhibitors.

In-vitro Callus Induction and Rosmarinic Acid Quantification in Callus Culture of Satureja khuzistanica Jamzad (Lamiaceae)

In the present study, an efficient protocol has been developed for callus induction and production of RA in callus culture of Satureja khuzistanica for the first time. In-vitro callus induction was achieved from young shoot tip explants cultured on MS and B5 media supplemented with different concentrations of IBA (0.1, 1.0, 2.0 and 5.0 mgL(-1)) solely or in combination with cytokinins BAP and KIN (1.0, 2.0 and 5.0 mgL(-1)). B5 medium supplemented with 1.0 mgL(-1) IBA plus 5.0 mgL(-1) BAP and MS medium fortified with 2.0 mgL(-1) IBA and 2.0 mgL(-1) BAP were the most favorable media for callus formation with the highest induction rate (96%). Maximum growth index (2.89 and 2.63) and maximum callus biomass (2.34 and 2.33 g fresh weight) were obtained from the callus cultured on B5 medium supplemented with 1.0 mgL(-1) IBA plus 5.0 mgL(-1) BAP and MS medium fortified with 1.0 mgL(-1) IBA plus 1.0 mgL(-1) KIN, respectively. Determination and quantification of RA in cultured calli were performed by HPLC UV/MS analysis. Calli induced from the plant and maintained on supplements of IBA and BAP in the absence of light produced RA 7.5% based on dry weight (DW). No differentiation was observed in any callus during the course of this study.

Cloning and characterization of a putative R2R3 MYB transcriptional repressor of the rosmarinic acid biosynthetic pathway from Salvia miltiorrhiza

Salvia miltiorrhiza Bunge is one of the most renowned traditional medicinal plants in China. Phenolic acids that are derived from the rosmarinic acid pathway, such as rosmarinic acid and salvianolic acid B, are important bioactive components in S. miltiorrhiza. Accumulations of these compounds have been reported to be induced by various elicitors, while little is known about transcription factors that function in their biosynthetic pathways. We cloned a subgroup 4 R2R3 MYB transcription factor gene (SmMYB39) from S. miltiorrhiza and characterized its roles through overexpression and RNAi-mediated silencing. As the results showed, the content of 4-coumaric acid, rosmarinic acid, salvianolic acid B, salvianolic acid A and total phenolics was dramatically decreased in SmMYB39-overexpressing S. miltiorrhiza lines while being enhanced by folds in SmMYB39-RNAi lines. Quantitative real-time PCR and enzyme activities analyses showed that SmMYB39 negatively regulated transcripts and enzyme activities of 4-hydroxylase (C4H) and tyrosine aminotransferase (TAT). These data suggest that SmMYB39 is involved in regulation of rosmarinic acid pathway and acts as a repressor through suppressing transcripts of key enzyme genes.

Is rosmarinic acid underestimated as an experimental cardiovascular drug?

PURPOSE

The rationale of the present review is to analize the activity of Rosmarinus officinalis in the the cardiovascular system

METHODS

A MEDLINE database search (from January 1970 to December 2011) using only rosmarinic acid as searched term.

RESULTS

The references search revealed 509 references about rosmarinic acid in 40 years (the first reference is from 1970). There is a powerful prevalence of antioxidant and cancer studies. Other diseases are few cited, as inflammation, brain (Alzheimer and Parkinson disease) and, memory; allergy; diabetes; atherosclerosis, and; hypertension. It is necessary to consider the complete absence of studies on coronary artery disease, myocardial ischemia, heart failure or ischemia/reperfusion injury.

CONCLUSION

Rosmarinic acid is underestimated as an experimental cardiovascular drug and deserves more attention.

In vitro production of alkaloids: Factors, approaches, challenges and prospects

The wide diversity of plant secondary metabolites is largely used for the production of various pharmaceutical compounds. In vitro cell tissue or organ culture has been employed as a possible alternative to produce such industrial compounds. Tissue culture techniques provide continuous, reliable, and renewable source of valuable plant pharmaceuticals and might be used for the large-scale culture of the plant cells from which these secondary metabolites can be extracted. Alkaloids are one of the most important secondary metabolites known to play a vital role in various pharmaceutical applications leading to an increased commercial importance in recent years. The tissue culture techniques may be utilized to improve their production of alkaloids via somaclonal variations and genetic transformations. The focus of this review is toward the application of different tissue culture methods/techniques employed for the in vitro production of alkaloids with a systematic approach to improve their production.

Metabolic engineering of novel lignin in biomass crops

Lignin, a phenolic polymer in the secondary wall, is the major cause of lignocellulosic biomass recalcitrance to efficient industrial processing. From an applications perspective, it is desirable that second-generation bioenergy crops have lignin that is readily degraded by chemical pretreatments but still fulfill its biological role in plants. Because plants can tolerate large variations in lignin composition, often without apparent adverse effects, substitution of some fraction of the traditional monolignols by alternative monomers through genetic engineering is a promising strategy to tailor lignin in bioenergy crops. However, successful engineering of lignin incorporating alternative monomers requires knowledge about phenolic metabolism in plants and about the coupling properties of these alternative monomers. Here, we review the current knowledge about lignin biosynthesis and the pathways towards the main phenolic classes. In addition, the minimal requirements are defined for molecules that, upon incorporation into the lignin polymer, make the latter more susceptible to biomass pretreatment. Numerous metabolites made by plants meet these requirements, and several have already been tested as monolignol substitutes in biomimetic systems. Finally, the status of detection and identification of compounds by phenolic profiling is discussed, as phenolic profiling serves in pathway elucidation and for the detection of incorporation of alternative lignin monomers.

Hydroxycinnamate conjugates as potential monolignol replacements: in vitro lignification and cell wall studies with rosmarinic acid

The plasticity of lignin biosynthesis should permit the inclusion of new compatible phenolic monomers, such as rosmarinic acid (RA) and analogous catechol derivatives, into cell-wall lignins that are consequently less recalcitrant to biomass processing. In vitro lignin polymerization experiments revealed that RA readily underwent peroxidase-catalyzed copolymerization with monolignols and lignin oligomers to form polymers with new benzodioxane inter-unit linkages. Incorporation of RA permitted extensive depolymerization of synthetic lignins by mild alkaline hydrolysis, presumably by cleavage of ester intra-unit linkages within RA. Copolymerization of RA with monolignols into maize cell walls by in situ peroxidases significantly enhanced alkaline lignin extractability and promoted subsequent cell wall saccharification by fungal enzymes. Incorporating RA also improved cell wall saccharification by fungal enzymes and by rumen microflora even without alkaline pretreatments, possibly by modulating lignin hydrophobicity and/or limiting cell wall cross-linking. Consequently, we anticipate that bioengineering approaches for partial monolignol substitution with RA and analogous plant hydroxycinnamates would permit more efficient utilization of plant fiber for biofuels or livestock production.

Enzymes of phenylpropanoid metabolism in the important medicinal plant Melissa officinalis L

Lemon balm (Melissa officinalis, Lamiaceae) is a well-known medicinal plant. Amongst the biologically active ingredients are a number of phenolic compounds, the most prominent of which is rosmarinic acid. To obtain better knowledge of the biosynthesis of these phenolic compounds, two enzymes of the general phenylpropanoid pathway, phenylalanine ammonia-lyase (PAL) and 4-coumarate:coenzyme A-ligase (4CL), were investigated in suspension cultures of lemon balm. MoPAL1 and Mo4CL1 cDNAs were cloned and heterologously expressed in Escherichia coli and the enzymes characterised. Expression analysis of both genes showed a correlation with the enzyme activities and rosmarinic acid content during a cultivation period of the suspension culture. Southern-blot analysis suggested the presence of most probably two gene copies in the M. officinalis genome of both PAL and 4CL. The genomic DNA sequences of MoPAL1 and Mo4CL1 were amplified and sequenced. MoPAL1 contains one phase 2 intron of 836 bp at a conserved site, whilst Mo4CL1 was devoid of introns.

Accumulation of salicylic acid-induced phenolic compounds and raised activities of secondary metabolic and antioxidative enzymes in Salvia miltiorrhiza cell culture

The present work investigated the effects of salicylic acid (SA) on the accumulation of phenolic compounds and the activities of PAL, TAT, SOD, CAT and POD enzymes in the Salvia miltiorrhiza cell culture. When SA is applied to the cell culture, phenolic compounds will increase and PAL, TAT, SOD, CAT, and POD enzymes will become more active. The accumulations of phenolic compounds and the PAL activity were stimulated 8h after the treatment with SA. The TAT activity was stimulated after 48 h. The resulting antioxidative enzymes' activities were greatly improved. SA elicitation on the phenolic acid accumulation was depended upon the application dosage and the time-duration. The suitable SA concentration for eliciting phenolic compound accumulations was 6.25-22.5mg/L. The elicitation effect of SA on phenolic compound accumulations correlated with the PAL activity, but not with the TAT activity. This indicates that PAL may be the key enzyme for the biosynthesis of salvianolic acid B and caffeic acid. The raised PAL activity leads to the improvement of the quantity of phenolic compounds. This could be of particular significance by using plant cell culture systems for biotechnological production of plant secondary metabolites such as salvianolic acid B and caffeic acid.

Influence of organic supplements on production of shoot and callus biomass and accumulation of bacoside in Bacopa monniera (L.) Pennell

Production of valuable secondary metabolites through plant cell or organ culture is the best suited alternative to extraction of whole plant material and to increase production of secondary metabolites in in-vitro systems, feeding precursor or intermediate metabolites is an obvious and popular approach. The present investigation was aimed to study the influence of feeding of organic supplements, glycine (0-125 μM), ferulic acid (0-200 μM), phenylalanine (0-200 μM), α-ketoglutaric acid (0-200 μM) and pyruvic acid (0-200 μM) on production of bacoside-A (a triterpenoid type secondary metabolite responsible for cognition effects) in shoot and callus biomass of Bacopa monniera (L.) Pennell. The shoots were raised in liquid Murashige and Skoog's (MS) medium fortified with 5 μM 6-benzyladenine (BA) and callus biomass on agar solidified MS medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4 -D) in conjunction with 5 μM 1-napthaleneacetic acid (NAA). Among the organic supplements used, 100 μM pyruvic acid effectively enhanced the production of bacoside-A in shoot as well as callus biomass. The bacoside-A content in in-vitro raised shoot biomass was 4.0 and 1.2 times higher as compared to control and shoot biomass of naturally grown plants respectively. Inclusion of pyruvic acid in MS medium for in-vitro shoot cultures of B. monniera, can be adapted for enhanced production of bacoside-A.

cDNA cloning and functional characterisation of CYP98A14 and NADPH:cytochrome P450 reductase from Coleus blumei involved in rosmarinic acid biosynthesis

The final reactions of rosmarinic acid biosynthesis, the introduction of the aromatic 3- and 3'-hydroxyl groups, are catalysed by cytochrome P450-dependent hydroxylases. The cDNAs encoding CYP98A14 as well as a NADPH:cytochrome P450 reductase (CPR) were isolated from Coleus blumei and actively expressed in Saccharomyces cerevisiae. The CYP98A14-cDNA showed an open reading frame of 1521 nucleotides with high similarities to 4-coumaroylshikimate/quinate 3-hydroxylases. Yeast microsomes harbouring the CYP98A14 protein catalysed the 3-hydroxylation of 4-coumaroyl-3',4'-dihydroxyphenyllactate and the 3'-hydroxylation of caffeoyl-4'-hydroxyphenyllactate, in both cases forming rosmarinic acid. Apparent K (m)-values for 4-coumaroyl-3',4'-dihydroxyphenyllactate and caffeoyl-4'-hydroxyphenyllactate were determined to be at 5 microM and 40 microM, respectively. CYP98A14 differs from CYP98s from other plants, since 4-coumaroylshikimate or -quinate were not accepted as substrates. Coexpression of the Coleus blumei CPR and CYP98A14 in the same yeast cells increased the hydroxylation activity up to sevenfold. CYP98A14 from Coleus blumei is a novel bifunctional cytochrome P450 specialised for rosmarinic acid biosynthesis.

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.

An economic and technical assessment of the use of plant cell cultures for natural product synthesis on an industrial scale

Plant cell cultures may be used as an alternative source of established natural products, as a source of novel 'lead' compounds or as a source of enzymes for modification of precursors. Only a few plant cell processes are operating commercially and their performance characteristics are industrial secrets. The economic aspects of natural product synthesis in plant cell cultures are presented on the basis of data derived from work on a pilot plant with bioreactors of 5-80 litres in which cells are grown in batch liquid culture. Cost analysis shows that the labour costs of operating plant cell culture processes are much higher than those for microbial processes, which reflects the longer process times of plant systems. These can be reduced by increasing the cell growth rate, the biomass yield and/or the product yield. Higher yields can be obtained by optimizing media conditions, but there are no standard guidelines for this. Each system has to be developed individually. Reducing the number of production runs a year, usually by increasing the number of days for which each batch of cells is synthesizing product, can markedly decrease costs. Economic assessment of the viability of production in plant cell cultures must consider not only production costs but also the expected market price of the product and the volume of sales.

Rosmarinic acid synthase is a new member of the superfamily of BAHD acyltransferases

Purification of rosmarinic acid synthase (hydroxycinnamoyl-CoA:hydroxyphenyllactate hydroxycinnamoyltransferase) from suspension cells of Coleus blumei Benth. (Lamiaceae) by fractionated ammonium sulphate precipitation, hydrophobic interaction chromatography and two affinity chromatography steps led to the identification of peptide sequences, which enabled a PCR-based approach to isolate the full-length cDNA encoding this enzyme. The open reading frame of the cDNA had a length of 1290 base pairs encoding a protein of 430 amino acid residues with a molecular mass of 47,932 Da with typical characteristics of an acyltransferase of the BAHD superfamily. The cDNA was heterologously expressed in Escherichia coli. The enzyme displayed the activity of rosmarinic acid synthase using 4-coumaroyl- and caffeoyl-coenzyme A and 4-hydroxyphenyllactate as well as 3.4-dihydroxyphenyllactate as substrates. Shikimic acid and quinic acid were not able to serve as hydroxycinnamoyl acceptors. This therefore is the first report of the cDNA-cloning of a rosmarinic acid synthase.

Orally administered rosmarinic acid is present as the conjugated and/or methylated forms in plasma, and is degraded and metabolized to conjugated forms of caffeic acid, ferulic acid and m-coumaric acid

Rosmarinic acid (RA) is contained in various Lamiaceae herbs used commonly as culinary herbs. Although RA has various potent physiological actions, little is known on its bioavailability. We therefore investigated the absorption and metabolism of orally administered RA in rats. After being deprived of food for 12 h, RA (50 mg/kg body weight) or deionized water was administered orally to rats. Blood samples were collected from a cannula inserted in the femoral artery before and at designated time intervals after administration of RA. Urine excreted within 0 to 8 h and 8 to 18 h post-administration was also collected. RA and its related metabolites in plasma and urine were measured by LC-MS after treatment with sulfatase and/or beta-glucuronidase. RA, mono-methylated RA (methyl-RA) and m-coumaric acid (COA) were detected in plasma, with peak concentrations being reached at 0.5, 1 and 8 h after RA administration, respectively. RA, methyl-RA, caffeic acid (CAA), ferulic acid (FA) and COA were detected in urine after RA administration. These components in plasma and urine were present predominantly as conjugated forms such as glucuronide or sulfate. The percentage of the original oral dose of RA excreted in the urine within 18 h of administration as free and conjugated forms was 0.44 +/- 0.21% for RA, 1.60 +/- 0.74% for methyl-RA, 1.06 +/- 0.35% for CAA, 1.70 +/- 0.45% for FA and 0.67 +/- 0.29% for COA. Approximately 83% of the total amount of these metabolites was excreted in the period 8 to 18 h after RA administration. These results suggest that RA was absorbed and metabolized as conjugated and/or methylated forms, and that the majority of RA absorbed was degraded into conjugated and/or methylated forms of CAA, FA and COA before being excreted gradually in the urine.

Purification, cloning and functional expression of hydroxyphenylpyruvate reductase involved in rosmarinic acid biosynthesis in cell cultures of Coleus blumei

Hydroxyphenylpyruvate reductase (HPPR) is an enzyme involved in the biosynthesis of rosmarinic acid in Lamiaceae reducing hydroxyphenylpyruvates in dependence of NAD(P)H to the corresponding hydroxyphenyllactates. The HPPR protein was purified from suspension cells of Coleus blumei accumulating high levels of rosmarinic acid by ammonium sulfate precipitation, anion exchange chromatography, hydroxylapatite chromatography, chromatography on 2',5'-ADP-Sepharose 4B and SDS-polyacrylamide gel electrophoresis. The protein was tryptically digested and the peptides sequenced. Sequence information was used to isolate a full-length cDNA-clone for HPPR (EMBL accession number AJ507733) by RT-PCR, screening of a C. blumei cDNA-library and 5'-RACE-PCR. The open reading frame of the HPPR-cDNA consists of 939 nucleotides encoding a protein of 313 amino acid residues. The sequence showed that HPPR belongs to the family of D-isomer-specific 2-hydroxyacid dehydrogenases. The HPPR-cDNA was heterologously expressed in Escherichia coli and the protein was shown to catalyse the NAD(P)H-dependent reduction of 4-hydroxyphenylpyruvate to 4-hydroxyphenyllactate and 3,4-dihydroxyphenylpyruvate to 3,4-dihydroxyphenyllactate.

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.