Regulation of water-soluble phenolic acid biosynthesis in Salvia miltiorrhiza Bunge

Salvia miltiorrhiza Bunge Ameliorates Benign Prostatic Hyperplasia through Regulation of Oxidative Stress via Nrf-2/HO-1 Activation

Oxidative stress is a key factor in the pathogenesis of benign prostatic hyperplasia (BPH) that leads to inflammation. This study aimed to evaluate the ameliorative effects of Salvia miltiorrhiza Bunge extract (HLT-101) on BPH through the regulation of oxidative stress and inflammation. A testosterone propionate (TP)-induced BPH rat model was orally administered HLT-101 (20, 40, or 80 mg/kg), and its effects on oxidative stress- and inflammation-related gene expression were examined. Further, HLT-101 was assessed for its effect on reactive oxygen species (ROS) levels and Nrf-2/HO-1 signaling pathways in BPH-1 cells. HLT-101 decreased testosterone-induced excessive free radical production and inflammatory factor activation. Moreover, HLT-101 treatment significantly decreased the intracellular ROS level in the TNF-α and IFN-γ treated BPH-1 cells through the activation of Nrf-2. In addition, HLT-101 treatment inhibited the NF-κB pathway and androgen receptor (AR) signaling, which is highly linked to the pathogenesis of BPH. Therefore, HLT-101 has the potential to be an effective treatment reagent for BPH because of its ability to reduce inflammation and oxidative stress via Nrf-2/HO-1 signaling.

Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for Screening Potential Citrate Lyase Inhibitors from a Library of Marine Compounds

Tuberculosis, a persistent illness caused by Mycobacterium tuberculosis, remains a significant global public health challenge. The widespread use of anti-tuberculosis drugs has resulted in the emergence of drug-resistant strains, which complicates treatment efforts. Addressing this issue is crucial and hinges on the development of new drugs that can effectively target the disease. This involves identifying novel therapeutic targets that can disrupt the bacterium's survival mechanisms in various environments such as granulomas and lesions. Citrate lyase, essential for the survival of Mycobacterium species at lesion sites and in granulomatous conditions, is a potential target for the treatment of tuberculosis. This manuscript aimed to construct an efficient enzyme inhibitor screening platform using ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF MS). This system can accurately identify compounds with enzyme inhibitory activity from a library of marine terpenoids and phenolic compounds. Utilizing the screened herbal enzyme inhibitors as a starting point, we analyzed their chemical structures and skillfully built a library of marine compounds based on these structures. The results showed that all of the tested compounds from the phenolics library inhibited citrate lyase by more than 50%, and a significant portion of terpenoids also demonstrated inhibition, with these active terpenoids comprising over half of the terpenoids tested. The study underscores the potential of marine-derived phenolic and terpenoid compounds as potent inhibitors of citrate lyase, indicating a promising direction for future investigations in treating tuberculosis and associated disorders.

Overexpression of AtMYB2 Promotes Tolerance to Salt Stress and Accumulations of Tanshinones and Phenolic Acid in Salvia miltiorrhiza

Salvia miltiorrhiza is a prized traditional Chinese medicinal plant species. Its red storage roots are primarily used for the treatment of cardiovascular and cerebrovascular diseases. In this study, a transcription factor gene AtMYB2 was cloned and introduced into Salvia miltiorrhiza for ectopic expression. Overexpression of AtMYB2 enhanced salt stress resistance in S. miltiorrhiza, leading to a more resilient phenotype in transgenic plants exposed to high-salinity conditions. Physiological experiments have revealed that overexpression of AtMYB2 can decrease the accumulation of reactive oxygen species (ROS) during salt stress, boost the activity of antioxidant enzymes, and mitigate oxidative damage to cell membranes. In addition, overexpression of AtMYB2 promotes the synthesis of tanshinones and phenolic acids by upregulating the expression of biosynthetic pathway genes, resulting in increased levels of these secondary metabolites. In summary, our findings demonstrate that AtMYB2 not only enhances plant tolerance to salt stress, but also increases the accumulation of secondary metabolites in S. miltiorrhiza. Our study lays a solid foundation for uncovering the molecular mechanisms governed by AtMYB2 and holds significant implications for the molecular breeding of high-quality S. miltiorrhiza varieties.

FvbHLH1 Regulates the Accumulation of Phenolic Compounds in the Yellow Cap of Flammulina velutipes

Flammulina velutipes is a renowned edible and medicinal fungus. Commercially cultivated F. velutipes occurs in two distinct phenotypes: white and yellow. However, the underlying mechanism contributing to the yellow phenotype and high nutritional value remain uncertain. We reconfirmed that the browning process in F. velutipes is attributable to melanin accumulation, although the initial yellow cap seemed unrelated to melanin. A transcriptomic and metabolomic joint analysis revealed that 477 chemical compounds categorized into 11 classes, among which 191 exhibited significantly different levels of accumulation between different phenotypes. Specifically, 12 compounds were unique to the yellow F. velutipes, including ferulic acid, and 3-Aminosalicylic acid. Free fatty acids and xanthine were identified as the primary compounds correlating with the yellow and oily cap. A total of 44,087 genes were identified, which were more homologous to Pleurotus ostreatus PC15. Structural genes such as PAL (phenylalanine ammonialyase), C4H (cinnamate 4-hydroxylase), C3H (Coumarin-3-hydroxylase), AoMT (caffeoyl coenzyme A-O-methyltransferase), and 4CL (4-coumarate: CoA ligase) were up-regulated, thereby activating the lignin biosynthesis and metabolism pathway. Additionally, FvbHLH1 can lead to the consumption of a huge amount of phenylalanine while generating flavonoids and organic acid compounds. Meanwhile, ferulic acid biosynthesis was activated. Therefore, this study clarifies the chemical and molecular bases for the yellow phenotype and nutritional value of F. velutipes.

Salicylic acid regulates phenolic acid biosynthesis via SmNPR1-SmTGA2/SmNPR4 modules in Salvia miltiorrhiza

Phenolic acids are the main active ingredients in Salvia miltiorrhiza, which can be used for the treatment of many diseases, particularly cardiovascular diseases. It is known that salicylic acid (SA) can enhance phenolic acid content, but the molecular mechanism of its regulation is still unclear. Nonexpresser of PR genes 1 (NPR1) plays a positive role in the SA signaling pathway. In this study, we identified a SmNPR1 gene that responds to SA induction and systematically investigated its function. We found that SmNPR1 positively affected phenolic acid biosynthesis. Then, we identified a novel TGA transcription factor, SmTGA2, which interacts with SmNPR1. SmTGA2 positively regulates phenolic acid biosynthesis by directly up-regulating SmCYP98A14 expression. After double-gene transgenic analysis and other biochemical assays, it was found that SmNPR1 and SmTGA2 work synergistically to regulate phenolic acid biosynthesis. In addition, SmNPR4 forms a heterodimer with SmNPR1 to inhibit the function of SmNPR1, and SA can alleviate this effect. Collectively, these findings elucidate the molecular mechanism underlying the regulation of phenolic acid biosynthesis by SmNPR1-SmTGA2/SmNPR4 modules and provide novel insights into the SA signaling pathway regulating plant secondary metabolism.

Phenolic metabolites as therapeutic in inflammation and neoplasms: molecular pathways explaining their efficacy

Polyphenols, also known as phenolic compounds, are chemical substances containing aromatic rings as well as at least two hydroxyl groups. Natural phenolic compounds exist widely in plants, which protect plants from ultraviolet radiation and other insults. Phenolic compounds have superior pharmacological and nutritional properties (antimicrobial, antibacterial, antiviral, anti-sclerosis, antioxidant, and anti-inflammatory activities), which have been paid more and more attention by the scientific community. Phenols can protect key cellular components from reactive free radical damage, which is mainly due to their property to activate antioxidant enzymes and alleviate oxidative stress and inflammation. It can also inhibit or isolate reactive oxygen species and transfer electrons to free radicals, thereby avoiding cell damage. It has a regulatory role in glucose metabolism, which has a promising prospect in the prevention and intervention of diabetes. It also prevents cardiovascular disease by regulating blood pressure and blood lipids. Polyphenols can inhibit cell proliferation by affecting Erk1/2, CDK, and PI3K/Akt signaling pathways. Polyphenols can function as enhancers of intrinsic defense systems, including superoxide dismutase (SOD) and glutathione peroxidase (GPX). Simultaneously, they can modulate multiple proteins and transcription factors, making them promising candidates in the investigation of anti-cancer medications. This review focuses on multiple aspects of phenolic substances, including their natural origins, production process, disinfection activity, oxidative and anti-inflammatory functions, and the effects of different phenolic substances on tumors.

Biosynthetic regulatory network of flavonoid metabolites in stems and leaves of Salvia miltiorrhiza

Flavonoid secondary metabolites can treat and prevent many diseases, but systematic studies on regulation of the biosynthesis of such metabolites in aboveground parts of Salvia miltiorrhiza are lacking. In this study, metabonomic and transcriptomic analyses of different S. miltiorrhiza phenotypes were conducted to explore pathways of synthesis, catalysis, accumulation, and transport of the main flavonoid secondary metabolites regulating pigment accumulation. Tissue localization and quantitative analysis of flavonoid secondary metabolites were conducted by laser scanning confocal microscopy (LSCM). A total 3090 differentially expressed genes were obtained from 114,431 full-length unigenes in purple and green phenotypes, and 108 functional genes were involved in flavonoid biosynthesis. Five key phenylpropane structural genes (PAL, 4CL, ANS, 3AT, HCT) were highly differentially expressed, and four transcription factor genes (MYB, WRKY, bHLH, bZiP) were identified. In addition, six GST genes, nine ABC transporters, 22 MATE genes, and three SNARE genes were detected with key roles in flavonoid transport. According to LSCM, flavonoids were mainly distributed in epidermis, cortex, and collenchyma. Thus, comprehensive and systematic analyses were used to determine biosynthesis, accumulation, and transport of flavonoids in stems and leaves of different S. miltiorrhiza phenotypes. The findings will provide a reference for flavonoid production and cultivar selection.

The SmMYB36-SmERF6/SmERF115 module regulates the biosynthesis of tanshinones and phenolic acids in salvia miltiorrhiza hairy roots

Tanshinone and phenolic acids are the most important active substances of Salvia miltiorrhiza, and the insight into their transcriptional regulatory mechanisms is an essential process to increase their content in vivo. SmMYB36 has been found to have important regulatory functions in the synthesis of tanshinone and phenolic acid; paradoxically, its mechanism of action in S. miltiorrhiza is not clear. Here, we demonstrated that SmMYB36 functions as a promoter of tanshinones accumulation and a suppressor of phenolic acids through the generation of SmMYB36 overexpressed and chimeric SmMYB36-SRDX (EAR repressive domain) repressor hairy roots in combination with transcriptomic-metabolomic analysis. SmMYB36 directly down-regulate the key enzyme gene of primary metabolism, SmGAPC, up-regulate the tanshinones biosynthesis branch genes SmDXS2, SmGGPPS1, SmCPS1 and down-regulate the phenolic acids biosynthesis branch enzyme gene, SmRAS. Meanwhile, SmERF6, a positive regulator of tanshinone synthesis activating SmCPS1, was up-regulated and SmERF115, a positive regulator of phenolic acid biosynthesis activating SmRAS, was down-regulated. Furthermore, the seven acidic amino acids at the C-terminus of SmMYB36 are required for both self-activating domain and activation of target gene expression. As a consequence, this study contributes to reveal the potential relevance of transcription factors synergistically regulating the biosynthesis of tanshinone and phenolic acid.

Identification and Characterization of Jasmonic Acid Biosynthetic Genes in Salvia miltiorrhiza Bunge

Jasmonic acid (JA) is a vital plant hormone that performs a variety of critical functions for plants. Salvia miltiorrhiza Bunge (S. miltiorrhiza), also known as Danshen, is a renowned traditional Chinese medicinal herb. However, no thorough and systematic analysis of JA biosynthesis genes in S. miltiorrhiza exists. Through genome-wide prediction and molecular cloning, 23 candidate genes related to JA biosynthesis were identified in S. miltiorrhiza. These genes belong to four families that encode lipoxygenase (LOX), allene oxide synthase (AOS), allene oxide cyclase (AOC), and 12-OPDA reductase3 (OPR3). It was discovered that the candidate genes for JA synthesis of S. miltiorrhiza were distinct and conserved, in contrast to related genes in other plants, by evaluating their genetic structures, protein characteristics, and phylogenetic trees. These genes displayed tissue-specific expression patterns concerning to methyl jasmonate (MeJA) and wound tests. Overall, the results of this study provide valuable information for elucidating the JA biosynthesis pathway in S. miltiorrhiza by comprehensive and methodical examination.

Functional pleiotropism, diversity, and redundancy of Salvia miltiorrhiza Bunge JAZ family proteins in jasmonate-induced tanshinone and phenolic acid biosynthesis

Jasmonate (JA) signaling regulates plant growth and development, biotic and abiotic stress tolerance, and primary and secondary metabolism biosynthesis. It is extensively modulated by JA-ZIM-domain (JAZ) family genes. In previous work, we obtained nine SmJAZ genes of Salvia miltiorrhiza and proved that SmJAZ8 was the core repressor of JA-induced tanshinone and phenolic acid biosynthesis. Here, we demonstrate that SmJAZ3 and SmJAZ4 act as repressors of JA-induced biosynthesis of tanshinones and salvianolic acid B (Sal B). This suggests that SmJAZ3/4 are functionally redundant in tanshinone and Sal B biosynthesis. SmJAZ1/2/5/6/9 are activators of JA-induced tanshinone biosynthesis and repressors of JA-induced Sal B biosynthesis. This demonstrates the redundancy and diversity of SmJAZ1/2/5/6/9 functions. Besides, SmJAZ10 inhibited JA-induced Sal B synthesis, but had no effect on the synthesis of tanshinone. Two-hybrid screening (Y2H) showed that SmJAZs formed homologous or heterogeneous dimers. Y2H and firefly luciferase complementation imaging (LCI) assays revealed that SmJAZs also formed a complex regulatory network with SmMYC2a, SmMYC2b, SmMYB39, and SmPAP1. Quantitative reverse transcription-PCR (qRT-PCR) indicated that SmJAZs regulated each other at the transcriptional level. Herein, we prove that SmJAZs have functional pleiotropism, diversity, and redundancy in JA-induced tanshinone and phenolic acid biosynthesis. This study provides an important clue for further understanding the inherent biological significance and molecular mechanisms of the JAZ family as the gene number increases during plant evolution.

MAPKK2/4/5/7-MAPK3-JAZs modulate phenolic acid biosynthesis in Salvia miltiorrhiza

Phenolic acids are the major bioactive metabolites produced in Salvia miltiorrhiza, a traditional Chinese medicine called Danshen. Many phytohormone elicitor treatments induce phenolic acid biosynthesis, even though the underlying mechanism remains obscure. Expression pattern analysis showed that SmMAPK3 was highly expressed in leaves, and SmMAPK3 was significantly induced by salicylic acid (SA) and methyl jasmonate (JA). Bioinformatics analysis revealed that SmMAPK3 belongs to group A and contains a TEY motif in the activation loop together with three conserved regions (P-loop, C-loop and CD-domain). A previous study speculated that SmMAPK3 is likely a positive regulator in the biosynthesis of phenolic acids in S. miltiorrhiza. In this study, overexpression of SmMAPK3 increased phenolic acid biosynthetic gene expression and enhanced the accumulation of phenolic acids in S. miltiorrhiza plantlets. Yeast two-hybrid (Y2H) analysis and firefly luciferase complementation imaging (LCI) assays revealed that SmMAPKK2/4/5/7-SmMAPK3-SmJAZs form a cascade that regulates the accumulation of phenolic acids. In summary, this work deepens our understanding of the posttranscriptional regulatory mechanisms of phenolic acid biosynthesis and sheds new light on metabolic engineering in S. miltiorrhiza.

5-Azacytidine increases tanshinone production in Salvia miltiorrhiza hairy roots through epigenetic modulation

Recent studies have indicated strong connections between epigenetic modulation and secondary metabolites in plants. It is vital to understand the roles of epigenetics in the production of secondary metabolites. In this study, the inhibitor of DNA methylation 5-azacytidine (5-Az) was used on the hairy roots of the medicinal plant Salvia miltiorrhiza to investigate its effect on secondary metabolite production, gene expression, methylation levels in genomic DNA and promoter regions. Our results showed that the contents of tanshinones in S. miltiorrhiza hairy roots increased by 1.5–5 times, and some genes in the biosynthesis pathway showed an upward trend. According to our NGS analysis, the methylation pattern in the promotor of the gene encoding copalyl diphosphate synthase (CPS) was altered, and 51 out of 145 cytosines were demethylated during 5-Az treatment. A total of 36 putative transcription factors (TFs) binding cites were identified in these demethylation sites. Among these TFs binding cites, cis-regulatory elements for the binding of NF-Y and MYB were frequently found in our results. This is the first report to demonstrate a possible mechanism of DNA methylation participating in tanshinone biosynthesis in S. miltiorrhiza hairy roots by modulating the CPS promoter and TFs binding sites.

Targeting Oxidative Stress and Endothelial Dysfunction Using Tanshinone IIA for the Treatment of Tissue Inflammation and Fibrosis

Salvia miltiorrhiza Burge (Danshen), a member of the Lamiaceae family, has been used in traditional Chinese medicine for many centuries as a valuable medicinal herb with antioxidative, anti-inflammatory, and antifibrotic potential. Several evidence-based reports have suggested that Salvia miltiorrhiza and its components prevent vascular diseases, including myocardial infarction, myocardial ischemia/reperfusion injury, arrhythmia, cardiac hypertrophy, and cardiac fibrosis. Tanshinone IIA (TanIIA), a lipophilic component of Salvia miltiorrhiza, has gained attention because of its possible preventive and curative activity against cardiovascular disorders. TanIIA, which possesses antioxidative, anti-inflammatory, and antifibrotic properties, could be a key component in the therapeutic potential of Salvia miltiorrhiza. Vascular diseases are often initiated by endothelial dysfunction, which is accompanied by vascular inflammation and fibrosis. In this review, we summarize how TanIIA suppresses tissue inflammation and fibrosis through signaling pathways such as PI3K/Akt/mTOR/eNOS, TGF-β1/Smad2/3, NF-κB, JNK/SAPK (stress-activated protein kinase)/MAPK, and ERK/Nrf2 pathways. In brief, this review illustrates the therapeutic value of TanIIA in the alleviation of oxidative stress, inflammation, and fibrosis, which are critical components of cardiovascular disorders.

Dynamic Metabolomics and Transcriptomics Analyses for Characterization of Phenolic Compounds and Their Biosynthetic Characteristics in Wheat Grain

Phenolic compounds are important bioactive phytochemicals with potential health benefits. In this study, integrated metabolomics and transcriptomics analysis was used to analyze the metabolites and differentially expressed genes in grains of two wheat cultivars (HPm512 with high antioxidant activity, and ZM22 with low antioxidant activity) during grain development. A total of 188 differentially expressed phenolic components, including 82 phenolic acids, 81 flavonoids, 10 lignans, and 15 other phenolics, were identified in the developing wheat grains, of which apigenin glycosides were identified as the primary flavonoid component. The relative abundance of identified phenolics showed a decreasing trend with grain development. Additionally, 51 differentially expressed phenolic components were identified between HPm512 and ZM22, of which 41 components, including 23 flavonoids, were up-regulated in HPm512. In developing grain, most of the identified differentially expressed genes involved in phenolic accumulation followed a similar trend. Integrated metabolomics and transcriptomics analysis revealed that certain genes encoding structural proteins, glycosyltransferase, and transcription factors were closely related to metabolite accumulation. The relatively higher accumulation of phenolics in HPm512 could be due to up-regulated structural and regulatory genes. A sketch map was drawn to depict the synthetic pathway of identified phenolics and their corresponding genes. This study enhanced the current understanding of the accumulation of phenolics in wheat grains. Besides, active components and their related genes were also identified, providing crucial information for the improvement of wheat's nutritional quality.

Potential of natural products in the treatment of myocardial infarction: focus on molecular mechanisms

Although conventional drugs are widely used in the prevention and treatment of cardiovascular disease (CVD), they are being used less frequently due to concerns about possible side effects over the long term. There has been a renewed research interest in medicinal plant products, and their role in protecting the cardiovascular system and treating CVD, which are now being considered as potential alternatives to modern drugs. The most important mechanism causing damage to the myocardium after heart attack and reperfusion, is increased levels of free radicals and oxidative stress. Therefore, treatment approaches often focus on reducing free radicals or enhancing antioxidant defense mechanism. It has been previously reported that bioactive natural products can protect the heart muscle in myocardial infarction (MI). Since these compounds are readily available in fruits and vegetables, they could prevent the risk of MI if they are consumed daily. Although the benefits of a healthy diet are well known, many scientific studies have focused on whether pure natural compounds can prevent and treat MI. In this review we summarize the effects of curcumin, resveratrol, quercitin, berberine, and tanshinone on MI and CVD, and focus on their proposed molecular mechanisms of action.

Wheat grain phenolics: a review on composition, bioactivity, and influencing factors

Wheat (Triticum aestivum L.) is a widely cultivated crop and one of the most commonly consumed food grains in the world. It possesses several nutritional elements. Increasing attention to wheat grain phenolics bioactivity is due to the increasing demand for foods with natural antioxidants. To provide a comprehensive understanding of phenolics in wheat grain, this review first summarizes the phenolics' form and distribution and the phenolic components identified in wheat grain. In particular, the biosynthesis path for phenolics is discussed, identifying some candidate genes involved in the biosynthesis of phenolic acids and flavonoids. After discussing the methods for determining antioxidant activity, the effect of genotypes, environmental conditions, and cultivation systems on grain phenolic component content are explored. Finally, the bioavailability of phenolics under different food processing method are reported and discussed. Future research is recommended to increase wheat grain phenolic content by genetic engineering, and to improve its bioavailability through proper food processing. © 2021 Society of Chemical Industry.

Phenolic profiles and their responses to pre- and post-harvest factors in small fruits: a review

The consumption of small fruits has increased in recent years. Besides their appealing flavor, the commercial success of small fruits has been partially attributed to their high contents of phenolic compounds with multiple health benefits. The phenolic profiles and contents in small fruits vary based on the genetic background, climate, growing conditions, and post-harvest handling techniques. In this review, we critically compare the profiles and contents of phenolics such as anthocyanins, flavonols, flavan-3-ols, and phenolic acids that have been reported in bilberries, blackberries, blueberries, cranberries, black and red currants, raspberries, and strawberries during fruit development and post-harvest storage. This review offers researchers and breeders a general guideline for the improvement of phenolic composition in small fruits while considering the critical factors that affect berry phenolics from cultivation to harvest and to final consumption.

Integrative Omics Analyses Reveal the Effects of Copper Ions on Salvianolic Acid Biosynthesis

Salvianolic acids, a group of secondary metabolites produced by Salvia miltiorrhiza, are widely used for treating cerebrovascular diseases. Copper is recognized as a necessary microelement and plays an essential role in plant growth. At present, the effect of copper on the biosynthesis of SalAs is unknown. Here, an integrated metabolomic and transcriptomic approach, coupled with biochemical analyses, was employed to dissect the mechanisms by which copper ions induced the biosynthesis of SalAs. In this study, we identified that a low concentration (5 μM) of copper ions could promote growth of S. miltiorrhiza and the biosynthesis of SalAs. Results of the metabolomics analysis showed that 160 metabolites (90 increased and 70 decreased) were significantly changed in S. miltiorrhiza treated with low concentration of copper ions. The differential metabolites were mainly involved in amino acid metabolism, the pentose phosphate pathway, and carbon fixation in photosynthetic organisms. The contents of chlorophyll a, chlorophyll b, and total chlorophyll were significantly increased in leaves of low concentration of copper-treated S. miltiorrhiza plants. Importantly, core SalA biosynthetic genes (laccases and rosmarinic acid synthase), SalA biosynthesis-related transcription factors (MYBs and zinc finger CCCH domain-containing protein 33), and chloroplast proteins-encoding genes (blue copper protein and chlorophyll-binding protein) were upregulated in the treated samples as indicated by a comprehensive transcriptomic analysis. Bioinformatics and enzyme activity analyses showed that laccase 20 contained copper-binding motifs, and its activity in low concentration of copper ions-treated S. miltiorrhiza was much higher than that in the control. Our results demonstrate that enhancement of copper ions of the accumulation of SalAs might be through regulating laccase 20, MYBs, and zinc finger transcription factors, and photosynthetic genes.

R2R3-MYB Transcription Factor SmMYB52 Positively Regulates Biosynthesis of Salvianolic Acid B and Inhibits Root Growth in Salvia miltiorrhiza

The dried root of Salvia miltiorrhiza is a renowned traditional Chinese medicine that was used for over 1000 years in China. Salvianolic acid B (SalB) is the main natural bioactive product of S. miltiorrhiza. Although many publications described the regulation mechanism of SalB biosynthesis, few reports simultaneously focused on S. miltiorrhiza root development. For this study, an R2R3-MYB transcription factor gene (SmMYB52) was overexpressed and silenced, respectively, in S. miltiorrhiza sterile seedlings. We found that SmMYB52 significantly inhibited root growth and indole-3-acetic acid (IAA) accumulation, whereas it activated phenolic acid biosynthesis and the jasmonate acid (JA) signaling pathway. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that SmMYB52 suppressed the transcription levels of key enzyme-encoding genes involved in the IAA biosynthetic pathway and activated key enzyme-encoding genes involved in the JA and phenolic acid biosynthesis pathways. In addition, yeast one-hybrid (Y1H) and dual-luciferase assay showed that SmMYB52 directly binds to and activates the promoters of several key enzyme genes for SalB biosynthesis, including SmTAT1, Sm4CL9, SmC4H1, and SmHPPR1, to promote the accumulation of SalB. This is the first report of a regulator that simultaneously affects root growth and the production of phenolic acids in S. miltiorrhiza.

Transcriptional Factor-Mediated Regulation of Active Component Biosynthesis in Medicinal Plants

Plants produce thousands of chemically diverse secondary metabolites, many of which have valuable pharmaceutical properties. There is much interest in the synthesis of these pharmaceuticallyvaluable compounds, including the key enzymes and the transcription factors involved. The function and regulatory mechanism of transcription factors in biotic and abiotic stresses have been studied in depth. However, their regulatory roles in the biosynthesis of bioactive compounds, especially in medicinal plants, have only begun. Here, we review what is currently known about how transcription factors contribute to the synthesis of bioactive compounds (alkaloids, terpenoids, flavonoids, and phenolic acids) in medicinal plants. Recent progress has been made in the cloning and characterization of transcription factors in medicinal plants on the genome scale. So far, several large transcription factors have been identified in MYB, WRKY, bHLH, ZIP, AP2/ERF transcription factors. These transcription factors have been predicted to regulate bioactive compound production. These transcription factors positively or negatively regulate the expression of multiple genes encoding key enzymes, and thereby control the metabolic flow through the biosynthetic pathway. Although the research addressing this niche topic is in its infancy, significant progress has been made, and advances in high-throughput sequencing technology are expected to accelerate the discovery of key regulatory transcription factors in medicinal plants. This review is likely to be useful for those interested in the synthesis of pharmaceutically- valuable plant compounds, especially those aiming to breed or engineer plants that produce greater yields of these compounds.

Quantitative Determination and Validation of Four Phenolic Acids in Salvia Miltiorrhiza Bunge using 1H-NMR Spectroscopy

Background:

Although chromatography and spectrometry-based methods have been used to analyse phenolic acids in Chinese traditional medicine Salvia miltiorrhiza Bunge (SMB), quantitative nuclear magnetic resonance (qNMR) has never previously been used to analyse fresh SMB root extracts.

Objective:

To establish a fast and simple method of quantitating danshensu, lithospermic acid, rosmarinic acid, and salvianolic acid B content in fresh SMB root using 1H-NMR spectroscopy.

Method:

Fresh SMB root was extracted using a 70% methanol aqueous solution and quantitatively analysed for danshensu, lithospermic acid, rosmarinic acid, and salvianolic acid B using 1H-NMR spectroscopy. Different internal standards were compared and the results were validated using highperformance liquid chromatography.

Results:

The established method was accurate and precise with good recovery. The LOD and LOQ indicated the excellent sensitivity of the method. The robustness was testified by the modification of four different parameters, and the differences among each parameter were all less than 2%.

Conclusion:

qNMR offers a fast, reliable, and accurate method of identifying and quantifying danshensu, lithospermic acid, rosmarinic acid, and salvianolic acid B in fresh SMB root extracts.

Transcription Factor: A Powerful Tool to Regulate Biosynthesis of Active Ingredients in Salvia miltiorrhiza

Salvia miltiorrhiza Bunge is a common Chinese herbal medicine, and its major active ingredients are phenolic acids and tanshinones, which are widely used to treat vascular diseases. However, the wild form of S. miltiorrhiza possess low levels of these important pharmaceutical agents; thus, improving their levels is an active area of research. Transcription factors, which promote or inhibit the expressions of multiple genes involved in one or more biosynthetic pathways, are powerful tools for controlling gene expression in biosynthesis. Several families of transcription factors have been reported to participate in regulating phenolic acid and tanshinone biosynthesis and influence their accumulation. This review summarizes the current status in this field, with focus on the transcription factors which have been identified in recent years and their functions in the biosynthetic regulation of phenolic acids and tanshinones. Otherwise, the new insight for further research is provided. Finally, the application of the biosynthetic regulation of active ingredients by the transcription factors in S. miltiorrhiza are discussed, and new insights for future research are explored.

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.

Integrative omic and transgenic analyses reveal the positive effect of ultraviolet-B irradiation on salvianolic acid biosynthesis through upregulation of SmNAC1

Salvianolic acids (SalAs), a group of secondary metabolites in Salvia miltiorrhiza, are widely used for treating cerebrovascular diseases. Their biosynthesis is modulated by a variety of abiotic factors, including ultraviolet-B (UV-B) irradiation; however, the underlying mechanisms remain largely unknown. Here, an integrated metabolomic, proteomic, and transcriptomic approach coupled with transgenic analyses was employed to dissect the mechanisms underlying UV-B irradiation-induced SalA biosynthesis. Results of metabolomics showed that 28 metabolites, including 12 SalAs, were elevated in leaves of UV-B-treated S. miltiorrhiza. Meanwhile, the contents of several phytohormones, including jasmonic acid and salicylic acid, which positively modulate the biosynthesis of SalAs, also increased in UV-B-treated S. miltiorrhiza. Consistently, 20 core biosynthetic enzymes and numerous transcription factors that are involved in SalA biosynthesis were elevated in treated samples as indicated by a comprehensive proteomic analysis. Correlation and gene expression analyses demonstrated that the NAC1 gene, encoding a NAC transcriptional factor, was positively involved in UV-B-induced SalA biosynthesis. Accordingly, overexpression and RNA interference of NAC1 increased and decreased SalA contents, respectively, through regulation of key biosynthetic enzymes. Furthermore, ChIP-qPCR and Dual-LUC assays showed that NAC1 could directly bind to the CATGTG and CATGTC motifs present in the promoters of the SalA biosynthesis-related genes PAL3 and TAT3, respectively, and activate their expression. Our results collectively demonstrate that NAC1 plays a crucial role in UV-B irradiation-induced SalA biosynthesis. Taken together, our findings provide mechanistic insights into the UV-B-induced SalA biosynthesis in S. miltiorrhiza, and shed light on a great potential for the development of SalA-abundant varieties through genetic engineering.

Genome-wide characterization and expression profiling of MAPK cascade genes in Salvia miltiorrhiza reveals the function of SmMAPK3 and SmMAPK1 in secondary metabolism

BACKGROUND

The contribution of mitogen-activated protein kinase (MAPK) cascades to plant growth and development has been widely studied, but this knowledge has not yet been extended to the medicinal plant Salvia miltiorrhiza, which produces a number of pharmacologically active secondary metabolites.

RESULTS

In this study, we performed a genome-wide survey and identified six MAPKKK kinases (MAPKKKKs), 83 MAPKK kinases (MAPKKKs), nine MAPK kinases (MAPKKs) and 18 MAPKs in the S. miltiorrhiza genome. Within each class of genes, a small number of subfamilies were recognized. A transcriptional analysis revealed differences in the genes' behaviour with respect to both their site of transcription and their inducibility by elicitors and phytohormones. Two genes were identified as strong candidates for playing roles in phytohormone signalling. A gene-to-metabolite network was constructed based on correlation analysis, highlighting the likely involvement of two of the cascades in the synthesis of two key groups of pharmacologically active secondary metabolites: phenolic acids and tanshinones.

CONCLUSION

The data provide insight into the functional diversification and conservation of MAPK cascades in S. miltiorrhiza.

Impacts of foliar exposure to multi-walled carbon nanotubes on physiological and molecular traits of Salvia verticillata L., as a medicinal plant

Owing to the growing applications of the multi-walled carbon nanotubes (MWCNTs) in the communications and energy industries, they have attracted increasing attention for their effects on the environment and plants. Therefore, we investigated the impact of foliar exposure to MWCNTs on the oxidative stress responses in the Salvia verticillata as a medicinal plant. Furthermore, we evaluated the possible correlations between gene expression and activity of the key enzymes in the phenolic acids biosynthesis pathways and their accumulation in the treated leaves. The leaves of two-month-old plants were sprayed with different concentrations (0-1000 mg L^-1) of MWCNTs. Raman's data and Transmission Electron Microscopy images have confirmed the absorption of MWCNTs via epidermal cells layer into the parenchymal cells of the exposed leaves. The results showed that exposure to MWCNTs led to a decrease in the photosynthetic pigments and increases in the oxidative stress indices (enzymatic and non-enzymatic antioxidants) in the leaves with a dose-dependent manner. The content of rosmarinic acid as a main phenolic acid was increased in the MWCNTs-exposed leaves to 50 and 1000 mg L^-1, nearly four times relative to the control. Unlike with other examined enzymes, a positive correlation was deduced between the activity and gene expression patterns of the rosmarinic acid synthase with the rosmarinic acid accumulation in the treatments. Overall, MWCNTs at the low concentrations could promote the production of the pharmaceutical metabolites by the changes in the ROS generation. However, at the higher concentrations, MWCNTs were toxic and induced the oxidative damages in S. verticillata.

Discrimination of Salvia miltiorrhiza Bunge from Different Geographical Locations Employing High-Performance Liquid Chromatography, Near-Infrared Fingerprinting Combined with Chemometrics

To evaluate the quality of Salvia miltiorrhiza Bunge, high-performance liquid chromatography-diode array detector (HPLC/UV-PAD), near infrared (NIR) spectroscopy, and chemometrics were used to discriminate nine components of samples from four different geographical locations. HPLC was performed with a C18 (5 μm, 4.6 mm × 250 mm) column and 0.1% formic acid aqueous solution-acetonitrile with a gradient elution system. Orthogonal partial least squares discriminant analysis was used to identify the amounts of salvianolic acid B. NIR was used to distinguish rapidly S. miltiorrhiza Bunge samples from different geographical locations. In this assay, discriminant analysis was performed, and the accuracy was found to be 100%. The combination of these two methods can be used to quickly and accurately identify S. miltiorrhiza Bunge from different geographical locations.

Wound Healing and the Use of Medicinal Plants

Cutaneous wound healing is the process by which skin repairs itself. It is generally accepted that cutaneous wound healing can be divided into 4 phases: haemostasis, inflammation, proliferation, and remodelling. In humans, keratinocytes re-form a functional epidermis (reepithelialization) as rapidly as possible, closing the wound and reestablishing tissue homeostasis. Dermal fibroblasts migrate into the wound bed and proliferate, creating “granulation tissue” rich in extracellular matrix proteins and supporting the growth of new blood vessels. Ultimately, this is remodelled over an extended period, returning the injured tissue to a state similar to that before injury. Dysregulation in any phase of the wound healing cascade delays healing and may result in various skin pathologies, including nonhealing, or chronic ulceration. Indigenous and traditional medicines make extensive use of natural products and derivatives of natural products and provide more than half of all medicines consumed today throughout the world. Recognising the important role traditional medicine continues to play, we have undertaken an extensive survey of literature reporting the use of medical plants and plant-based products for cutaneous wounds. We describe the active ingredients, bioactivities, clinical uses, formulations, methods of preparation, and clinical value of 36 medical plant species. Several species stand out, including Centella asiatica, Curcuma longa, and Paeonia suffruticosa, which are popular wound healing products used by several cultures and ethnic groups. The popularity and evidence of continued use clearly indicates that there are still lessons to be learned from traditional practices. Hidden in the myriad of natural products and derivatives from natural products are undescribed reagents, unexplored combinations, and adjunct compounds that could have a place in the contemporary therapeutic inventory.

Salvia miltiorrhiza in Treating Cardiovascular Diseases: A Review on Its Pharmacological and Clinical Applications

Bioactive chemical constitutes from the root of Salvia miltiorrhiza classified in two major groups, viz., liposoluble tanshinones and water-soluble phenolics. Tanshinone IIA is a major lipid-soluble compound having promising health benefits. The in vivo and in vitro studies showed that the tanshinone IIA and salvianolate have a wide range of cardiovascular and other pharmacological effects, including antioxidative, anti-inflammatory, endothelial protective, myocardial protective, anticoagulation, vasodilation, and anti-atherosclerosis, as well as significantly help to reduce proliferation and migration of vascular smooth muscle cells. In addition, some of the clinical studies reported that the S. miltiorrhiza preparations in combination with Western medicine were more effective for treatment of various cardiovascular diseases including angina pectoris, myocardial infarction, hypertension, hyperlipidemia, and pulmonary heart diseases. In this review, we demonstrated the potential applications of S. miltiorrhiza, including pharmacological effects of salvianolate, tanshinone IIA, and its water-soluble derivative, like sodium tanshinone IIA sulfonate. Moreover, we also provided details about the clinical applications of S. miltiorrhiza preparations in controlling the cardiovascular diseases.

Climatic factors control the geospatial distribution of active ingredients in Salvia miltiorrhiza Bunge in China

Climate change profoundly influences the geospatial distribution of secondary metabolites and causes the geographical migration of plants. We planted seedlings of the same species in eighteen ecological regions along a latitudinal gradient in eastern and western China, in order to explore the regulation of multi-climatic factors on active ingredient accumulation in Salvia miltiorrhiza Bunge. The correlations between six active ingredient contents and ten climatic factors were investigated to clarify their relationships. We found that climatic factors not only regulated active ingredient contents but also markedly influenced their composition and led to a specific geospatial distribution of these active ingredients in China. The main climatic factors include the air temperature, precipitation, atmospheric vapour pressure and sunshine duration. Future warming in high-latitude regions could cause continued northward expansion of planting areas suitable for S. miltiorrhiza. The effect of extreme climatic conditions on active ingredients should not be overlooked. The findings of this study can help farmers scientifically choose suitable cultivation regions in the future. Furthermore, this study provides an innovative idea for the exploration of secondary metabolic responses to changing ecological factors in medicinal plants.

Biosynthesis, Chemistry, and Pharmacology of Polyphenols from Chinese Salvia Species: A Review

Salvia species find widespread application in food and pharmaceutical products owing to their large polyphenol content. The main polyphenols in Chinese Salvia species are phenolic acids and flavonoids, which exhibit anti-oxygenation, anti-ischemia-reperfusion injury, anti-thrombosis, anti-tumour, and other therapeutic effects. However, there are few peer-reviewed studies on polyphenols in Chinese Salvia species, especially flavonoids. This review is a systematic, comprehensive collation of available information on the biosynthesis, chemistry, and pharmacology of Chinese Salvia species. We believe that our study makes a significant contribution to the literature because this review provides a detailed literary resource on the currently available information on various polyphenolic components of Chinese Salvia species, including their bioactivities and structures. In addition, the study provides information that would encourage further investigation of this plant material as a natural resource with potential for a broad range of applications in various industries, such as the food and pharmaceutical industries.

SmJAZ8 acts as a core repressor regulating JA-induced biosynthesis of salvianolic acids and tanshinones in Salvia miltiorrhiza hairy roots

Jasmonates (JAs) are important plant hormones that regulate a variety of plant development and defense processes, including biosynthesis of secondary metabolites. The JASMONATE ZIM DOMAIN (JAZ) proteins act as negative regulators in the JA signaling pathways of plants. We first verified that methyl jasmonate (MeJA) enhanced the accumulation of both salvianolic acids and tanshinones in Salvia miltiorrhiza (Danshen) hairy roots by inducing the expression of their biosynthetic pathway genes. Nine JAZ genes were cloned from Danshen and their expression levels in hairy roots were all increased by treatment with MeJA. When analyzed in detail, however, SmJAZ8 showed the strongest expression in the induced hairy roots. Overexpression or RNAi of SmJAZ8 deregulated or up-regulated the yields of salvianolic acids and tanshinones in the MeJA-induced transgenic hairy roots, respectively, and transcription factors and biosynthetic pathway genes showed an expression pattern that mirrored the production of the compounds. Genetic transformation of SmJAZ8 altered the expression of other SmJAZ genes, suggesting evidence of crosstalk occurring in JAZ-regulated secondary metabolism. Furthermore, the transcriptome analysis revealed a primary-secondary metabolism balance regulated by SmJAZ8. Altogether, we propose a novel role for SmJAZ8 as a negative feedback loop controller in the JA-induced biosynthesis of salvianolic acids and tanshinones.

SmbHLH37 Functions Antagonistically With SmMYC2 in Regulating Jasmonate-Mediated Biosynthesis of Phenolic Acids in Salvia miltiorrhiza

Jasmonates (JAs) are integral to various defense responses and induce biosynthesis of many secondary metabolites. MYC2, a basic helix-loop-helix (bHLH) transcription factor (TF), acts as a transcriptional activator of JA signaling. MYC2 is repressed by the JASMONATE ZIM-domain (JAZ) proteins in the absence of JA, but de-repressed by the protein complex SCF^COI1 on perception of JA. We previously reported that overexpression of SmMYC2 promotes the production of salvianolic acid B (Sal B) in Salvia miltiorrhiza. However, the responsible molecular mechanism is unclear. Here, we showed that SmMYC2 binds to and activates the promoters of its target genes SmTAT1, SmPAL1, and SmCYP98A14 to activate Sal B accumulations. SmbHLH37, a novel bHLH gene significantly up-regulated by constitutive expression of SmMYC2, was isolated from S. miltiorrhiza for detailed functional characterization. SmbHLH37 forms a homodimer and interacts with SmJAZ3/8. Overexpression of SmbHLH37 substantially decreased yields of Sal B. SmbHLH37 binds to the promoters of its target genes SmTAT1 and SmPAL1 and blocks their expression to suppress the pathway for Sal B biosynthesis. These results indicate that SmbHLH37 negatively regulates JA signaling and functions antagonistically with SmMYC2 in regulating Sal B biosynthesis in S. miltiorrhiza.

HPPR encodes the hydroxyphenylpyruvate reductase required for the biosynthesis of hydrophilic phenolic acids in Salvia miltiorrhiza

Salvia miltiorrhiza is a medicinal plant widely used in the treatment of cardiovascular and cerebrovascular diseases. Hydrophilic phenolic acids, including rosmarinic acid (RA) and lithospermic acid B (LAB), are its primary medicinal ingredients. However, the biosynthetic pathway of RA and LAB in S. miltiorrhiza is still poorly understood. In the present study, we accomplished the isolation and characterization of a novel S. miltiorrhiza Hydroxyphenylpyruvate reductase (HPPR) gene, SmHPPR, which plays an important role in the biosynthesis of RA. SmHPPR contained a putative catalytic domain and a NAD(P)H-binding motif. The recombinant SmHPPR enzyme exhibited high HPPR activity, converting 4-hydroxyphenylpyruvic acid (pHPP) to 4-hydroxyphenyllactic acid (pHPL), and exhibited the highest affinity for substrate 4-hydroxyphenylpyruvate. SmHPPR expression could be induced by various treatments, including SA, GA3, MeJA and Ag+, and the changes in SmHPPR activity were correlated well with hydrophilic phenolic acid accumulation. SmHPPR was localized in cytoplasm, most likely close to the cytosolic NADPH-dependent hydroxypyruvate reductase active in photorespiration. In addition, the transgenic S. miltiorrhiza hairy roots overexpressing SmHPPR exhibited up to 10-fold increases in the products of hydrophilic phenolic acid pathway. In conclusion, our findings provide a new insight into the synthesis of active pharmaceutical compounds at molecular level.

Overexpression of SmMYB9b enhances tanshinone concentration in Salvia miltiorrhiza hairy roots

A Salvia miltiorrhiza R2R3-MYB gene, SmMYB9b , has been cloned and characterized. Overexpression of SmMYB9b resulted in a significant improvement of tanshinones, the lipophilic active ingredients in danshen hairy roots. Plant R2R3-MYB transcription factors play important roles in various physiological and biochemical processes. Danshen (Salvia miltiorrhiza bunge) is a valuable medicinal herb with tanshinones and salvianolic acids as the principal bioactive ingredients. A number of putative R2R3-MYB transcription factors have been identified in the plant, but their function remains to be studied. Here, we report the cloning of SmMYB9b, an S20 R2R3-MYB member and its regulatory properties. SmMYB9b contains an open reading frame of 792 bp in length and encodes a 264-amino acid protein. Its transcripts were most abundant in blooming flowers (except for calyces) and increased with flower development. Exogenous abscisic acid strongly activated its transcription. Gibberellins and methyl jasmonate also showed a time-dependent activation effect on its transcription, but to a weaker degree. Overexpression of SmMYB9b in danshen hairy roots enhanced tanshinone concentration to 2.16 ± 0.39 mg/g DW, a 2.2-fold improvement over the control. In addition to increased tanshinone concentration, the hairy root growth and lateral hairy root formation were also suppressed. KEGG pathway enrichment analysis with de novo RNAseq data indicated that stress-response-related metabolic pathways, such as the terpenoid and plant hormone signal transduction pathways, were significantly enriched, implying possible implication of SmMYB9b in such processes. Quantitative RT-PCR analysis showed that the transcription of terpenoid biosynthetic genes SmDXS2, SmDXR, SmGGPPS, and SmKSL1 was significantly up-regulated in danshen hairy roots over expressing SmMYB9b. These data suggest that overexpression of SmMYB9b results in enhanced tanshinone concentration through stimulation of the MEP pathway. The present findings shed new light on elucidating the roles of R2R3-MYB in the biosynthesis of diterpenoids in S. miltiorrhiza.

SmMYB36, a Novel R2R3-MYB Transcription Factor, Enhances Tanshinone Accumulation and Decreases Phenolic Acid Content in Salvia miltiorrhiza Hairy Roots

Phenolic acids and tanshinones are two major bioactive components in Salvia miltiorrhiza Bunge. A novel endogenous R2R3-MYB transcription factor, SmMYB36, was identified in this research. This transcript factor can simultaneously influence the content of two types of components in SmMYB36 overexpression hairy roots. SmMYB36 was mainly localized in the nucleus of onion epidermis and it has transactivation activity. The overexpression of SmMYB36 promoted tanshinone accumulation but inhibited phenolic acid and flavonoid biosynthesis in Salvia miltiorrhiza hairy roots. The altered metabolite content was due to changed metabolic flow which was regulated by transcript expression of metabolic pathway genes. The gene transcription levels of the phenylpropanoid general pathway, tyrosine derived pathway, methylerythritol phosphate pathway and downstream tanshinone biosynthetic pathway changed significantly due to the overexpression of SmMYB36. The wide distribution of MYB binding elements (MBS, MRE, MBSI and MBSII) and electrophoretic mobility shift assay results indicated that SmMYB36 may be an effective tool to regulate metabolic flux shifts.

Meristem Plant Cells as a Sustainable Source of Redox Actives for Skin Rejuvenation

Recently, aggressive advertisement claimed a “magic role” for plant stem cells in human skin rejuvenation. This review aims to shed light on the scientific background suggesting feasibility of using plant cells as a basis of anti-age cosmetics. When meristem cell cultures obtained from medicinal plants are exposed to appropriate elicitors/stressors (ultraviolet, ultrasound ultraviolet (UV), ultrasonic waves, microbial/insect metabolites, heavy metals, organic toxins, nutrient deprivation, etc.), a protective/adaptive response initiates the biosynthesis of secondary metabolites. Highly bioavailable and biocompatible to human cells, low-molecular weight plant secondary metabolites share structural/functional similarities with human non-protein regulatory hormones, neurotransmitters, pigments, polyamines, amino-/fatty acids. Their redox-regulated biosynthesis triggers in turn plant cell antioxidant and detoxification molecular mechanisms resembling human cell pathways. Easily isolated in relatively large quantities from contaminant-free cell cultures, plant metabolites target skin ageing mechanisms, above all redox imbalance. Perfect modulators of cutaneous oxidative state via direct/indirect antioxidant action, free radical scavenging, UV protection, and transition-metal chelation, they are ideal candidates to restore photochemical/redox/immune/metabolic barriers, gradually deteriorating in the ageing skin. The industrial production of plant meristem cell metabolites is toxicologically and ecologically sustainable for fully “biological” anti-age cosmetics.

The Protein Kinase SmSnRK2.6 Positively Regulates Phenolic Acid Biosynthesis in Salvia miltiorrhiza by Interacting with SmAREB1

Subclass III members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2) play essential roles in both the abscisic acid signaling and abiotic stress responses of plants by phosphorylating the downstream ABA-responsive element (ABRE)-binding proteins (AREB/ABFs). This comprehensive study investigated the function of new candidate genes, namely SmSnRK2.3, SmSnRK2.6, and SmAREB1, with a view to breeding novel varieties of Salvia miltiorrhiza with improved stress tolerance stresses and more content of bioactive ingredients. Exogenous ABA strongly induced the expression of these genes. PlantCARE predicted several hormones and stress response cis-elements in their promoters. SmSnRK2.6 and SmAREB1 showed the highest expression levels in the leaves of S. miltiorrhiza seedlings, while SmSnRK2.3 exhibited a steady expression in their roots, stems, and leaves. A subcellular localization assay revealed that both SmSnRK2.3 and SmSnRK2.6 were located in the cell membrane, cytoplasm, and nucleus, whereas SmAREB1 was exclusive to the nucleus. Overexpressing SmSnRK2.3 did not significantly promote the accumulation of rosmarinic acid (RA) and salvianolic acid B (Sal B) in the transgenic S. miltiorrhiza hairy roots. However, overexpressing SmSnRK2.6 and SmAREB1 increased the contents of RA and Sal B, and regulated the expression levels of structural genes participating in the phenolic acid-branched and side-branched pathways, including SmPAL1, SmC4H, Sm4CL1, SmTAT, SmHPPR, SmRAS, SmCHS, SmCCR, SmCOMT, and SmHPPD. Furthermore, SmSnRK2.3 and SmSnRK2.6 interacted physically with SmAREB1. In summary, our results indicate that SmSnRK2.6 is involved in stress responses and can regulate structural gene transcripts to promote greater metabolic flux to the phenolic acid-branched pathway, via its interaction with SmAREB1, a transcription factor. In this way, SmSnRK2.6 contributes to the positive regulation of phenolic acids in S. miltiorrhiza hairy roots.

Recent insights into the biological activities and drug delivery systems of tanshinones

Tanshinones, the major lipid-soluble pharmacological constituents of the Chinese medicinal herb Tanshen (Salvia miltiorrhiza), have attracted growing scientific attention because of the prospective biomedical applications of these compounds. Numerous pharmacological activities, including anti-inflammatory, anticancer, and cardio-cerebrovascular protection activities, are exhibited by the three primary bioactive constituents among the tanshinones, ie, tanshinone I (TNI), tanshinone IIA (TNIIA), and cryptotanshinone (CPT). However, due to their poor solubility and low dissolution rate, the clinical applications of TNI, TNIIA, and CPT are limited. To solve these problems, many studies have focused on loading tanshinones into liposomes, nanoparticles, microemulsions, cyclodextrin inclusions, solid dispersions, and so on. In this review, we aim to offer an updated summary of the biological activities and drug delivery systems of tanshinones to provide a reference for these constituents in clinical applications.

Enhancing diterpenoid concentration in Salvia miltiorrhiza hairy roots through pathway engineering with maize C1 transcription factor

Tanshinones are valuable natural diterpenoids from danshen (Salvia miltiorrhiza Bunge). Here, it was demonstrated that maize transcription factor C1 improved the accumulation of tanshinones by comprehensively upregulating the pathway genes, especially SmMDC and SmPMK in danshen hairy roots, yielding total tanshinones up to 3.59mg g(-1) of dry weight in line C1-6, a 3.4-fold increase compared with the control. Investigation of 2024bp of the SmMDC promoter fragment revealed that C1-mediated upregulation of terpenoid genes was possibly due to the direct interaction of C1 with its recognition sequences. The increase of tanshinones was accompanied by a decrease of salvianolic acid production, the other bioactive ingredient in danshen, by up to 37% compared with the control. This was the result of the downregulation of SmTAT, the entry-point gene of the tyrosine pathway, which promoted metabolic flow to anthocyanins rather than to salvianolic acids. Based on the findings of the present study, it was concluded that cis-acting elements shared by terpenoid and phenylpropanoid biosynthetic genes are partially responsible for the C1-stimulated variation of tanshinone and salvianolic acid concentrations.

Methyl jasmonate affects phenolic metabolism and gene expression in blueberry (Vaccinium corymbosum)

Blueberry (Vaccinium corymbosum) is a fruit very much appreciated by consumers for its antioxidant potential and health-promoting traits. Its beneficial potential properties are mainly due to a high content of anthocyanins and their amount can change after elicitation with methyl jasmonate. The aim of this work is to evaluate the changes in expression of several genes, accumulation of phenolic compounds and alterations in antioxidant potential in two different blueberry cultivars ('Duke' and 'Blueray') in response to methyl jasmonate (0.1 mM). Results showed that 9 h after treatment, the expression of phenylalanine ammonium lyase, chalcone synthase and anthocyanidin synthase genes was stimulated more in the 'Blueray' variety. Among the phenols measured an increase was recorded also for epicatechin and anthocyanin concentrations. 'Duke' is a richer sourche of anthocyanins compared to 'Blueray', treatment with methyl jasmonate promoted in 'Blueray' an increase in pigments as well as in the antioxidant potential, especially in fully ripe berries, but treated 'Duke' berries had greater levels, which were not induced by methyl jasmonate treatment. In conclusion, methyl jasmonate was, in some cases, an effective elicitor of phenolic metabolism and gene expression in blueberry, though with different intensity between cultivars.

Regulation and metabolic engineering of tanshinone biosynthesis

We summarize recent discoveries regarding the mechanisms underlying tanshinone biosynthesis and how the process is regulated.

Ag+ as a more effective elicitor for production of tanshinones than phenolic acids in Salvia miltiorrhiza hairy roots

Phenolic acids and tanshinones are two groups of bioactive ingredients in Salvia miltiorrhiza Bunge. As a heavy metal elicitor, it has been reported that Ag+ can induce accumulations of both phenolic acids and tanshinones in S. miltiorrhiza hairy roots. In this study, the effects of Ag+ treatment on accumulations of six phenolic acids and four tanshinones in S. miltiorrhiza hairy roots were investigated. To further elucidate the molecular mechanism, expressions of key genes involved in the biosynthesis of these ingredients were also detected. The results showed that although the total phenolic acids content was almost not affected by Ag+, accumulations of rosmarinic acid (RA), caffeic acid and ferulic acid were significantly increased, while accumulations of salvianolic acid B (LAB), danshensu (DSU) and cinnamic acid were decreased. We speculate that LAB probably derived from the branch pathway of DSU biosynthesis. Contents of four tanshinones were enhanced by Ag+ and their accumulations were more sensitive to Ag+ than phenolic acids. Genes in the upstream biosynthetic pathways of these ingredients responded to Ag+ earlier than those in the downstream biosynthetic pathways. Ag+ probably induced the whole pathways, upregulated gene expressions from the upstream pathways to the downstream pathways, and finally resulted in the enhancement of ingredient production. Compared with phenolic acids, tanshinone production was more sensitive to Ag+ treatments. This study will help us understand how secondary metabolism in S. miltiorrhiza responds to elicitors and provide a reference for the improvement of the production of targeted compounds in the near future.

Effects of Danshensu and Salvianolic Acid B from Salvia miltiorrhiza Bunge (Lamiaceae) on cell proliferation and collagen and melanin production

Danshensu (DSU) and salvianolic acid B (SAB) are the primary water-soluble compounds of Salvia miltiorrhiza Bunge (Lamiaceae). In this study, we analyzed the effects of DSU, SAB and a S. miltiorrhiza extract (SME) on cell proliferation. Additionally, the effects of DSU and SAB on collagen synthesis in Detroit 551 human normal fibroblast cells and on melanin production in B16 melanoma cells were verified. The results demonstrated that SME can enhance the proliferation of Detroit 551 cells and that this boost may be caused by DSU and SAB. This research showed that SME, DSU and SAB all have the ability to increase the production of collagen in Detroit 551 cells. The results also confirmed that DSU and SAB can attenuate the α-MSH-stimulated melanin production of B16 cells by inhibiting tyrosinase activity. Therefore, SME, DSU and SAB each have the potential to be utilized as active ingredients in wound healing or cosmetic treatments. In the future, DSU and SAB could also be used as functional components for treating hyperpigmentation.