Content Of Baicalin Research Articles

Study on Preparation Technology and Quality Standard of Acne Granules

AbstractThe study aimed to optimize the preparation process of acne granules and establish their quality standards. In this work, the extraction process of Chinese herbal extract was optimized by the amount of water added, the number of decoction, the extraction time, and the soaking time with extraction yield as an evaluation index. The indexes of the acne granules such as molding rate, dissolvability, angle of repose, moisture content, and ease of preparation were evaluated. Thin-layer chromatography (TLC) was used to identify Salviae, Scutellaria baicalensis, and Indigowoad Leaf. High-performance liquid chromatography (HPLC) was used to determine the baicalin content in the granules. Based on orthogonal and single-factor experiments, the optimized extraction process of the prescription of nine medicinal materials was as follows: soaked in cold water for 2 hours, boiled three times, decocted with eight times the amount of water for 1.5 hours for the first time, and six times the amount of water for 1 hour for the second and third times. The combined extracts were concentrated to a relative density of 1.30 to 1.40 (20–30°C), and mixed evenly according to the mass ratio of extract to excipient 1:5, and dextrin: powdered sugar = 1:3. The mixture was granulated, dried, prepared into granules, and the acne granules were formed at a molding rate of 95.52% and a critical relative humidity of 82%. The spots in TLC were clear and easy to identify. The HPLC result showed that the content of baicalin was not less than 1.0 mg/g. The study provides a valuable reference for the production and preparation of the granules through optimization of the wet process and the excipient dosage. Furthermore, the established TLC method for the identification and the HPLC method for baicalin quantification laid the foundation for the quality control of the preparation in future studies.

Improvement effects of a novel Chinese herbal formula in imiquimod and IL-23-stimulated mouse models of psoriasis

BackgroundPsoriasis is a long-term inflammatory skin disease. A novel herbal formula containing nine Chinese herbal medicines, named Inflammation Skin Disease Formula (ISDF), has been prescribed in clinics for decades.AimsTo investigate the efficacy and action mechanisms of ISDF on psoriasis using imiquimod (IMQ) and Interleukin-23 (IL-23)-induced models in mice and reveal the pharmacokinetics profile of ISDF in rats.MethodsTopical administration of IMQ and intradermal injection with IL-23 respectively induced skin lesions like psoriasis on the dorsal area of Balb/c and C57 mice. The mice's body weight, skin thickness, and psoriasis area and severity index (PASI) were assessed weekly. SD rats were used in the pharmacokinetics study and the contents of berberine and baicalin were determined.ResultsThe PASI scores and epidermal thickness of mice were markedly decreased after ISDF treatment in both models. ISDF treatment significantly decreased the contents of IL-17A and IL-22 in the serum of IMQ- and IL-23-treated mice. Importantly, ISDF markedly downregulated IL-4, IL-6, IL-1β, and tumor necrosis factor α (TNF-α) gene expression, and the phosphorylation of NF-κB p65, JNK, ERKs and MAPK p38 in IMQ-treated mice. The protein phosphorylation of Jak1, Jak2, Tyk2 and Stat3 was significantly mitigated in the ISDF-treated groups. The absorption of baicalin and berberine of ISDF through the gastrointestinal tract of rats was limited, and their distribution and metabolism in rats were also very slow, which suggested ISDF could be used in the long-term application.ConclusionsISDF has a strong anti-psoriatic therapeutic effect on mouse models induced with psoriasis through IMQ and IL-23, which is achieved by inhibiting the activation of the Jak/Stat3-activated IL-23/Th17 axis and the downstream NF-κB signalling and MAPK signalling pathways. ISDF holds great potential to be a therapy for psoriasis and should be further developed for this purpose.

Integrated A/O-MBR–NF process for treating high COD content wastewater from traditional Chinese medicine

Traditional Chinese medicine (TCM) wastewater poses a significant environmental challenge due to its high chemical oxygen demand (COD) and complex components. This study demonstrates a highly effective treatment approach for complex TCM wastewater using a combination of hydrolysis-acidification (HA) pre-treatment, anaerobic-aerobic membrane bioreactor (A/O-MBR), and nanofiltration (NF). Pudilan Xiaoyan Oral Liquid (PDL) wastewater, characterized by high COD (around 5500 mg/L) and baicalin content, served as the model feedstock. The A/O-MBR demonstrated removal rates of 23.6 mg COD g biomass−1 h−1 and 1.0 mg NH3-N g biomass−1 h−1. The combined A/O-MBR-NF process achieved exceptional COD removal exceeding 99 %, significantly reducing the wastewater's environmental impact. Importantly, the treated effluent exhibited no biological toxicity in zebrafish acute toxicity tests, demonstrating the effectiveness of this approach in detoxifying PDL wastewater. Analysis of the A/O-MBR's bacterial community further elucidates the treatment mechanism. This study indicates that MBR treatment for complex TCM wastewater is feasible and holds promising industrial prospects, offering a fresh perspective on the treatment of TCM wastewater with high COD levels.

Rapid and comprehensive quality evaluation of Huang-qin from different origins by FT-IR and NIR spectroscopy combined with chemometrics.

Quality evaluation of Huang-qin is significant to ensure its clinical efficacy. This study aims to establish an accurate, rapid and comprehensive Huang-qin quality evaluation method to overcome the time-consuming and laborious shortcomings of traditional herbal medicine quality assessment methods. The contents of baicalin, baicalein and scutellarin in Huang-qin from five different origins were analyzed by FT-IR and NIR spectra combined with multivariate data technology. The quality of Huang-qin from different origins was evaluated by TOPSIS and consistency analysis based on the content of three active ingredients. The correlation between ecological factors and the accumulation of active ingredients was explored. Satisfactory prediction results of PLS models were obtained. Relatively, the model based on FT-IR combined with the PLS regression method has higher R2 and smaller RMSE than the NIR combined with the PLS method. TOPSIS and consistency analysis results showed that the quality of Huang-qin from different geographical origins was significantly different. The results showed that the quality of Huang-qin produced in Shanxi Province was the best among the five origins studied. The results also found that the quality of Huang-qin in different growing areas of the same origin was not completely consistent. The correlation study showed that altitude, sunshine duration and rainfall were the main factors that caused the quality difference of medicinal materials in different geographical origins. This study provides a reference for the rapid quantitative analysis of the active components of herbal medicine and the quality evaluation of them.

Scutellaria Root extract-induced hepatocytotoxicity can be controlled by regulating its baicalin content.

Scuellaria Root (SR, root of Scutellaria baicalensis), which has potent anti-inflammatory effects, is a component of useful Kampo formulae. Albeit a low frequency, SR induces serious interstitial pneumonia and liver dysfunction. In this study, to control the adverse effects of SR, we investigated the causal constituent responsible for its hepatocytotoxicity and aimed to develop a method to control it. As a result, we revealed that the hepatocytotoxicity of SR was correlated with its baicalin content, a major constituent in SR. It was confirmed by preparing a baicalin-free SR extract, which exhibited reduced hepatocytotoxicity. The addition of baicalin to the baicalin-free SR extract restored the hepatocytotoxicity, indicating that the hepatocytotoxicity of SR is dependent on its baicalin content. Thus, SR extract-induced hepatocytotoxicity can be controlled by regulating its baicalin content.

Elucidating the active ingredients and potential anti-inflammatory mechanism of Qingwei Huanglian Wan

Qingwei Huanglian Wan (QHW) is a traditional Chinese medicine used for treating inflammation. As the compositions of QHW preparations are complex and varied, it has proven difficult to identify the active ingredients in QHW and control the quality. In this study, high-performance liquid chromatography (HPLC) fingerprints, network pharmacology, molecular docking, and the Griess method were used to screen for and verify the potential active ingredients of QHW. First, sixteen batches of QHW were studied as two groups using multivariate statistical analysis. Thirteen peaks were detected in the HPLC results to establish a fingerprint similarity model, and six chemical constituents (phellodendrine hydrochloride, geniposide, berberine hydrochloride, baicalin, wogonoside, and glycyrrhizic acid) were identified. Among these six constituents, four components (glycyrrhizic acid, berberine hydrochloride, baicalin, and wogonoside) were considered as potential active ingredients. Second, network pharmacology, molecular docking, and the Griess method were used to further elucidate the potential active ingredients. There was no significant difference in the NO content of the active ingredients administration group (dose converted into the medium-dose group) and medium-dose QHW administration group. Then, the contents of berberine hydrochloride, baicalin, wogonoside, and glycyrrhizic acid were determined using the HPLC method. This study provides a comprehensive and reliable strategy for the quality control of QHW preparations and identifies potential active ingredients in QHW. Our methodology may also be useful for studying other traditional Chinese medicines.

Identification of SbWRKY Transcription Factors in Scutellaria baicalensis Georgi under Drought Stress and Their Relationship with Baicalin

One of the most significant transcription factors in plants, WRKYs, are crucial for plant growth and stress response. In this study, we analyzed the physicochemical properties, evolutionary relationships, conservation structure, and expression of the WRKY gene family in S. baicalensis. The WRKY family has highly conserved structural domains, which have been classified into three major categories, I, II, and III, based on the number of WRKY structural domains and zinc finger structural features. SbWRKYs of the same subgroup are functionally similar and essentially contain the same motif. Additionally, different drought stress situations resulted in varying levels of SbWRKYs expression, with the majority of these factors being up-regulated in moderate drought stress settings, and fewer of them were up-regulated under severe drought stress conditions. Under moderate drought stress, the expression of key enzymes increased, while under severe drought stress, the expression of key enzymes decreased. Mild drought stress resulted in a 26.42% increase in baicalin accumulation, while severe drought stress led to a 22.88% decrease. The protein interaction analysis of key enzyme genes and SbWRKYs revealed that the expression of key enzyme genes affected the expression of SbWRKYs. We screened nine SbWRKYs with a significant relationship with baicalin accumulation, and SbWRKY8 and SbWRKY16 showed the highest correlation with the baicalin content. These findings offer a theoretical framework for more research on the roles of SbWRKYs and show that SbWRKYs can respond to drought stress in S. baicalensis.

A 13-LOX participates in the biosynthesis of JAs and is related to the accumulation of baicalein and wogonin in Scutellaria baicalensis.

Although baicalein and wogonin contents in Scutellaria baicalensis, a traditional Chinese herb, are known to be regulated by jasmonic acid, the exact mechanism by which jasmonic acid regulates the accumulation of baicalein and wogonin remains unclear. In this study, we discovered SbLOX3, a gene encoding 13-lipoxygenase from the roots of S. baicalensis, which plays an important role in the biosynthesis of jasmonic acid. The contents of methyl jasmonate, baicalin, wogonin, and three metabolic intermediates of methyl jasmonate, 13-HPOT, OPDA, and OPC-8, were downregulated in the hair roots of the SbLOX3 RNAi lines. We confirmed that SbLOX3 was induced by drought stress simulated by PEG and Fusarium oxysporum, which subsequently led to changes in the content of MeJA, baicalin, and wogonin. Taken together, our results indicate that a 13-LOX is involved in the biosynthesis of jasmonic acid, and regulates the accumulation of baicalein and wogonin in S. baicalensis roots.

SbWRKY75- and SbWRKY41-mediated jasmonic acid signaling regulates baicalin biosynthesis.

Scutellaria baicalensis Georgi is a traditional Chinese medicinal plant with broad pharmacological activities whose main active ingredient is the flavonoid baicalin. Given its medicinal value and increasing market demand, it is essential to improve the plant's baicalin content. Flavonoid biosynthesis is regulated by several phytohormones, primarily jasmonic acid (JA). In this study, we conducted transcriptome deep sequencing analysis of S. baicalensis roots treated with methyl jasmonate for different durations (1, 3, or 7 hours). Leveraging weighted gene co-expression network analysis and transcriptome data, we identified candidate transcription factor genes involved in the regulation of baicalin biosynthesis. To validate the regulatory interactions, we performed functional assays such as yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase assays. Our findings demonstrated that SbWRKY75 directly regulates the expression of the flavonoid biosynthetic gene SbCLL-7, whereas SbWRKY41 directly regulates the expression of two other flavonoid biosynthetic genes, SbF6H and SbUGT, thus regulating baicalin biosynthesis. We also obtained transgenic S.baicalensis plants by somatic embryo induction and determined that overexpressing SbWRKY75 increased baicalin content by 14%, while RNAi reduced it by 22%. Notably, SbWRKY41 indirectly regulated baicalin biosynthesis by modulating the expression of SbMYC2.1, SbJAZ3 and SbWRKY75. This study provides valuable insights into the molecular mechanisms underlying JA-mediated baicalin biosynthesis in S. baicalensis. Our results highlight the specific roles of transcription factors, namely SbWRKY75 and SbWRKY41, in the regulation of key biosynthetic genes. Understanding these regulatory mechanisms holds significant potential for developing targeted strategies to enhance baicalin content in S. baicalensis through genetic interventions.

Equivalence of combined decoction and mixed single decoctions of Gegen Qinlian Decoction in alleviating chemotherapy-associated diarrhea

This study compared the chemical profiles, component content, dry paste yield, and pharmacological effects of samples obtained from the mixed single decoctions and the combined decoction of Gegen Qinlian Decoction(GQD), aiming to provide an experimental foundation for evaluating the equivalence of the two decocting methods and the suitability of TCM formula granules in clinical application. The same decoction process was used to prepare the combined decoction and mixed single decoctions of GQD. Ultra-performance liquid chromatography coupled with Q-Exactive Orbitrap mass spectrometry(UPLC-Q-Exactive Orbitrap MS) was employed to compare the chemical profiles between the two groups. High-performance liquid chromatography(HPLC) was used to compare the content of nine characteristic components between the two groups. Then, a delayed diarrhea mouse model induced by irinotecan was established to compare the pharmacological effects of the two groups on chemotherapy-induced diarrhea. The UPLC-Q-Exactive Orbitrap MS in ESI~+ and ESI~- modes identified 59 chemical components in the compound decoction and mixed single decoctions, which showed no obvious differences in component species. The content of baicalin and wogonoside was higher in the compound decoction, while that of puerarin, daidzein-8-C-apiosylglucoside, berberine, epiberberine, wogonin, glycyrrhizic acid, and daidzein was higher in the mixed single decoctions. Further statistical analysis revealed no significant difference in the content of the nine characteristic components between the compound decoction and the mixed single decoctions. The dry paste yield had no significant difference between the two groups. Compared with the model group, both compound decoction and mixed single decoctions alleviated the weight loss and reduced diarrhea index in mice. Both of them lowered the levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), cyclooxygenase-2(COX-2), intercellular adhesion molecule-1(ICAM-1), interleukin-10(IL-10), malondialdehyde(MDA), and nitric oxide(NO) in the colon tissue. Furthermore, they significantly increased the levels of glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD). Hematoxylin-eosin(HE) staining showed that colon tissue cells were tightly arranged with clear nuclei in both groups without obvious difference. The compound decoction and mixed single decoctions showed no significant differences in chemical component species, content of nine characteristic components, dry paste yield, or the pharmacological effects on alleviating chemotherapy-induced diarrhea. The findings provide a reference for evaluating the flexibility and superiority of combined or single decocting method in the preparation of TCM decoctions or formula granules.

Post-harvest freezing injury reduces exterior quality of medicinal material and promotes transformation from glycosides to aglycones in Scutellaria baicalensis

Appropriate post-harvest processing plays a critical role in the exterior quality and the yield of bioactive ingredients of medicinal crops. However, fresh medicinal materials harvested in winter often suffer from freezing injury, leading to poor quality and instability of clinical efficacy in practical production. Revealing the responses of freezing injury in medicinal crops will significantly prevent economic losses for farmers and potential risks for clinical medication. In this study, we comprehensively analyzed the effect of post-harvest freezing injury on a well-known traditional Chinese medicine, Scutellaria baicalensis (Huangqin), that harvested in late autumn or early winter in China. The exterior quality and eight active ingredients of medicinal materials processed by natural drying (ND), natural freezing (NF) and simulated freezing treatments (FT) with different treating time (T0 to T5) of S. baicalensis were analyzed and compared by high performance liquid chromatography (HPLC). The results showed that fresh roots under NF and FT treatments exhibited loose texture and green or even dark brown color, and the unique smell of S. baicalensis medicinal materials nearly disappeared. Compared with the contents of baicalin (152.48 mg/g), wogonoside (27.16 mg/g), and scutellarin (5.55 mg/g) in T0 under FT treatment, those contents in T5 significantly decreased (92.60 mg/g, 10.30 mg/g, and 0.25 mg/g, respectively) with increasing repeated freezing and thawing time. Interestingly, freezing injury dramatically improved the contents of baicalein (from 2.97 mg/g to 29.58 mg/g), wogonin (from 0.31 mg/g to 6.96 mg/g), scutellarein (from 0.96 mg/g to 1.75 mg/g), apigenin (from 0.03 mg/g to 0.07 mg/g), and chrysin (from 0.01 mg/g to 0.80 mg/g). The content of eight medicinal active ingredients and the content of glycosides under FT for 72 h (FT-72) treatment (138.98 mg/g, 102.59 mg/g) were significantly lower than those under ND treatment (189.30 mg/g, 184.58 mg/g), but that of aglycones significantly increased about eight times (36.39 mg/g for FT-72 and 4.07 mg/g for ND). Furthermore, there were significant negative correlations between the contents of baicalin and baicalein (r2 = 0.9499, P < 0.0001), wogonoside and wogonin (r2 = 0.9190, P < 0.0001), and scutellarin and scutellarein (r2 = 0.4344, P < 0.001) under FT-72 treatment. The extracting rate of active ingredients under NF treatment increased rapidly and reached almost 100% within 30 min, but that under ND treatment increased slowly and reached 100% for 50 min. It is speculated that repeated freezing and thawing destroyed cellular structures of fresh roots and strongly accelerated extracting rate of active ingredients. Subsequent ion outflow and enzyme activation led to oxidative hydrolysis that induced the transformation from glycosides to aglycones. Collectively, the above results would provide valuable guidance for medicinal farmers to avoid freezing injury in post-harvest processing, thereby ensuring medicinal quality of S. baicalensis for pharmaceutical industry. Furthermore, these results will shed light on revealing the effect and mechanism of freezing injury on product quality and help formulating technical specifications for standardized production of medicinal crops.

The transcription factors SbMYB45 and SbMYB86.1 regulate flavone biosynthesis in Scutellaria baicalensis

Scutellaria baicalensis Georgi is an important Chinese medicinal plant that is rich in the flavones baicalin, wogonoside, and wogonin, providing it with anti-cancer, anti-inflammatory, and antibacterial properties. However, although the biosynthetic pathways of baicalin and its derivates have been elucidated, the regulation of flavone biosynthesis in S. baicalensis is poorly understood. Here, we found that the contents of baicalin and its derivates increased and that baicalin biosynthetic pathway genes were induced in response to light, and baicalin and baicalein are not exclusively produced in the roots of S. baicalensis. Based on the fact that MYB transcription factors are known to play important roles in flavone biosynthesis, we identified SbMYB45 and SbMYB86.1 in S. baicalensis and determined that they bind to the promoter of the flavone biosynthesis gene SbCHI to enhance its transcription. Moreover, overexpressing SbMYB45 and SbMYB86.1 enhanced the accumulation of baicalin in S. baicalensis leaves. We demonstrate that SbMYB45 and SbMYB86.1 bind to the cis-acting element MBSII in the promoter of CHI to redundantly induce its expression upon light exposure. These findings indicate that SbMYB45 and SbMYB86.1 transcriptionally activate SbCHI in response to light and enhance flavone contents in S. baicalensis.

Chemical Influence of Scutellaria baicalensis—Coptis chinensis Pair on the Extraction Efficiencies of Flavonoids and Alkaloids at Different Extraction Times and Temperatures

The Scutellaria baicalensis—Coptis chinensis pair is an herbal combination used for the treatment of various heat-related diseases. During the extraction process, two herbs can mutually influence the extraction efficiency of the chemical constituents contained in each herb. The concentrations of five flavonoids from S. baicalensis and seven alkaloids from C. chinensis were compared in paired or single hot-water extracts at different temperatures (80, 90, and 100 °C) and extraction times (60, 90, and 120 min). Temperature- and time-dependent increases in marker compound concentrations were observed in both paired and single extracts, with the exception of baicalin, berberine, and coptisine in the paired extracts at 100 °C. However, the extractions of the compounds in the paired and single extracts were affected differently by the extraction conditions. Furthermore, the concentrations of most marker compounds in single extracts were 1.09–44.13 times those in paired extracts. The contents of baicalin, wogonoside, coptisine, and berberine, known to be easily aggregated by the flavonoid–alkaloid complex, were changed by 0.024–0.764-fold in the paired extract. The effect of extraction temperature and time on the formation of the flavonoid–alkaloid complex was not significant. The extraction efficiency of the flavonoids and alkaloids can be affected by the pair of S. baicalensis—C. chinensis, which is a primary factor in the chemical modification of two herb-containing herbal extracts.

Comparative Study of the Flavonoid Content in Radix Scutellaria from Different Cultivation Areas in China.

Scutellariabaicalensis Georgi, an important perennial herb, is widely distributed and used all over the world. The root of S. baicalensis (Radix Scutellaria) is rich in flavonoids with a variety of bioactive effects and is widely used in clinic. The different geographical and climatic conditions of different cultivated areas of S. baicalensis lead to the differences of the main components in Radix Scutellaria. The main objective of this study was to evaluate the difference of flavonoid content in Radix Scutellaria from different cultivated areas in China. The mobile phase system, elution gradient, detection wavelength, and other chromatographic conditions for high-performance liquid chromatography-diode array detection (HPLC-DAD) determination of 8 flavonoids in Radix Scutellaria were optimized. The contents of flavonoids in 38 samples of Radix Scutellaria collected from seven main genuine cultivated areas were determined, and the correlation between the content, cultivated area, and the biological activities of Radix Scutellaria was compared. The results implied that baicalin, wogonoside, and baicalein were the three main flavonoids with the highest contents in Radix Scutellaria. The content of flavonoids in different cultivated areas was very different, which had significant regionality and was closely related to the natural conditions of various places. The antioxidant and antitumor activities of the extract of Radix Scutellaria were closely related to the content of flavonoids, and high contents of baicalin, wogonoside, and baicalein positively improved biological activities.

SbMYB3 transcription factor promotes root-specific flavone biosynthesis in Scutellaria baicalensis.

Scutellaria baicalensis Georgi produces abundant root-specific flavones (RSFs), which provide various benefits to human health. We have elucidated the complete biosynthetic pathways of baicalein and wogonin. However, the transcriptional regulation of flavone biosynthesis in S. baicalensis remains unclear. We show that the SbMYB3 transcription factor functions as a transcriptional activator involved in the biosynthesis of RSFs in S. baicalensis. Yeast one-hybrid and transcriptional activation assays showed that SbMYB3 binds to the promoter of flavone synthase II-2 (SbFNSII-2) and enhances its transcription. In S. baicalensis hairy roots, RNAi of SbMYB3 reduced the accumulation of baicalin and wogonoside, and SbMYB3 knockout decreased the biosynthesis of baicalein, baicalin, wogonin, and wogonoside, whereas SbMYB3 overexpression enhanced the contents of baicalein, baicalin, wogonin, and wogonoside. Transcript profiling by qRT-PCR demonstrated that SbMYB3 activates SbFNSII-2 expression directly, thus leading to more abundant accumulation of RSFs. This study provides a potential target for metabolic engineering of RSFs.

Inter-specific differences of medicinal bioactive products are correlated with differential expressions of key enzyme genes in Scutellaria baicalensis and Scutellaria viscidula

Revealing the dynamic accumulation and synthesizing mechanism of medicinal bioactive products is critical for the evaluation and utilization of crops in medicinal industry. Huangqin ( Scutellaria baicalensis Georgi) and Nianmao-Huangqin ( Scutellaria viscidula Bge) are important medicinal crops containing flavonoids with good bioactivities. Previous studies have found significant differences of flavonoid contents between the two species. Nevertheless, the dynamic changes of bioactive products and related differential synthesizing mechanism remains unknown. In this study, an inter-specific comparative study was reported on the dynamic accumulation of eight bioactive products (scutellarin, scutellarein, baicalin , wogonoside, apigenin , baicalein, wogonin, and chrysin) and the expression of seven key enzyme genes in different organs (root, stem, and leaf) during different growth stages (May, June, July, August, September, and October) of S. baicalensis and S . viscidula . The results showed that the eight bioactive products were differentially accumulated in different growth stages for the two species. Specifically, the contents of five ingredients (except wogonoside, scutellarein and apigenin) in roots of S. baicalensis were significantly higher than those in S. viscidula in harvest stage (October). Meanwhile, the relative expression of seven key enzyme genes in baicalin synthesizing pathway showed significant spatio-temporal specificities. The expression of UBGAT in downstream baicalin synthesis was significantly higher in roots of S. baicalensis than that of S. viscidula ( P < 0.05). Moreover, there exist significant correlations between the content of bioactive products and the expression of key enzyme genes. The expression of upstream ( CLL-7 , FNSII-1 , FNSII-2 ) and downstream ( F6H and UBGAT ) key enzyme genes were significantly positively correlated with the contents of baicalin in both S. baicalensis and S. viscidula. On the contrary, the expression of GUS was significantly negatively correlated with the content of baicalin in the two species. Collectively, these results give clear evidences that the expression of key enzyme genes (e.g., FNSII-2 , GUS , and UBGAT ) in baicalin synthesis is probably the main reason for the difference of bioactive products, suggesting that S . viscidula can be used as an alternative to S. baicalensis in pharmaceutical industry. Furthermore, these findings will provide a theoretical basis for exploring the inter-specific differences of bioactive products in medicinal crops within the same genus, thereby revealing the molecular mechanism of quality formation of Chinese medicinal materials. • Eight bioactive products showed content difference between two Scutellaria crops. • Seven key genes were differentially expressed in S. baicalensis and S. viscidula . • Difference of product content was correlated with difference of gene expression. • S. viscidula can be used as alternative medicinal source to S. baicalensis . • Molecular mechanism of differential bioactive product contents was revealed.

Metabolomic association analysis reveals defense related secondary metabolic reprogramming in callus of Scutellaria baicalensis Georgi induced by endophytic Pseudomonas sp. 2B

Interactions between plants and endophyte can influence the secondary metabolism in host plants. Scutellaria baicalensis Georgi, is widely used as traditional Chinese medicine and cultivated extensively in China. Until now, the influence of endophytes on secondary metabolism of S. baicalensis is still unclear. To address this issue, non-targeted metabolomics tool was performed to explore the global secondary metabolic changes in S. baicalensis with a dual culture of callus and endophytic Pseudomonas sp. 2B. Further, the activity of polyphenol oxidase (PPO) and the expression patterns of key genes in flavonoid biosynthesis pathway were detected. Through the analysis of non-targeted metabolomics, a total of 1814 differential metabolites were found and the identified differential metabolites were mainly belonged to flavonoids, anthraquinones, lignin and phenylethanoids. The target quantitative analysis revealed that the contents of baicalin and wogonoside decreased in callus of S. baicalensis co-cultured with Pseudomonas sp. 2B, but the accumulations of baicalein, wogonin and chrysin were promoted. The activity of PPO was also increased in this process. Furthermore, there was a significant decrease in flavone synthase (sbFNS II-2) and chalcone synthase (sbCHS2) transcripts in dual culture of endophyte-callus. The expression of cinnamic acid–specific coenzyme A ligase (sbCLL7) and the UDP-glucuronate baicalein 7-O-glucuronosyltransferase (sbUBGAT) transcripts were promoted. The results demonstrated that endophytic Pseudomonas sp. 2B could reprogram defense related secondary metabolism in S. baicalensis and had a potential application value in biocontrol for cultivation of S. baicalensis.

Enhancement of flavonoid synthesis and antioxidant activity in Scutellaria baicalensis aerial parts by UV-A radiation

Ultraviolet-A (UV-A) can affect plant secondary metabolism, but the flavonoid synthesis in Scutellaria baicalensis Georgi aerial parts in response to UV-A radiation was not clear. Therefore, the effects of UV-A radiation on flavonoid synthesis in S. baicalensis aerial parts were investigated in this study. The results showed that the total flavonoid content in aerial parts of S. baicalensis reached the maximum value (41.86 mg g−1) after 7 d of UV-A radiation. Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis showed that the composition of flavonoids was not changed, but the contents of different components were changed according to High-Performance Liquid Chromatography (HPLC) analysis. Compared with the control treatment, the contents of scutellarin, baicalin and wogonoside were increased by 2.70-fold, 2.22-fold and 2.31-fold, respectively. However, scutellarein and baicalein decreased by 1.80-fold and 1.91-fold respectively. Meanwhile, UV-A radiation significantly increased the contents of nitric oxide (NO) and hydrogen peroxide (H2O2), and enhanced the activities of Phenylalanine ammonia lyase (PAL), Cinnamic acid 4-hydroxylase (C4H), and 4-coumarate CoA ligase (4CL). In addition, the antioxidant activity of S. baicalensis aerial part extracts after UV-A radiation was stronger than that of the control treatment. Further correlation analysis showed that there was a significant correlation between total flavonoid content and NO, H2O2, PAL, C4H, and 4CL. The enhancement of the antioxidant activity of S. baicalensis aerial part extracts was significantly correlated with total flavonoid, baicalin, wogonin and scutellarin content. This study shows that UV-A radiation can be used as an effective and economic way to increase the flavonoid contents in S. baicalensis aerial parts and promote the antioxidant activity of its extracts.

A study of flavonoid composition and antimicrobial activity of Scutellaria altissima L. from different floristic regions of Bulgaria.

Scutellaria extracts and its constituents, especially the characteristic flavonoids such as baicalein and its glycoside baicalin, exhibit significant antimicrobial activity. To perform a comparative analysis of flavonoid composition and antimicrobial activity of extracts obtained from aerial parts and roots of Scutellaria altissima from the regions of Mezek and Bachkovo, Bulgaria. 70% ethanol and aqueous extracts of aerial parts and roots of S. altissima were used. HPLC analysis of S. altissima extracts was performed. Microbiological tests were done on clinical isolates of Streptococcus mitis, Staphylococcus aureus, Escherichia coli, and Candida albicans. Minimal bactericidal and minimal bacteriostatic concentrations of S. altissima extracts were determined by the agar method. The ethanol extracts contain flavonoids approximately twice as much in comparison with the aqueous extracts. The baicalin content in the aerial parts of S. altissima from the region of Mezek is 5 times higher than that in the roots. S. altissima extracts have effective antimicrobial activity against S. mitis only. The minimal bactericidal concentration of ethanol extracts of S. altissima aerial parts and S. altissima roots is 2000µg/ml and 8000µg/ml at 24 hours, respectively. The bactericidal effect of aqueous extracts occurs at 48 hours at minimal bactericidal concentration of S. altissima aerial parts - 2000µg/ml and of S. altissima roots - 6000µg/ml. The finding that extracts of Bulgarian S. altissima possess effective antimicrobial properties against S. mitis suggests that it can be used as a potential source for the development of natural antimicrobial agents to suppress oral pathogens and prevent some oral infections.

Pharmacophylogenetic study of Scutellaria baicalensis and its substitute medicinal species based on the chloroplast genomics, metabolomics, and active ingredient.

The genetic relationships among the species in Scutellaria genus remain unclear because of the variation in the number of species and complex trait. The usage of S. baicalensis and its four substitute medicinal species (S. amoena, S. hypericifolia, S. likiangensis, and S. viscidula) in traditional medicines make their specialized metabolism important in China, but interspecific genetic and chemical differences have rarely been reported for these species. In this study, the chloroplast genomes of four substitute species for S. baicalensis were assembled, and comparative and phylogenetic analyses were performed with these species and other Scutellaria relatives. In addition, metabolomics analyses were performed and the contents of the main active compounds were determined to reveal the interspecific chemical diversity of S. baicalensis and its four substitute species. The full lengths of their chloroplast genomes ranged from 151,574 to 151,816 bp with an average GC content of 38.34%, and a total of 113 genes were annotated. In the chloroplast genomes of S. baicalensis and its four substitutes, one hypervariable region (petA-psbL) is proposed as a potential DNA barcode. Phylogenetic analysis showed that the subdivision of the genus Scutellaria should be reconsidered. The metabolomics and content determination analyses showed that the four species exhibit a metabolism similar to that of S. baicalensis in different parts. Except for the roots of S. likiangensis, all parts of the substitute species showed high contents of baicalin. Genetic and chemical analyses of four substitute medicinal species for S. baicalensis were performed here for the first time, and their pharmacophylogenetic relationships were further explored, providing a scientific basis for the subsequent development of the medicinal value and resource utilization of Scutellaria.