Identification of flavonoids in the stems and leaves of Scutellaria baicalensis Georgi

Unraveling the Mechanism of Xiaochaihu Granules in Alleviating Yeast-Induced Fever Based on Network Analysis and Experimental Validation

Xiaochaihu granules (XCHG) are extensively used to treat fever. Nevertheless, the underlying mechanism remains elusive. This study aimed to explore the potential of XCHG in mitigating yeast-induced fever and the underlying metabolic pathways. The chemical composition of XCHG was ascertained using ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS), followed by integrated network analysis to predict potential targets. We then conducted experimental validation using pharmacological assays and metabolomics analysis in a yeast-induced mouse fever model. The study identified 133 compounds in XCHG, resulting in the development of a comprehensive network of herb-compound-biological functional modules. Subsequently, molecular dynamic (MD) simulations confirmed the stability of the complexes, including γ-aminobutyric acid B receptor 2 (GABBR2)-saikosaponin C, prostaglandin endoperoxide synthases (PTGS2)-lobetyolin, and NF-κB inhibitor IκBα (NFKBIA)-glycyrrhizic acid. Animal experiments demonstrated that XCHG reduced yeast-induced elevation in NFKBIA's downstream regulators [interleukin (IL)-1β and IL-8], inhibited PTGS2 activity, and consequently decreased prostaglandin E2 (PGE2) levels. XCHG also downregulated the levels of 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), corticotropin releasing hormone (CRH), and adrenocorticotrophin (ACTH). These corroborated the network analysis results indicating XCHG's effectiveness against fever in targeting NFKBIA, PTGS2, and GABBR2. The hypothalamus metabolomics analysis identified 14 distinct metabolites as potential antipyretic biomarkers of XCHG. In conclusion, our findings suggest that XCHG alleviates yeast-induced fever by regulating inflammation/immune responses, neuromodulation, and metabolism modules, providing a scientific basis for the anti-inflammatory and antipyretic properties of XCHG.

Scutellaria baicalensis Georgi stems and leaves flavonoids promote neuroregeneration and ameliorate memory loss in rats through cAMP-PKA-CREB signaling pathway based on network pharmacology and bioinformatics analysis

The aim of this study was to investigate the possible molecular mechanism of Scutellaria baicalensis Georgi stems and leaves flavonoids (SSF) in Alzheimer's disease (AD). The active ingredients of SSF and their targets were identified via network pharmacology and bioinformatics analysis. To test the successful establishment of a rat model of AD by Aβ25-35 combined with RHTGF-β1 and AlCl3, the Morris water maze test was used. To intervene, three different doses of SSF were administered. The model group and the control group were included among the parallel groups. A shuttle box test, immunohistochemistry, an enzyme-linked immunosorbent assay, qPCR and Western blot were performed to verify the results. Based on the intersection of genes among AD disease targets, SSF component targets, and differentially expressed genes in the single cell dataset GSE138852 and bulk-seq dataset GSE5281, nine genes related to the action of SSF on AD were identified. SSF have an important anti-AD pathway in the cAMP signaling pathway. SSF can ameliorate the conditioned memory impairment, augment Brdu protein expression and cAMP content; and differentially regulate the mRNA and protein expressions of GPCR, Gαs, AC1, PKA, and VEGF. The cAMP-PKA-CREB pathway in the SSF may mediate the ability of the SSF to ameliorate the composite-induced memory loss and nerve regeneration in rats induced by composite Aβ.

Chemical Compositions of Scutellaria baicalensis Georgi. (Huangqin) Extracts and Their Effects on ACE2 Binding of SARS-CoV-2 Spike Protein, ACE2 Activity, and Free Radicals

The water and ethanol extracts of huangqin, the roots of Scutellaria baicalensis Georgi. with potential antiviral properties and antioxidant activities, were investigated for their chemical profiles and their abilities to interfere with the interaction between SARS-CoV-2 spike protein and ACE2, inhibiting ACE2 activity and scavenging free radicals. A total of 76 compounds were tentatively identified from the extracts. The water extract showed a greater inhibition on the interaction between SARS-CoV-2 spike protein and ACE2, but less inhibition on ACE2 activity than that of the ethanol extract on a per botanical weight concentration basis. The total phenolic content was 65.27 mg gallic acid equivalent (GAE)/g dry botanical and the scavenging capacities against HO●, DPPH●, and ABTS●+ were 1369.39, 334.37, and 533.66 µmol trolox equivalent (TE)/g dry botanical for the water extract, respectively. These values were greater than those of the ethanol extract, with a TPC of 20.34 mg GAE/g, and 217.17, 10.93, and 50.21 µmol TE/g against HO●, DPPH●, and ABTS●+, respectively. The results suggested the potential use of huangqin as a functional food ingredient in preventing COVID-19.

Unraveling spatial metabolome of the aerial and underground parts of Scutellaria baicalensis by matrix-assisted laser desorption/ionization mass spectrometry imaging

BACKGROUND

Scutellaria baicalensis Georgi, a traditional Chinese medicine, is clinically applied mainly as the dried root of Scutellaria baicalensis, and the aerial parts of Scutellaria baicalensis, its stems and leaves, are often consumed as "Scutellaria baicalensis tea" to clear heat, dry dampness, reduce fire and detoxify, while few comparative analyses of the spatial metabolome of the aerial and underground parts of Scutellaria baicalensis have been carried out in current research.

METHODS

In this work, Matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) was used to visualize the spatial imaging of the root, stem, and leaf of Scutellaria baicalensis at a high resolution of 10 μm, respectively, investigating the spatial distribution of the different secondary metabolites in the aerial and underground parts of Scutellaria baicalensis.

RESULTS

In the present results, various metabolites, such as flavonoid glycosides, flavonoid metabolites, and phenolic acids, were systematically characterized in Scutellaria baicalensis root, stem, and leaf. Nine glycosides, 18 flavonoids, one organic acid, and four other metabolites in Scutellaria baicalensis root; nine glycosides, nine flavonoids, one organic acid in Scutellaria baicalensis stem; and seven flavonoids and seven glycosides in Scutellaria baicalensis leaf were visualized by MALDI-MSI. In the underground part of Scutellaria baicalensis, baicalein, wogonin, baicalin, wogonoside, and chrysin were widely distributed, while there was less spatial location in the aerial parts. Moreover, scutellarein, carthamidin/isocarthamidin, scutellarin, carthamidin/isocarthamidin-7-O-glucuronide had a high distribution in the aerial parts of Scutellaria baicalensis. In addition, the biosynthetic pathways involved in the biosynthesis of significant flavonoid metabolites in aerial and underground parts of Scutellaria baicalensis were successfully localized and visualized.

CONCLUSIONS

MALDI-MSI offers a favorable approach for investigating the spatial distribution and effective utilization of metabolites of Scutellaria baicalensis. The detailed spatial chemical information can not only improve our understanding of the biosynthesis pathways of flavonoid metabolites, but more importantly, suggest that we need to fully exert the overall medicinal value of Scutellaria baicalensis, strengthening the reuse and development of the resources of Scutellaria baicalensis aboveground parts.

Study on the targeted regulation of Scutellaria baicalensis leaf on glutamine-glutamate metabolism and glutathione synthesis in the liver of d-gal ageing rats

OBJECTIVES

Scutellaria baicalensis leaf (SLE), the above-ground part of the traditional Chinese medicine Scutellaria baicalensis Georgi, is rich in resources and contains a large number of flavonoids with anti-inflammatory, antioxidant and neuroprotective functions. The present study evaluated the ameliorative effects and related mechanisms of SLE on d-gal-induced ageing rats, providing a theoretical basis for the exploitation of SLE.

METHODS

This experiment investigated the mechanism of SLE for anti-ageing by non-targeted metabonomics technology combined with targeted quantitative analysis and molecular biology technology.

KEY FINDINGS

Non-targeted metabonomics analysis showed that 39 different metabolites were screened out. Among them, 38 metabolites were regulated by SLE (0.4 g/kg), and 33 metabolites were regulated by SLE (0.8 g/kg). Through enrichment analysis, glutamine-glutamate metabolic pathway was identified as the key metabolic pathway. Subsequently, the results of targeted quantitative and biochemical analysis displayed that the contents of key metabolites and the activities of enzymes in glutamine-glutamate metabolic pathway and glutathione synthesis could be regulated by SLE. Furthermore, the results of Western blotting indicated that SLE significantly modulated the expression of Nrf2, GCLC, GCLM, HO-1, and NQO1 proteins.

CONCLUSION

To sum up, the anti-ageing mechanism of SLE was related to glutamine-glutamate metabolism pathway and Nrf2 signalling pathway.

Chemical Characterization and Determination of the Antioxidant Properties of Phenolic Compounds in Three Scutellaria sp. Plants Grown in Colombia

Plants of the genus Scutellaria (Lamiaceae) have a wide variety of bioactive secondary metabolites with diverse biological properties, e.g., anti-inflammatory, antiallergenic, antioxidant, antiviral, and antitumor activities. The chemical composition of the hydroethanolic extracts, obtained from dried plants of S. incarnata, S. coccinea, and S. ventenatii × S. incarnata, was determined by UHPLC/ESI-Q-Orbitrap-MS. The flavones were found in a higher proportion. Baicalin and dihydrobaicalein-glucuronide were the major extract components in S. incarnata (287.127 ± 0.005 mg/g and 140.18 ± 0.07 mg/g), in S. coccinea (158.3 ± 0.34 mg/g and 51.20 ± 0.02 mg/g), and in S. ventenatii × S. incarnata (186.87 ± 0.01 mg/g and 44.89 ± 0.06 mg/g). The S. coccinea extract showed the highest antioxidant activity in the four complementary techniques employed to evaluate all extracts: ORAC (3828 ± 3.0 µmol Trolox^®/g extract), ABTS^+• (747 ± 1.8 µmol Trolox^®/g extract), online HPLC-ABTS^+• (910 ± 1.3 µmol Trolox^®/g extract), and β-carotene (74.3 ± 0.8 µmol Trolox^®/g extract).

The leaves of Scutellaria baicalensis Georgi attenuate brain aging in D-galactose-induced rats via regulating glutamate metabolism and Nrf2 signaling pathway

The present study aimed to evaluate the anti-aging effect of the leaves of Scutellaria baicalensis Georgi (LSBG) and investigate its mechanisms. For this purpose, SD rats were received D-galactose (D-gal) subcutaneously (0.3 g/kg) and LSBG intragastrically (0.4 g/kg or 0.8 g/kg) for 7 weeks. Behavior tests were conducted to evaluate the cognitive function of all rats. Results showed that memory impairment was reversed by LSBG. Then, metabolomics of the cortex and hippocampus were used to investigate the potential mechanisms. 21 metabolites in the cortex and 22 metabolites in the hippocampus of aging rats were altered, respectively. Additionally, results showed that the content of key metabolites and activities of enzymes in glutamate metabolism and its downstream metabolism (glutathione metabolism) could be regulated by the LSBG. Additionally, proteins in the Nrf2 signaling pathway were analyzed by western blot. And the protein expression levels of Nrf2, GCLC, HO-1, NQO-1 were significantly regulated by the LSBG in the cortex and hippocampus. Above all, the anti-aging effects of the LSBG were involved in regulating the glutamate metabolism and Nrf2 signaling pathway.

Effects of Chilling Treatment on Baicalin, Baicalein, and Wogonin Biosynthesis in Scutellaria baicalensis Plantlets

When plants are exposed to stressful conditions, they modulate their nutrient balance by regulating their primary and secondary metabolisms to adapt. In this study, changes in primary and secondary metabolites elicited by chilling stress treatment and the effects of treatment duration were examined in roots of Scutellaria baicalensis (S. baicalensis) plantlets. The concentrations of most sugars (maltose, glucose, sucrose, and fructose) and of several amino acids (proline and GABA), which are crucial regarding plant defense mechanisms, increased with increasing duration of chilling stress. Furthermore, salicylic acid levels increased after two-day chilling treatments, which may enhance plant tolerance to cold temperatures. The concentrations of flavones (baicalin, baicalein, and wogonin) increased during chilling stress, and those of phenolic acids (ferulic acid and sinapic acid) increased after two-day chilling treatments. The concentrations of these flavones were positively correlated with sucrose levels which acted as energy sources.

Rapid separation and identification of 96 main constituents in Huanglian Jiedu decoction via ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer

Huanglian Jiedu decoction is a widely used traditional Chinese medicine with a broad spectrum of therapeutic effects, including heat clearing, detoxification, and attenuation of inflammation. However, the composition of Huanglian Jiedu decoction is still unclear due to its complexity and limitations of analytical methods. In this study, we established a fast and reliable analytical method based on ultra-performance LC-Orbitrap Fusion Tribrid mass spectrometer for high-speed separation and structural identification of multiple compounds in Huanglian Jiedu decoction. The analysis was carried out using a Hypersil GOLD C18 column (2.1 × 100 mm, 1.9 μm) with gradient elution coupled to a high-definition mass spectrometer system operating in both positive and negative ESI modes. According to the chromatographic retention time, precise molecular weight, fragment ion peaks, and published data, the main chromatographic peaks were attributed to specific molecules whose chemical structures were determined. In total, 96 components were identified, including 34 flavonoids and their glycosides, 23 alkaloids, 18 organic acids, 13 terpenoids, and 8 miscellaneous compounds. This study revealed the detailed chemical composition of Huanglian Jiedu decoction, which is of great importance for quality control and further pharmacological and mechanistic studies.

A strategy integrating parent ions list-modified mass defect filtering-diagnostic product ions for rapid screening and systematic characterization of flavonoids in Scutellaria barbata using hybrid quadrupole-orbitrap high-resolution mass spectrometry

In this study, full scan (FS)-parent ions list (PIL)-higher energy collision induced dissociation (HCD)-MS/MS (FS-PIL-HCD-MS/MS) was used to acquire the chemical profile of flavonoids in Scutellaria barbata. Mass defect filtering (MDF) induced subtype classification and diagnostic product ions (DPIs) dominated structural confirmation were integrated into an effective strategy for the systematic screening and identification of the flavonoids. An in-house flavonoid MS database based on molecular design was established to construct a modified triangle MDF algorithm for progressive screening and subtype classification. The obtained results demonstrated that the modified MDF was capable of simplifying the workload in formula editing and subsequent screening process, and distinguishing different subtypes. The fragmentation behaviors of eleven reference standards were evaluated to obtain the MS² fragmentation pathway and DPIs which can provide a criterion to eliminate false-positive results and judge the target flavonoids with the exact number and position of substituents for the first time. Structure confirmation was characterized by comparing with the reference substance, searching the database, and analyzing DPIs. To distinguish some isomers, ClogP (the calculated lipophilicity parameter) was adopted. As a result, 127 target flavonoids, including 30 flavone/flavonol aglycones, 10 flavanone/flavanonol aglycones, 49 flavone/flavonol monoglycosides, 16 flavanone/flavanonol monoglycosides, 21 flavone/flavonol diglycosides and 1 flavanone/flavanonol diglycoside, were ultimately identified or tentatively characterized based on the MS fragmentation pathway and DPIs analysis. This study provides a novel MDF method with improved subtype classification and develops a novel strategy for the progressive screening, subtype classification and systematic characterization of complex components in herbal medicines.

Submicron 3,4-dihydroxybenzoic acid–TiO2 composite particles for enhanced MALDI MS imaging of secondary metabolites in the root of differently aged baical skullcap

This work provides a high-efficient organic-inorganic hybrid matrix for MALDI MSI of secondary metabolites in plant tissues.

Systematic chemical characterization of Xiexin decoctions using high performance liquid chromatography coupled with electrospray ionization mass spectrometry

Xiexin decoctions (XXDs) display beneficial anti-inflammatory and anti-diabetic effects, which raises interests on this group of formulae for broad clinical applications. However, there was no report about systematic analysis of XXDs to elucidate the constitution of chemical components, which hampers further investigations on the therapeutic values of XXDs. In this work, crude herbs were extracted and prepared to obtain the XXDs for systemic analysis on their chemical compositions, according to the information described in the ancient Zhang Zhongjing's herbal formulae. LC-MS analysis of five XXDs was carried out to facilitate recognition of the source herbs for compounds in the mixture. A total number of 93 compounds were identified through our methods and their chemical classes encompassed five major groups, including protoberberine alkaloids, flavonoids, stilbenes, anthraquinones and saponins. Our current work provided important information about material basis for pharmacological studies on XXDs and would help shed light on relationships between chemical compositions and therapeutic effects.

Structure, Biological Activities and Metabolism of Flavonoid Glucuronides

BACKGROUND

Flavonoid glucuronides are a kind of natural products which present a flavone linked directly with one or several glucuronides through O-glycoside bond. They had become of interest in natural product research in the past decades for their antioxidant, anti-inflammatory, and anti-bacteria activities. In particular, the compound breviscapine has a notable effect on cardio-cerebrovascular diseases. Several other compounds even have antitumor activity.

METHODS

Through searching the database and reading a large number of documents, we summarized the related findings of flavonoid glucuronides.

RESULTS

We summarized 211 naturally occurring flavonoid glucuronides in 119 references with their chemical structures, biological activities, and metabolism. A total of 220 references from 1953 to 2020 were cited in this paper according to literature databases such as CNKI, Weipu, Wanfang data, Elsevier, Springer, Wiley, NCBI, PubMed, EmBase, etc..

CONCLUSION

Flavonoid glucuronides are a class of compounds with various chemical structures and a diverse range of biological activities. And they are thought to be potential candidates for drug discovery, but the specific study on their mechanisms is still limited until now. We hope this article can provide references for natural product researchers and draw more attention to flavonoid glucuronides' biological activities and mechanisms.

Norwogonin attenuates hypoxia-induced oxidative stress and apoptosis in PC12 cells

Background

Norwogonin is a natural flavone with three phenolic hydroxyl groups in skeletal structure and has excellent antioxidant activity. However, the neuroprotective effect of norwogonin remains unclear. Here, we investigated the protective capacity of norwogonin against oxidative damage elicited by hypoxia in PC12 cells.

Methods

The cell viability and apoptosis were examined by MTT assay and Annexin V-FITC/PI staining, respectively. Reactive oxygen species (ROS) content was measured using DCFH-DA assay. Lactate dehydrogenase (LDH), malondialdehyde (MDA) and antioxidant enzyme levels were determined using commercial kits. The expression of related genes and proteins was measured by real-time quantitative PCR and Western blotting, respectively.

Results

We found that norwogonin alleviated hypoxia-induced injury in PC12 cells by increasing the cell viability, reducing LDH release, and ameliorating the changes of cell morphology. Norwogonin also acted as an antioxidant by scavenging ROS, reducing MDA production, maintaining the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and decreasing the expression levels of HIF-1α and VEGF. In addition, norwogonin prevented cell apoptosis via inhibiting the expression levels of caspase-3, cytochrome c and Bax, while increasing the expression levels of Bcl-2 and the ratio of Bcl-2/Bax.

Conclusions

Norwogonin attenuates hypoxia-induced injury in PC12 cells by quenching ROS, maintaining the activities of antioxidant enzymes, and inhibiting mitochondrial apoptosis pathway.

Application of multi-dimensional and multi-informational (MD-MI) integrated xanthine oxidase and superoxide anion fingerprint in quality evaluation of Scutellariae Radix

A multi-hyphenated analytical method that was successfully established in previous research was applied to quality evaluation of traditional Chinese medicine (TCM) to verify its feasibility in complex systems. Scutellariae Radix (SR), which significantly protects against oxidative damage from ischemia and reperfusion, was selected as the TCM for this study. A dual-activity detection system based on xanthine oxidase (XOD) inhibition and superoxide anion (O₂^-) scavenging activity was used to generate a multi-dimensional-multi-informational (MD-MI) integrated fingerprint of SR. Combined with HPLC-ESI-Q-TOF-MS analysis, 17 active compounds in SR were tentatively identified by comparison with reference substances or literature data. The quality of SR from different habitats was comprehensively and systematically evaluated in respect of chemical composition, XOD inhibition and O₂^- scavenging activity. It was confirmed that SR contains many antioxidants and XOD inhibitory substances with diverse functions. Among them, baicalin, norwogonin-7-O-glucuronide and baicalein are the main contributors to direct antioxidant activity. Acteoside, 5,7,2',5'-tetrahydroxy-8,6'-dimethoxy flavone, baicalin and baicalein are the main XOD inhibitory components of SR. Comprehensive analysis found that the antioxidant activity of SR from Gansu Province was superior to that from other provinces in terms of both XOD inhibition and O₂^- scavenging activity. It has been demonstrated that the method is capable of analyzing complex TCM matrices, and can provide a useful reference for establishing quality control of TCM from the perspective of MD-MI.

The herbal extract deriving from aerial parts of Scutellaria baicalensis shows anti-inflammation and anti-hypoxia responses in cultured fin cells from rabbit fish

A new cell line derived from dorsal fin of rabbit fish Siganus fuscescens was developed and characterized. The cell line was isolated from the dorsal fin, named as rabbit fish fin (RFF) cell line, and which was sub-cultured for 50 cycles since the development. This cell line was tested for growth in different temperatures and serum concentrations, and the best growing condition was at 20% serum at 28 °C. In cultured RFF cells, amplification of 18S rRNA from genomic DNA and immunostaining of cellular cytokeratin confirmed the proper identity of S. fuscescens fish. After 30th passage of cultures, the cells were exposed to challenge of inflammation, triggered by LPS, and hypoxia, mimicked by CoCl2. Cultured RFF cells showed robust sensitive responses to inflammation and hypoxia in directing the expressions of cytokines and hypoxia inducible factor-1α (HIF-1α). The water extract of aerial part of Scutellaria baicalensis (SBA) has been shown in rabbit fish to prevent inflammation. Here, we extended this notion of testing the efficacy of SBA extract in the developed cultured RFF cells. Application of SBA extract inhibited the expression of LPS-induced inflammatory cytokines, i.e. IL-1β, IL-6, as well as the signaling of NF-κB. The application of CoCl2 in cultured RFF cells triggered the hypoxia-induced cell death and up regulation of HIF-1α. As expected, applied SBA extract in the cultures prevented the hypoxia-induced signaling. Our results show the established RFF cell line may be served as an ideal in vitro model in drug screening relating to inflammation and hypoxia. Additionally, we are supporting the usage of SBA herbal extract in fish aquaculture, which possesses efficacy against inflammation and hypoxia.

Characterization of Anti-Inflammatory and Antioxidant Constituents from Scutellaria baicalensis Using LC-MS Coupled with a Bioassay Method

An effective and previously demonstrated screening method for active constituents in natural products using LC-MS coupled with a bioassay was reported in our earlier studies. With this, the current investigation attempted to identify bioactive constituents of Scutellaria baicalensis through LC-MS coupled with a bioassay. Peaks at broadly 17-20 and 24-25 min on the MS chromatogram displayed an inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. Similarly, peaks at roughly 17-19 and 22 min showed antioxidant activity with an 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)/2,2-diphenyl-1- picrylhydrazyl (DPPH) assay. For confirmation of LC-MS coupled with a bioassay, nine compounds (1-9) were isolated from an MeOH extract of S. baicalensis. As we predicted, compounds 1, 8, and 9 significantly reduced lipopolysaccharide (LPS)-induced NO production in BV2 cells. Likewise, compounds 5, 6, and 8 exhibited free radical-scavenging activities with the ABTS/DPPH assay. In addition, the structural similarity of the main components was confirmed by analyzing the total extract and EtOAc fractions through molecular networking. Overall, the results suggest that the method comprised of LC-MS coupled with a bioassay can effectively predict active compounds without an isolation process, and the results of molecular networking predicted that other components around the active compound node may also be active.

The anti-aging effect of Scutellaria baicalensis Georgi flowers extract by regulating the glutamine-glutamate metabolic pathway in d-galactose induced aging rats

Scutellaria baicalensis Georgi flowers is rich in flavonoids resources but not effectively exploited. This study aimed to investigate the anti-aging effects and potential mechanism of Scutellaria baicalensis Georgi flowers extract (SFE). The chemical components of the SFE were analyzed by UPLC-MS and the anti-aging effects of SFE were investigated in d-galactose (d-gal) induced aging rats by behavior examination and biochemical indexes, and the potential anti-aging mechanism of SFE were explored by 1H NMR-based liver metabolomics. Chemical composition research showed that 19 flavonoids were identified in SFE, and pharmacological research showed that SFE could significantly ameliorate spatial learning and memory ability. SFE could significantly regulate malondialdehyde (MDA), superoxide dismutase (SOD) and advanced glycation end products (AGEs). It also ameliorated the pathological abnormalities in liver. Additionally, anti-aging mechanism of SFE showed that total of 10 potential biomarkers were found by metabolomics techniques, which involved in 6 metabolic pathways. Among them, SFE could significantly increased the levels of d-glutamine and d-glutamate. Furthermore, the levels of glutamine and glutamate, and the levels of the key amino acids, enzymes and final product in the synthesis process of glutathione (GSH) were quantitatively determined in the liver by commercial kits and enzyme-linked immunosorbent assay. These results indicated that regulation of the glutamine-glutamate metabolic pathway is involved in the anti-aging effect of SFE in d-gal induced aging rats.

Natural Deep Eutectic Solvent Extraction of Flavonoids of Scutellaria baicalensis as a Replacement for Conventional Organic Solvents

Natural deep eutectic solvents (NADES) are a type of ionic liquid (IL) or deep eutectic solvent (DES), the ingredients of which are exclusively natural products (non-toxic and environmentally friendly). Here, we explore the potential of NADES as an alternative to conventional organic solvents (e.g., aqueous methanol or ethanol) for the extraction of flavonoids from Scutellaria baicalensis stem bark to investigate their extractability depending on structural variation. Four NADES, each containing citric acid in combination with β-alanine, glucose, xylitol, or proline (at a molar ratio of 1:1), and a variable amount of water, were used to extract the flavonoid aglycones: baicalein (1), scutellarein (3), wogonin (5), and oroxylin A (7), and their glycosides, baicalin (2), scutellarin (4), wogonoside (6) and oroxyloside (8) from the powdered bark of S. baicalensis. The chemical profile and yield of the extracts were determined using HPTLC and HPLC. The extractability of individual flavonoids was found to be influenced by the concentration of water (20-60%, w/w) in the NADES. Among the tested flavonoids, the extraction yield of baicalein (1), scutellarein (3), wogonin (5), oroxylin A (7) with NADES was 2 to 6 times that of aqueous methanol. However, the amount of their corresponding glycosides (baicalin (2), wogonoside (6) and oroxyloside (8)) extracted with NADES was only 1.5-1.8 times higher than with aqueous methanol. Interestingly, the more hydrophilic glycosides were less extracted than their corresponding aglycones despite the high hydrophilicity of the NADES. These results prove that NADES may be used for extraction of compounds with a wide range of hydrophilicity.

Flavonoid aglycone-oriented data-mining in high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry: efficient and targeted profiling of flavonoids in Scutellaria barbata

The high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) technique is a powerful tool for compound identification in complex natural products. However, untargeted MS/MS data analysis needs skillful experience and sometimes neglects minor compounds, which are co-eluted with major ones or overshadowed by the matrix. Flavonoids are the main bioactive components in Scutellaria barbata, and the total flavonoid content is 47.02 ± 3.23 mg QE/g DW. Although some flavonoid aglycones and their O-glycosides have been found in S. barbata, comprehensive profiling of flavonoids is unknown. Therefore, we report a flavonoid aglycone-oriented data-mining strategy for efficient and targeted profiling of flavonoids in S. barbata. The strategy includes four steps: (1) HPLC-QTOF-MS analysis of S. barbata; (2) construction of a flavonoid aglycone-based database according to biosynthetic pathway analysis and reported data; (3) extraction of through flavonoid aglycone-based ion chromatography; (4) identification of targeted flavonoids by MS/MS analysis. As a result, 45 flavonoids, including 24 flavones, 1 flavonol, 13 flavanones, and 7 flavanonols, were unambiguously or tentatively identified, while 20 of them were reported in S. barbata for the first time. Moreover, 14 available flavonoids were sensitively, precisely, and accurately determined by standard calibration curves, with limit of detection at 0.06 to 1.55 μg/g, limit of quantification at 0.16 to 3.70 μg/g, relative standard deviation (RSD) less than 9.0% for intra- and inter-day variations, and recovery at 92.6-108.1%. The matrix did not obviously suppress or enhance the ionization of 14 flavonoids, and finally their contents ranging from 0.04 to 4.49 mg/g in S. barbata were successfully achieved. Collectively, our results demonstrate that an efficient, reliable, and valuable strategy has been provided to rapidly and sensitively screen, profile, and quantify chemical components of complex natural products. Graphical abstract.

Evaluation of the effect of a toothpaste containing Pudilan extract on inhibiting plaques and reducing chronic gingivitis: A randomized, double-blinded, parallel controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Pudilan is a famous traditional Chinese medicine compound which contains several Chinese herbal ingredients, and has been wildly used to treat a variety of inflammatory diseases in China. Recently, it was reported that Pudilan extract had been used in the oral field, especially in the treatment of minor oral ulcers for its anti-inflammatory, pain relieving, antibacterial, clearing heat, and detoxifying effects.

AIM OF THE STUDY

To evaluate the effectiveness and safety of Pudilan extract-containing toothpaste in controlling plaques and reducing chronic gingivitis.

MATERIALS AND METHODS

A total of 120 patients with chronic gingivitis were randomized into an experiment group and a control group (n = 60 patients per group) based on a double-blinded method. Patients in the experiment group used a Pudilan extract-containing toothpaste, whereas patients in the control group used a Pudilan toothpaste simulator, which were identical as the toothpaste used by the experiment group, except for not containing the Pudilan extract. The Plaque Index (PI), Gingival Index (GI), Bleeding Index (BI), and Bleeding On Probing proportion (BOP%) were recorded at baseline, 4 weeks, 8 weeks and 12 weeks after using the toothpaste.

RESULTS

After using the toothpaste for 8 and 12 weeks, PI, BI, GI, and BOP% of the experiment group were significantly lower when compared to the control group (both p < 0.001). Moreover, after using the toothpaste for 4, 8, and 12 weeks, the decline of the PI and GI in the experiment group were significantly higher than the control group (p < 0.001, except 4weeks PI p = 0.011). After 12 weeks, the PI of the experiment group decreased 35.73% (p < 0.001) whereas the GI decreased 29.04% (p < 0.001). BI and BOP decline rates were statistically significant when compared to those of the control group at 8 and 12 weeks (both p < 0.001). Moreover, at 12 weeks, the BI of the experiment group decreased 34.33% (p < 0.001) and BOP% decreased 54.71% (p < 0.001).

CONCLUSION

Toothpaste with Pudilan extract demonstrated good effect on relieving symptoms of chronic gingivitis by inhibiting plaque formation, reducing gingival inflammation and the degree of bleeding, and the bleeding rate. Toothpaste containing Pudilan extract has prospective application potentials in the prevention and treatment of chronic gingivitis.

Antioxidant capacity of plant raw material of Scutellaria baicalensis Georgi

The aim of this study was to evaluate antioxidant capacity of Scutellaria baicalensis Georgi from two regions of Ukraine: Kyiv city (M. M. Gryshko National Botanical Garden of NAS of Ukraine (NBG)) and Kherson region (Experimental Facility “Novokakhovska” of Rice Research Institute of Ukrainian Academy of Agrarian Sciences (EFN of RRI)). Observation of plants and biochemical analyses conducted with plants collected in the stage of flowering. In study investigated and compared above-ground part of plants and separated organs: inflorescences, stems, leaves. Measured morphometric parameters (height of plants, length, and width of leaves, length, and diameter of inflorescence, the diameter of the stem) showed that the most variable was the length of inflorescence (12.79%) for NBG sample and diameter of the stem (33.33%) for EFN of RRI sample. Ethanolic extracts were screened for the antioxidant capacity. As standards were used gallic acid for polyphenol content (GAE), quercetin for flavonoids (QE), caffeic acid for phenolic acids (CAE), Trolox for antioxidant capacity (TE). The total content of polyphenol compounds was 42.43 – 86.13 mg GAE.g-1 DW (dry weight) (NBG sample) and 28.06 – 96.76 mg GAE.g-1 DW (EFN of RRI sample). The content of flavonoids was 9.39 – 62.97 mg QE.g-1 DW (NBG sample) and 10.64 – 66.07 mg QE.g-1 DW (EFN of RRI sample). The concentration of phenolic acids was 2.60 – 16.13 mg CA.g-1 DW (NBG sample) and 12.02 – 30.12 CA.g-1 DW (EFN of RRI sample). Antioxidant activity of plant extracts was measured by DPPH assay and reducing power method. The first method indicated an antioxidant ability 8.24 – 8.56 mg TE.g-1 DW (NBG sample) and 7.63 – 8.83 mg TE.g-1 DW (EFN of RRI sample). Reducing power of extracts was 51.48 – 306.09 mg TE.g-1 DW (NBG sample) and 63.33 – 260.24 mg TE.g-1 DW (EFN of RRI sample). Very strong positive correlation identified between total polyphenol content, total flavonoid content and reducing power. Scutellaria baicalensis is a rich source of antioxidants and potential raw of further pharmacological study in Ukraine as well as in other regions for improving and enrichment of relevant production.

Use of UHPLC-QTOF-MS/MS with combination of in silico approach for distributions and metabolites profile of flavonoids after oral administration of Niuhuang Shangqing tablets in rats

Niuhuang Shangqing tablet (NHSQT), a well-known traditional Chinese medicine preparation, has been used as an over- the- counter drug for the treatment of headache, dizziness in China. The flavonoids are the main active components in NHSQT, however, there have no reports about their distribution and metabolic fate in vivo after oral administration of NHSQTs so far. An novel UHPLC-QTOF-MS/MS method combined with in silico approach was applied to identify the flavonoids and metabolites profiling in biological samples following oral administration NHSQTs for the first time. As a result, 127 compounds including 34 original compounds of flavonoids and 93 metabolites were identified. There were 20 flavones, 9 flavonols, 4 flavanones and 1 flavan-3, 4-diol found in biological samples. Rutin, wogonoside, apigenin, baicalein, wogonin, oroxylin A, quercetin and acacetin were considered as the potential flavonoids in NHSQT against brain diseases. The docking-based metabolism models were established and applied to propose the sites of hydroxylation of flavonoids, which indicated baicalin was engaged in dihydroxylation at C2', C3', tilianin was engaged in hydroxylation at C3, wogonin and wogonside were engaged in dihydroxylation at C3', C4'. Some novel metabolic pathways were discovered for oroxylin A, acacetin, diosmetin, tilianin. The metabolic spots and pathways of flavonoids vary as much between flavones, flavonols and flavanones. The results presented here would be helpful for the further study of pharmacokinetics and quality control of NHSQT.

A comprehensive review on phytochemistry, pharmacology, and flavonoid biosynthesis of Scutellaria baicalensis

CONTEXT

Scutellaria baicalensis Georgi (Lamiaceae) is a popular medicinal plant. Its roots are used as the famous traditional Chinese medicine Huang-Qin, which is recorded in Chinese Pharmacopoeia, European Pharmacopoeia, and British Pharmacopoeia.

OBJECTIVE

This review comprehensively summarizes research progress in phytochemistry, pharmacology, and flavonoid biosynthesis of S. baicalensis.

METHODS

English and Chinese literature from 1973 to March 2018 was collected from databases including Web of Science, SciFinder, PubMed, Elsevier, Baidu Scholar (Chinese), and CNKI (Chinese). Scutellaria baicalensis, chemical constituents, phytochemistry, biological activities, and biosynthesis were used as the key words.

RESULTS

A total of 126 small molecules (1-126) and 6 polysaccharides have been isolated from S. baicalensis. The small molecules can be classified into four structural types, namely, free flavonoids, flavonoid glycosides, phenylethanoid glycosides, and other small molecules. Extracts of S. baicalensis and its major chemical constituents have been reported to possess anti-viral, anti-tumor, anti-bacterial, antioxidant, anti-inflammatory, hepatoprotective, and neuroprotective activities. Key steps in the biosynthetic pathways of Scutellaria flavonoids have also been summarized.

CONCLUSIONS

This article could be helpful for researchers who are interested in the chemical constituents, bioactivities, biosynthesis, and clinical applications of S. baicalensis.

Chemical profile, antioxidant, and enzyme inhibitory properties of two Scutellaria species: S. orientalis L. and S. salviifolia Benth

OBJECTIVES

This study investigates into the biological effects of solvent extracts (ethyl acetate, methanol, and water) of Scutellaria orientalis L. and Scutellaria salviifolia Benth. based on its enzyme inhibitory activity and antioxidant ability together with the screening of bioactive compounds.

METHODS

Total and individual bioactive components were determined using spectrophotometric and HPLC-ESI-MS methods. Six antioxidant assays were conducted and enzyme inhibition was tested against key enzymes linked to the pathology of common chronic disorders.

KEY FINDINGS

Results revealed that the aqueous extracts of both plants exerted better 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid scavenging, reducing power, metal chelating, and α-glucosidase inhibitory activities. The methanol extracts showed highest tyrosinase inhibition and antioxidant activity in phosphomolybdenum assay while the less polar ethyl acetate extracts showed better acetylcholinesterase, butyrylcholinesterase, and α-amylase inhibition. Phytochemical evaluation by HPLC-ESI-MS revealed the presence of high amounts of flavones.

CONCLUSIONS

Scutellaria orientalis and S. salviifolia are important sources of bioactive agents that warrants further studies.

Inhibitory effects against α-glucosidase and α-amylase of the flavonoids-rich extract from Scutellaria baicalensis shoots and interpretation of structure-activity relationship of its eight flavonoids by a refined assign-score method

A flavonoids-rich extract of Scutellaria baicalensis shoots and its eight high content flavonoids were investigated for their inhibitory effects against α-glucosidase and α-amylase. Results show that abilities of the extract in inhibiting the two enzymes were obviously higher than those of acarbose. Moreover, inhibitory abilities of all the eight individual flavonoids against the two enzymes show exactly a same order (i.e., apigenin > baicalein > scutellarin > chrysin > apigenin-7-O-glucuronide > baicalin > chrysin-7-O-glucuronide > isocarthamidin-7-O-glucuronide), and their structure-activity relationship could be well-interpretated by the refined assign-score method. Furthermore, based on the inhibitory abilities and their contents in the extract, it was found that the eight flavonoids made predominant contributions, among which baicalein and scutellarin played roles as preliminary contributors, to overall inhibitory effects of the extract against the two enzymes. Beyond these, contributions of the eight flavonoids to the overall enzyme inhibitory activity were compared with those to the overall antioxidant activity characterized in our recent study, and it could be inferred that within the basic flavonoid structure the hydroxyl on C-4' of ring B was more effective than that on C-6 of ring A in enzyme inhibitory activities while they behaved inversely in antioxidant activities; scutellarin and apigenin contributed more to the overall enzyme inhibitory activity, and baicalin and scutellarin, to the overall antioxidant activity of the extract; and flavonoids of the extract, apart from directly inhibiting enzymes, might also be conducive to curing type 2 diabetes via scavenging various free radicals caused by increased oxidative stresses.

Organ-Specific Metabolic Shifts of Flavonoids in Scutellaria baicalensis at Different Growth and Development Stages

Scutellaria baicalensis Georgi is a traditional Chinese herbal medicine mainly containing flavonoids that contribute to its bioactivities. In this study, the distributions and dynamic changes of flavonoid levels in various organs of S. baicalensis at different development stages were investigated by UHPLC-QTOF-MS/MS and HPLC-DAD methods. The results indicated that the metabolic profiles of S. baicalensis changed with growth and development. During the initial germination stage, the seeds mainly contained flavonols. With growth, the main kinds of flavonoids in S. baicalensis changed from flavonols to flavanones and flavones. The results also revealed that the accumulation of flavonoids in S. baicalensis is organ-specific. The flavones without 4′-OH groups mainly accumulate in the root and the flavanones mainly accumulate in aerial organs. Dynamic accumulation analysis showed that the main flavonoids in the root of S. baicalensis accumulated rapidly before the full-bloom stage, then changed to a small extent. The results suggested the proper harvest time for the aerial parts was at the initial stage of reproductive growth and the flower buds should be collected before flowering. This study deepening the knowledge of S. baicalensis should provide valuable information for guiding the scientific cultivation of this plant and the development and utilization of S. baicalensis.

Systematic study on metabolism and activity evaluation of Radix Scutellaria extract in rat plasma using UHPLC with quadrupole time-of-flight mass spectrometry and microdialysis intensity-fading mass spectrometry

Radix Scutellaria is a widely used traditional Chinese medicine in the treatment of various diseases. However, the activities of the absorbed components and metabolites of its main flavones in rat plasma need further investigation. In this study, a systematic method based on ultra-high performance liquid chromatography with quadruple time-of-flight mass spectrometry was developed to speculate the absorbed components and metabolites of the main flavonoids in Radix Scutellaria extract in rat plasma sample after oral administration of the extract. Twelve compounds, including four prototype components and eight metabolites, were confirmed in drug-containing plasma. In these metabolites, five were originally detected in rat plasma. The possible metabolic pathways of these polyhydroxy flavones in vivo were described and clarified. Microdialysis with intensity-fading mass spectrometry was originally employed to investigate the binding affinities of the absorbed components and metabolites with α-glucosidase. The order of their binding affinities was P4 > P3 > P2 > P1≥M5 > M3 > M1. The research result is helpful to deepen the understanding of the absorbed components and metabolic pathways of main flavones from Radix Scutellaria, and provide a new approach to screen potential inhibitors from in vivo components originated from Chinese herb.

Chemical compositions and biological activities of Scutellaria pinnatifida A. Hamilt aerial parts

Phytochemical analysis of the methanolic and dichloromethane extracts of the aerial parts of Scutellaria pinnatifida led to the isolation of a phenylpropanoid, 1-o-feruloyl-β-D-glucose (1), two known flavonoids including luteolin-7-o-glucoside (2) and apigenin-7-o-glucoside (3), three known phenylethanoid glycosides composed of phlomisethanoside (4), syringalide A (5), and verbascoside (6), and oleic acid (7). Isolation and structural elucidation of compounds were accomplished by HPLC and spectroscopic methods (UV, ¹H-NMR, ¹³C-NMR). The extracts were also evaluated for their radical scavenging activity and insecticidal property by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay and contact toxicity method, respectively. Among the extracts, the methanol extract showed the most potent free radical scavenging activity with a RC₅₀ value of 0.044 ± 0.350 mg/mL which could be attributed to the presence of the isolated phenolic compounds. In the case of insecticidal activity, the n-hexane extract displayed the most potent activity and caused 10%, 15%, and 40% mortality to Oryzaephilus mercator at the concentration of 5, 10, and 15 mg/mL after 4 h of exposure.

The Use of Mass Spectrometric Techniques to Differentiate Isobaric and Isomeric Flavonoid Conjugates from Axyris amaranthoides

Flavonoids are a group of compounds that are commonly found in various plants, where they play important roles in many processes, including free radical scavenging and UV protection. These compounds can also act as chemical messengers, physiological regulators or protectants against pathogens in the defense reactions of plants. Flavonoid activity is regulated by the addition of various substituents, usually mono- or oligosaccharides of common sugars, such as glucose, rhamnose or galactose. In some plants, glucuronic acid is attached, and this sugar is often acylated by phenylpropanoic acids. Identification of these compounds and their derivatives is of great importance to understanding their role in plant metabolism and defense mechanisms; this research is important because flavonoids are frequently a significant constituent of the human diet. In this study, we identify the flavonoid conjugates present in Axyris amaranthoides L. extracts and demonstrate the usefulness of high-resolution mass spectrometry (HRMS) analyzers for the differentiation of isobaric compounds and the utility of fragmentation spectra for the differentiation of isomeric structures. According to our knowledge, some of the structures, especially dehydrodiferulated conjugates of tricin, whose structures are proposed here have been found for the first time in plant material.

HPLC-DAD-ESI-MS Analysis of Flavonoids from Leaves of Different Cultivars of Sweet Osmanthus

Osmanthus fragrans Lour. has traditionally been a popular ornamental plant in China. In this study, ethanol extracts of the leaves of four cultivar groups of O. fragrans were analyzed by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD) and high-performance liquid chromatography with electrospray ionization and mass spectrometry (HPLC-ESI-MS). The results suggest that variation in flavonoids among O. fragrans cultivars is quantitative, rather than qualitative. Fifteen components were detected and separated, among which, the structures of 11 flavonoids and two coumarins were identified or tentatively identified. According to principal component analysis (PCA) and hierarchical cluster analysis (HCA) based on the abundance of these components (expressed as rutin equivalents), 22 selected cultivars were classified into four clusters. The seven cultivars from Cluster III (‘Xiaoye Sugui’, ‘Boye Jingui’, ‘Wuyi Dangui’, ‘Yingye Dangui’, ‘Danzhuang’, ‘Foding Zhu’, and ‘Tianxiang Taige’), which are enriched in rutin and total flavonoids, and ‘Sijigui’ from Cluster II which contained the highest amounts of kaempferol glycosides and apigenin 7-O-glucoside, could be selected as potential pharmaceutical resources. However, the chemotaxonomy in this paper does not correlate with the distribution of the existing cultivar groups, demonstrating that the distribution of flavonoids in O. fragrans leaves does not provide an effective means of classification for O. fragrans cultivars based on flower color.

Chemical and pharmacological evaluations on the extract of Scutellaria baicalensis Georgi (Huang-Qin) prepared by various extraction methods

Background

This study reported a comprehensive approach (comparing the extraction yields, chemical profiles, antioxidant properties and CYP450-inhibitory effects) to evaluated the effectiveness of various extraction methods [microwave-assisted extraction using water (MAE-W), heat reflux extraction using water (HRE-W), ultrasonic extraction using 70 % ethanol and ultrasonic extraction using ethanol (UE-E)] for Huang-Qin (HQ), the dried root of Scutellaria baicalensis Georgi.

Results

The HQ extraction efficiency by MAE-W was the best. The chemical profiles of extracts obtained using HRE-W and MAE-W were similar; whereas more flavones but less flavone glycosides were detected in the UE-E extract. There was no difference in the antioxidant properties among different extracts. In vitro human liver microsome assays illustrated that all extracts possessed herb–drug interaction potentials but the UE-E extract are shown with a potent interaction with CYP3A4-metabolized drugs.

Conclusion

MAE-W is a favorable method for the preparation of HQ extracts based on extraction yield, pharmacological properties and safety.

Rapid Identification and Assignation of the Active Ingredients in Fufang Banbianlian Injection Using HPLC-DAD-ESI-IT-TOF-MS

Fufang Banbianlian Injection (FBI) is a well-known traditional Chinese medicine formula composed of three herbal medicines. However, the systematic investigation on its chemical components has not been reported yet. In this study, a high-performance liquid chromatography combined with diode-array detector, and coupled to an electrospray ionization with ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method, was established for the identification of chemical profile in FBI. Sixty-six major constituents (14 phenolic acids, 14 iridoids, 20 flavonoids, 2 benzylideneacetone compounds, 3 phenylethanoid glycosides, 1 coumarin, 1 lignan, 3 nucleosides, 1 amino acids, 1 monosaccharides, 2 oligosaccharides, 3 alduronic acids and citric acid) were identified or tentatively characterized by comparing their retention times and MS spectra with those of standards or literature data. Finally, all constituents were further assigned in the individual herbs (InHs), although some of them were from multiple InHs. As a result, 11 compounds were from Lobelia chinensis Lour, 33 compounds were from Scutellaria barbata D. Don and 38 compounds were from Hedyotis diffusa Willd. In conclusion, the developed HPLC-DAD-ESI-IT-TOF-MS method is a rapid and efficient technique for analysis of FBI sample, and could be a valuable method for the further study on the quality control of the FBI.

Phenolic Compounds and Their Fates In Tropical Lepidopteran Larvae: Modifications In Alkaline Conditions

Lepidopteran larvae encounter a variety of phenolic compounds while consuming their host plants. Some phenolics may oxidize under alkaline conditions prevailing in the larval guts, and the oxidation products may cause oxidative stress to the larvae. In this study, we aimed to find new ways to predict how phenolic compounds may be modified in the guts of herbivorous larvae. To do so, we studied the ease of oxidation of phenolic compounds from 12 tropical tree species. The leaf extracts were incubated in vitro in alkaline conditions, and the loss of total phenolics during incubation was used to estimate the oxidizability of extracts. The phenolic profiles of the leaf extracts before and after incubation were compared, revealing that some phenolic compounds were depleted during incubation. The leaves of the 12 tree species were each fed to 12 species of lepidopteran larvae that naturally feed on these trees. The phenolic profiles of larval frass were compared to those of in vitro incubated leaf extracts. These comparisons showed that the phenolic profiles of alkali-treated samples and frass samples were similar in many cases. This suggested that certain phenolics, such as ellagitannins, proanthocyanidins, and galloylquinic acid derivatives were modified by the alkaline pH of the larval gut. In other cases, the chromatographic profiles of frass and in vitro incubated leaf extracts were not similar, and new modifications of phenolics were detected in the frass. We conclude that the actual fates of phenolics in vivo are often more complicated than can be predicted by a simple in vitro method.

Comprehensive identification of 125 multifarious constituents in Shuang-huang-lian powder injection by HPLC-DAD-ESI-IT-TOF-MS

A high-performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method was established for excellent separation and structural identification of constituents in Shuang-huang-lian powder injection (SHLPI). The typical ultraviolet absorptions, accurate empirical molecular formula and reasonable fragmentation mechanisms of these ingredients were used for their structural elucidation. In consequence, 125 constituents (33 phenolic acids, 29 flavonoids, 32 phenylethanoid glycosides, 15 iridoid glycosides, 8 lignans, 3 amino acids and 2 purines nucleosides, 2 quinoid glycosides and 1 alkylbenzene glycoside) were either unequivocally identified or tentatively characterized by comparing authentic standards or published data. The result showed that this study could provide valuable information for the quality control and further investigation of SHLPI formula.

Optimization of the extraction of total flavonoids from Scutellaria baicalensis Georgi using the response surface methodology

The response surface methodology (RSM) was used to optimize the conditions for total flavonoid extraction from Scutellaria baicalensis Georgi. The influences of the ethanol concentration, extraction time, temperature, and the liquid-solid ratio on flavonoid yield were investigated. Based on ANOVA results, a second-order quadratic polynomial model could be applied to characterize the extraction process. The following optimal extraction conditions were identified: ethanol concentration, 52.98 %; extraction time, 2.12 h; extraction temperature, 62.46 °C; and liquid-solid ratio, 35.23. The predicted extraction yield was 19.437 mg/g when these optimal conditions were used. The proposed method was successfully employed to extract flavonoids from S. baicalensis.