Development of a SPE-LC/MS/MS method for simultaneous quantification of baicalein, wogonin, oroxylin A and their glucuronides baicalin, wogonoside and oroxyloside in rats and its application to brain uptake and plasma pharmacokinetic studies

Exploring the anti-ischemic stroke potential of wogonoside: Insights from Nrf2/Sirt3 signaling pathway and UPLC-TripleTOF-MS/MS-based metabolomics

Ischemic stroke, accounting for 80 % of all strokes, is a major cause of morbidity and mortality worldwide. However, effective and safe pharmacotherapy options for ischemic injury are limited. This study investigated the therapeutic effects of wogonoside, a compound derived from Radix Scutellariae, on ischemia/reperfusion (I/R) injury. The results showed that wogonoside treatment had significant therapeutic effects in rats with middle cerebral artery occlusion. It effectively reduced mortality rates, neurological deficits, cerebral infarct size, and brain water content. In an in vitro model using PC12 cells, wogonoside activated the Nrf2/Sirt3 signaling pathway. This activation contributed to the attenuation of oxidative damage and inflammation. Metabolomics analysis revealed increased levels of γ-aminobutyric acid (GABA) and glutathione in response to wogonoside treatment, suggesting their potential as therapeutic biomarkers for ischemic stroke. Additionally, wogonoside restored perturbed energy metabolism, including the tricarboxylic acid cycle. Wogonoside has the potential to ameliorate cerebral ischemic injury by targeting GABA-related amino acid metabolism, energy metabolism, and glutathione metabolism, maintaining redox homeostasis, and attenuating oxidative stress. These findings provide valuable insights into the protective mechanisms of wogonoside in cerebral I/R injury and highlight the promising therapeutic approach of wogonoside in the treatment of ischemic stroke.

Botanical Mixture Containing Nitric Oxide Metabolite Enhances Neural Plasticity to Improve Cognitive Impairment in a Vascular Dementia Rat Model

Vascular dementia (VD), caused by impaired cerebral blood flow, is the most common form of dementia after Alzheimer's disease (AD) in the elderly and is characterized by severe neuronal damage and cognitive decline. Nitric oxide (NO) is an important determinant of vascular homeostasis, and its deficiency is associated with the progression of VD. In this study, we investigated the role of nitrite ion, a NO metabolite in a botanical mixture (BM) of fermented garlic, fermented Scutellaria baicalensis, and Rhodiola rosea on neuron loss and cognitive impairment using a VD rat model. The BM containing the NO metabolite alleviated cognitive deficits and enhanced neural plasticity, as reflected by an increase in long-term potentiation. The BM also alleviated neuron apoptosis, decreased GFAP expression, and oxidative stress, and increased parvalbumin and brain-derived neurotrophic factor (BDNF) levels. These results indicate that BM exerts neuroprotective effects and alleviates cognitive dysfunction while enhancing neuroplasticity, and thus has therapeutic potential against VD.

Medicinal plant molecules against hepatitis C virus: Current status and future prospect

Hepatitis C virus (HCV), a global malady, causes acute and chronic hepatitis leading to permanent liver damage, hepatocellular carcinoma, and death. Modern anti-HCV therapies are efficient, but mostly inaccessible for residents of underdeveloped regions. To innovate more effective treatments at affordable cost, medicinal plant-based products need to be explored. The aim of this article is to review plant constituents in the light of putative anti-HCV mechanisms of action, and discuss existing problems, challenges, and future directions for their potential application in therapeutic settings. One hundred sixty literatures were collected by using appropriate search strings via scientific search engines: Google Scholar, PubMed, ScienceDirect, and Scopus. Bibliography was prepared using Mendeley desktop software. We found a substantial number of plants that were reported to inhibit different stages of HCV life cycle. Traditional medicinal plants such as Phyllanthus amarus Schumach. and Thonn., Eclipta alba (L.) Hassk., and Acacia nilotica (L.) Delile exhibited strong anti-HCV activities. Again, several phytochemicals such as epigallocatechin-3-gallate, honokilol, punicalagin, and quercetin have shown broad-spectrum anti-HCV effect. We have presented promising phytochemicals like silymarin, curcumin, glycyrrhizin, and camptothecin for nanoparticle-based hepatocyte-targeted drug delivery. Nevertheless, only a few animal studies have been performed to validate the anti-HCV effect of these plant products. Again, insufficient clinical evaluation of the safety and effectiveness of herbal medications remain a problem. Selected plants products could be developed as novel therapeutics for HCV patients only after scrupulous evaluation of their safety and efficacy in a clinical set-up.

Scutellaria baicalensis Georgi and Their Natural Flavonoid Compounds in the Treatment of Ovarian Cancer: A Review

Ovarian cancer (OC) is one of the most common types of cancer in women with a high mortality rate, and the treatment of OC is prone to high recurrence rates and side effects. Scutellaria baicalensis (SB) is a herbal medicine with good anti-cancer activity, and several studies have shown that SB and its flavonoids have some anti-OC properties. This paper elucidated the common pathogenesis of OC, including cell proliferation and cell cycle regulation, cell invasion and metastasis, apoptosis and autophagy, drug resistance and angiogenesis. The mechanisms of SB and its flavonoids, wogonin, baicalein, baicalin, Oroxylin A, and scutellarein, in the treatment of OC, are revealed, such as wogonin inhibits proliferation, induces apoptosis, inhibits invasion and metastasis, and increases the cytotoxicity of the drug. Baicalein also inhibits vascular endothelial growth factor (VEGF) expression etc. Analyzing their advantages and disadvantages in treating OC provides a new perspective on the role of SB and its flavonoids in OC treatment. It serves as a resource for future OC research and development.

Autophagy Induction by Scutellaria Flavones in Cancer: Recent Advances

In parallel with a steady rise in cancer incidence worldwide, the scientific community is increasingly focused on finding novel, safer and more efficient modalities for managing this disease. Over the past decades, natural products have been described as a significant source of new structural leads for novel drug candidates. Scutellaria root is one of the most studied natural products because of its anticancer potential. Besides just describing the cytotoxic properties of plant constituents, their molecular mechanisms of action in different cancer types are equally important. Therefore, this review article focuses on the role of the Scutellaria flavones wogonin, baicalein, baicalin, scutellarein and scutellarin in regulating the autophagic machinery in diverse cancer models, highlighting these molecules as potential lead compounds for the fight against malignant neoplasms. The knowledge that autophagy can function as a dual-edged sword, acting in both a pro- and antitumorigenic manner, further complicates the issue, revealing an amazing property of flavonoids that behave either as anti- or proautophagic agents.

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

HPLC method for simultaneous estimation of paclitaxel and baicalein: pharmaceutical and pharmacokinetic applications

Aim: A novel HPLC method was developed and validated for the simultaneous estimation of paclitaxel (PTX) and baicalein (BAC). Materials & methods: The analytes were resolved in a C18 column using the aqueous solution of formic acid (0.10% v/v) and MeOH (30:70 v/v). Results: The developed method was found to be linear over the concentration ranges 0.039-10 μg/ml and 0.019-10 μg/ml for PTX and BAC, respectively. The lower limits of quantification obtained were 0.042 μg/ml and 0.361 μg/ml for PTX and BAC, respectively. Conclusion: The developed method was found to be precise and accurate as per the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines, for simultaneous estimation of PTX and BAC, having an application in formulation development and bioanalytical studies.

Oroxylin A: A Promising Flavonoid for Prevention and Treatment of Chronic Diseases

There have been magnificent advancements in the understanding of molecular mechanisms of chronic diseases over the past several years, but these diseases continue to be a considerable cause of death worldwide. Most of the approved medications available for the prevention and treatment of these diseases target only a single gene/protein/pathway and are known to cause severe side effects and are less effective than they are anticipated. Consequently, the development of finer therapeutics that outshine the existing ones is far-reaching. Natural compounds have enormous applications in curbing several disastrous and fatal diseases. Oroxylin A (OA) is a flavonoid obtained from the plants Oroxylum indicum, Scutellaria baicalensis, and S. lateriflora, which have distinctive pharmacological properties. OA modulates the important signaling pathways, including NF-κB, MAPK, ERK1/2, Wnt/β-catenin, PTEN/PI3K/Akt, and signaling molecules, such as TNF-α, TGF-ꞵ, MMPs, VEGF, interleukins, Bcl-2, caspases, HIF-1α, EMT proteins, Nrf-2, etc., which play a pivotal role in the molecular mechanism of chronic diseases. Overwhelming pieces of evidence expound on the anti-inflammatory, anti-bacterial, anti-viral, and anti-cancer potentials of this flavonoid, which makes it an engrossing compound for research. Numerous preclinical and clinical studies also displayed the promising potential of OA against cancer, cardiovascular diseases, inflammation, neurological disorders, rheumatoid arthritis, osteoarthritis, etc. Therefore, the current review focuses on delineating the role of OA in combating different chronic diseases and highlighting the intrinsic molecular mechanisms of its action.

Qualitative and quantitative determination of the primary active components and metabolites in human plasma after oral administration of Shuanghuanglian liquid

Shuanghuanglian oral liquid is a common traditional Chinese medicine used to treat respiratory tract infections. Its major components are baicalin, chlorogenic acid, and forsythin. In this study, the main drug-related components in human plasma after oral administration of Shuanghuanglian were initially identified using ultra-performance liquid chromatography-ultraviolet detector/quadrupole time-of-flight mass spectrometry. Thirteen components from baicalin were identified, including the parent drug baicalin and aglycone baicalein. Only one metabolite related to chlorogenic acid, a sulfate conjugate formed after hydrolysis, and one metabolite related to forsythin, a sulfate conjugate of forsythin aglycone, were detected. Subsequently, a liquid chromatography-tandem mass spectrometry method was established and validated to simultaneously determine baicalin and baicalein, the primary active components. After simple protein precipitation, the analytes were separated on a BEH C18 column using a 5 min-gradient elution to avoid interference from baicalin isomers and their in-source dissociation. Excellent linearity was observed over the concentration ranges of 5.00-2000 ng/ml for baicalin and 1.00-100 ng/ml for baicalein. The validated method was successfully applied to a pharmacokinetic study of an oral administration of 60 ml Shuanghuanglian in healthy subjects. This study provided a foundation to investigate the clinical efficacy and safety of Shuanghuanglian further.

Baicalein Induces Mitochondrial Autophagy to Prevent Parkinson's Disease in Rats via miR-30b and the SIRT1/AMPK/mTOR Pathway

Parkinson's disease (PD) is a prevailing neurodegenerative disorder. Baicalein has neuroprotective effects on PD animals, but its mechanism is not clarified. We explored baicalein effects on PD rats. PD rat models were established by injecting 6-hydroxydopamine into the striatum of substantia nigra on the left side of the rat brain and treated with baicalein. Dopamine (DA) content, neuronal apoptosis, neuronal injury, neuronal mitochondria, and autophagy were assessed. Baicalein-treated PD rats were treated with autophagy inhibitor 3-methyladenine to identify the role of autophagy in PD. PD rats were injected with AgomiR-30b-5p or sh-SIRT1 plasmids and treated with baicalein. PD rats elicited decreased neurological score and DA secretion of the striatum, increased neuronal apoptosis, and injury, and reduced number of mitochondria and autophagy, whereas baicalein alleviated neuronal injury and partly recovered mitochondrial dysfunction, 3-methyladenine inhibited the protection of baicalein. miR-30b-5p was elevated and SIRT1 was diminished in PD rats and inhibited by baicalein. miR-30b-5p targeted SIRT1. miR-30b-5p overexpression or SIRT1 silencing annulled the protection of baicalein. The phosphorylation level of AMPK in the substantia nigra of PD rats was decreased and mTOR was increased, whereas baicalein annulled these trends. Briefly, baicalein activated mitochondrial autophagy via miR-30b-5p and the SIRT1/AMPK/mTOR pathway, thus protecting PD rats.

Immunosuppressant flavonoids from Scutellaria baicalensis

Some plants used in Traditional Chinese Medicine serve as treatment for disease states where a suppression of the cellular immune response is desired. However, the compounds responsible for the immunosuppressant effects of these plants are not necessarily known. The immunosuppressant compounds in the roots of Scutellaria baicalensis, one of the most promising plants identified in a previous screening, were tracked by HPLC activity profiling and concomitant on-line spectroscopic analysis. Compounds were then isolated by preparative chromatography, and structures elucidated by spectroscopic methods. Twelve flavonoids (5-16) were identified from the active time windows, and structurally related flavones 2, 4, and 17, and flavanones 1 and 3 were isolated from adjacent fractions. All flavonoids possessed an unusual substitution pattern on the B-ring, with an absence of substituents at C-3 and C-4. Compounds 11, 13, 14, and 16 inhibited T-cell proliferation (IC₅₀ values at 12.1-39 μM) at non-cytotoxic concentrations. The findings may support the use of S. baicalensis in disorders where a modulation of the cellular immune response is desirable.

Identification of Active Compounds and Mechanism of Huangtu Decoction for the Treatment of Ulcerative Colitis by Network Pharmacology Combined with Experimental Verification

Introduction

Huangtu decoction (HTD) has been widely used in the treatment of gastrointestinal bleeding, ulcerative colitis (UC) and gastrointestinal tumors in China, but its active compounds and mechanism are still not clear yet. The present research aimed to identify the active compounds and mechanism of HTD for the treatment of UC.

Methods

Firstly, the chemical compounds of HTD were qualitatively identified based on Q Exactive Orbitrap LC-MS/MS, and their potential targets were predicted through SwissTargetPrediction. Secondly, the differential expressed genes (DEGs) in colon tissues of UC patients and normal controls were retrieved from the GEO database. Thirdly, the overlapping targets of DEGs and the predicted targets were obtained and subjected to GO and KEGG analysis. Finally, the key targets in the most significantly enriched pathway were verified by in vivo experiment, and the protein and mRNA expressions of matrix metalloproteinase-1 (MMP1), MMP3, MMP7, MMP9 and MMP12 were determined by immunohistochemistry (IHC), Western blotting (WB) and quantitative real-time-PCR (qRT-PCR).

Results

A total of 47 compounds were identified and 29 overlapping targets were obtained from HTD extract. The most significantly enriched pathway of overlapping targets involved was MMP. HTD improved the pathological damage in colon tissues of DSS-induced UC model and significantly decreased the serum levels of IL-1β and IL-6. The protein and mRNA expressions of MMP1, MMP3 and MMP9 in colon tissues were significantly decreased after HTD treatment.

Conclusion

HTD treatment can alleviate the colonic inflammation via inhibiting MMPs including MMP1, MMP3 and MMP9.

Simultaneous Determination of Four Bioactive Flavonoids in Rat Plasma by UPLC-MS/MS and Comparative Pharmacokinetic Study after Oral Administration of Danyikangtai Powder and Three Compatibilities

Background:

Danyikangtai powder, a Traditional Chinese Medicine (TCM) formula, shows promise to become a novel drug candidate for the simultaneous treatment of chronic cholecystitis and chronic pancreatitis. However, the pharmacokinetic behavior of Danyikangtai powder remains unclear.

Objective:

We investigated the comparative pharmacokinetics of four flavonoids in rats after oral administration of Danyikangtai powder and three compatibilities.

Materials and Methods:

The comparative pharmacokinetics was studied by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS). Chromatographic separation was performed on a Universil XB-C18 column with a gradient mobile phase containing 0.1% (v/v) aqueous formic acid and acetonitrile. All analytes and internal standard were quantitated in the multiple reaction monitoring modes with a positive electrospray ionization interface.

Results and Discussion:

Danyikangtai powder and Scutellariae radix have similar pharmacokinetic behaviors in rats after oral administration. However, the elimination of four flavonoids in rats after oral administration of Danyikangtai powder was accelerated, which was possibly related to the reduction of the potential hepatotoxicity of Scutellariae radix. The varying degrees of change in pharmacokinetic parameters after oral administration of different herb combinations suggested that herb–herb interactions occurred in vivo.

Conclusions:

This study will be helpful to reveal the safety, rational and mechanism of Danyikangtai powder formula compatibility, thereby providing pre-clinical research data for its new drug development and guidance for its rational clinical application.

The Biological Activities and Therapeutic Potentials of Baicalein Extracted from Oroxylum indicum: A Systematic Review

In Southeast Asia, traditional medicine has a longestablished history and plays an important role in the health care system. Various traditional medicinal plants have been used to treat diseases since ancient times and much of this traditional knowledge remains preserved today. Oroxylum indicum (beko plant) is one of the medicinal herb plants that is widely distributed throughout Asia. It is a versatile plant and almost every part of the plant is reported to possess a wide range of pharmacological activities. Many of the important bioactivities of this medicinal plant is related to the most abundant bioactive constituent found in this plant-the baicalein. Nonetheless, there is still no systematic review to report and vindicate the biological activities and therapeutic potential of baicalein extracted from O. indicum to treat human diseases. In this review, we aimed to systematically present in vivo and in vitro studies searched from PubMed, ScienceDirect, Scopus and Google Scholar database up to 31 March 2020 based on keywords "Oroxylum indicum" and "baicalein". After an initial screening of titles and abstracts, followed by a full-text analysis and validation, 20 articles that fulfilled all the inclusion and exclusion criteria were included in this systematic review. The searched data comprehensively reported the biological activities and therapeutic potential of baicalein originating from the O. indicum plant for anti-cancer, antibacterial, anti-hyperglycemia, neurogenesis, cardioprotective, anti-adipogenesis, anti-inflammatory and wound healing effects. Nonetheless, we noticed that there was a scarcity of evidence on the efficacy of this natural active compound in human clinical studies. In conclusion, this systematic review article provides new insight into O. indicum and its active constituent baicalein as a prospective complementary therapy from the perspective of modern and scientific aspect. We indicate the potential of this natural product to be developed into more conscientious and judicious evidencebased medicine in the future. However, we also recommend more clinical research to confirm the efficacy and safety of baicalein as therapeutic medicine for patients.

Simultaneous determination of asarinin, β-eudesmol, and wogonin in rats using ultraperformance liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies following administration of standards and Gumiganghwal-tang

Asarinin, β-eudesmol, and wogonin have common antiangiogenic activities and have the potential for use in chemotherapy. Besides, they are multivalent substances that are combined in various herbal medicines. The purpose of this study was to develop a method for simultaneous analysis of asarinin, β-eudesmol, and wogonin, which are representative pharmacological components of Asarum heterotropoides, Atractylodes lancea, and Scutellaria baicalensis, respectively, in rat biosamples using ultraperformance liquid chromatography-tandem mass spectrometry. The three components were separated using 5 mm aqueous ammonium acetate containing 0.1% formic acid and acetonitrile as a mobile phase, equipped with a KINETEX core-shell C₁₈ column. The analysis was quantitated on a triple-quadrupole mass-spectrometer employing electrospray ionization, and operated in the multiple reaction monitoring mode. The chromatograms showed high resolution, sensitivity, and selectivity with no interference with plasma, urine, and feces constituents. The developed analytical method satisfied international guidance criteria and could be successfully applied to the pharmacokinetic (PK) studies evaluating oral bioavailability of asarinin, β-eudesmol, and wogonin after oral and intravenous administration and their urinary and fecal excretion ratios after oral administration to rats. Furthermore, the analysis was extended to PK studies following oral administration of Gumiganghwal-tang. This study was the first simultaneous analysis of the aforesaid three constituents in rat plasma, urine, and feces that also determined their PK parameters.

Investigation on the Metabolism of Curcumin and Baicalein in Zebrafish by Liquid Chromatography-tandem Mass Spectrometry Analysis

Background:

Curcumin (CUR) and baicalein (BAI) are the main active ingredients in Curcuma longa and Scutellaria baicalensis, which are used together in Jiang-Qin-Si-Wu decoction to treat gynecological diseases. On the other hand, zebrafish, as a metabolic model has become more popular, therefore, the metabolism of CUR and BAI in zebrafish is investigated in the present study.

Methods:

Zebrafish embryos after hatching 48 hours were divided into four experimental groups. The blank group was exposed to 1 mL of ultra-pure water. Three drug-treated groups were exposed to CUR (8 μM, 1 mL), BAI (8 μM, 1 mL), CUR and BAI (8 μM, 2 mL), respectively. After homogenization, they were analyzed by liquid chromatography-tandem mass spectrometry (LCMS/ MS). The structure of the metabolites was determined by comparing their corresponding mass spectra with those of relevant literature. According to the change of metabolite content, the metabolic effect of curcumin and baicalein was explored.

Results:

Five and six metabolites of CUR and BAI in zebrafish were identified by LC-MS/MS, respectively. Their metabolic pathways in zebrafish were glucuronidation and sulfation. Reduction and methylation reactions also occurred for CUR and BAI, respectively. In addition, after combined exposure of both the drugs, CUR reduced the BAI glucuronide metabolites and inhibited the metabolism of BAI in zebrafish, which is consistent with the mammalian metabolism.

Conclusion:

Using LC-MS/MS analysis, zebrafish is a feasible model for drug metabolism study. The results of metabolic study indicated that CUR might affect the therapeutic effect of BAI.

Determination of oroxylin A, oroxylin A 7-O-glucuronide, and oroxylin A sodium sulfonate in beagle dogs by using UHPLC MS/MS Application in a pharmacokinetic study

Oroxylin A, obtained from the root of Scutellaria baicalensis Georgi, is a flavonoid with antitumor and other pharmacological activities. Our previous studies showed for the first time that it is mainly metabolized to oroxylin A sodium sulfonate by sulfotransferase enzymes in beagle dogs. In this study, rapid, universal, selective, and robust ultra-high-performance liquid chromatography-tandem mass spectrometry methods were established and fully validated to quantitatively detect oroxylin A, oroxylin A 7-O-glucuronide, and oroxylin A sodium sulfonate in beagle dog plasma. The quantitative analysis for oroxylin A sodium sulfonate was reported for the first time. Plasma samples were processed with acetonitrile, a universal protein precipitant. Gradient elution was performed to resolve carryover effects and to achieve separation efficiency and sufficient chromatographic retention. The linear relationships of oroxylin A, oroxylin A 7-O-glucuronide, and oroxylin A sodium sulfonate in plasma were in the range of 2.0-500.0, 5.0-500.0, and 1.881-940.5 ng/mL, respectively. The assay method was successfully applied to pharmacokinetic study. This is the first paper that reveals the pharmacokinetic profile of oroxylin A, oroxylin A 7-O-glucuronide, and oroxylin A sodium sulfonate after single-dose intravenous and oral administration of Oroxylin A in beagle dogs.

Wogonin glucuronidation in liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice

Wogonin, one of the flavonoids isolated from Scutellaria baicalensis, exhibits some beneficial bioactivities, including anti-inflammatory and anticancer effects, and is metabolized into glucuronide by UDP-glucuronosyltransferase (UGT) enzymes in humans. In the present study, wogonin glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis.The kinetics of wogonin glucuronidation by liver microsomes followed the biphasic model in all species examined. CL_int values (x-intercept) based on v versus V/[S] plots were rats > humans ≈ monkeys > mice > dogs. The kinetics of intestinal microsomes fit the Michaelis-Menten model for humans, monkeys, rats, and mice and the substrate inhibition model for dogs. CL_int values were rats > monkeys > mice > dogs > humans. The tissue dependence of CL_int values was liver microsomes > intestinal microsomes for humans, dogs, and rats, and liver microsomes ≈ intestinal microsomes for monkeys and mice.These results demonstrated that the metabolic abilities of UGT enzymes toward wogonin in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice, and suggest that species differences are closely associated with the biological effects of wogonin.

Medicinal Plant Analysis: A Historical and Regional Discussion of Emergent Complex Techniques

The analysis of medicinal plants has had a long history, and especially with regard to assessing a plant's quality. The first techniques were organoleptic using the physical senses of taste, smell, and appearance. Then gradually these led on to more advanced instrumental techniques. Though different countries have their own traditional medicines China currently leads the way in terms of the number of publications focused on medicinal plant analysis and number of inclusions in their Pharmacopoeia. The monographs contained within these publications give directions on the type of analysis that should be performed, and for manufacturers, this typically means that they need access to more and more advanced instrumentation. We have seen developments in many areas of analytical analysis and particularly the development of chromatographic and spectroscopic methods and the hyphenation of these techniques. The ability to process data using multivariate analysis software has opened the door to metabolomics giving us greater capacity to understand the many variations of chemical compounds occurring within medicinal plants, allowing us to have greater certainty of not only the quality of the plants and medicines but also of their suitability for clinical research. Refinements in technology have resulted in the ability to analyze and categorize plants effectively and be able to detect contaminants and adulterants occurring at very low levels. However, advances in technology cannot provide us with all the answers we need in order to deliver high-quality herbal medicines and the more traditional techniques of assessing quality remain as important today.

Baicalein-Enriched Fraction Extracted from Oroxylum indicum (L.) Benth. ex Kurz Leaves Exerts Antioxidant and Inhibitory Effects Against Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most malignant subtype of primary brain cancer. To date, standard clinical treatment for GBM is limited in effectiveness and could impose additional side effects. Recently, numerous bioactive compounds isolated from natural plants appear to have beneficial anti-cancer properties. Here, the GBM inhibitory effect of baicalein, a bioactive flavonoid extracted from Oroxylum indicum (L.) Benth. ex Kurz, was evaluated. Firstly, three solvents were used to extract the baicalein. We found that the binary extraction system, using a combination of petroleum ether and methanol (PM), yielded the highest amount of baicalein (15%) compared to the mono extraction system using methanol (13%) or aqueous (0.04%) only. In order to further enhance the baicalein yield in PM crude extract, it was subjected to an enrichment fractionation procedure, which successfully increased the baicalein by nearly two-fold from the initial crude extract (15%) to the enriched fraction 5 (F5) (29%). The enriched F5 not only showed significantly higher (~2.5-fold) antioxidant properties as compared to the crude extract, it was also found to significantly suppress GBM cell proliferation ~2.5-fold better than the crude extract. In conclusion, this study successfully optimized an extraction procedure for increased yield of baicalein metabolite from O. indicum leaves and enhanced its therapeutic potential for GBM treatment.

Baicalein as a Potential Inhibitor against BACE1 and AChE: Mechanistic Comprehension through In Vitro and Computational Approaches

One of the major neurodegenerative features of Alzheimer's disease (AD) is the presence of neurotoxic amyloid plaques composed of amyloid beta peptide (Aβ). β-Secretase (BACE1) and acetylcholinesterase (AChE), which promote Aβ fibril formation, have become attractive therapeutic targets for AD. P-glycoprotein (P-gp), the major efflux pump of the blood-brain barrier (BBB), plays a critical role in limiting therapeutic molecules. In pursuit of discovering a natural anti-AD candidate, the bioactivity, physicochemical, drug-likeness, and molecular docking properties of baicalein, a major compound from Scutellaria baicalensis, was investigated. Baicalein exhibited strong BACE1 and AChE inhibitory properties (IC50 23.71 ± 1.91 µM and 45.95 ± 3.44 µM, respectively) and reacted in non-competitive and competitive manners with substrates, respectively. in Silico docking analysis was in full agreement with the in vitro results, demonstrating that the compound exhibited powerful binding interaction with target enzymes. Particularly, three continuous hydroxyl groups on the A ring demonstrated strong H-bond binding properties. It is also noteworthy that baicalein complied with all requirements of Lipinski's rule of five by its optimal physicochemical properties for both oral bioavailability and blood-brain barrier permeability. Overall, the present study strongly demonstrated the possibility of baicalein having in vivo pharmacological efficacy for specific targets in the prevention and/or treatment of AD.

Pharmacokinetics of B-Ring Unsubstituted Flavones

B-ring unsubstituted flavones (of which the most widely known are chrysin, baicalein, wogonin, and oroxylin A) are 2-phenylchromen-4-one molecules of which the B-ring is devoid of any hydroxy, methoxy, or other substituent. They may be found naturally in a number of herbal products used for therapeutic purposes, and several have been designed by researchers and obtained in the laboratory. They have generated interest in the scientific community for their potential use in a variety of pathologies, and understanding their pharmacokinetics is important for a grasp of their optimal use. Based on a comprehensive survey of the relevant literature, this paper examines their absorption (with deglycosylation as a preliminary step) and their fate in the body, from metabolism to excretion. Differences among species (inter-individual) and within the same species (intra-individual) variability have been examined based on the available data, and finally, knowledge gaps and directions of future research are discussed.

Validation of an LC-MS/MS method for simultaneous detection of diverse components of Qinxing Qingre Zhike Granule in rat plasma and its application to pharmacokinetic study after oral administration to rats

A sensitive and validated method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established to test the plasma concentrations of active ingredients in Qinxing Qingre Zhike Granule, namely geniposide, liquiritin, isoliquiritin, baicalin, wogonoside, baicalein, liquiritigenin, isoliquiritigenin and glycyrrhetinic acid. The analysis was performed on an Ultimate XB-C₁₈ column at the flow rate of 0.4 mL min^-1 in a single run of 18 min. The mobile phase was composed of 0.05% formic acid in water and acetonitrile with gradient elution. Positive and negative scanning and selected multiple reaction monitoring modes were applied for quantization. The proposed method showed good linearity in the given ranges from 0.6800-340.0 to 3.920-1960 ng mL^-1 with r²  > 0.9917 for all the analytes. The precision (RSD) was no more than 12%, and the accuracy (RE) was less than ±11% for intra- and inter-day. The extract recovery and matrix effect were acceptable for the requirements of biological sample analysis. Moreover, the developed method was effectively applied to the pharmacokinetic investigation of Qinxing Qingre Zhike Granule after oral administration in rats.

Oroxylin A increases the sensitivity of temozolomide on glioma cells by hypoxia-inducible factor 1α/hedgehog pathway under hypoxia

Microenvironmental hypoxia-mediated drug resistance is responsible for the failure of cancer therapy. To date, the role of the hedgehog pathway in resistance to temozolomide (TMZ) under hypoxia has not been investigated. In this study, we discovered that the increasing hypoxia-inducible factor 1α (HIF-1α) activated the hedgehog pathway in hypoxic microenvironment by promoting autocrine secretion of sonic hedgehog protein (Shh), and then upregulating transfer of Gli1 to the nucleus, finally contributed to TMZ resistance in glioma cells. Oroxylin A (C16H12O5), a bioactive flavonoid, could induce HIF-1α degradation via prolyl-hydroxylases-VHL signaling pathway, resulting in the inactivation of the hedgehog. Besides, oroxylin A increased the expression of Sufu, which is a negative regulator of Gli1. By this mechanism, oroxylin A sensitized TMZ on glioma cells. U251 intracranial transplantation model and GL261 xenograft model were used to confirm the reversal effects of oroxylin A in vivo. In conclusion, our results demonstrated that HIF-1α/hedgehog pathway conferred TMZ resistance under hypoxia, and oroxylin A was capable of increasing the sensitivity of TMZ on glioma cells in vitro and in vivo by inhibiting HIF-1α/hedgehog pathway and depressing the activation of Gli1 directly.

Effect of type 2 diabetes mellitus on flavonoid pharmacokinetics and tissue distribution after oral administration of Radix Scutellaria extract in rats

Radix Scutellaria is widely applied to the treatment of diabetes mellitus in China. Its main bioactive constituents contain baicalin, wogonoside, oroxyloside, and their aglycones. To investigate the effect of type 2 diabetes mellitus on both pharmacokinetics and tissue distribution of these flavonoid compounds, the six flavonoids in plasma and tissues from the normal and type 2 diabetic rats after oral administration of Radix Scutellaria extract were simultaneously measured by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The results showed that baicalin, wogonoside, and oroxyloside had higher C_max and AUC values (P < 0.05) in type 2 diabetic rats than that in normal rats and the tissue-distribution behaviors of the six flavonoid compounds in hearts, livers, spleens, lungs, kidneys, brains, pancreas, fat and muscle of the type 2 diabetic rats showed obviously differences from the normal rats (P < 0.05). In conclusion, the differences in the pharmacokinetics of oroxyloside and tissue distribution of the six flavanoids in Radix Scutellaria extract between diabetic and normal rats were found for the first time. The results from the present study provided a crucial basis for a better understanding of in vivo anti-diabetic mechanism of action of the six flavonoids from Radix Scutellaria.

Oroxyloside inhibits human glioma progression by suppressing proliferation, metastasis and inducing apoptosis related pathways

Malignant glioma are linked to a high mortality rate. Therefore, it is necessary to explore and develop effective therapeutic strategy. Oroxyloside is a metabolite of oroxylin A. However, its inhibitory effects on cancer are little to be known. In the present study, we investigated the effects of oroxyloside on cell proliferation, migration, and apoptosis in vitro and in vivo in human glioma. The results indicated that oroxyloside significantly suppressed the proliferation of human glioma cells through inducing cell cycle arrest at G0/G1 phase through reducing Cyclin D1 and cyclin-dependent kinase 2 (CDK2) while enhancing p53 and p21 expressions. In addition, the migration of glioma cells was dramatically inhibited by oroxyloside in a dose-dependent manner, which was related to its modulation on extracellular matrix (ECM), as evidenced by up-regulated E-cadherin, and metastasis-associated protein 3 (MTA3), whereas down-regulated N-cadherin, Vimentin, Twist, alpha-smooth muscle actin (α-SMA) and Syndecan-2. Furthermore, oroxyloside treatment markedly induced apoptosis in glioma cells through improving Caspase-9, Caspase-3 and PARP cleavage, accompanied with high release of cytochrome c (Cyto-c) into cytoplasm and subsequently increase of apoptotic protease-activating factor 1 (Apaf-1). In vivo, oroxyloside administration significantly inhibited the glioma cell xenograft tumorigenesis through various signaling pathways, including suppression of Cyclin D1/CDK2 and ECM pathways, as well as potentiation of p53/p21 and Caspases pathways. Together, the findings above illustrated that oroxyloside, for the first time, was used as a promising candidate against human glioma.

Development of a new HPLC method for wogonin in rat plasma: Compatibility of standard and test samples

In the current paper, an HPLC/UV method was developed and validated for determination of wogonin in plasma. Considerable attention was paid to the preparation of standard samples and factors affecting drug distribution. A preparation procedure was devised to simulate the conditions the drug is expected to experience in vivo while pointing to the shortcomings of previously published methods. The method was validated according to the FDA regulations and showed to be highly efficient and capable of extracting the drug and IS from the plasma accurately and precisely within the specified range of 50-500 ng mL-1. Further, the standard sample preparation of this method can be used as a guideline for other methods, particularly when highly hydrophobic drugs with considerable protein binding are involved and could be valuable in the field of bioanalysis to improve the reliability of methods.

Oroxyloside A Overcomes Bone Marrow Microenvironment-Mediated Chronic Myelogenous Leukemia Resistance to Imatinib via Suppressing Hedgehog Pathway

Imatinib (IM), as first inhibitor of the oncogenic tyrosine kinase BCR-ABL, has been widely used to treat chronic myeloid leukemia (CML) for decades in clinic. However, resistance to IM usually occurs in CML patients. The bone marrow (BM), as the predominant microenvironment of CML, secretes an abundant amount of cytokines, which may contribute to drug resistance. In current study, we utilized in vitro K562 co-culture model with BM stroma to investigate IM resistance. As a result, co-culturing of K562 with BM stroma was sufficient to cause resistance to IM, which was accompanied with the activation of hedgehog (Hh) signaling pathway and upregulation of BCR-ABL as well as its downstream proteins like phosphorylated Akt, Bcl-xL and survivin, etc. On the other hand, oroxyloside A (OAG), a metabolite of oroxylin A from the root of Scutellaria baicalensis Georgi, which had low toxic effect on K562 cells, was able to sensitize K562 cells co-cultured with BM stroma to IM treatment in vitro and in vivo. We observed that OAG suppressed Hh pathway and subsequently nuclear translocation of GLI1, followed by downregulation of BCR-ABL and its downstream effectors, thus facilitating IM to induce apoptosis of K562 cells. Together, BM microenvironment rendered K562 cells drug resistance through activating Hh signaling, however, OAG could overcome IM resistance of CML cells through inhibiting Hh-BCR-ABL axis in vitro and in vivo.

Glucuronidation: driving factors and their impact on glucuronide disposition

Glucuronidation is a well-recognized phase II metabolic pathway for a variety of chemicals including drugs and endogenous substances. Although it is usually the secondary metabolic pathway for a compound preceded by phase I hydroxylation, glucuronidation alone could serve as the dominant metabolic pathway for many compounds, including some with high aqueous solubility. Glucuronidation involves the metabolism of parent compound by UDP-glucuronosyltransferases (UGTs) into hydrophilic and negatively charged glucuronides that cannot exit the cell without the aid of efflux transporters. Therefore, elimination of parent compound via glucuronidation in a metabolic active cell is controlled by two driving forces: the formation of glucuronides by UGT enzymes and the (polarized) excretion of these glucuronides by efflux transporters located on the cell surfaces in various drug disposition organs. Contrary to the common assumption that the glucuronides reaching the systemic circulation were destined for urinary excretion, recent evidences suggest that hepatocytes are capable of highly efficient biliary clearance of the gut-generated glucuronides. Furthermore, the biliary- and enteric-eliminated glucuronides participate into recycling schemes involving intestinal microbes, which often prolong their local and systemic exposure, albeit at low systemic concentrations. Taken together, these recent research advances indicate that although UGT determines the rate and extent of glucuronide generation, the efflux and uptake transporters determine the distribution of these glucuronides into blood and then to various organs for elimination. Recycling schemes impact the apparent plasma half-life of parent compounds and their glucuronides that reach intestinal lumen, in addition to prolonging their gut and colon exposure.

Brain Uptake of Bioactive Flavones in Scutellariae Radix and Its Relationship to Anxiolytic Effect in Mice

Scutellariae Radix (SR) and its bioactive flavones elicit a variety of effects in the brain. However, the brain uptake of individual SR flavones and its relationship to the elicited effects after SR administration remain unknown. Moreover, previous studies seldom measured pharmacokinetic and pharmacodynamic outcomes simultaneously. In the current study, the brain uptake of six major SR flavones and the anxiolytic behavior following oral administration of a SR extract at two clinically relevant doses (600 and 1200 mg/kg twice daily) were simultaneously investigated in mice (n = 18 per group). Brain and plasma concentrations of the flavones were measured by LC-MS/MS, while the anxiolytic effect was evaluated using the elevated plus maze. To further investigate the mechanism behind the differential brain uptake of the six SR flavones, these flavones were separately administered to mice at an equivalent molar oral dose (n = 6). The brain tissue bindings of the SR flavones were also measured with the in vitro brain slice method. Our results indicated that all six SR flavones including three aglycons (baicalein, wogonin, and oroxylin A) and three glucuronides (baicalin, wogonoside, and oroxyloside) could pass through the blood-brain barrier, with brain concentrations ranging from 7.9 to 224.0 pmol/g. It provided novel evidence that oroxylin A had the highest brain uptake among the six SR flavones regardless of its limited content in SR extract, in which 3.6-3.9% of the administered oroxylin A dose was present in the brain 6 h postdosing and with a brain-to-plasma ratio of 0.42-0.46. Although SR extract contains flavones that are positive modulators of the benzodiazepine binding site of GABA_A receptors (baicalein, wogonin, and baicalin), our behavioral study for the first time indicated that SR extract (a mixture of six flavones) did not elicit significant anxiolytic effect at the studied doses. Oroxylin A also demonstrated the highest brain uptake when the six flavones were separately administered to mice, and the highest affinity to brain tissues in the in vitro tissue binding assay. The high brain uptake of oroxylin A, a GABA_A antagonist which had been reported to antagonize diazepam-induced anxiolytic effect, might have suppressed the anxiolytic effects of the other flavones and account for the lack of overall anxiolytic effect of SR extract. The current study illustrates the importance of monitoring pharmacokinetics in a behavioral study, particularly for herbal medicines which consist of multiple components that might have different or even opposite pharmacological effects on the same target.

Simultaneous determination of wogonin, oroxylin a, schisandrin, paeoniflorin and emodin in rat serum by HPLC-MS/MS and application to pharmacokinetic studies

Wogonin and oroxylin A in Scutellariae Radix, schisandrin in Chinensis Fructus, paeoniflorin in Moutan Cortex and emodin in Polygoni Cuspidate Rhizome et Radix are anti-inflammatory active compounds. A method for simultaneous determination of the five compounds in rat was developed and validated using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). The separation was performed on a Symmetry C₁₈ column (4.6 × 50 mm, 3.5 μm) with acetonitrile and 0.1% formic acid aqueous solution as the mobile phases. The detection was performed using multiple-reaction monitoring with electrospray ionization source in positive-negative ion mode. The calibration curves showed good linearity (r ≥ 0.9955). The lower limit of quantification (LLOQ) was 5 ng/mL for wogonin and schisandrin, 10 ng/mL for oroxylin A and emodin, and 15 ng/mL for paeoniflorin, respectively. The relative standard deviations of intraday and interday precisions were <11.49 and 14.28%, respectively. The extraction recoveries and matrix effects were acceptable. The analytes were stable under the experiment conditions. The validated method has been successfully applied to pharmacokinetic studies of the five compounds in rats after oral administration of Hu-gan-kan-kang-yuan capsule. This paper would be a valuable reference for pharmacokinetic studies of Chinese medicine preparations containing the five compounds.

Drug activity screening based on microsomes-hydrogel system in predicting metabolism induced antitumor effect of oroxylin A

A novel microsomes-hydrogel added cell culture system (MHCCS) was employed in the antitumor activity screening of natural compounds, aiming to achieve drug screening with better in vivo correlation, higher initiative to explore the potential active metabolites, and investigation of the antitumor mechanism from the perspective of metabolism. MTT assay and cell apoptosis detection showed that test drug oroxylin A (OA) had enhanced cytotoxicity and wogonin (W) with reduced cytotoxicity on MCF-7 cell line upon MHCCS incubation. In vivo antitumor evaluations also demonstrated that OA induced higher tumor inhibition than W at the same dosage. To explore the reasons, nine major metabolites of OA were separated and collected through UPLC-Q-TOF and semi-preparative HPLC. Metabolites M318 exhibited higher cytotoxicity than OA and other metabolites by MTT assay. (1)H NMR spectrums, HPLC and TOF MS/MS results revealed that OA was catalyzed into its active metabolite M318 via a ring-opening reaction. M318 induced significant cell apoptosis and S-phase arrest through affecting tumor survival related genes after mechanism study. In conclusion, our MHCCS could be a useful tool for drug activity screening from a perspective of metabolism.

Highly selective enrichment of baicalin in rat plasma by boronic acid-functionalized core-shell magnetic microspheres: Validation and application to a pharmacokinetic study

To the best of our knowledge, this study is the first to successfully apply a novel, highly selective enrichment technique based on boronic acid-functionalized core-shell magnetic microspheres (BA-Fe3O4@SiO2-Au@mSiO2) with a large surface area and uniform pore size, to determine the baicalin concentration in rat plasma by HPLC. By taking advantage of the special interaction between boronic acid and baicalin under alkaline conditions, as well as the microspheres' size exclusion ability, baicalin was selectively extracted from protein-rich biosamples, such as plasma, without any other pretreatment procedure except for a 10-min vortexing step. BA-Fe3O4@SiO2-Au@mSiO2 microsphere-adsorbed baicalin was straightforwardly and rapidly isolated from the matrix using a magnet. Baicalin was subsequently eluted from the microspheres under acidic conditions for 2min for further HPLC analysis. The extraction conditions, such as the amount of microspheres added, adsorption time, adsorption pH, and elution time and pH, were also determined. Furthermore, method validation, including the linear range, detection limit, precision, accuracy, and recovery, were determined. This newly developed method based on BA-Fe3O4@SiO2-Au@mSiO2 microspheres is a simple, accurate, selective, and green analytical preparatory technique for analyzing baicalin in rat plasma. This study will be further novel research on the analysis of complex plasma samples and the pharmacokinetics of drugs similar to baicalin.

Simultaneous Determination of 10 Flavonoids in Crude and Wine-Processed Radix scutellariae by UHPLC

Radix scutellariae is a well-known traditional Chinese medicine used for the treatments of inflammation, pyrexia, hepatitis, etc. Flavonoids are its main active compounds. The aim of this study is to develop and validate the ultra high-performance liquid chromatography (UHPLC) method for simultaneous determination of 10 flavonoids (baicalin, wogonoside, baicalein, wogonin, oroxylin A, chrysin, scutellarin, oroxylin A-7-O-glucuronide, apigenin and apigenin-7-glucuronide) in crude and wine-processed R. scutellariae. The quantitative determination was conducted by UHPLC. Optimal separation was achieved by gradient elution with mobile phase consisting of 0.01% aqueous formic acid and methanol on a Waters ACQUITY UHPLC BEH C18 column. Detection wavelength was set at 275 nm. Method validation was accomplished with linearity, precision and recovery tests. All calibration curves showed good linearity (R(2) > 0.9993). The limit of detection and limit of quantification of these compounds were from 0.08 to 0.24 µg/mL and from 0.23 to 0.76 µg/mL, respectively. The average recoveries of these compounds were from 96.95 to 109.51% with relative standard deviation (RSD) values from 2.14 to 3.26% for crude R. scutellariae, while from 94.73 to 108.38% with RSD values from 1.83 to 3.47% for wine-processed R. scutellariae. The developed method can be applied to the intrinsic quality control of crude and wine-processed R. scutellariae.

Herb-drug interactions between Scutellariae Radix and mefenamic acid: Simultaneous investigation of pharmacokinetics, anti-inflammatory effect and gastric damage in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellariae Radix (SR), the dried root of Scutellariae baicalensis Georgi, has a lot in common with non-steroidal anti-inflammatory drugs (NSAIDs). Their similarities in therapeutic action (anti-inflammation) and metabolic pathways (phase II metabolisms) may lead to co-administration by patients with the potential of pharmacokinetic and/or pharmacodynamic interactions. The current study aims to investigate the potential interactions between SR and an NSAID, mefenamic acid (MEF), on the overall pharmacokinetic dispositions, anti-inflammatory effects and adverse effects in rats.

MATERIALS AND METHODS

The current study simultaneously monitored the pharmacokinetic and pharmacodynamic interactions in a single animal. Four groups of Sprague-Dawley rats (n=7 each) received oral doses of a standardized SR extract (300mg/kg, twice daily), MEF (40mg/kg, daily), combination of SR extract and MEF, and vehicle control, respectively, for 5 days. On Day 5, blood samples were collected after first dose over 24h for the determination of (1) plasma concentrations of SR bioactive components, MEF and its metabolites by LC-MS/MS, and (2) prostaglandin E2 (PGE2) production and cyclooxygenase-2 (COX-2) gene expression by ex vivo analyses using LPS-stimulated RAW264.7 macrophage cells, ELISA and real time-PCR. After the rats were sacrificed, stomachs were isolated to assess their gross mucosal damage. Statistical comparisons were conducted using ANOVA and t-test.

RESULTS

Minimal pharmacokinetic interaction between SR extract and MEF was observed. Co-administration of SR extract and MEF did not significantly alter the plasma concentration-time profile or the pharmacokinetic parameters such as Cmax, AUC0→24, Tmax or clearance. Pharmacodynamic interaction via the COX-2 pathway was observed. The PGE2 level in LPS-stimulated RAW264.7 cells treated with plasma collected from control group over the 24h sampling (AUC0→24[PGE2]) was 191981±8789pg/mlhr, which was significantly reduced to 174,780±6531 and 46,225±1915pg/mlhr by plasma collected from rats administered with SR extract and MEF, respectively. Co-administration of SR extract and MEF further potentiated the PGE2 inhibition, with an AUC0→24[PGE2] of 37013±2354pg/mlhr (p<0.05, compared to SR or MEF group). By analyzing the COX-2 gene expression, SR extract significantly prolonged the COX-2 inhibitory effect of MEF over the 24h (p<0.05). Furthermore, the MEF-induced stomach ulcer after the 5-day treatment, as evidenced by the increased gross ulcer index and sum of lesion length (p<0.05, compared to control), could be alleviated by co-administration with SR extract (p<0.05).

CONCLUSIONS

Co-administration of SR extract and MEF potentiated the anti-inflammatory effects, alleviated the MEF-induced stomach adverse effect while having minimal pharmacokinetic interactions. Our findings provide insight for combination therapy of SR extract and MEF against inflammatory diseases.

Synthesis of surface nano-molecularly imprinted polymers for sensitive baicalin detection from biological samples

Surface molecularly imprinted polymers (MIP@SBA-15) imprinted on the surface of hybrid nanostructured organic/inorganic materials (SBA-15) were prepared for the selective extraction and detection of baicalin (BA) from biological samples. The surface morphologies and characteristics of the imprinted and non-imprinted polymers were characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA) and nitrogen adsorption-desorption isotherms. The results indicated that the polymers were successfully grafted on the surface of SBA-15 and possessed a highly ordered mesoporous structure. In binding tests, MIP@SBA-15 reached saturated adsorption within 80 min and exhibited significant specific recognition toward BA with large adsorption capacity. Meanwhile, the prepared MIP@SBA-15 was used as a selective sorbent for solid-phase extraction of BA from biological samples. Recoveries of BA from the liver and spleen ranged from 90.6% to 90.9% with RSD < 3.7%. All these results reveal that this method is simple, rapid and sensitive for effectively extracting and detecting trace BA in biological samples.