Pharmacokinetic profiles of the five isoflavonoids from Pueraria lobata roots in the CSF and plasma of rats

Gut microbiota and metabolome in sporadic Creutzfeldt-Jakob disease

BACKGROUND

Gut dysbiosis and the resulting changes in the metabolites have been associated with neurological diseases. However, the relationship between the gut microbiota and sporadic Creutzfeldt-Jakob disease (sCJD) need to be clarified. The aim of this study was to evaluate the changes in the composition of gut microbiota and metabolome accompanying sCJD, and determine their correlation with disease severity.

METHODS

Fecal samples were collected from 25 sCJD patients and 23 healthy controls. The composition of the fecal microbiota and metabolites was respectively analyzed by 16S ribosomal RNA sequencing and untargeted metabolomics. The correlation of gut microbiota and metabolites with MMSE, MoCA and MRC scores was analyzed.

RESULTS

The sCJD patients showed significant differences in the composition of gut microbiota and metabolites relative to the healthy controls. Several bacteria taxa in sCJD patients were increased at genus level, such as Turicibacter, norank_f_Christensenellaceae, Eisenbergiella, Bilophila and Holdemania. A total of 547 differential metabolites were identified between these two groups (VIP > 1, FDR p < 0.05). As per KEGG analysis, the metabolites related to the biosynthesis of phenylpropanoids, especially biochanin A, showed the most obvious decrease in the sCJD group. In addition, most metabolites involved in the pathways related to linoleic acid metabolism and steroid hormone biosynthesis were associated with MRC scale.

CONCLUSION

Our findings provide new insights into the relationship between gut microbiota and metabolites and sCJD. Some compounds, especially those related to the biosynthesis of phenylpropanoids were significantly altered in patients with sCJD, and those related to linoleic acid metabolism and steroid hormone biosynthesis might be biomarkers of evaluating disease severity.

Design, synthesis and the evaluation of cholinesterase inhibition and blood-brain permeability of daidzein derivatives or analogs

In the present study, a series of derivatives and analogs of daidzein were designed and synthesized to investigate cholinesterase inhibition and blood-brain barrier permeability. The enzyme assay showed that most of the compounds containing a tertiary amine group exhibit moderate cholinesterase inhibition, 7-hydroxychromone derivatives (absence of B ring of daidzein scaffold) only have a weaker bioactivity, while those compounds without the tertiary amine group have no bioactivity. Among them compound 15a (4'-N,N-dimethylaminoethoxy-7-methoxyisoflavone) appeared the best inhibitory activity (IC50 : 2.14 ± 0.31 μmol/L) and higher selectivity for AChE over BuChE (Ratio: 7.07). It was selected for the further investigation by UPLC-MS/MS. The results show that CBrain/Serum of compound 15a in mice was more than 2.87 within 240 min. This discovery may provide worthy information for the future development of central nervous drugs including but not limited to cholinesterase inhibitors.

Unveiling the Pharmacological and Nanotechnological Facets of Daidzein: Present State-of-the-Art and Future Perspectives

Herbal drugs have been attracting much scientific interest in the last few decades and nowadays, phytoconstituents-based research is in progress to disclose their unidentified medicinal potential. Daidzein (DAI) is the natural phytoestrogen isoflavone derived primarily from leguminous plants, such as the soybean and mung bean, and its IUPAC name is 4',7-dihydroxyisoflavone. This compound has received great attention as a fascinating pharmacophore with remarkable potential for the therapeutic management of several diseases. Certain pharmacokinetic properties of DAI such as less aqueous solubility, low permeability, and poor bioavailability are major obstacles restricting the therapeutic applications. In this review, distinctive physicochemical characteristics and pharmacokinetics of DAI has been elucidated. The pharmacological applications in treatment of several disorders like oxidative stress, cancer, obesity, cardiovascular, neuroprotective, diabetes, ovariectomy, anxiety, and inflammation with their mechanism of action are explained. Furthermore, this review article comprehensively focuses to provide up-to-date information about nanotechnology-based formulations which have been investigated for DAI in preceding years which includes polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carrier, polymer-lipid nanoparticles, nanocomplexes, polymeric micelles, nanoemulsion, nanosuspension, liposomes, and self-microemulsifying drug delivery systems.

Isolation of Mirificin and Other Bioactive Isoflavone Glycosides from the Kudzu Root Lyophilisate Using Centrifugal Partition and Flash Chromatographic Techniques

Pueraria lobata (Willd.) Ohwi is a legume taxon native to Southeast Asia and widely used in traditional medicine systems of that region. The therapeutic applications of the underground parts of this species (known as kudzu root) are related to its high content of isoflavones, mainly the characteristic C-glycoside derivatives. Within this group, the most explored compound both phytochemically and pharmacologically is puerarin. However, current scientific findings document important anti-biodegenerative effects for some of the minor isoflavones from kudzu roots. Therefore, the main objective of the study was to develop an original preparative method that allowed the efficient isolation of closely related hydrophilic daidzein C-glycosides, including mirificin, from vacuum-dried aqueous-ethanolic extracts of kudzu roots. For this purpose, the combined centrifugal partition (CPC) and flash chromatographic (FC) techniques were elaborated and used. The optimized biphasic solvent system in CPC, with ethyl acetate, ethanol, water, and 0.5% (V/V) acetic acid as a mobile phase modifier, enabled the purification and separation of the polar fraction containing bioactive isoflavones and ultimately the isolation of mirificin, 3′-hydroxy- and 3′-methoxypuerarin, puerarin, and daidzin using FC. The identity of isoflavones was confirmed using spectroscopic (UV absorption and nuclear magnetic resonance) and mass spectrometric methods. The determined purity of isolated mirificin was 63%.

In vitro and in silico evaluation of Ononis isoflavonoids as molecules targeting the central nervous system

Isoflavonoids with various structural elements show a promising potential effect on central nervous system activities. Despite their favorable medicinal properties, the pharmacokinetic characteristics of this thoroughly investigated group of natural phenolics have only been described to a limited extent. Regarding the lack of information about the BBB permeability of isoflavones, isoflavanones, and pterocarpans found in Ononis species, the aim of our study was to investigate their physico-chemical properties influencing their absorption and distribution. Furthermore, we aimed to characterize the possible MAO-B inhibiting features of Ononis isoflavonoids in silico. Octanol-water partitioning and BBB-PAMPA permeability of formononetin, calycosin D, onogenin, sativanone, medicarpin and maackiain were assessed for the first time in our study. The log P values ranged from 2.21 to 3.03 and log D^7.4 values from 2.48 to 3.03, respectively, indicating optimal polarity for BBB permeation. The results of PAMPA-BBB expressed as log P_e values fell between -5.60 and -4.45, predicting their good permeation capability as well. The effective permeability values showed structure-dependent differences, indicating that the pterocarpan type skeleton was the most preferred type, followed by isoflavanones, then isoflavones. The methoxy or methylenedioxy substitution of the same skeleton did not influence the permeability significantly, contrary to an additional hydroxyl group. Membrane retention showed a similar structure dependent pattern to that of effective permeability, ranging from 16% to 70%. For the identification of volumes of chemical space related to particular biological activities the ChemGPS-NP framework was used. The MAO-B inhibitory potency and selectivity were also predicted and validated. Based on our results, MAO-B inhibitory potency could be predicted with good precision, but in the case of selectivity, only the direction could be concluded (favors MAO-B or MAO-A), not the magnitude. Our finding reflects that Ononis isoflavonoid aglycones show an excellent fit with the suggested parameters for BBB permeability and this is the first study to confirm the highly favorable position of these natural products for MAO-B inhibition.

Neuroprotective Potency of Tofu Bio-Processed Using Actinomucor elegans against Hypoxic Injury Induced by Cobalt Chloride in PC12 Cells

Fermented soybean products have attracted great attention due to their health benefits. In the present study, the hypoxia-injured PC12 cells induced by cobalt chloride (CoCl₂) were used to evaluate the neuroprotective potency of tofu fermented by Actinomucor elegans (FT). Results indicated that FT exhibited higher phenolic content and antioxidant activity than tofu. Moreover, most soybean isoflavone glycosides were hydrolyzed into their corresponding aglycones during fermentation. FT demonstrated a significant protective effect on PC12 cells against hypoxic injury by maintaining cell viability, reducing lactic dehydrogenase leakage, and inhibiting oxidative stress. The cell apoptosis was significantly attenuated by the FT through down-regulation of caspase-3, caspases-8, caspase-9, and Bax, and up-regulation of Bcl-2 and Bcl-xL. S-phase cell arrest was significantly inhibited by the FT through increasing cyclin A and decreasing the p21 protein level. Furthermore, treatment with the FT activated autophagy, indicating that autophagy possibly acted as a survival mechanism against CoCl₂-induced injury. Overall, FT offered a potential protective effect on nerve cells in vitro against hypoxic damage.

Neuroprotective Phytochemicals in Experimental Ischemic Stroke: Mechanisms and Potential Clinical Applications

Ischemic stroke is a challenging disease with high mortality and disability rates, causing a great economic and social burden worldwide. During ischemic stroke, ionic imbalance and excitotoxicity, oxidative stress, and inflammation are developed in a relatively certain order, which then activate the cell death pathways directly or indirectly via the promotion of organelle dysfunction. Neuroprotection, a therapy that is aimed at inhibiting this damaging cascade, is therefore an important therapeutic strategy for ischemic stroke. Notably, phytochemicals showed great neuroprotective potential in preclinical research via various strategies including modulation of calcium levels and antiexcitotoxicity, antioxidation, anti-inflammation and BBB protection, mitochondrial protection and antiapoptosis, autophagy/mitophagy regulation, and regulation of neurotrophin release. In this review, we summarize the research works that report the neuroprotective activity of phytochemicals in the past 10 years and discuss the neuroprotective mechanisms and potential clinical applications of 148 phytochemicals that belong to the categories of flavonoids, stilbenoids, other phenols, terpenoids, and alkaloids. Among them, scutellarin, pinocembrin, puerarin, hydroxysafflor yellow A, salvianolic acids, rosmarinic acid, borneol, bilobalide, ginkgolides, ginsenoside Rd, and vinpocetine show great potential in clinical ischemic stroke treatment. This review will serve as a powerful reference for the screening of phytochemicals with potential clinical applications in ischemic stroke or the synthesis of new neuroprotective agents that take phytochemicals as leading compounds.

Selectivity of Current Extraction Techniques for Flavonoids from Plant Materials

Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.

A Reliable LC-MS/MS Method for the Quantification of Two Pairs of Isomeric Flavonoids from Commelina Communis Linn in Rat Plasma: Validation and Pharmacokinetic Applications

Background:

Commelina communis Linn (Commelinae Herba) is a traditional Chinese medicine that can be used both as food and as medicine. It has been used to treat a variety of disorders, including a cold, high fever, sore throat, edema and oliguria for many years. Two pairs of isomeric flavonoid glycosides are the main active components in Commelina communis Linn, and they have a high content.

Objective:

The objective of this study was to determine the pharmacodynamic and pharmacological effects of Commelina communis Linn.

Method:

A sensitive, efficient, and rapid LC-MS/MS method was developed to simultaneously identify two pairs of isomeric flavonoid glycosides in rats. Chromatographic separation was carried out on a Wonda Cract ODS-2 C18 column (150 mm x 4.6 mm, 5 μm) using a mobile phase composed of 0.1% formic acid (aqueous solution) and methanol at a flow rate of 0.8 mL/min. The detection of the four analytes and the internal standard (IS) sulfamethoxazole was performed with multiple reaction monitoring (MRM) in negative electrospray ionization mode. All the analytes were eluted within 20 min.

Results:

This method was successfully applied for simultaneous identification of the concentrations of the four compounds in the plasma after the oral administration of 10 mL/kg Commelina communis Linn extract to rats. The pharmacokinetic study indicated that analytes reached their Cmax in approximately 15 min and could be detected until 12 h.

Conclusion:

The method complies with the State Food and Drug Administration guidelines for selectivity, sensitivity, accuracy, precision, matrix effect, extraction recovery and stability. This is the first report on the pharmacokinetics of Commelina communis Linn. The information gained from this research may be valuable for the preclinical and clinical applications of Commelina communis Linn.

Coexisting flavonoids and administration route effect on pharmacokinetics of Puerarin in MCAO rats

A pharmacokinetic comparison was made to evaluate the influence from other components in the Radix Puerariae Extract on pharmacokinetic behavior of Puerarin. Samples of blood and brain were collected by microdialysis and determined by high-performance liquid chromatography–mass spectrometry (MS)/MS. Pharmacokinetic parameters were estimated from the concentration versus time data using non-compartmental methods. In addition, a comparative pharmacokinetic study of Puerarin in stroke rats was studied after administration of the Radix Puerariae Extract via different routes to find an effective way to deliver drug into brain. Obvious pharmacokinetic differences were also observed in comparison between the Puerarin group and the Radix Puerariae Extract group based on middle cerebral artery occlusion (MCAO) rats. The Cmax and area under the curve (AUC) of Puerarin in olfactory bulb of the Extract group significantly reduced when it was intravenously administered. However, the AUCs of Puerarin in plasma are 134.72 and 1707.02 mg/L min, via intranasal and intravenous administration of the Radix Puerariae Extract, respectively. The AUC of the intranasal group in brain is seven times higher than that of intravenous administration. Other ingredients in the Extract may affect the disposition of Puerarin and its transportation through the blood–brain barrier via intravenous administration. But intranasal administration is an effective route to deliver isoflavone-C-glycoside with poor hydrophilicity into brain.

A Pharmacological Appraisal of Neuroprotective and Neurorestorative Flavonoids Against Neurodegenerative Diseases

BACKGROUND & OBJECTIVE

Alzheimer's disease (AD) and Parkinson's disease (PD) affect an increasing number of the elderly population worldwide. The existing treatments mainly improve the core symptoms of AD and PD in a temporary manner and cause alarming side effects. Naturally occurring flavonoids are well-documented for neuroprotective and neurorestorative effects against various neurodegenerative diseases. Thus, we analyzed the pharmacokinetics of eight potent natural products flavonoids for the druggability and discussed the neuroprotective and neurorestorative effects and the underlying mechanisms.

CONCLUSION

This review provides valuable clues for the development of novel therapeutics against neurodegenerative diseases.

A reliable and rapid pharmacokinetic study of pueraria isoflavones using pueraria reference extractive substance in beagle plasma: Application to study of Yufeng Ningxin Tablets

Objective

In order to evaluate the reliability and feasibility of pueraria reference extractive substance (RES) used in biological sample, the pharmacokinetics of 3′‑hydroxy puerarin (3′-HP), puerarin, 3′‑methoxy puerarin (3′-MP), and daidzein-8-C-apiosyl-(1-6)-glucoside (DAG) in beagle plasma following oral administration of Yufeng Ningxin Tablet were quantitated.

Methods

A reliable and sensitive high-performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-QQQ-MS/MS) method developed with chromatographic separation was operated on a Merck C₁₈ column, and acetonitrile-5 mmol/L ammonium was used as mobile phase in gradient elution. The plasma samples were deproteinized by acetone, detected by triple quadrupole mass spectrometry with an electrospray ionization interface, and quantified using selected ion monitoring mode. The pharmacokinetic parameters were calculated by Winnonlin 4.1.

Results

The calibration curves of the reference extractive substance and standard substance methods were linear over the ranges 0.0417–11.3309 µg/mL and 0.0394–10.0000 µg/mL. The intra-day and inter-day precision of the two methods at three concentrations were less than 13.63%, and the average recoveries of 3′-HP, puerarin, 3′-MP, and DAG were more than 70.67%. The RSD of the mean plasma concentrations of the analytes calculated by the two methods was less than 5%, and cos (ϑ) = =1.000. Among the analytes, puerarin showed the highest blood concentration [(940 ± 185) ng/mL] and the longest retention time [(5 ± 1) h] in the dog's bodies.

Conclusion

Pueraria reference extractive substance can be seen as an alternative to the standard substance to overcome the scarcity of standard substance for the analysis of biological samples.

Alleviation of Inflammatory Response of Pulmonary Fibrosis in Acute Respiratory Distress Syndrome by Puerarin via Transforming Growth Factor (TGF-β1)

BACKGROUND Acute respiratory distress syndrome (ARDS) in infants is acute and progressive hypoxic respiratory failure caused by various extrapulmonary pathogenic factors besides cardiogenic factors. Diffuse alveolar injury and progression to pulmonary fibrosis are pathological features of ARDS. The present study sought to determine how puerarin influences the inflammatory response caused by pulmonary fibrosis in ARDS in infants. MATERIAL AND METHODS The human lung fibroblasts cell line HLF1 was treated with different concentrations of puerarin in different groups for various times. TGF-ß1 was overexpressed by TGF-ß1 (2 ng/mL) in routine experiments, and the treated cells and culture supernatant were collected for analysis in each step. Cell apoptosis was measured by flow cytometry, TUNEL assay, and detection of caspase 3 and Bcl-2. Cell proliferation was assessed by CCK-8 assay. Real-time PCR and Western blot assay were used to assess mRNA and protein levels of TGF-ß1 and Smad3, respectively. The related cytokines were assessed by ELISA. RESULTS Results showed that puerarin promoted the apoptosis and inhibited the proliferation of HLF1 cells. Caspase 3 was upregulated, whereas Bcl-2, TGF-ß1, and Smad3 were downregulated by puerarin. IL-1, IL-2, and IL-4, secreted by HLF1 cells, were reduced, but IL-10 showed the opposite trend. When TGF-ß1 was overexpressed, Smad3 was promoted, and IL-1, IL-2, and IL-4 was increased in HLF1 cells. Finally, overexpression of TGF-ß1 reversed the effect of puerarin in HLF1 cells. CONCLUSIONS Puerarin regulated the proliferation and apoptosis of pulmonary fibrosis cells, and affected the secretion of inflammatory cytokines. Thus, puerarin alleviated the inflammatory response resulting from pulmonary fibrosis by regulating the TGF-ß1/Smad3 pathway in infants with ARDS.

The anxiolytic-like effects of puerarin on an animal model of PTSD

Post traumatic stress disorder (PTSD) is a mental illness that affected numerous people. The anti-PTSD-like effects of puerarin is unknown, although the antidepressant- and anxiolytic- like effects of puerarin have been reported. The PTSD behavioral deficits in rats were induced by single prolonged stress (SPS), mainly including the reduced time/entries in the open arms and the elevated time/entries in the closed arms in elevated plus maze test, increased freezing duration in contextual fear paradigm and lowered time/entries in the central zone in open field test. However, the behavioral deficits were attenuated by puerarin (50 and 100 mg/kg) without affecting the locomotor activity. For the evaluation of mechanism, the decreased levels of progesterone, allopregnanolone, and the increased levels of corticosterone, corticotropin releasing hormone, and adrenocorticotropic hormone in the brain or serum were induced by SPS, which is blocked by puerarin. In summary, the anti-PTSD-like effects of puerarin were associated with biosynthesis of neurosteroids and normalized levels of stress hormones in HPA axis.

Pharmacokinetics study of 16 representative components from Baoyuan Decoction in rat plasma by LC-MS/MS with a large-volume direct injection method

BACKGROUND

Baoyuan decoction (BYD), a well-known traditional Chinese medicine (TCM) formula, is clinically used for the treatment of aplastic anemia, chronic renal failure, coronary heart disease, etc. PURPOSE: The purpose of this study was to develop a large-volume direct injection liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of 16 representative flavonoids and saponins in rat plasma after oral administration of BYD.

METHODS

The rat plasma sample was injected directly into a pre-column, which was eluted firstly by 0.05% formic acid in water. Then, the accumulated components were eluted from the pre-column and transferred into a Waters BEH C18 column with acetonitrile and water system (contain 0.05% formic acid) as the mobile phase at a rate of 0.3 ml/min. The detection was accomplished in a negative mode using the schedule multiple-reaction monitoring (sMRM).

RESULTS

The correlation coefficients for calibration curves were all higher than 0.9920 for formononetin, ononin, calycosin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, glycyrrhetinic acid, liquiritin, isoliquiritin, liquiritin apioside, isoliquiritin apioside, ginsenoside Rb1, ginsenoside Re, ginsenoside Rd, ginsenoside Rg1 and astragaloside. The intra- and inter-day precisions (RSD) and accuracy (RE) for the investigated components were in the range of -10.9 to 13.7%. The average recoveries were in the range of 75.7-108.6%. This method was successfully applied to investigate the pharmacokinetics of 16 compounds of BYD in rats. The absorption and elimination rates of the representative saponins were significantly slower than most of the targeted-flavonoids after oral administration of BYD in rats.

CONCLUSION

The results demonstrated that the large-volume direct injection LC-MS method provided a rapid and efficient approach for multi-components pharmacokinetics of TCM.

Daidzein, its effects on impaired glucose and lipid metabolism and vascular inflammation associated with type 2 diabetes

Over the last decades, the incidence of type 2 diabetes (T2D) is increasing substantially. Emerging evidences from epidemiological studies have shown the association between higher intake of soy isoflavones and reduced risk of T2D and its associated health risks. Daidzein, a soy isoflavone, has been found to have a promising therapeutic potential in managing T2D pathophysiology. Fermented soybean is the major source of daidzein; however, it can also be formed via the consumption of its glycosylated moiety, daidzin with subsequent hydrolysis by intestinal bacterial enzyme. Many studies reported the prophylactic effect of daidzein on the improvement of hyperglycemia, insulin resistance, dislipidemia, obesity, inflammation, and other complications associated with T2D. The molecular mechanisms underlying the action of daidzein include diverged pathways where daidzein has been shown to interact with several signaling molecules and receptors to achieve desirable effect. Although the specific molecular mechanism is still elusive, further studies are thus needed to understand it in detail. In this review, we discuss the antidiabetic potential of daidzein with respect to the evidences from various clinical, preclinical, and cell culture studies and the underlying molecular mechanism in a precise way to have a comprehensive account on this isoflavone with promising therapeutic potential. © 2018 BioFactors, 44(5):407-417, 2018.

Pharmacokinetics of Nuciferine and N-Nornuciferine, Two Major Alkaloids From Nelumbo nucifera Leaves, in Rat Plasma and the Brain

The leaf of the lotus (Nelumbo nucifera) is a natural plant resource used as both food and herbal medicine (He-Ye) in China. Alkaloids are considered the major bioactive compound of the herb and exhibit various biological activities, including anti-hyperlipidemia, anti-obesity, anti-inflammatory, and anti-hyperuricemic effects. Nuciferine (NF) and N-nuciferine (N-NF) are two major alkaloids found in the herb. In the present work, the plasma and brain pharmacokinetics of the two compounds were investigated after oral and intravenous (i.v.) administration of a lotus leaf alkaloid fraction to SD rats via ultra-performance liquid chromatography coupled with photodiode array detection and brain microdialysis. After oral administration (50 mg/kg), the two compounds NF and N-NF were rapidly absorbed into the blood and reached a mean maximum concentration (C_max) of 1.71 μg/mL at 0.9 h and 0.57 μg/mL at 1.65 h, respectively. After i.v. administration (10 mg/kg), NF and N-NF were found to have a relatively wide volume of distribution (V_{d, λz}, 9.48 and 15.17 L/kg, respectively) and slow elimination half-life (t_{1/2, λz}, 2.09 and 3.84 h, respectively). The oral bioavailability of NF and N-NF was estimated as 58.13% and 79.91%, respectively. After i.v. dosing (20 mg/kg), the two compounds rapidly crossed the blood-brain barrier and reached their C_max (in unbound form): 0.32 and 0.16 μg/mL at 0.89 and 1.22 h, respectively. Both alkaloids had widespread distribution in the brain, with V_{d, λz}/F-values of 19.78 L/kg and 16.17 L/kg, respectively. The mean t_{1/2, λz} values of NF and N-NF in the brain were 1.24 and 1.39 h, respectively. These results can help us to better understand the characteristics and neuro-pharmacological effects of the lotus alkaloid fraction.

Anti-inflammatory Activity of 8-Hydroxydaidzein in LPS-Stimulated BV2 Microglial Cells via Activation of Nrf2-Antioxidant and Attenuation of Akt/NF-κB-Inflammatory Signaling Pathways, as Well As Inhibition of COX-2 Activity

It was demonstrated that isoflavones can cross the blood-brain barrier, making them desirable candidate agents for the prevention of neurological symptoms. 8-Hydroxydaidzein (8-OHD, 4',7,8-trihydoxyisoflavone) is an isoflavone found only in fermented soy food. Current results showed that 8-OHD inhibited LPS-stimulated production of nitric oxide (NO) and proinflammatory cytokines, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6, by inhibiting gene expression in BV2 microglial cells. Moreover, 8-OHD markedly quenched reactive oxygen species (ROS) and activated NF-E2-related factor 2 (Nrf2) so as to upregulate expression of Phase II enzymes, including heme oxygenase (HO)-1, NAD(P)H quinone dehydrogenase 1 (NQO1), and the modifier subunit of glutamate cysteine ligase (GCLM). 8-OHD also suppressed LPS-stimulated phosphorylation of Akt and NF-κB-p65. The anti-inflammatory activity of 8-OHD was attenuated by the HO-1 inhibitor zinc protoporphyrin (Znpp) but augmented by the PI3K/Akt inhibitor LY294002. 8-OHD also diminished LPS-induced prostaglandin E₂ (PGE₂) production without affecting cyclooxygenase (COX)-2 expression. In vitro assay shows that 8-OHD displayed mixed-type inhibition of COX-2 with an IC₅₀ of 8.9 ± 1.2 μM. These data suggest that the anti-inflammatory activity of 8-OHD may be associated with the activation of Nrf2/HO-1 and attenuation of Akt/NF-κB signaling pathways as well as inhibition of COX-2 enzyme activity. In conclusion, 8-OHD, a potent Nrf2 activator, Akt/NF-κB activation suppressor, and COX-2 enzyme inhibitor, may have health-promoting effects for mitigating microglia activation and preventing neuroinflammation.

Development of a liquid chromatography-tandem mass spectrometry method for simultaneous determination of five isoflavonoids and seven neurochemicals in rat brain dialysate and its application to a pharmacological study

Pueraria lobata is a medicinal plant widely used in traditional Chinese medicine. The total pueraria isoflavones have demonstrated positive effect against neurological disorders. In the present study, we first develop an ultra high performance liquid chromatography and tandem mass spectrometry method to quantify the multiple active pueraria isoflavonoids and neurochemical markers in brain dialysate to provide tools for further exploring the functional mechanism of pueraria isoflavones for neuroactivities. A phenomenex Luna C18 column (50 × 2.0 mm, 5 μm) was employed with acetonitrile/0.05% formic acid in water as the mobile phase for the separation of analytes. A mass spectrometer with electrospray ionization source in positive/negative ion switching mode was used for multiple reaction monitoring of the detected compounds. The method was validated and proved acceptable. The intra- and interday precision across quality control levels was within 13.87 for all analytes, whereas the deviation of assay accuracies ranged between 0.03 and 11.53%. The method was successfully applied to a pharmacological study of pueraria isoflavones in rat brain.

Discrimination of geographical origin and detection of adulteration of kudzu root by fluorescence spectroscopy coupled with multi-way pattern recognition

In this work, fluorescence spectroscopy combined with multi-way pattern recognition techniques were developed for determining the geographical origin of kudzu root and detection and quantification of adulterants in kudzu root. Excitation-emission (EEM) spectra were obtained for 150 pure kudzu root samples of different geographical origins and 150 fake kudzu roots with different adulteration proportions by recording emission from 330 to 570nm with excitation in the range of 320-480nm, respectively. Multi-way principal components analysis (M-PCA) and multilinear partial least squares discriminant analysis (N-PLS-DA) methods were used to decompose the excitation-emission matrices datasets. 150 pure kudzu root samples could be differentiated exactly from each other according to their geographical origins by M-PCA and N-PLS-DA models. For the adulteration kudzu root samples, N-PLS-DA got better and more reliable classification result comparing with the M-PCA model. The results obtained in this study indicated that EEM spectroscopy coupling with multi-way pattern recognition could be used as an easy, rapid and novel tool to distinguish the geographical origin of kudzu root and detect adulterated kudzu root. Besides, this method was also suitable for determining the geographic origin and detection the adulteration of the other foodstuffs which can produce fluorescence.

Radix Puerariae modulates glutamatergic synaptic architecture and potentiates functional synaptic plasticity in primary hippocampal neurons

ETHNOPHARMACOLOGICAL RELEVANCE

Neurologic disorders are frequently characterized by synaptic pathology, including abnormal density and morphology of dendritic spines, synapse loss, and aberrant synaptic signaling and plasticity. Therefore, to promote and/or protect synapses by the use of natural molecules capable of modulating neurodevelopmental events, such as, spinogenesis and synaptic plasticity, could offer a preventive and curative strategy for nervous disorders associated with synaptic pathology. Radix Puerariae, the root of Pueraria monatana var. lobata (Willd.) Sanjappa&Pradeep, is a Chinese ethnomedicine, traditionally used for the treatment of memory-related nervous disorders including Alzheimer's disease. In the previous study, we showed that the ethanolic extracts of Radix Puerariae (RPE) and its prime constituent, puerarin induced neuritogenesis and synapse formation in cultured hippocampal neurons, and thus could improve memory functions.

AIMS OF THE STUDY

In the present study, we specifically investigated the abilities of RPE and puerarin to improve memory-related brain disorders through modulating synaptic maturation and functional potentiation.

MATERIALS AND METHODS

Rat embryonic (E19) brain neurons were cultured in the absence or presence of RPE or puerarin. At predetermined times, cells were live-stained with DiO or fixed and immunostained to visualize neuronal morphologies, or lysed for protein harvesting. Morphometric analyses of dendritic spines and synaptogenesis were performed using Image J software. Functional pre- and postsynaptic plasticity was measured by FM1-43 staining and whole-cell patch clamping, respectively. RPE or puerarin-mediated changes in actin-related protein 2 were assessed by Western blotting. Neuronal survivals were measured using propidium iodide exclusion assay.

RESULTS

RPE and puerarin both: (1) promoted a significant increase in the numbers, and maturation, of dendritic spines; (2) modulated the formation of glutamatergic synapses; (3) potentiated synaptic transmission by increasing the sizes of reserve vesicle pools at presynaptic terminals; (4) enhanced NMDA receptor-mediated postsynaptic currents, and (5) increased cell viability against naturally occurring cell death. Moreover, upregulation of actin-related protein 2 (ARP2) in RPE and puerarin treated brain neurons suggest that RPE and puerarin induced synaptic plasticity might be associated, at least in part, with ARP2-mediated actin-dependent regulation of spinogenesis.

CONCLUSIONS

Our findings indicate that RPE and puerarin might play a substantial role in the morphological and functional maturation of brain neurons and suggest that RPE and puerarin are potentially valuable preventative therapeutics for memory-related nervous disorders.

Effect of cortex mori on pharmacokinetic profiles of main isoflavonoids from pueraria lobata in rat plasma

ETHNOPHARMACOLOGICAL RELEVANCE

Radix pueraria (the root of pueraria lobata (Wild.) Ohwi.), which contains a class of isoflavonoids as the main active components, as well as cortex mori (the root bark of Morus alba L), which contains abundant active alkaloids, have been employed for the treatment of diabetes in traditional Chinese medicine for centuries. In previous studies, pharmacodynamic synergistic reactions have been observed in compatible application of pueraria lobata isoflavonoids extracts (PLF) and cortex mori alkaloids extracts (CME) for inhibiting α-glycosidase activity. It has also been demonstrated that PLF can effectively slow down the absorption of active alkaloid from CME, so as to produce a higher effective concentration in small intestine for depressing the elevation of postprandial blood glucose through inhibiting α-glycosidase activity.

AIM OF THE STUDY

In this study, the hypoglycemic effect of PLF, CME or CME-PLF mixture (the mixture of CME and PLF at a ratio of 1:6.3) was further evaluated through in vivo glucose tolerance studies. And the effect of CME on pharmacokinetic profiles of main isoflavonoids from PLF in rat plasma was investigated to further underlie compatibility mechanism of the two herbs.

MATERIALS AND METHODS

Four groups of rats received an oral dose of starch solution alone or simultaneously with drugs by gavage feeding. The blood samples were collected to determine glucose concentrations by glucose oxidase method. In addition, another two groups of rats were orally administered with PLF or CME-PLF. The plasma samples were collected and assayed using an LC/MS/MS method for comparatively pharmacokinetic studies of five main isoflavonoids.

RESULTS

For starch loading, co-administration of CME-PLF resulted in more potent inhibition effects on glucose responses compared to those by CME or PLF in rat. The isoflavonoids from PLF were rapidly absorbed, presenting similarly low concentrations in plasma. When CME was added, the C_max and AUC of all the five isoflavonoids were increased. A phenomenon of double peaks was found for all analysts. The elimination rates of all the detected isoflavonoids were also slowed down with extension of t_1/2. CONCLUSIONS: CME has been found to increase the absorption and delay the elimination of main isoflavonoids from PLF, which might result in higher concentrations of circulating active compounds for anti diabetes.

Brain Pharmacokinetics and the Pharmacological Effects on Striatal Neurotransmitter Levels of Pueraria lobata Isoflavonoids in Rat

Isoflavonoids are putatively active components of Pueraria lobata and has been demonstrated prominent neuro-protection effect against cerebrovascular disorders, hypertension or Parkinson's disease (PD). However, the molecular basis for the beneficial effect of Pueraria lobata on nervous systems has not been well revealed. The present study aims to assess striatum exposure to main active isoflavonoids and changes of striatal extracellular neurotransmitters levels in rat brain after intravenous administration of Pueraria lobata isoflavonoids extracts (PLF), to further elucidate its' substantial bases for neuro activities. Fifteen rats were divided into 3 groups (five rats in each group) to receive a dose of PLF at 80 or 160 mg/kg or normal saline (vehicle), respectively. An LC-MS/MS method was employed to determine the concentrations of five main isoflavonoids and multiple neurotransmitters in microdialysate from striatal extracellular fluid (ECF) of the rats. The exposed quantities of puerarin (PU), 3′-methoxypuerarin (MPU), daidzein-8-C-apiosyl-(1-6)-glucoside (DAC), and 3′-hydroxypuerarin (HPU) in striatum were dose-dependent. The content of daidzein (DAZ) was too low to be detected in all dialysate samples through the experiment. Optimal dose PLF (80 mg/kg) promoted DA metabolism and inhibited 5-HT metabolism. No obvious change in the level of GLu was determined. The concentration of GABA presented a temporary decline firstly and then a gradual uptrend followed by a further downtrend. Higher dose (160 mg/kg) PLF could enhance the metabolism of both DA and 5-HT, and lower the extracellular level of GLu, without changing GABA concentrations, which might result in alleviation on excitatory toxicity under conditions, such as ischemia. The results infer that different dose of PLF should be chosen to achieve appropriate neurochemical modulation effects under conditions, such as hypertension or ischemia/stroke. These findings may significantly contribute to a better understanding of the neuroprotective effect of Pueraria lobata and provide new insights into its application toward neuro-degenerative diseases in the future.

Extraction Methods for the Isolation of Isoflavonoids from Plant Material

The purpose of this review is to describe and compare selected traditional and modern extraction methods employed in the isolation of isoflavonoids from plants. Conventional methods such as maceration, percolation, or Soxhlet extraction are still frequently used in phytochemical analysis. Despite their flexibility, traditional extraction techniques have significant drawbacks, including the need for a significant investment of time, energy, and starting material, and a requirement for large amounts of potentially toxic solvents. Moreover, these techniques are difficult to automate, produce considerable amount of waste and pose a risk of degradation of thermolabile compounds. Modern extraction methods, such as: ultrasound-assisted extraction, microwave-assisted extraction, accelerated solvent extraction, supercritical fluid extraction, and negative pressure cavitation extraction, can be regarded as remedies for the aforementioned problems. This manuscript discusses the use of the most relevant extraction techniques in the process of isolation of isoflavonoids, secondary metabolites that have been found to have a plethora of biological and pharmacological activities.

Interaction of Plant Extracts with Central Nervous System Receptors

Background: Plant extracts have been used in traditional medicine for the treatment of various maladies including neurological diseases. Several central nervous system receptors have been demonstrated to interact with plant extracts and components affecting the pharmacology and thereby potentially playing a role in human disease and treatment. For instance, extracts from Hypericum perforatum (St. John’s wort) targeted several CNS receptors. Similarly, extracts from Piper nigrum, Stephania cambodica, and Styphnolobium japonicum exerted inhibition of agonist-induced activity of the human neurokinin-1 receptor. Methods: Different methods have been established for receptor binding and functional assays based on radioactive and fluorescence-labeled ligands in cell lines and primary cell cultures. Behavioral studies of the effect of plant extracts have been conducted in rodents. Plant extracts have further been subjected to mood and cognition studies in humans. Results: Mechanisms of action at molecular and cellular levels have been elucidated for medicinal plants in support of standardization of herbal products and identification of active extract compounds. In several studies, plant extracts demonstrated affinity to a number of CNS receptors in parallel indicating the complexity of this interaction. In vivo studies showed modifications of CNS receptor affinity and behavioral responses in animal models after treatment with medicinal herbs. Certain plant extracts demonstrated neuroprotection and enhanced cognitive performance, respectively, when evaluated in humans. Noteworthy, the penetration of plant extracts and their protective effect on the blood-brain-barrier are discussed. Conclusion: The affinity of plant extracts and their isolated compounds for CNS receptors indicates an important role for medicinal plants in the treatment of neurological disorders. Moreover, studies in animal and human models have confirmed a scientific basis for the application of medicinal herbs. However, additional investigations related to plant extracts and their isolated compounds, as well as their application in animal models and the conducting of clinical trials, are required.

Recent advances in pharmacokinetics approach for herbal medicine

Traditional Chinese Medicine (TCM), an indispensable part of herbal medicine, has been used for treating many diseases and/or symptoms for thousands of years.