Human UDP-glucuronosyltransferase 1As catalyze aristolochic acid D O-glucuronidation to form a lesser nephrotoxic glucuronide.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochic acids (AAs) are naturally occurring nitro phenanthrene carboxylic acids primarily found in plants of the Aristolochiaceae family. Aristolochic acid D (AAD) is a major constituent in the roots and rhizomes of the Chinese herb Xixin (the roots and rhizomes of Asarum heterotropoides F. Schmidt), which is a key material for preparing a suite of marketed Chinese medicines. Structurally, AAD is nearly identical to the nephrotoxic aristolochic acid I (AAI), with an additional phenolic group at the C-6 site. Although the nephrotoxicity and metabolic pathways of AAI have been well-investigated, the metabolic pathway(s) of AAD in humans and the influence of AAD metabolism on its nephrotoxicity has not been investigated yet. AIM OF THE STUDY: To identify the major metabolites of AAD in human tissues and to characterize AAD O-glucuronidation kinetics in different enzyme sources, as well as to explore the influence of AAD O-glucuronidation on its nephrotoxicity. MATERIALS AND METHODS: The O-glucuronide of AAD was biosynthesized and its chemical structure was fully characterized by both 1H-NMR and 13C-NMR. Reaction phenotyping assays, chemical inhibition assays, and enzyme kinetics analyses were conducted to assess the crucial enzymes involved in AAD O-glucuronidation in humans. Docking simulations were performed to mimic the catalytic conformations of AAD in human UDP-glucuronosyltransferases (UGTs), while the predicted binding energies and distances between the deprotonated C-6 phenolic group of AAD and the glucuronyl moiety of UDPGA in each tested human UGT isoenzyme were measured. The mitochondrial membrane potentials (MMP) and reactive oxygen species (ROS) levels in HK-2 cells treated with either AAI, or AAD, or AAD O-glucuronide were tested, to elucidate the impact of O-glucuronidation on the nephrotoxicity of AAD. RESULTS: AAD could be rapidly metabolized in human liver and intestinal microsomes (HLM and HIM, respectively) to form a mono-glucuronide, which was purified and fully characterized as AAD-6-O-ß-D-glucuronide (AADG) by NMR. UGT1A1 was the predominant enzyme responsible for AAD-6-O-glucuronidation, while UGT1A9 contributed to a lesser extent. AAD-6-O-glucuronidation in HLM, HIM, UGT1A1 and UGT1A9 followed Michaelis-Menten kinetics, with the Km values of 4.27 µM, 9.05 µM, 3.87 µM, and 7.00 µM, respectively. Docking simulations suggested that AAD was accessible to the catalytic cavity of UGT1A1 or UGT1A9 and formed catalytic conformations. Further investigations showed that both AAI and AAD could trigger the elevated intracellular ROS levels and induce mitochondrial dysfunction and in HK-2 cells, but AADG was hardly to trigger ROS accumulation and mitochondrial dysfunction. CONCLUSION: Collectively, UGT1A-catalyzed AAD 6-O-glucuronidation represents a crucial detoxification pathway of this naturally occurring AAI analogs in humans, which is very different from that of AAI.

[Development progress of stationary phase for supercritical fluid chromatography and related application in natural products].

Supercritical fluid chromatography (SFC) is an environment-friendly and efficient column chromatography technology that was developed to expand the application range of high performance liquid chromatography (HPLC) using a supercritical fluid as the mobile phase. A supercritical fluid has a temperature and pressure that are above the critical values as well as relatively dynamic characteristics that are between those of a gas and liquid. Supercritical fluids combine the advantages of high solubility and diffusion, as their diffusion and viscosity coefficients are equivalent to those of a gas, while maintaining a density that is comparable with that of a liquid. Owing to the remarkable compressibility of supercritical fluids, analyte retention in SFC is significantly influenced by the density of the mobile phase. Thus, the column temperature and back pressure are crucial variables that regulate analyte retention in SFC. Increasing the back pressure can increase the density and solubility of the mobile phase, leading to reductions in retention time. The column temperature can affect selectivity and retention, and the degree to which different analytes are affected by this property varies. On the one hand, increasing the temperature reduces the density of the mobile phase, thereby extending the retention time of the analytes; on the other hand, it can also increase the energy of molecules, leading to a shorter retention time of the analyte on the stationary phase. CO2, the most widely employed supercritical fluid to date, presents moderate critical conditions and, more importantly, is miscible with a variety of polar organic solvents, including small quantities of water. In comparison with the mobile phases used in normal-phase liquid chromatography (NPLC) and reversed-phase liquid chromatography (RPLC), the mobile phase for SFC has a polarity that can be extended over a wide range on account of its extensive miscibility. The compatibility of the mobile phase determines the diversity of the stationary phase. Nearly all stationary phases for HPLC, including the nonpolar stationary phases commonly used for RPLC and the polar stationary phases commonly used for NPLC, can be applied to SFC. Because all stationary phases can use the same mobile-phase composition, chromatographic columns with completely different polarities can be employed in SFC. The selectivity of SFC has been effectively expanded, and the technique can be used for the separation of diverse analytes ranging from lipid compounds to polar compounds such as flavonoids, saponins, and peptides. The choice of stationary phase has a great impact on the separation effect of analytes in SFC. As new stationary phases for HPLC are constantly investigated, specialized stationary phases for SFC have also been continuously developed. Researchers have discovered that polar stationary phases containing nitrogen heterocycles such as 2-EP and PIC are highly suitable for SFC because they can effectively manage the peak shape of alkaline compounds and provide good selectivity in separating acidic and neutral compounds.The development of various stationary phases has promoted the applications of SFC in numerous fields such as pharmaceuticals, food production, environmental protection, and natural products. In particular, natural products have specific active skeletons, multiple active groups, and excellent biological activity; hence, these materials can provide many new opportunities for the discovery of novel drugs. According to reports, compounds related to natural products account for 80% of all commercial drugs. However, natural products are among the most challenging compounds to separate because of their complex composition and low concentration of active ingredients. Thus, superior chromatographic methods are required to enable the qualitative and quantitative analysis of natural products. Thanks to technological improvements and a good theoretical framework, the benefits of SFC are gradually becoming more apparent, and its use in separating natural products is expanding. Indeed, in the past 50 years, SFC has developed into a widely used and efficient separation technology. This article provides a brief overview of the characteristics, advantages, and development process of SFC; reviews the available SFC stationary phases and their applications in natural products over the last decade; and discusses prospects on the future development of SFC.

[Monoterpenoids from Paeoniae Radix Rubra based on UPLC-Q-TOF-MS].

The ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used to conduct the qualitative analysis of the monoterpene chemical components from Paeoniae Radix Rubra. Gradient elution was performed on C_(18) HD(2.1 mm×100 mm, 2.5 µm) column with a mobile phase of 0.1% formic acid(A) and acetonitrile(B). The flow rate was 0.4 mL·min~(-1) and the column temperature was 30 ℃. MS analysis was conducted in both positive and negative ionization modes using electrospray ionization(ESI) source. Qualitative Analysis 10.0 was used for data processing. The identification of chemical components was realized by the combination of standard compounds, fragmentation patterns, and mass spectra data reported in the literature. Forty-one monoterpenoids in Paeoniae Radix Rubra extract were identified. Among them, 8 compounds were reported in Paeoniae Radix Rubra for the first time and 1 was presumed to be the new compound 5″-O-methyl-galloylpaeoniflorin or its positional isomer. The method in this study realizes the rapid identification of monoterpenoids from Paeoniae Radix Rubra and provides a material and scientific basis for quality control and further study on the pharmaceutical effect of Paeoniae Radix Rubra.

[Investigation of the chemical components of Ciwujia injection using ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry].

Ciwujia injection is commonly used to treat cerebrovascular and central nervous system diseases in clinical practice. It can significantly improve blood lipid levels and endothelial cell function in patients with acute cerebral infarction and promote the proliferation of neural stem cells in cerebral ischemic brain tissues. The injection has also been reported to have good curative effects on cerebrovascular diseases, such as hypertension and cerebral infarction. At present, the material basis of Ciwujia injection remains incompletely understood, and only two studies have reported dozens of components, which were determined using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF MS). Unfortunately, the lack of research on this injection restricts the in-depth study of its therapeutic mechanism.In the present study, a qualitative method based on ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry (UHPLC-Q/Orbitrap HRMS) was developed to analyze the chemical components of Ciwujia injection. Separation was performed on a BEH Shield RP18 column (100 mm×2.1 mm, 1.7 µm) using 0.1% formic acid aqueous solution (A) and acetonitrile (B) as the mobile phases, and gradient elution was performed as follows: 0-2 min, 0%B; 2-4 min, 0%B-5%B; 4-15 min, 5%B-20%B; 15-15.1 min, 20%B-90%B; 15.1-17 min, 90%B. The flow rate and column temperature were set to 0.4 mL/min and 30 ℃ respectively. MS1 and MS2 data were acquired in both positive- and negative-ion modes using a mass spectrometer equipped with an HESI source. For data post-processing, a self-built library including component names, molecular formulas, and chemical structures was established by collecting information on the isolated chemical compounds of Acanthopanax senticosus. The chemical components of the injection were identified by comparison with standard compounds or MS2 data in commercial databases or literature based on precise relative molecular mass and fragment ion information. The fragmentation patterns were also considered. For example, the MS2 data of 3-caffeoylquinic acid (chlorogenic acid), 4-caffeoylquinic acid (cryptochlorogenic acid), and 5-caffeoylquinic acid (neochlorogenic acid) were first analyzed. The results indicated that these compounds possessed similar fragmentation behaviors, yielding product ions at m/z 173 and m/z 179 simultaneously. However, the abundance of the product ion at m/z 173 was much higher in 4-caffeoylquinic acid than in 5-caffeoylquinic acid or 3-caffeoylquinic acid, and the fragment signal at m/z 179 was much stronger for 5-caffeoylquinic acid than for 3-caffeoylquinic acid. Four caffeoylquinic acids were identified using a combination of abundance information and retention times. MS2 data in commercial database and literature were also used to identify unknown constituents. For example, compound 88 was successfully identified as possessing a relative molecular mass and neutral losses similar to those of sinapaldehyde using the database, and compound 80 was identified as salvadoraside because its molecular and fragmentation behaviors were consistent with those reported in the literature. A total of 102 constituents, including 62 phenylpropanoids, 23 organic acids, 7 nucleosides, 1 iridoid, and 9 other compounds, were identified. The phenylpropanoids can be further classified as phenylpropionic acids, phenylpropanols, benzenepropanals, coumarins, and lignans. Among the detected compounds, 16 compounds were confirmed using reference compounds and 65 compounds were identified in Ciwujia injection for the first time. This study is the first to report the feasibility of using the UHPLC-Q/Orbitrap HRMS method to quickly and comprehensively analyze the chemical components of Ciwujia injection. The 27 newly discovered phenylpropanoids provide further material basis for the clinical treatment of neurological diseases and new research targets for the in-depth elucidation of the pharmacodynamic mechanism of Ciwujia injection and its related preparations.

Preparation and identification of isoquinoline alkaloids with ATP citrate lyase inhibitory activity from Dactylicapnos scandens.

Three new isoquinoline alkaloids including a morphine derivative (1), two aporphine alkaloids (2-3), together with five known alkaloids (4-8) were obtained from the extract of Dactylicapnos scandens (D.Don) Hutch. (D. scandens). Their structures and absolute configurations were elucidated by extensive spectroscopic data analysis including HRESIMS, NMR and electronic circular dichroism (ECD) and ECD calculation. Compounds 1-8 were evaluated for ATP Citrate Lyase (ACLY) inhibitory activity through an enzymatic assay. Among them, 2 and 3 showed the high ACLY inhibitory activity with an IC50 value of 10.48 ± 1.59 and 10.89 ± 4.89 µM.

Updated clinical and glycomic features of mannosyl-oligosaccharide glucosidase deficiency: Two case reports.

BACKGROUND: Mannosyl-oligosaccharide glucosidase (MOGS) deficiency is an extremely rare type of congenital disorder of glycosylation (CDG), with only 12 reported cases. Its clinical, genetic, and glycomic features are still expanding. Our aim is to update the novel clinical and glycosylation features of 2 previously reported patients with MOGS-CDG. CASE SUMMARY: We collected comprehensive clinical information, and conducted the immunoglobulin G1 glycosylation assay using nano-electrospray ionization source quadruple time-of-flight mass spectrometry. Novel dysmorphic features included an enlarged tongue, forwardly rotated earlobes, a birth mark, overlapped toes, and abnormal fat distribution. Novel imaging findings included pericardial effusion, a deep interarytenoid groove, mild congenital subglottic stenosis, and laryngomalacia. Novel laboratory findings included peripheral leukocytosis with neutrophil predominance, elevated C-reactive protein and creatine kinase, dyslipidemia, coagulopathy, complement 3 and complement 4 deficiencies, decreased proportions of T lymphocytes and natural killer cells, and increased serum interleukin 6. Glycosylation studies showed a significant increase of hypermannosylated glycopeptides (Glc3Man7GlcNAc2/N2H10 and Man5GlcNAc2/N2H5) and hypersialylated glycopeptides. A compensatory glycosylation pathway leading to an increase in Man5GlcNAc2/N2H5 was indicated with the glycosylation profile. CONCLUSION: We confirmed abnormal glycomics in 1 patient, expanding the clinical and glycomic spectrum of MOGS-CDG. We also postulated a compensatory glycosylation pathway, leading to a possible serum biomarker for future diagnosis.

Inhibition of astrocytic DRD2 suppresses CNS inflammation in an animal model of multiple sclerosis.

Astrocyte activation is associated with progressive inflammatory demyelination in multiple sclerosis (MS). The molecular mechanisms underlying astrocyte activation remain incompletely understood. Recent studies have suggested that classical neurotransmitter receptors are implicated in the modulation of brain innate immunity. We investigated the role of dopamine signaling in the process of astrocyte activation. Here, we show the upregulation of dopamine D2 receptor (DRD2) in reactive astrocytes in MS brain and noncanonical role of astrocytic DRD2 in MS pathogenesis. Mice deficient in astrocytic Drd2 exhibit a remarkable suppression of reactive astrocytes and amelioration of experimental autoimmune encephalomyelitis (EAE). Mechanistically, DRD2 regulates the expression of 6-pyruvoyl-tetrahydropterin synthase, which modulates NF-κB activity through protein kinase C-δ. Pharmacological blockade of astrocytic DRD2 with a DRD2 antagonist dehydrocorybulbine remarkably inhibits the inflammatory response in mice lacking neuronal Drd2. Together, our findings reveal previously an uncharted role for DRD2 in astrocyte activation during EAE-associated CNS inflammation. Its therapeutic inhibition may provide a potent lever to alleviate autoimmune diseases.

Menisperdaurines A-W, structurally diverse isoquinoline alkaloids from Menispermum dauricum and their dopamine D1 receptor activities.

A total of 33 structurally diverse isoquinoline alkaloids were isolated from the rhizomes of Menispermum dauricum, including seventeen benzylisoquinoline analogues (menisperdaurines A-Q, 1-17), five protoberberine analogues (menisperdaurines R-V, 18-22), a quaternary phenanthrene alkaloid (menisperdaurine W, 23) and ten known compounds (24-33). Compound structures, including absolute configurations, were determined by extensive spectroscopic methods, quantum chemical calculations of chemical shifts, and calculated and experimental electronic circular dichroism (ECD) data. Compounds 1-5 were glycosidic benzylisoquinolines with glucose moieties attached at the C-12 position. Compound 8 was the first example that was isolated from the rhizomes of Menispermum dauricum, benzylisoquinoline and an aromatic unit connected by a sugar bridge. Compounds were evaluated for their inhibitory effects on the dopamine D1 receptor. Compounds 1, 8, 21, 24 and 29 showed potent D1 antagonistic activities, with IC50 values ranging from 1.0 to 4.5 µM. Compound 1 exhibited the highest antagonistic activity with an IC50 value of 1.0 ± 0.2 µM.

Corybungines A-K: Isoquinoline alkaloids from Corydalis bungeana with dopamine D2 receptor activity.

Eleven undescribed isoquinoline alkaloids corybungines A-K including a protoberberine-type alkaloid, an isoquinoline alkaloid with a unique 6-norprotoberberine skeleton, one 13,14-seco-protoberberine-type alkaloid, two 1a,14-seco-protoberberine-type alkaloids with a 4-(hydroxymethyl)phenoxy moiety and six aporphine alkaloids, together with seven known alkaloids, have been isolated from the whole herb extract of Corydalis bungeana Turcz. Their structures and absolute configurations were elucidated based on an analysis of spectroscopic data and electronic circular dichroism (ECD) spectra. (R)-stephanine displayed high antagonistic activity against the dopamine D2 receptor with an IC50 value of 0.85 ± 0.09 µM in CHO-D2 cells. Additionally, corybungines D, F, H, (R)-roemerine, (R)-vireakine and (R)-tuduranine showed moderate D2 antagonism (IC50 5.20-26.07 µM). The preliminary structure-activity relationships (SARs) of aporphine alkaloids were discussed.

Structurally diverse isoquinoline and amide alkaloids with dopamine D2 receptor antagonism from Corydalis bungeana.

Four new isoquinoline alkaloids including a benzophenanthridine alkaloid (1), a morphine derivative (2), a narceine-type alkaloid (3) and a simple isoquinoline alkaloid (4), a new amide alkaloid (5) and a new phthalic acid derivative (6), together with eleven known alkaloids (7-17) were obtained from the whole herbs extract of Corydalis bungeana Turcz. Their structures and absolute configurations were elucidated by extensive spectroscopic data analysis including HRESIMS, NMR and electronic circular dichroism (ECD) and ECD calculation. Compounds 1-17 were evaluated for dopamine D2 receptor activity in CHO-D2 cells. Among them, 16 showed the highest antagonistic activity on the D2 receptor with an IC50 value of 2.04 ± 0.01 µM. Compounds 14 and 15 exhibited moderate antagonism with IC50 values of 13.66 ± 2.28 and 31.72 ± 2.52 µM, respectively.

Comprehensive profiling and characterization of the absorbed components and metabolites in mice serum and tissues following oral administration of Qing-Fei-Pai-Du decoction by UHPLC-Q-Exactive-Orbitrap HRMS.

Qing-Fei-Pai-Du decoction (QFPDD) is a Chinese medicine compound formula recommended for combating corona virus disease 2019 (COVID-19) by National Health Commission of the People's Republic of China. The latest clinical study showed that early treatment with QFPDD was associated with favorable outcomes for patient recovery, viral shedding, hospital stay, and course of the disease. However, the effective constituents of QFPDD remain unclear. In this study, an UHPLC-Q-Orbitrap HRMS based method was developed to identify the chemical constituents in QFPDD and the absorbed prototypes as well as the metabolites in mice serum and tissues following oral administration of QFPDD. A total of 405 chemicals, including 40 kinds of alkaloids, 162 kinds of flavonoids, 44 kinds of organic acids, 71 kinds of triterpene saponins and 88 kinds of other compounds in the water extract of QFPDD were tentatively identified via comparison with the retention times and MS/MS spectra of the standards or refereed by literature. With the help of the standards and in vitro metabolites, 195 chemical components (including 104 prototypes and 91 metabolites) were identified in mice serum after oral administration of QFPDD. In addition, 165, 177, 112, 120, 44, 53 constituents were identified in the lung, liver, heart, kidney, brain, and spleen of QFPDD-treated mice, respectively. These findings provided key information and guidance for further investigation on the pharmacologically active substances and clinical applications of QFPDD.

Inhibition of drug-metabolizing enzymes by Qingfei Paidu decoction: Implication of herb-drug interactions in COVID-19 pharmacotherapy.

Corona Virus Disease 2019 (COVID-19) has spread all over the world and brings significantly negative effects on human health. To fight against COVID-19 in a more efficient way, drug-drug or drug-herb combinations are frequently used in clinical settings. The concomitant use of multiple medications may trigger clinically relevant drug/herb-drug interactions. This study aims to assay the inhibitory potentials of Qingfei Paidu decoction (QPD, a Chinese medicine compound formula recommended for combating COVID-19 in China) against human drug-metabolizing enzymes and to assess the pharmacokinetic interactions in vivo. The results demonstrated that QPD dose-dependently inhibited CYPs1A, 2A6, 2C8, 2C9, 2C19, 2D6 and 2E1 but inhibited CYP3A in a time- and NADPH-dependent manner. In vivo test showed that QPD prolonged the half-life of lopinavir (a CYP3A substrate-drug) by 1.40-fold and increased the AUC of lopinavir by 2.04-fold, when QPD (6 g/kg) was co-administrated with lopinavir (160 mg/kg) to rats. Further investigation revealed that Fructus Aurantii Immaturus (Zhishi) in QPD caused significant loss of CYP3A activity in NADPH-generating system. Collectively, our findings revealed that QPD potently inactivated CYP3A and significantly modulated the pharmacokinetics of CYP3A substrate-drugs, which would be very helpful for the patients and clinicians to avoid potential drug-interaction risks in COVID-19 treatment.

Scocycamides, a Pair of Macrocyclic Dicaffeoylspermidines with Butyrylcholinesterase Inhibition and Antioxidation Activity from the Roots of Scopolia tangutica.

A pair of new macrocyclic spermidine alkaloids, (+)-(S)-scocycamide and (-)-(R)-scocycamide, were isolated from the roots of Scopolia tangutica. Their structures were established by extensive spectroscopic data, electronic circular dichroism analyses, and chemical synthesis. They featured a unique 6/18 fused bicyclic framework with spermidine and catechol units, representing a new subtype of natural spermidine alkaloids. A plausible biosynthetic pathway was also proposed. They inhibited butyrylcholinesterase and exhibited antioxidant capacity, suggesting beneficial constituents against Alzheimer's disease and oxidation.

Schisantherin A attenuates ischemia/reperfusion-induced neuronal injury in rats via regulation of TLR4 and C5aR1 signaling pathways.

Toll-like receptor 4 (TLR4) and C5aR1 (CD88) have been recognized as potential therapeutic targets for the reduction of inflammation and secondary damage and improvement of outcome after ischemia and reperfusion (I/R). The inflammatory responses which induce cell apoptosis and necrosis after I/R brain injury lead to a limited process of neural repair. To further comprehend how these targets function in I/R state, we investigated the pathological changes and TLR4 and C5aR1 signaling pathways in vitro and in vivo models of I/R brain injury in this study. Meanwhile, we explored the roles of schisantherin A on I/R brain injury, and whether it exerted neuroprotective effects by regulating the TLR4 and C5aR1 signaling pathways or not. The results showed that schisantherin A significantly reduced the neuronal apoptosis induced by oxygen and glucose deprivation and reperfusion (OGD/R) injury in primary culture of rat cortical neurons. Also, schisantherin A alleviated neurological deficits, reduced infarct volume, attenuated oxidation stress, inflammation and apoptosis in ischemic parietal cortex of rats after middle cerebral artery occlusion and reperfusion (MCAO/R) injury. Moreover, the activated TLR4 and C5aR1 signaling pathways were inhibited by schisantherin A treatment. In conclusion, TLR4 and C5aR1 played a vital role during I/R brain injury in rats, and schisantherin A exhibited neuroprotective effects by TLR4 and C5aR1 signaling pathways. These findings also provided new insights that would aid in elucidating the effect of schisantherin A against cerebral I/R and support the development of schisantherin A as a potential treatment for ischemic stroke.

Isoquercetin Ameliorates Cerebral Impairment in Focal Ischemia Through Anti-Oxidative, Anti-Inflammatory, and Anti-Apoptotic Effects in Primary Culture of Rat Hippocampal Neurons and Hippocampal CA1 Region of Rats.

Ischemic stroke is a major disability and cause of death worldwide due to its narrow therapeutic time window. Neuroprotective agent is a promising strategy to salvage acutely ischemic brain tissue and extend the therapeutic time window for stroke treatment. In this study, we aimed to evaluate the neuroprotective effects of isoquercetin in (1) primary culture of rat hippocampal neurons exposure on oxygen and glucose deprivation and reperfusion (OGD/R) injury and (2) rats subjected to transient middle cerebral artery occlusion and reperfusion (MCAO/R) injury. The results showed that isoquercetin post-treatment reduced the infarct size, number of apoptotic cells, oxidative stress, and inflammatory response after ischemia and reperfusion injury. The underlying mechanism study indicated that the neuroprotective effects of isoquercetin were elicited via suppressing the activation of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) and caspase-1; the phosphorylation of ERK1/2, JNK1/2, and p38 mitogen-activated protein kinase (MAPK); and the secretion of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and IL-6. In addition, isoquercetin also effectively alleviated hippocampus neuron apoptosis by regulation of cyclic AMP responsive element-binding protein (CREB), Bax, Bcl-2, and caspase-3. Our report provided new considerations into the therapeutic action and the underlying mechanisms of isoquercetin to improve brain injury in individuals who have suffered from ischemic stroke. As a potent anti-inflammatory and anti-oxidative compound with neuroprotective capacities, the beneficial effects of isoquercetin when used to treat ischemic stroke and related diseases in humans warrant further studies.

Identification and characterization of naturally occurring inhibitors against human carboxylesterase 2 in White Mulberry Root-bark.

White Mulberry Root-bark (WMR) is an edible Chinese herbal used for the treatment of inflammation, nephritis and asthma. This study aimed to investigate the inhibitory effects of ethanol extract from WMR against human carboxylesterase 2 (hCE2), as well as to identity and character natural hCE2 inhibitors in this herbal. Our results demonstrated that the ethanol extract of WMR displayed potent inhibitory effects against hCE2, while three major bioactive constitutes in WMR were identified on the basis of LC fingerprinting combined with activity-based screening of LC fractions. Three bioactive compounds including SD, KG and SC were efficiently identified by comparison of LC retention times, UV and MS spectral data, with the help of authentic standards. The inhibition potentials and inhibition types of these natural compounds against hCE2 were further investigated in human liver microsomes. The results demonstrated that these bioactive compounds are potent non-competitive inhibitors against hCE2, with the Ki values ranging from 0.76µM to 1.09µM. All these findings suggested that three abundant natural compounds in WMR displayed potent inhibitory effects against hCE2, which could be used as lead compounds to develop more potent hCE2 inhibitors for the alleviation of hCE2-mediated severe delayed-onset diarrhea.

Neuroprotective effect of schizandrin A on oxygen and glucose deprivation/reperfusion-induced cell injury in primary culture of rat cortical neurons

Brain ischemia appears to be associated with innate immunity. Recent reports showed that C3a and C5a, as potent targets, might protect against ischemia induced cell death. In traditional Chinese medicine, the fruit of Schizandra chinesis Baill (Fructus schizandrae) has been widely used as a tonic. In the present study, we sought to evaluate the neuroprotective effects of schizandrin A, a composition of S. chinesis Baill, against oxygen and glucose deprivation followed by reperfusion (OGD/R)-induced cell death in primary culture of rat cortical neurons, and to test whether C3a and C5a affected cortical neuron recovery from ischemic injury after schizandrin A treatment. The results showed that schizandrin A significantly reduced cell apoptosis and necrosis, increased cell survival, and decreased intracellular calcium concentration ([Ca2+]i) and lactate dehydrogenase (LDH) release in primary culture of rat cortical neurons after OGD/R. Mechanism studies suggested that the modulation of extracellular-regulated kinase (ERK), c-Jun NH2-terminal kinases (JNK), and p38, as well as caspase-3 activity played an important role on the progress of neuronal apoptosis. C5aR participated in the neuroprotective effect of schizandrin A in primary culture of rat cortical neurons after OGD/R. Our findings suggested that schizandrin A might act as a candidate therapeutic target drug used for brain ischemia and related diseases

Neuroprotective effect of schizandrin A on oxygen and glucose deprivation/reperfusion-induced cell injury in primary culture of rat cortical neurons.

Brain ischemia appears to be associated with innate immunity. Recent reports showed that C3a and C5a, as potent targets, might protect against ischemia induced cell death. In traditional Chinese medicine, the fruit of Schizandra chinesis Baill (Fructus schizandrae) has been widely used as a tonic. In the present study, we sought to evaluate the neuroprotective effects of schizandrin A, a composition of S. chinesis Baill, against oxygen and glucose deprivation followed by reperfusion (OGD/R)-induced cell death in primary culture of rat cortical neurons, and to test whether C3a and C5a affected cortical neuron recovery from ischemic injury after schizandrin A treatment. The results showed that schizandrin A significantly reduced cell apoptosis and necrosis, increased cell survival, and decreased intracellular calcium concentration ([Ca(2+)]i) and lactate dehydrogenase (LDH) release in primary culture of rat cortical neurons after OGD/R. Mechanism studies suggested that the modulation of extracellular-regulated kinase (ERK), c-Jun NH2-terminal kinases (JNK), and p38, as well as caspase-3 activity played an important role on the progress of neuronal apoptosis. C5aR participated in the neuroprotective effect of schizandrin A in primary culture of rat cortical neurons after OGD/R. Our findings suggested that schizandrin A might act as a candidate therapeutic target drug used for brain ischemia and related diseases.

Mulberroside A protects against ischemic impairment in primary culture of rat cortical neurons after oxygen-glucose deprivation followed by reperfusion.

Mulberroside A is a natural polyhydroxylated stilbene compound present at relatively high abundance in the roots and twigs of Morus alba L. It is known for its nephroprotective, hypoglycemic, and antidiabetic effects. Because its metabolite, oxyresveratrol, possessed purported anti-inflammatory and neuroprotective effects, we proposed that mulberroside A may elicit neuroprotective effects that can be used in the treatment of brain ischemic injury. Therefore, we decided to investigate the pharmacological properties of mulberroside A in primary culture of rat cortical neurons after oxygen-glucose deprivation followed by reperfusion (OGD/R), evaluating its ability to counteract the hypoxia-ischemia impairment. The results showed that mulberroside A elicited neuroprotective effects comparable to nimodipine. The mechanistic studies showed that mulberroside A decreased the expressions of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6 and inhibited the activation of NALP3, caspase-1, and nuclear factor-κB and the phosphorylation of extracellular signal-regulated protein kinases, the c-Jun N-terminal kinase, and p38, exhibiting anti-inflammatory antiapoptotic effects. Our results also further demonstrate that the proinflammatory cytokines of IL-1ß, IL-6, and TNF-α are promising targets for treatment of cerebral ischemic injury. Although further investigation is required for its development, all of these findings led us to speculate that mulberroside A is a candidate for the treatment of ischemic stroke, which would act as a multifactorial neuroprotectant.