Development and validation of a simple and rapid UPLC-MS/MS method for loganin and its application in pharmacokinetic and tissue distribution studies

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis Sieb. et Zucc. is a medicinal and edible homolog in traditional Chinese medicine. Loganin, an iridoid glycoside, is one of the main active components of Cornus officinalis Sieb. et Zucc. Loganin has been demonstrated to improve depression-like behavior and may be a potential antidepressant candidate. However, the pharmacokinetic characteristics and tissue distribution of loganin, especially in the brain region, are still unclear.

AIM OF THE STUDY

This study aims to investigate the pharmacokinetic characteristics and tissue distribution after oral administration of loganin in rats.

MATERIALS AND METHODS

A simple, rapid and reproducible UPLC-MS/MS method was developed and validated for the determination of loganin in rat plasma and tissues. The samples were prepared by acetonitrile precipitation with chloramphenicol as internal standard (IS). Loganin was separated by gradient elution on ACQUITY UPLC®BEH C18 (2.1 × 50 mm, 1.7 μm) using multiple reactions monitoring (MRM) mode. Concentration-time data was subjected to pharmacokinetic analysis. The pharmacokinetic parameters of loganin in rat plasma were analyzed by compartment model using DAS 2.0 software.

RESULTS

The established UPLC-MS/MS method was accurate and reliable with a good linearity (R2 > 0.99) in the respective concentration range, satisfying the quantitative requirements. This method was successfully used to study the pharmacokinetics and tissue distribution after oral administration of loganin in rats. The peak time (Tmax) of oral administration was about 40 min, and the half-life (t1/2) was about 50 min, indicating that loganin was quickly absorbed and eliminated in rats. Oral bioavailability was 5.50%. The dose correlation results showed that AUC had a poor correlation with dose, while Cmax had a good correlation with dose. In tissues, loganin (35 mg/kg) was highly distributed in the stomach, small intestine, kidney, liver and lung. When the dose was 70 mg/kg, loganin had significant distribution in the cortex.

CONCLUSION

In this study, a simple and sensitive UPLC-MS/MS method was developed and validated for the determination of loganin in rat plasma and tissues. Loganin was absorbed quickly, eliminated quickly, and had low bioavailability. The distribution of loganin in the cortex was higher than that in the hippocampus. We hope that our results can provide a reference for loganin to become a new antidepressant.

Pharmacological activities and therapeutic potential of galangin, a promising natural flavone, in age-related diseases

BACKGROUND

The extension of average life expectancy and the aggravation of population aging have become the inevitable trend of human development. In an aging society, various problems related to medical care for the elderly have become increasingly prominent. However, most of the age-related diseases have the characteristics of multiple diseases at the same time, prone to complications, and atypical clinical manifestations, which bring great difficulties to its treatment. Galangin (3,5,7-trihydroxyflavone) is a natural active compound extracted from the root of Alpinia officinarum Hance (Zingiberaceae). Recently, many studies have shown that galangin has potential advantages in the treatment of neurodegenerative diseases and cardiovascular and cerebrovascular diseases, which are common in the elderly. In addition, it also showed that galangin had prospective activities in the treatment of tumor, diabetes, liver injury, asthma and arthritis.

PURPOSE

This review aims to systematically summarize and discuss the effects and the underlying mechanism of galangin in the treatment of age-related diseases.

METHODS

We searched PubMed, SciFinder, Web of Science and CNKI literature database resources, combined with the keywords "galangin", "neurodegenerative disease", "tumor", "diabetes", "pharmacological activity", "drug combination", "pharmacokinetics", "drug delivery system" and "safety", and comprehensively reviewed the pharmacological activities and mechanism of galangin in treating age-related diseases.

RESULTS

According to the previous studies on galangin, the anti-neurodegenerative activity, cardiovascular and cerebrovascular protective activity, anti-tumor activity, anti-diabetes activity, anti-arthritis activity, hepatoprotective activity and antiasthmatic activity of galangin were discussed, and the related mechanisms were classified and summarized in detail. In addition, the drug combination, pharmacokinetics, drug delivery system and safety of galangin were furtherly discussed.

CONCLUSIONS

This review will provide reference for galangin in the treatment of age-related diseases. Meanwhile, further experimental research and long-term clinical trials are needed to determine the therapeutic safety and efficacy of galangin.

New Rosane Diterpenoids and Their Analogs from Euphorbia ebracteolata Hayata

Phytochemical investigation of the roots of Euphorbia ebracteolata Hayata resulted in the isolation of three new rosane diterpenoids, euphebracteolatins C-E (1-3), along with fourteen known analogs (4-17). Their structures were determined on the basis of extensive spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR. Euphebracteolatin C (1) contains a C-1/C-10 double bond and a keto group at C-7, and euphebracteolatins D and E (2-3) possess an aromatic ring-A in their skeleton. The plausible biogenetic pathways of all the isolates were also proposed. Furthermore, compounds 1 and 9 showed selective cytotoxicity against HepG2 cells with IC₅₀ values of 14.29 and 12.33 μM, respectively, and 2-3 displayed moderate cytotoxicity against three human cancer lines, with IC₅₀ values ranging from 23.69 to 39.25 μM.

The NLRP3 inflammasome in depression: Potential mechanisms and therapies

Increasing evidence suggests that the failure of clinical antidepressants may be related with neuroinflammation. The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome is an intracellular multiprotein complex, and has been considered as a key contributor to the development of neuroinflammation. Inhibition of NLRP3 inflammasome is an effective method for depression treatment. In this review, we summarized current researches highlighting the role of NLRP3 inflammasome in the pathology of depression. Firstly, we discussed NLRP3 inflammasome activation in patients with depression and animal models. Secondly, we outlined the possible mechanisms driving the activation of NLRP3 inflammasome. Thirdly, we discussed the pathogenetic role of NLRP3 inflammasome in depression. Finally, we overviewed the current and potential antidepressants targeting the NLRP3 inflammasome. Overall, the inhibition of NLRP3 inflammasome activation may be a potential therapeutic strategy for inflammation-related depression.

Jolkinolide B: A comprehensive review of its physicochemical properties, analytical methods, synthesis and pharmacological activity

Jolkinolide B is a typical ent-abietane-type diterpenoid, which is first found in Euphorbia jolkini. It is one of the most important active components in many toxic Euphorbia plants. In recent years, jolkinolide B has garnered increasing attention due to its high potent and multiple pharmacological activities. In order to better understand the research status of jolkinolide B, relevant information about jolkinolide B was collected from scientific databases (SciFinder Scholar, PubMed, ACS website, Elsevier, Web of Science, Google Scholar, Science Direct, and CNKI). There are few studies on chemical synthesis and biosynthesis of jolkinolide B. In addition, researchers on the activities of jolkinolide B are mostly concentrated at the cellular level, and there is a lack of research on the mechanism. In this review, the possible applications of jolkinolide B were systematically illustrated for the first time, from plant sources, physicochemical properties, analytical methods, synthesis and pharmacological activities. Jolkinolide B exhibits extensive pharmacological properties, including anticancer, anti-inflammatory, anti-osteoporosis, and anti-tuberculosis activities. Pharmacological activities of jolkinolide B were mainly focused on anticancer and anti-inflammatory activities, and the mechanism of action may be related with inhibition of JAK/STAT pathway, NF-κB pathway and PI3K/Akt/mTOR pathway. In addition, the extraction methods and analytical methods discussed in this review, will facilitate the development of novel herbal products for better healthcare solutions.

Review of the pharmacological effects of astragaloside IV and its autophagic mechanism in association with inflammation

Astragalus membranaceus Bunge, known as Huangqi, has been used to treat various diseases for a long time. Astragaloside IV (AS-IV) is one of the primary active ingredients of the aqueous Huangqi extract. Many experimental models have shown that AS-IV exerts broad beneficial effects on cardiovascular disease, nervous system diseases, lung disease, diabetes, organ injury, kidney disease, and gynaecological diseases. This review demonstrates and summarizes the structure, solubility, pharmacokinetics, toxicity, pharmacological effects, and autophagic mechanism of AS-IV. The autophagic effects are associated with multiple signalling pathways in experimental models, including the PI3KI/Akt/mTOR, PI3K III/Beclin-1/Bcl-2, PI3K/Akt, AMPK/mTOR, PI3K/Akt/mTOR, SIRT1–NF-κB, PI3K/AKT/AS160, and TGF-β/Smad signalling pathways. Based on this evidence, AS-IV could be used as a replacement therapy for treating the multiple diseases referenced above.

Sigma-1 receptor: A potential target for the development of antidepressants

Though a great many of studies on the development of antidepressants for the therapy of major depression disorder (MDD) and the development of antidepressants have been carried out, there still lacks an efficient approach in clinical practice. The involvement of Sigma-1 receptor in the pathological process of MDD has been verified. In this review, recent research focusing on the role of Sigma-1 receptor in the etiology of MDD were summarized. Preclinical studies and clinical trials have found that stress induce the variation of Sigma-1 receptor in the blood, brain and heart. Dysfunction and absence of Sigma-1 receptor result in depressive-like behaviors in rodent animals. Agonists of Sigma-1 receptor show not only antidepressant-like activities but also therapeutical effects in complications of depression. The mechanisms underlying antidepressant-like effects of Sigma-1 receptor may include suppressing neuroinflammation, regulating neurotransmitters, ameliorating brain-derived neurotrophic factor and N-Methyl-D-Aspartate receptor, and alleviating the endoplasmic reticulum stress and mitochondria damage during stress. Therefore, Sigma-1 receptor represents a potential target for antidepressants development.

Cornuside ameliorates cognitive impairments in scopolamine induced AD mice: Involvement of neurotransmitter and oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis Sieb. et Zucc., traditional Chinese medicine, has been widely used in the treatment of dementia. Cornel iridoid glycosides of Cornus officinalis is therapeutic to Alzheimer's disease (AD), while its pharmacodynamic material basis is not clear. Cornuside, an iridoid glycoside extracted from of Cornus officinalis Sieb. et Zucc, might be a potential anti-AD candidate.

AIM OF THE STUDY

Cornuside was evaluated for its effect on scopolamine induced AD mice, and its action mechanisms were explored.

MATERIALS AND METHODS

ICR mice were administered with 1 mg/kg scopolamine intraperitoneally to induce amnesia. The therapeutic effect of cornuside of cognitive function was evaluated via series of behavioral tests, including Morris water maze test, step-through test and step-down test. In addition, specific enzyme reaction tests were used to detect the content of acetylcholine (ACh) and malondialdehyde (MDA), as well as the activities of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), choline acetyltransferase (ChAT), superoxide dismutase (SOD), catalase (CAT), monoamine oxidase (MAO) in the brain. The levels of monoamine neurotransmitters were detected by high performance liquid chromatography-electrochemical detection (HPLC-ECD).

RESULTS

Cornuside ameliorated the spatial memory impairment in Morris water maze test and cognitive disruption in step-through and step-down test. Furthermore, cornuside improved the level of ACh by reducing the activities of AChE and BuChE, and increasing the activity of ChAT in hippocampus. Cornuside also increased the levels of monoamine neurotransmitters by inhibiting MAO activity in hippocampus and cortex. In addition, cornuside attenuated MDA by enhancing the activities of SOD and CAT in hippocampus and cortex.

CONCLUSION

Cornuside improved cognitive dysfunction induced by scopolamine in behavioral tests. The mechanisms of cornuside were further investigated from the aspects of neurotransmitters and oxidative stress. Cornuside could inhibit oxidative stress and neurotransmitter hydrolases, increase ACh and monoamine neurotransmitters, which finally contributed to its therapeutic effect on scopolamine induced amnesia.

Phytochemistry, synthesis, analytical methods, pharmacological activity, and pharmacokinetics of loganin: A comprehensive review

Iridoid glycosides (IGs) are found in many medicinal and edible plants, such as Gardenia jasminoides, Cistanche tubulosa, Eucommia ulmoides, Rehmanniae Radix, Lonicera japonica, and Cornus officinalis. Loganin, an IG, is one of the main active ingredient of Cornus officinalis Sieb. et Zucc., which approved as a medicinal and edible plant in China. Loganin has been widely concerned due to its extensive pharmacological effects, including anti-diabetic, antiinflammatory, neuroprotective, and anti-tumor activities, etc. Studies have shown that these underlying mechanisms include anti-oxidation, antiinflammation and anti-apoptosis by regulating a variety of signaling pathways, such as STAT3/NF-κB, JAK/STAT3, TLR4/NF-κB, PI3K/Akt, MCP-1/CCR2, and RAGE/Nox4/p65 NF-κB signaling pathways. In order to better understand the research status of loganin and promote its application in human health, this paper systematically summarized the phytochemistry, analysis methods, synthesis, pharmacological properties and related mechanisms, and pharmacokinetics based on the research in the past decades.

Identifying the mechanism underlying antidepressant-like effects of loganin by network pharmacology in combination with experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Loganin, an iridoid glycoside, is one of the quality control indexes of Cornus officinalis Sieb. et Zucc. Increasing evidence emphasize the important role of inflammation in the pathology of depression, which links depression with other chronic diseases. Loganin prevents inflammatory response in multiple diseases and reverses depressive-like behaviors. However, the mechanisms underlying antidepressant-like effects of loganin for the treatment of inflammation-associated depression are not utterly understood.

AIM OF THE STUDY

The present study was designed to predict the potential targets of loganin against inflammation-associated depression using a network pharmacology approach.

MATERIALS AND METHODS

Pharmmapper and Uniport were used to predict loganin-related targets. Targets of inflammation were identified through GeneCards databases and Online Mendelian Inheritance in Man (OMIM). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to identify the potential mechanism. Finally, qRT-PCR and ELISA were used to confirm the role of loganin on these targets.

RESULTS

There were 15 nodes in the loganin-inflammation-depression intersection targets network. In the network, the degree value of CTNNB1 was above 3. Among top ten pathways identified by KEGG analysis, Th1/Th2 cell differentiation and IL-17 signaling pathways were related with both inflammation and depression. As indicated by qRT-PCR results, loganin increased CTNNB1 mRNA level. Moreover, loganin elevated M2 markers of microglia but decreased M1 markers of microglia against lipopolysaccharide (LPS), indicated by qRT-PCR results and ELISA results.

CONCLUSION

CTNNB1 was the main target of loganin. Loganin alleviated LPS-induced inflammation through inhibiting M1 polarization of microglia. Our results provide a better understanding of loganin-induced antidepressant-like effects for the treatment of inflammation-associated depression.

Secoiridoid dimers and their biogenetic precursors from the fruits of Cornus officinalis with potential therapeutic effects on type 2 diabetes

Cornusdiridoid A-F (1-6), six unusual cornuside-morroniside secoiridoid dimers, and their possible new biogenetic precursor, 3″,5″-dehydroxycornuside (7), together with four known secoiridoids (8-11), were obtained from the fruits of Cornus officinalis. Their structures were elucidated on the basis of various spectroscopic and chemical methods. A plausible biosynthetic pathway of compounds 1-11 was proposed. The α-glucosidase inhibitory, antioxidant and anti-inflammatory activities of these isolates were evaluated. Some of them emerged out as potent antidiabetic, anti-inflammatory and free radical scavenging agents. Molecular docking was also carried out for antidiabetic target α-glucosidase to investigate the possible binding modes of the most potent α-glucosidase inhibitor, vincosamide (9). These results revealed that the secoiridoids from C. officinalis fruits may be served as new potential antidiabetic agents to prevent and treat type 2 diabetes.

Euphorbia ebracteolata Hayata (Euphorbiaceae): A systematic review of its traditional uses, botany, phytochemistry, pharmacology, toxicology, and quality control

Euphorbia ebracteolata Hayata, as a traditional medicine, is widely distributed in China, Korea and Japan. In China, the dried root of this plant is named 'langdu'. It is traditionally used to treat oedema, skin ulcers, abdominal distension, cough, asthma, tuberculosis swelling and other diseases. Previous studies have found that the chemical constituents of E. ebracteolata are mainly concentrated in terpenoids, acetophenones, and flavonoids. Both extracts and pure compounds from E. ebracteolata were found to possess many pharmacological activities, such as anticancer, anti-inflammatory, antiviral, and antimicrobial effects. In addition, it was reported that E. ebracteolata shows toxicity. To provide inspiration for further in-depth studies on this plant, this review will provide a timely and systematic summary of E. ebracteolata in traditional uses, phytochemistry, pharmacology toxicology, and quality control.

Fischdiabietane A, an Antitumoral Diterpenoid Dimer Featuring an Unprecedented Carbon Skeleton from Euphorbia fischeriana

Fischdiabietane A (1), a novel asymmetric diterpenoid dimer with a unique nonacyclic 6/6/6/5/7/6/6/6/6 ring system possessing unprecedented 2-oxaspiro[4.5]decane-1-one and 2-oxabicyclo[3.2.2]nonane frameworks in D/E/F rings, was isolated from the roots of Euphorbia fischeriana. Its structure was determined by spectroscopic techniques, electronic circular dichroism calculations, and X-ray diffraction experiments. Notably, 1 is the first abietane-type [4 + 2] Diels-Alder dimer identified from nature. The IC₅₀ of 1 against T47D cells was about sixfold higher than that of cisplatin (the positive control). Furthermore, 1 induced apoptosis in T47D cells through the activation of caspase-3 and the degradation of poly(ADP-ribose) polymerase.

Ethnopharmacology, phytochemistry, pharmacology, clinical applications and toxicology of the genus Stellera Linn.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Stellera Linn. consists of species of perennial herbs and shrubs, and is mainly distributed in the temperate regions of east Asia to west Asia. There are 10∼12 species in the world, two species in China: Stellera chamaejasme Linn. and Stellera formosana Hayata ex Li. As recorded, the roots of Stellera species are used to dissipate phlegm and relieve pain. The roots and the barks can be used for papermaking.

AIM OF THIS REVIEW

This review aims to summarize the ethnopharmacological uses, chemical constituents, pharmacological activities, clinical applications and toxicology of the genus Stellera to better understand their therapeutic potential in the future.

MATERIALS AND METHODS

The relevant information of the genus Stellera was collected from scientific databases (Pubmed, ACS website, SciFinder Scholar, Elsevier, Google Scholar, Web of Science and CNKI). Information was also gathered from 'Flora Republicae Popularis Sinicae (〈〈〉〉)', folk records, conference papers on ethnopharmacology, Ph.D. and Masters' Dissertation.

RESULTS

Stellera plants have been studied as traditional folk medicines all around the world. The chemical constituents of Stellera species mainly comprise terpenoids, flavonoids, coumarins, lignans, and so on. Extracts and compounds of Stellera species exhibit extensive pharmacological activities, such as anti-tumor, anti-viral, anti-convulsive, anti-epileptic, anti-bacterial and anti-insect activities, etc. Clinical applications have suggested that the genus Stellera has the effects in treating several skin diseases and cancers, however, the results should be further verification. The genus Stellera plants are toxic and should be used reasonable.

CONCLUSION

This paper reviewed the ethnopharmacological uses, chemical constituents, pharmacology, clinical applications and toxicology of the genus Stellera. The genus Stellera has broad application prospects. However, further in-depth studies are needed to determine the medical uses of the genus and its chemical constituents, pharmacological activities, clinical applications and toxicology.

DL0410 ameliorates cognitive deficits in APP/PS1 transgenic mice by promoting synaptic transmission and reducing neuronal loss

At present, few available drugs can be used to either improve pathological features or prevent the progression of Alzheimer's disease (AD). DL0410 ((1,1'-([1,1'-biphenyl]-4,4'-diyl) bis (3-(piperidin-1-yl) propan-1-one) dihydrochloride) is a multiple-target small molecule that has been found to reverse cognitive impairment in different animal models of AD. In this study we evaluated the cognition-improving effects of DL0410 in APP/PS1 transgenic mice and explored the underlying mechanisms. APP/PS1 transgenic mice were administered DL0410 (3, 10, 30 mg· kg-1· d-1, ig) for 2 months. We found that DL0410 administration significantly ameliorated cognitive deficits in both the nest-building and Morris water maze tests. In electrophysiological analysis of hippocampal slices, we showed that DL0410 administration significantly enhanced the field EPSP slope and HFS-induced LTP in CA1 area. Furthermore, we revealed that DL0410 administration significantly increased the phosphorylation of AKT and the activity of GSK-3β in the hippocampus and cortex. Moreover, DL0410 administration dose-dependently increased the expression level of phosphorylated ERK1/2 in the hippocampus and cortex. In addition, DL0410 dose-dependently decreased the neuronal loss by decreasing the production of Aβ deposition, inhibited glial overactivation, and the production of inflammatory cytokines such as TNF-α, IL-1β, and IL-6. We conclude that DL0410 ameliorates cognitive deficits in APP/PS1 transgenic mice by promoting synaptic transmission via activating the AKT/GSK-3β and MAPK/ERK signaling pathway and reducing neuronal loss. DL0410 may be an effective agent for AD treatment in the future.

Connexins in oligodendrocytes and astrocytes: Possible factors for demyelination in multiple sclerosis

Increasing evidences support that glial connexins are involved in the demyelination pathology of multiple sclerosis (MS), a chronic inflammatory demyelinating disorder. Here, we review the data from patients with MS and animal models of MS that implicate connexins in demyelination. Connexins expressed in oligodendrocytes and astrocytes show diverse changes at the different phases of MS. Loss of oligodendrocyte or astrocyte connexins contributes to demyelination and exaggerates the pathology of MS. Channel-dependent and -independent connexins are involved in the pathology of demyelination, which is related with myelin integrity, metabolic homeostasis, the brain-blood barrier, the immune cell infiltration, and the inflammatory response. A comprehensive understanding of connexin function in demyelination may provide new therapeutic targets for MS.

Undescribed morroniside-like secoiridoid diglycosides with α-glucosidase inhibitory activity from Corni Fructus

Corni Fructus, also known as the fruit of Cornus officinalis Sieb. et Zucc., has long been used as a traditional Chinese medicine and is widely consumed as a nutritional food in the form of function drink and wine. Recently, Corni Fructus has attracted considerable interest because of its anti-diabetic effects. A systematic phytochemical investigation of Corni Fructus was performed to find anti-diabetic components, which led to the isolation of 10 unreported iridoid glycosides, cornusdiglycosides A-J (1-8, 9a/9b and 10a/10b). Their chemical structures were determined through spectroscopic analysis (ultraviolet [UV], infrared [IR], high-resolution electrospray ionisation mass spectroscopy [HRESIMS], one-dimensional [1D] and two-dimensional [2D] nuclear magnetic resonance [NMR]). Such morroniside-type diglycosides were first reported from natural sources, and all isolates were evaluated for α-glucosidase inhibitory activity. The results showed that all compounds (1-10) exhibited α-glucosidase (from Saccharomyces cerevisiae) inhibitory activities with IC₅₀ values ranging from 78.9 ± 4.09 to 162.2 ± 9.17 μM, whereas acarbose, the positive control, displayed α-glucosidase inhibitory activity with IC₅₀ value of 118.9 ± 7.89 μM.

Design, synthesis and biological evaluation of honokiol derivatives as influenza neuraminidase inhibitors

Honokiol, a natural polyphenol, which was reported to have satisfactory influenza neuraminidase (NA) inhibitory activity, was structurally modified. Twenty-three compounds were synthesized and the ortho-effects in the epoxidation and hydrolyzation reactions were studied. The derivatives were evaluated for NA inhibitory activity and the benzoylhydrazone derivatives showed much better anti-NA activity than honokiol. Structure-activity relationship analysis suggested that the polyphenols exhibited better anti-NA activity than monophenols and biphenols. Furthermore, probable binding mode of drug with target revealed that the most active compound had much stronger interactions with the active site of NA than honokiol suggesting the potent anti-influenza virus activity.

Loganin Exerts Sedative and Hypnotic Effects via Modulation of the Serotonergic System and GABAergic Neurons

Corni fructus, the fruit of Cornus officinalis Sieb. et Zucc., has been used as a tonic for the kidney in China for thousands of years. Loganin is one of the major constituents derived from Corni fructus. In this study, we revealed the sedative and hypnotic activity of loganin and investigated its mechanisms for the first time. Pentobarbital-induced sleep test and insomnia mice models [induced by caffeine and p-chlorophenylalanine (PCPA)] were used for the assessment of sedative and hypnotic effects of loganin. It was found that loganin (20–50 mg/kg) exerted sedative effect in normal mice. Loganin exhibited hypnotic effect by increasing sleep onset and sleep duration in pentobarbital-treated mice, recovering PCPA-induced insomnia and exerting synergistic hypnosis effect with 5-HTP. In addition, electroencephalograph (EEG) and electromyography (EMG) recordings of rats showed that loganin (35 mg/kg) prolonged the ratio of non-rapid eye movement (NREM) sleep and shortened wakefulness significantly, further immunohistochemistry showed that loganin (35 mg/kg) increased c-Fos expression in GABAergic neurons of rats in the ventrolateral preoptic nucleus (VLPO). The levels of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and its metabolite were measured in the hippocampus, prefrontal cortex and striatum of mice, 1 h after loganin (35 mg/kg) treatment. 5-HT, 5-HIAA/5-HT, DA, and DOPAC were decreased significantly in the prefrontal cortex. In conclusion, these results indicated that loganin produced beneficial sedative and hypnotic activity, which might be mainly mediated by modification of the serotonergic system and GABAergic neurons.

Astragaloside IV Inhibits Membrane Ca[Formula: see text] Current but Enhances Sarcoplasmic Reticulum Ca[Formula: see text] Release

Astragaloside IV (AS-IV) is one of the active ingredients in Astragalus membrananceus (Huangqi), a traditional Chinese medicine. The present study investigated the effects of AS-IV on Ca[Formula: see text] handling in cardiac myocytes to elucidate its possible mechanism in the treatment of cardiac disease. The results showed that AS-IV at 1 and 10[Formula: see text][Formula: see text]M reduced KCl-induced [Ca[Formula: see text]]_i increase ([Formula: see text] from 1.33[Formula: see text][Formula: see text][Formula: see text]0.04 (control, [Formula: see text] 28) to 1.22[Formula: see text][Formula: see text][Formula: see text]0.02 ([Formula: see text], [Formula: see text] 29) and 1.22[Formula: see text][Formula: see text][Formula: see text]0.02 ([Formula: see text] 0.01, [Formula: see text]), but it enhanced Ca[Formula: see text] release from SR ([Formula: see text] from 1.04[Formula: see text][Formula: see text][Formula: see text]0.01 (control, [Formula: see text]) to 1.44[Formula: see text][Formula: see text][Formula: see text]0.03 ([Formula: see text], [Formula: see text]) and 1.60[Formula: see text][Formula: see text][Formula: see text]0.04 ([Formula: see text] 0.01, [Formula: see text]0), in H9c2 cells. Similar results were obtained in native cardiomyocytes. AS-IV at 1 and 10[Formula: see text][Formula: see text]M inhibited L-type Ca[Formula: see text] current ([Formula: see text] from [Formula: see text]4.42[Formula: see text][Formula: see text][Formula: see text]0.58 pA/pF of control to [Formula: see text]2.25[Formula: see text][Formula: see text][Formula: see text]0.12 pA/pF ([Formula: see text] 0.01, [Formula: see text] 5) and [Formula: see text]1.78[Formula: see text][Formula: see text][Formula: see text]0.28 pA/pF ([Formula: see text] 0.01, [Formula: see text] 5) respectively, when the interference of [Ca[Formula: see text]]_i was eliminated due to the depletion of SR Ca[Formula: see text] store by thapsigargin, an inhibitor of Ca[Formula: see text] ATPase. Moreover, when BAPTA, a rapid Ca[Formula: see text] chelator, was used, CDI (Ca[Formula: see text]-dependent inactivation) of [Formula: see text] was eliminated, and the inhibitory effects of AS-IV on I_CaL were significantly reduced at the same time. These results suggest that AS-IV affects Ca[Formula: see text] homeostasis through two opposite pathways: inhibition of Ca[Formula: see text] influx through L-type Ca[Formula: see text] channel, and promotion of Ca[Formula: see text] release from SR.

Drug Discovery of Host CLK1 Inhibitors for Influenza Treatment

The rapid evolution of influenza virus makes antiviral drugs less effective, which is considered to be a major bottleneck in antiviral therapy. The key proteins in the host cells, which are related with the replication cycle of influenza virus, are regarded as potential drug targets due to their distinct advantage of lack of evolution and drug resistance. Cdc2-like kinase 1 (CLK1) in the host cells is responsible for alternative splicing of the M2 gene of influenza virus during influenza infection and replication. In this study, we carried out baculovirus-mediated expression and purification of CLK1 and established a reliable screening assay for CLK1 inhibitors. After a virtual screening of CLK1 inhibitors was performed, the activities of the selected compounds were evaluated. Finally, several compounds with strong inhibitory activity against CLK1 were discovered and their in vitro anti-influenza virus activities were validated using a cytopathic effect (CPE) reduction assay. The assay results showed that clypearin, corilagin, and pinosylvine were the most potential anti-influenza virus compounds as CLK1 inhibitors among the compounds tested. These findings will provide important information for new drug design and development in influenza treatment, and CLK1 may be a potent drug target for anti-influenza drug screening and discovery.

Ameliorative effects of baicalein in MPTP-induced mouse model of Parkinson's disease: A microarray study

Baicalein, a flavonoid from Scutellaria baicalensis Georgi, has been shown to possess neuroprotective properties. The purpose of this study was to explore the effects of baicalein on motor behavioral deficits and gene expression in N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice model of Parkinson's disease (PD). The behavioral results showed that baicalein significantly improves the abnormal behaviors in MPTP-induced mice model of PD, as manifested by shortening the total time for climbing down the pole, prolonging the latent periods of rotarod, and increasing the vertical movements. Using cDNA microarray and subsequent bioinformatic analyses, it was found that baicalein significantly promotes the biological processes including neurogenesis, neuroblast proliferation, neurotrophin signaling pathway, walking and locomotor behaviors, and inhibits dopamine metabolic process through regulation of gene expressions. Based on analysis of gene co-expression networks, the results indicated that the regulation of genes such as LIMK1, SNCA and GLRA1 by baicalein might play central roles in the network. Our results provide experimental evidence for the potential use of baicalein in the treatment of PD, and revealed gene expression profiles, biological processes and pathways influenced by baicalein in MPTP-treated mice.

[High intracellular Mg²⁺ affects the activities of L-type calcium channel in guinea- pig ventricular myocytes]

This study is aimed to investigate the effects of high intracellular Mg²⁺ on L-type calcium channel in guinea-pig ventricular myocytes. The cardiomyocytes were acutely isolated with enzyme digestion method. By adopting inside-out configuration of patch clamp technique, single channel currents of the L-type calcium channel were recorded under different intracellular Mg²⁺ concentrations ([Mg²⁺]i). In control group, which was treated with 0.9 mmol/L Mg²⁺, the relative activity of calcium channel was (176.5 ± 34.1)% (n = 7). When [Mg²⁺]i was increased from 0.9 to 8.1 mmol/L (high Mg²⁺ group), the relative activities of calcium channel decreased to (64.8 ± 18.1)% (n = 6, P < 0.05). Moreover, under 8.1 mmol/L Mg²⁺, the mean open time of calcium channel was shortened to about 25% of that under control condition (P < 0.05), but the mean close time of calcium channel was not altered. These results suggest that high intracellular Mg²⁺ may inhibit the activities of L-type calcium channel, which is mainly due to the shortening of the mean open time of single L-type calcium channel.

In vitro antiviral effects and 3D QSAR study of resveratrol derivatives as potent inhibitors of influenza H1N1 neuraminidase

The anti-influenza virus activities of 50 resveratrol (RV: 3, 5, 4'-trihydroxy-trans-stilbene) derivatives were evaluated using a neuraminidase (NA) activity assay. The results showed that 35 compounds exerted an inhibitory effect on the NA activity of the influenza virus strain A/PR/8/34 (H1N1) with 50% inhibitory concentration (IC50) values ranging from 3.56 to 186.1 μm. Next, the 35 RV derivatives were used to develop 3D quantitative structure-activity relationship (3D QSAR) models for understanding the chemical-biological interactions governing their activities against NA. The comparative molecular field analysis (CoMFA r2=0.973, q2=0.620, qtest2=0.661) and the comparative molecular similarity indices analysis (CoMSIA r2=0.956, q2=0.610, qtest2=0.531) were applied. Afterward, molecular docking was performed to study the molecular interactions between the RV derivatives and NA. Finally, a cytopathic effect (CPE) reduction assay was used to evaluate the antiviral effects of the RV derivatives in vitro. Time-of-addition studies demonstrated that the RV derivatives might have a direct effect on viral particle infectivity. Our results indicate that the RV derivatives are potentially useful antiviral compounds for new drug design and development for influenza treatment.