Isolation and identification of inhibitory compounds on TNF-alpha production from Magnolia fargesii

Machine learning-based evaluation of spontaneous pain and analgesics from cellular calcium signals in the mouse primary somatosensory cortex using explainable features

Introduction

Pain that arises spontaneously is considered more clinically relevant than pain evoked by external stimuli. However, measuring spontaneous pain in animal models in preclinical studies is challenging due to methodological limitations. To address this issue, recently we developed a deep learning (DL) model to assess spontaneous pain using cellular calcium signals of the primary somatosensory cortex (S1) in awake head-fixed mice. However, DL operate like a "black box", where their decision-making process is not transparent and is difficult to understand, which is especially evident when our DL model classifies different states of pain based on cellular calcium signals. In this study, we introduce a novel machine learning (ML) model that utilizes features that were manually extracted from S1 calcium signals, including the dynamic changes in calcium levels and the cell-to-cell activity correlations.

Method

We focused on observing neural activity patterns in the primary somatosensory cortex (S1) of mice using two-photon calcium imaging after injecting a calcium indicator (GCaMP6s) into the S1 cortex neurons. We extracted features related to the ratio of up and down-regulated cells in calcium activity and the correlation level of activity between cells as input data for the ML model. The ML model was validated using a Leave-One-Subject-Out Cross-Validation approach to distinguish between non-pain, pain, and drug-induced analgesic states.

Results and discussion

The ML model was designed to classify data into three distinct categories: non-pain, pain, and drug-induced analgesic states. Its versatility was demonstrated by successfully classifying different states across various pain models, including inflammatory and neuropathic pain, as well as confirming its utility in identifying the analgesic effects of drugs like ketoprofen, morphine, and the efficacy of magnolin, a candidate analgesic compound. In conclusion, our ML model surpasses the limitations of previous DL approaches by leveraging manually extracted features. This not only clarifies the decision-making process of the ML model but also yields insights into neuronal activity patterns associated with pain, facilitating preclinical studies of analgesics with higher potential for clinical translation.

Magnolin Inhibits Paclitaxel-Induced Cold Allodynia and ERK1/2 Activation in Mice

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of anti-cancer drugs. The main symptoms often include sensory disturbances and neuropathic pain, and currently there is no effective treatment for this condition. This study aimed to investigate the suppressive effects of magnolin, an extracellular signal-regulated kinase (ERK) inhibitor substance derived from a 95% EtOH extract of the seeds of Magnolia denudata, on the symptoms of CIPN. A taxol-based anti-cancer drug paclitaxel (PTX) was repeatedly injected (2 mg/kg/day, total 8 mg/kg) into mice to induce CIPN. A neuropathic pain symptom was assessed using a cold allodynia test that scores behaviors of licking and shaking paw after plantar administration of acetone drop. Magnolin was administered intraperitoneally (0.1, 1, or 10 mg/kg) and behavioral changes to acetone drop were measured. The effect of magnolin administration on ERK expression in the dorsal root ganglion (DRG) was investigated using western blot analysis. The results showed that the repeated injections of PTX induced cold allodynia in mice. Magnolin administration exerted an analgesic effect on the PTX-induced cold allodynia and inhibited the ERK phosphorylation in the DRG. These results suggest that magnolin could be developed as an alternative treatment to suppress paclitaxel-induced neuropathic pain symptoms.

Protective effects of verbenalin and (+)-eudesmin against 6-hydroxydopamine-induced oxidative/nitrosative stress in SH-SY5Y cells

BACKGROUND

The purpose of this research was to study whether verbenalin, an iridoid glucoside, and (+)-eudesmin, a furofuran lignan isolated from different plant families, can attenuate cell damage and death induced by 6-hydroxydopamine (6-OHDA) in human neuroblastoma SH-SY5Y cells.

METHODS

SH-SY5Y cells were incubated with 6-OHDA (35 µM) for 1 day. Verbenalin and (+)-eudesmin were administrated with various concentrations (1, 2.5, 5, 10, 20, and 50 µM) one hour before the 6-OHDA treatment. After 1 day, cell viability and neuroprotective effect were investigated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Nitrosative stress was determined with measurements of nitric oxide (NO) and 3-nitrotyrosine (3-NT), a biomarker of peroxynitrite formation.

RESULTS

We observed that 6-OHDA declined viability and augmented LDH leakage in SH-SY5Y cells. MTT analyses showed that pretreatment with verbenalin and (+)-eudesmin markedly prevented the toxicity due to 6-OHDA (P < 0.05). Verbenalin and (+)-eudesmin suppressed LDH release induced by 6-OHDA (P < 0.01). Although 6-OHDA treatment produced no marked effects on NO levels, (+)-eudesmin at high concentrations (10-50 µM) markedly attenuated NO levels (P < 0.01). There was a significant increase in 3-NT levels with 6-OHDA exposure in cells. Pretreatment with verbenalin, but not (+)-eudesmin, diminished 3-NT levels at low concentrations (1-20 µM) and prevented the cytotoxic effect of 6-OHDA (P < 0.01).

CONCLUSION

These results indicated that verbenalin and (+)-eudesmin exert potent cytoprotective activities against cytotoxicity triggered by 6-OHDA in neuroblastoma cells. This is the first report demonstrating that verbenalin may act as a peroxynitrite scavenger.

Protective effect and possible mechanism of arctiin on broilers challenged by Salmonella pullorum

This study was aimed to investigate the effects of dietary arctiin (ARC) supplementation (100, 200, and 400 mg/kg) on the growth performance and immune response of broilers after a Salmonella pullorum (S. pullorum) challenge, and we conducted in vitro antibacterial test to explore the bacteriostatic mechanism of ARC. The in vivo trial was randomly assigned to six groups: noninfected control (NC) group and positive control (PC) group received a basal diet; TET group, received a basal diet supplemented with 100 mg/kg chlortetracycline; ARC100, ARC200, and ARC400 groups received a basal diet containing 100, 200, and 400 mg/kg ARC, respectively. From days 14 to 16, all birds (except the NC group) were infected with 1 mL (1 × 108 CFU per mL) fresh S. pullorum culture by oral gavage per day. In vivo results showed that dietary supplementation of 200 mg/kg ARC significantly increased average daily gain (P < 0.05) and decreased feed-to-gain ratio of broilers vs. the PC group during days 15 to 28 after being challenged with S. pullorum (P < 0.05). The jejunal crypt depth (CD) was decreased by supplementing 100 or 200 mg/kg ARC in diets compared with PC birds at day 19 (P < 0.05). The jejunal villi height (VH) was increased by supplementing 100, 200, or 400 mg/kg ARC in diets compared with PC birds at day 28 (P < 0.05). Besides, dietary supplementation of 200 mg/kg ARC increased the jejunal VH to CD ratio than the PC group both at days 19 and 28 (P < 0.05). Notably, the broilers had lower serum lipopolysaccharide and diamine oxidase levels in the ARC100 and ARC200 groups at day 28 than those in the PC group (P < 0.05). Furthermore, in comparison to PC birds, the birds in ARC groups (100, 200, and 400 mg/kg) had higher serum contents of IgM and IL-10, and the birds in the ARC200 group had higher serum contents of IgA at day 19 (P < 0.05). At day 28, the birds in ARC groups (100, 200, and 400 mg/kg) had lower serum contents of IL-8, and the birds in the ARC200 group had lower serum contents of IFN-γ compared with PC birds (P < 0.05). The in vitro experiment showed that ARC significantly inhibited the biofilm formation and adhesion of S. pullorum (P < 0.05). Metabonomics analysis revealed that ARC can restrain the formation of the biofilm by affecting a variety of metabolic pathways of S. pullorum. Therefore, dietary supplementation of 200 mg/kg ARC might be a potential way to substitute antibiotics to control S. pullorum infection in broilers.

Kaempferol sensitizes cell proliferation inhibition in oxaliplatin-resistant colon cancer cells

Resolution to chemoresistance is a major challenge in patients with advanced-stage malignancies. Thus, identification of action points and elucidation of molecular mechanisms for chemoresist human cancer are necessary to overcome this challenge. In this study, we provide important evidence that kaempferol targeting RSKs might be a strategy to reduce the oxaliplatin-resistant colon cancer cells. We found that MAPK and PI3K-AKT signaling were increased in oxaliplatin (Ox)-resistant HCT116 (HCT116-Ox^R) cells compared to Ox-sensitive HCT116 (HCT116-Ox^S) cells. Comparison of cell sensitivities using SP600125 (JNK inhibitor), SB206580 (p38 kinase inhibitor), or MK-2206 (AKT inhibitor) revealed that cell proliferation inhibition was strongly observed in HT29 cells compared to that in HCT116 cells in both Ox^S and Ox^R cells. Interestingly, SP600125, SB206580, and MK-2206 treatment showed higher cell proliferation inhibition in Ox^S cells than that in Ox^R cells in both HCT116 and HT29 cells, except following treatments with 10 µM of SP600125, and 30 µM of SB206580. In comparison to magnolin and aschantin, kaempferol showed the strongest inhibitory effect on cell proliferation in both HCT116 and HT29 cells. Importantly, HCT116- and HT29-Ox^R cells showed higher sensitivities to cell proliferation inhibition than those of HCT116- and HT29-Ox^S cells, resulting in the accumulation of cells at the G₂/M-phases of the cell cycle. Finally, we showed that AP-1 transactivation activity was markedly decreased by kaempferol in HCT116- and HT29-Ox^R cells compared to the activity levels in HCT116- and HT29-Ox^S cells. Taken together, the results demonstrate that kaempferol-mediated AP-1 inhibition might be an important signaling mechanism to resolve the chemoresistance of Ox-resistant colon cancer cells.

An Affinity-Based, Cysteine-Specific ATP Analog for Kinase-Catalyzed Crosslinking

Kinases mediate cell signaling pathways by catalyzing protein phosphorylation. Irregularities in kinase activity are directly associated with disease conditions. Therefore, methods to identify substrates of a particular kinase are needed to understand signaling cascades in normal and diseased states. Photocrosslinking ATP analogs provide powerful tools to study kinases by covalently linking kinases with substrates. However, the involvement of UV light and nonspecific reactivity of current ATP-photocrosslinkers challenge kinase-substrate identification. We report here an affinity-based crosslinking ATP analog, ATP-methylacrylamide (ATP-MAc), that contains a cysteine-reactive acrylamide crosslinking group, which avoids the UV irradiation and non-specific reactivity of prior analogs. Using in vitro kinase assays, ATP-MAc acts as a kinase co-substrate and covalently crosslinks only kinases containing cysteines in the active site. ATP-MAc was also able to crosslink cellular proteins in lysates, documenting compatibility with cell-based studies.

Fargesin Inhibits EGF-Induced Cell Transformation and Colon Cancer Cell Growth by Suppression of CDK2/Cyclin E Signaling Pathway

Although the lignan compound fargesin is a major ingredient in Shin-Yi, the roles of fargesin in carcinogenesis and cancer cell growth have not been elucidated. In this study, we observed that fargesin inhibited cell proliferation and transformation by suppression of epidermal growth factor (EGF)-stimulated G₁/S-phase cell cycle transition in premalignant JB6 Cl41 and HaCaT cells. Unexpectedly, we found that signaling pathway analyses showed different regulation patterns in which fargesin inhibited phosphatidylinositol 3-kinase/AKT signaling without an alteration of or increase in mitogen activated protein kinase (MAPK) in JB6 Cl41 and HaCaT cells, while both signaling pathways were abrogated by fargesin treatment in colon cancer cells. We further found that fargesin-induced colony growth inhibition of colon cancer cells was mediated by suppression of the cyclin dependent kinase 2 (CDK2)/cyclin E signaling axis by upregulation of p21^WAF1/Cip1, resulting in G₁-phase cell cycle accumulation in a dose-dependent manner. Simultaneously, the suppression of CDK2/cyclin E and induction of p21^WAF1/Cip1 were correlated with Rb phosphorylation and c-Myc suppression. Taken together, we conclude that fargesin-mediated c-Myc suppression inhibits EGF-induced cell transformation and colon cancer cell colony growth by the suppression of retinoblastoma (Rb)-E2F and CDK/cyclin signaling pathways, which are mainly regulated by MAPK and PKB signaling pathways.

Phytochemicals against TNFα-Mediated Neuroinflammatory Diseases

Tumor necrosis factor-alpha (TNF-α) is a well-known pro-inflammatory cytokine responsible for the modulation of the immune system. TNF-α plays a critical role in almost every type of inflammatory disorder, including central nervous system (CNS) diseases. Although TNF-α is a well-studied component of inflammatory responses, its functioning in diverse cell types is still unclear. TNF-α functions through its two main receptors: tumor necrosis factor receptor 1 and 2 (TNFR1, TNFR2), also known as p55 and p75, respectively. Normally, the functions of soluble TNF-α-induced TNFR1 activation are reported to be pro-inflammatory and apoptotic. While TNF-α mediated TNFR2 activation has a dual role. Several synthetic drugs used as inhibitors of TNF-α for diverse inflammatory diseases possess serious adverse effects, which make patients and researchers turn their focus toward natural medicines, phytochemicals in particular. Phytochemicals targeting TNF-α can significantly improve disease conditions involving TNF-α with fewer side effects. Here, we reviewed known TNF-α inhibitors, as well as lately studied phytochemicals, with a role in inhibiting TNF-α itself, and TNF-α-mediated signaling in inflammatory diseases focusing mainly on CNS disorders.

Magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway

BACKGROUND

Magnolin is a natural compound abundantly found in Magnolia flos, which has been traditionally used in oriental medicine to treat headaches, nasal congestion and anti-inflammatory reactions. Our recent results have demonstrated that magnolin targets the active pockets of ERK1 and ERK2, which are important signaling molecules in cancer cell metastasis. The aim of this study is to evaluate the effects of magnolin on cell migration and to further explore the molecular mechanisms involved.

METHODS

Magnolin-mediated signaling inhibition was confirmed by Western blotting using RSK2(+/+) and RSK2(-/-) MEFs, A549 and NCI-H1975 lung cancer cells, and by NF-κB and Cox-2 promoter luciferase reporter assays. Inhibition of cell migration by magnolin was examined by wound healing and/or Boyden Chamber assays using JB6 Cl41 and A549 human lung cancer cells. The molecular mechanisms involved in cell migration and epithelial-to-mesenchymal transition were determined by zymography, Western blotting, real-time PCR and immunocytofluorescence.

RESULTS

Magnolin inhibited NF-κB transactivation activity by suppressing the ERKs/RSK2 signaling pathway. Moreover, magnolin abrogated the increase in EGF-induced COX-2 protein levels and wound healing. In human lung cancer cells such as A549 and NCI-H1975, which harbor constitutive active Ras and EGFR mutants, respectively, magnolin suppressed wound healing and cell invasion as seen by a Boyden chamber assay. In addition, it was observed that magnolin inhibited MMP-2 and -9 gene expression and activity. The knockdown or knockout of RSK2 in A549 lung cancer cells or MEFs revealed that magnolin targeting ERKs/RSK2 signaling suppressed epithelial-to-mesenchymal transition by modulating EMT marker proteins such as N-cadherin, E-cadherin, Snail, Vimentin and MMPs.

CONCLUSIONS

These results demonstrate that magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway.

Natural products and synthetic compounds as immunomodulators

Research on immunomodulation by natural products or synthetic derivatives is of key interest for anti-infective therapy for a number of reasons. Many plant remedies well-known in traditional medicine or refined natural products in clinical use exert their anti-infective effects not only (if at all) by directly affecting the pathogen. At least part of their effect is indirect, by stimulating natural and adaptive defense mechanisms of the host. These findings have now given many empirical therapies a rationale, scientific basis and thereby a means for 'intelligent' improvement. In discovering the molecular mechanisms by which known remedies exert their effects, chosen elements further down the 'chain of command' might be synthesized and applied directly for more rapid and selective cure, omitting unwanted side effects. The direct use of recombinant cytokines, often in combination with antibiotics, is one consequence of this rationale.

Targeting of magnolin on ERKs inhibits Ras/ERKs/RSK2-signaling-mediated neoplastic cell transformation

Mitogen-activated protein kinases play a key role in cell proliferation, cell cycle progression and cell transformation, and activated Ras/extracellular signal-regulated kinases (ERKs)/ribosomal S6 kinase 2 (RSK2) signaling pathways have been widely identified in many solid tumors. In this study, we found that magnolin, a compound found in the Magnolia species, directly targeted and inhibited ERK1 and ERK2 kinase activities with IC50 values of 87 and 16.5 nM by competing with adenosine triphosphate in an active pocket. Further, we demonstrated that magnolin inhibited epidermal growth factor (EGF)-induced p90RSKs phosphorylation at Thr359/Ser363, but not ERKs phosphorylation at Thr202/Tyr204, and this resulted in inhibition of cell proliferation by suppression of the G1/S cell cycle transition. Additionally, p38 kinases, Jun N-terminal kinases and Akts were not involved in the magnolin-mediated inhibitory signaling. Magnolin targeting of ERK1 and 2 activities suppressed the phosphorylation of RSK2 and downstream target proteins including ATF1 and c-Jun and AP-1, a dimer of Jun/Fos, and the transactivation activities of ATF1 and AP-1. Notably, ERKs inhibition by magnolin suppressed EGF-induced anchorage-independent cell transformation and colony growth of Ras(G12V)-harboring A549 human lung cancer cells and NIH3T3 cells stably expressing Ras(G12V) in soft agar. Taken together, these results demonstrated that magnolin might be a naturally occurring chemoprevention and therapeutic agent capable of inhibiting cell proliferation and transformation by targeting ERK1 and ERK2.

Fargesin, a component of Flos Magnoliae, stimulates glucose uptake in L6 myotubes

Flos Magnoliae (FM) is a commonly used Chinese medicinal herb for symptomatic relief of allergic rhinitis, sinusitis and headache. Although several FM species have been used as substitutes or adulterants for clinical use, possible differences in their pharmacological actions have not been reported. To confirm the effects of FM on skeletal muscle glucose metabolism, we tested the effects of several compounds isolated from FM on glucose uptake by L6 myotubes. We found that fargesin, a component of FM, dose-dependently stimulated glucose consumption in L6 myotubes, which was accompanied by enhanced glucose transporter (GLUT)-4 translocation to the cell surface. Fargesin-stimulated glucose uptake was blocked by wortmannin, a phosphatidylinositol-3 kinase (PI3 K) inhibitor. Fargesin stimulated Akt phosphorylation, a key component in the insulin signaling pathway, which was completely inhibited by wortmannin. Here, we demonstrated that fargesin, a bioactive component of Flos Magnoliae, increases basal glucose uptake and GLUT4 translocation in L6 myotubes by activating the PI3 K-Akt pathway.

Effects of add-on therapy with NDC-052, an extract from Magnoliae Flos, in adult asthmatic patients receiving inhaled corticosteroids

BACKGROUND/AIMS

There is a need for new anti-asthmatic medications with fewer side effects. NDC-052, an extract of the medicinal herb Magnoliae flos, which has a long history of clinical use, was recently found to have anti-inflammatory effects. Herein, we evaluated the effects of NDC-052 as an add-on therapy in patients with mild to moderate asthma using inhaled corticosteroids (ICS).

METHODS

In a non-comparative, multi-center trial, 148 patients taking ICS received NDC-052 for eight weeks. We evaluated their forced expiratory volume in one second (FEV1), morning and evening peak expiratory flow rate (AM and PM PEFR), AM/PM asthma symptom scores, visual analogue symptom (VAS) scores, night-time wakening, frequency of short-acting β2-agonist usage, and adverse events.

RESULTS

After eight weeks, both AM and PM PEFRs were significantly improved. Asthma symptom scores, VAS scores, the frequency of nights without awakening, and the frequency of β2-agonist use were also reduced. Most of the adverse drug reactions were mild and resolved spontaneously.

CONCLUSIONS

The addition of NDC-052 to ICS had a beneficial effect on asthma control in patients with mild to moderate asthma, with good tolerability and fewer side effects. Further studies are necessary to evaluate the effects of NDC-052 in patients with severe and/or refractory asthma.

In vitro evaluation on the antiobesity effect of lignans from the flower buds of Magnolia denudata

In the present study, an attempt has been made to isolate antiobesity components from crude extracts of the flower buds of Magnolia denudata by CH(2)Cl(2) and MeOH solvents. The crude extracts were partitioned into n-hexane, 85% aqueous MeOH, n-butanol, and water fractions. Their antiobesity effects were evaluated by measuring the effect on adipogenic differentiation using 3T3-L1 cells. Among the fractions, n-hexane and 85% aqueous MeOH fractions effectively reduced the lipid accumulation and the regulation of the adipogenic transcription factor. Both n-hexane and 85% aqueous MeOH fractions were further separated by diverse chromatographic methods to give four lignans (A-D). In comparative analysis, the presence of the lignans during adipogenic differentiation reduced the absorbance values of eluted Oil Red O solution in the order of potency C > D > B > A. Moreover, C and D effectively downregulated SREBP1, PPARγ, and C/EBPα.

Liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry for the simultaneous determination of dimethoxyaschantin, dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin in rat plasma

A rapid, selective, and sensitive liquid chromatography-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry method was developed for the simultaneous determination of dimethoxyaschantin, dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin, the pharmacologically active ingredients of Magnolia fargesii in rat plasma. These tetrahydrofurofuranoid lignans were extracted from rat plasma using tert-butyl methyl ether at pH 7.4. The analytes were separated on a Pinnacle DB biphenyl column with 65% methanol in 10 mm ammonium formate (pH 3.0) and detected by APCI tandem mass spectrometry in the selective reaction monitoring mode. The calibration curves were linear (r(2) ≥ 0.996) over the concentration range of 20.0-1000 ng/mL for six tetrahydrofurofuranoid lignans. The lower limit of quantification for these lignans was 20.0 ng/mL with 50 µL of plasma sample. The intra- and inter-assay coefficient of variation and relative error for the six tetrahydrofurofuranoid lignans at four quality control concentrations were 0.2-9.9% and -8.5-8.2%, respectively. There was no matrix effect for the six tetrahydrofurofuranoid lignans and tolterodine (internal standard). The pharmacokinetics of dimethylliroresinol, dimethylpinoresinol, epimagnolin A, fargesin and magnolin were evaluated after oral administration of a purified extract isolated from dried flower buds of Magnolia fargesii at doses of 5.5, 11.0 and 22.0 mg/kg in male rats.

Simultaneous determination of magnolin and epimagnolin A in rat plasma by liquid chromatography with tandem mass spectrometry: Application to pharmacokinetic study of a purified extract of the dried flower buds of Magnolia fargesii, NDC-052 in rats

A purified extract isolated from the dried flower buds of Magnolia fargesii (NDC-052) is currently being evaluated for phase III clinical trials as a new anti-asthma drug. A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method for the simultaneous determination of magnolin and epimagnolin A, the major bioactive components of NDC-052, in rat plasma was developed. After liquid-liquid extraction with tolterodine as an internal standard, magnolin and epimagnolin A were separated on a Luna phenyl-hexyl column with the mobile phase of 70% methanol in 10mM ammonium formate. The analytes were detected by an electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring mode. The standard curves were linear over the concentration range of 50-2500ng/mL for magnolin and epimagnolin A in rat plasma. The intra- and inter-day coefficients of variation and relative errors for magnolin and epimagnolin A at four QC concentrations were 1.5-11.4% and 5.9-12.5%, respectively. The lower limits of quantification for magnolin and epimagnolin A were 50.0ng/mL using 50microL of plasma. This method was successfully applied to the pharmacokinetic study of magnolin and epimagnolin A after an oral administration of NDC-052 in male Sprague-Dawley rats.

The lignan eudesmin extracted from Piper truncatum induced vascular relaxation via activation of endothelial histamine H1 receptors

In Brazilian folk medicine, extracts from Piper species are used to reduce blood pressure. Previously, we demonstrated the vasodilatory activity of crude extracts from leaves of Piper truncatum explaining their possible use in the treatment of hypertension in traditional medicine. In the present study, we investigated the effects of eudesmin, a lignan isolated from hexane extract of leaves from Piper truncatum, on the contractility of rat aortas and the possible mechanisms involved in its vascular action. Eudesmin induced an intense concentration-dependent relaxation of aortic rings precontracted with phenylephrine. The concentration of eudesmin necessary to reduce phenylephrine-induced aortic contraction by 50% (IC(50)) was 10.69+/-0.67 microg/ml. Eudesmin-induced vasodilation required an intact endothelium since vascular relaxation was inhibited by mechanic removal of endothelium, and by pretreatment with nitric oxide synthase inhibitor and soluble guanylate cyclase inhibitor. Relaxation induced by eudesmin was also impaired in the presence of indomethacin and diphenhydramine, a cyclooxygenase inhibitor and an antagonist of type 1 histamine receptor (H(1)), respectively. IC(50) was increased to 18.1+/-1.8 and 18.1+/-2.6 microg/ml (P<0.05; n=6) after exposure to indomethacin and diphenhydramine, respectively. Atropine (muscarinic receptor antagonist), propranolol (beta-adrenoceptor antagonist) and glibenclamide (ATP-sensitive K(+) channel blocker) did not alter the effect of eudesmin. These results indicate that eudesmin-induced vascular relaxation in rat aorta is mediated by release of nitric oxide and prostanoid through the involvement of histamine receptor present in the endothelial cells.

Chemical Characterization of Magnolia Biondii (Flos Magnoliae, Xin Yi)

Samples of Magnolia biondii buds (Xin Yi, Flos Magnoliae) from different sources were subjected to phytochemical analysis and compared to samples of M. denudata and M. liliiflora. Among the compounds found in the flower buds of M. biondii were eight tetrahydrofurofuran lignans as well as the sesquiterpene lactone parthenolide and the sesquiterpene alcohol oplodiol. A rapid TLC-method for the identification of plant material from M. biondii and its distinction from M. liliiflora was developed. Structure elucidation was carried out by means of NMR (1- and 2-D) and LC-MS.

Inhibitions of mast cell-derived histamine release by different Flos Magnoliae species in rat peritoneal mast cells

Flos Magnoliae (FM) is a commonly used Chinese medicinal herb for symptomatic relief of allergic rhinitis, sinusitis and headache. A number of FM species have been used as substitutes or adulterants for clinical application, although the differences in their pharmacological actions have not been reported. The present study investigated the effects of six identified FM species M. biondii, M. denudata, M. kobus, M. liliflora, M. sargentiana and M. sprengeri, as well as the marker compounds magnolin and fargesin on compound 48/80-induced histamine release in rat peritoneal mast cells (RPMC) in vitro. Ethanolic extracts of all FM species produced a concentration-dependent inhibition of compound 48/80-induced histamine release in RPMC. The rank order of the IC(50)s was M. biondii<M. kobus<M. liliflora<M. denudata<M. sprengeri<M. sargentiana. The marker compound magnolin, but not fargesin, only slightly inhibited the histamine release. The contents of magnolin and fargesin, determined by using RP-HPLC, varied significantly among these FM species. Magnolin was found in M. biondii, M. kobus and M. liliflora, but not in M. denudate, M. sprengeri and M. sargentiana, while fargesin was only found in M. biondii and M. kobus. These findings provide the first evidence of differences in pharmacological actions of different FM species on mast cell-derived histamine release in vitro. In addition, the marker compounds magnolin and fargesin may not play a major role in the observed pharmacological actions of FM species.

Two new stereoisomers of Tetrahydrofuranoid lignans from the flower buds of Magnolia fargesii

Two new stereoisomers of tetrahydrofuranoid lignans, 7S,8R,7'S,8'R- (1) and 7R,8S,7'S,8'R-3,4,3',4'-tetramethoxy-9,7'-dihydroxy-8.8',7.O.9'-lignan (2) along with nine known lignans including tetrahydrofuranoids (3, 4) and tetrahydrofurofuranoids (5-11) were isolated from a CHCl(3)-soluble fraction of the flower buds of Magnolia fargesii. Two tetrahydrofuranoids, magnostellin A (3) and lariciresinol dimethyl ether (4) were isolated from this species for the first time. The structures of these compounds (1-11) were identified by spectroscopic methods as well as by comparison with published values. Absolute configurations of new stereoisomers (1, 2) were determined by the Mosher's esterification method and Circular Dichroism (CD) studies. All the isolates (1-11) were evaluated for their antioxidant activities using modified superoxide radical-scavenging assay. Compounds 5-8 showed the potent superoxide radical-scavenging activities with the ED(50) values of 19.2, 19.2, 16.5, and 27.7 microM, respectively, as compared with standard antioxidants (BHA: 22.8 microM; Trolox: 940 microM).

An update on bioactive plant lignans

Lignans are a class of secondary plant metabolites produced by oxidative dimerization of two phenylpropanoid units. Although their molecular backbone consists only of two phenylpropane (C6-C3) units, lignans show an enormous structural diversity. There is a growing interest in lignans and their synthetic derivatives due to applications in cancer chemotherapy and various other pharmacological effects. This review deals with lignans possessing anticancer, antioxidant, antimicrobial, anti-inflammatory and immunosuppressive activities, and comprises the data reported in more than 100 peer-reviewed articles, so as to highlight the recently reported bioactive lignans that could be a first step towards the development of potential new therapeutic agents.

Nitric oxide, human diseases and the herbal products that affect the nitric oxide signalling pathway

1. Nitric oxide (NO) is formed enzymatically from l-arginine in the presence of nitric oxide synthase (NOS). Nitric oxide is generated constitutively in endothelial cells via sheer stress and blood-borne substances. Nitric oxide is also generated constitutively in neuronal cells and serves as a neurotransmitter and neuromodulator in non-adrenergic, non-cholinergic nerve endings. Furthermore, NO can also be formed via enzyme induction in many tissues in the presence of cytokines. 2. The ubiquitous presence of NO in the living body suggests that NO plays an important role in the maintenance of health. Being a free radical with vasodilatory properties, NO exerts dual effects on tissues and cells in various biological systems. At low concentrations, NO can dilate the blood vessels and improve the circulation, but at high concentrations it can cause circulatory shock and induce cell death. Thus, diseases can arise in the presence of the extreme ends of the physiological concentrations of NO. 3. The NO signalling pathway has, in recent years, become a target for new drug development. The high level of flavonoids, catechins, tannins and other polyphenolic compounds present in vegetables, fruits, soy, tea and even red wine (from grapes) is believed to contribute to their beneficial health effects. Some of these compounds induce NO formation from the endothelial cells to improve circulation and some suppress the induction of inducible NOS in inflammation and infection. 4. Many botanical medicinal herbs and drugs derived from these herbs have been shown to have effects on the NO signalling pathway. For example, the saponins from ginseng, ginsenosides, have been shown to relax blood vessels (probably contributing to the antifatigue and blood pressure-lowering effects of ginseng) and corpus cavernosum (thus, for the treatment of men suffering from erectile dysfunction; however, the legendary aphrodisiac effect of ginseng may be an overstatement). Many plant extracts or purified drugs derived from Chinese medicinal herbs with proposed actions on NO pathways are also reviewed.

Inhibitory activity of lignan components from the flower buds of Magnoliae fargesii on the expression of cell adhesion molecules

Inhibitory activity of lignans isolated from Magnoliae fargesii Cheng on cell adhesion molecules on the surface of THP-1 human monocytic cell lines were investigated. Among 16 lignan components tested, six displayed relatively potent inhibitory activity on the expression of both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1).

Savinin, a lignan from Pterocarpus santalinus inhibits tumor necrosis factor-alpha production and T cell proliferation

Two lignans were isolated from the heartwood of Pterocarpus santalinus by activity-guided fractionation and investigated for their biological properties and molecular mechanism of action. On the basis of their spectroscopic data, these compounds were identified as savinin (1) and calocedrin (2), dibenzyl butyrolactone-type lignan compounds having an alpha-arylidene gamma-lactone structure. These lignans significantly inhibited tumor necrosis factor (TNF)-a production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and T cell proliferation elicited by concanavalin (Con A), without displaying cytotoxicity. The molecular inhibitory mechanism of compound 1 was confirmed to be mediated by the non-polar butyrolactone ring, according to a structure-relationship study with structurally related and unrelated compounds, such as arctigenin (a dibenzyl butyrolactone type lignan), eudesmin (a furofuran type lignan), isolariciresinol (a dibenzylbutane type lignan), and cynaropicrin (a sesquiterpene lactone). The results suggest that savinin may act as an active principle in the reported biological activities of P. santalinus, such as antiinflammatory effect, by mediation of the butyrolactone ring as a valuable pharmacophore.

In vitro anti-inflammatory effects of cynaropicrin, a sesquiterpene lactone, from Saussurea lappa

We investigated in vitro anti-inflammatory effects of cynaropicrin, a sesquiterpene lactone from Saussurea lappa, on tumor necrosis factor (TNF)-alpha and nitric oxide (NO) release, and lymphocyte proliferation. Cynaropicrin strongly inhibited TNF-alpha release from lipopolysaccharide-stimulated murine macrophage, RAW264.7 cells, and differentiated human macrophage, U937 cells, proved to produce notable amount of TNF-alpha. It also potently attenuated the accumulation of NO released from lipopolysaccharide- and interferon-gamma-stimulated RAW264.7 cells in a dose-dependent manner. In addition, the immunosuppressive effects of the compound on lymphocyte proliferation in response to mitogenic stimuli were examined. Cynaropicrin also dose-dependently suppressed the proliferation of lymphocytes from splenocytes and interleukin-2-sensitive cytotoxic T lymphocyte, CTLL-2 cells, stimulated by lipopolysaccharide, concanavalin A, phytohemagglutinin and interleukin-2. However, treatment with sulphydryl compound, L-cysteine, abrogated all these inhibitory effects. These results suggest that cynaropicrin may participate in the inflammatory response by inhibiting the production of inflammatory mediators and the proliferation of lymphocytes and its inhibitory effect is mediated through conjugation with sulphydryl groups of target protein(s).

Inhibitor of tumor necrosis factor-alpha production in lipopolysaccharide-stimulated RAW264.7 cells from Amorpha fruticosa

Certain flavonoids were reported to show an immunoregulatory activity against lymphocyte proliferation and cytokine production. In the course of a search for tumor necrosis factor (TNF)-alpha inhibitory compounds from natural plants, we also isolated a prenylfavanone type of flavonoid, amoradicin, from the extract of Amorpha fruticosa by activity-guided fractionation. This compound significantly inhibited TNF-alpha production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells with an IC(50) value of 28.5 microM. The activity was comparable or higher than those of standard flavonoid compounds, genistein and silybin with IC(50) of 24.9 and 140.3 microM, respectively.

Immunomodulatory effect of arctigenin, a lignan compound, on tumour necrosis factor-alpha and nitric oxide production, and lymphocyte proliferation

We have investigated the immunomodulatory effects of arctigenin, a dibenzyl butyrolactone lignan compound, on tumour necrosis factor (TNF)-alpha and nitric oxide (NO) production, and lymphocyte proliferation. Arctigenin inhibited strongly TNF-alpha production by lipopolysaccharide-stimulated murine macrophage RAW264.7 and differentiated human macrophage U937 with IC50 values of 5.0 and 3.9 microM, respectively, without displaying cytotoxicity. The TNF-alpha inhibitory effect of arctigenin in lipopolysaccharide-triggered RAW264.7 cells was increased by co-treatment with several known TNF-alpha inhibitors. It also potently attenuated T and B cell proliferation stimulated by concanavalin A and lipopolysaccharide in a dose-dependent manner with IC50 values of 2.9 and 14.6 microM, respectively. In contrast, the compound showed a different pattern in lipopolysaccharide- and interferon (IFN)-gamma-induced NO production from RAW264.7 cells. Arctigenin inhibited NO release by IFN-gamma signal, whereas it significantly enhanced lipopolysaccharide-triggered NO production in RAW264.7 cells. The results suggested that arctigenin may regulate immune responses in activated macrophages and lymphocytes including TNF-alpha and NO production and lymphocyte proliferation.

Eudesmin inhibits tumor necrosis factor-alpha production and T cell proliferation

Possible antiinflammatory effects of eudesmin were examined by assessing the effects on tumor necrosis factor (TNF)-alpha production and lymphocyte proliferation as well as cytotoxicity against murine and human macrophages. The compound significantly inhibited TNF-alpha production by lipopolysaccharide (LPS)-stimulated murine macrophage RAW264.7 without displaying cytotoxicity suggesting that eudesmin may inhibit TNF-alpha production without any interference of normal cell function. It also significantly attenuated T cell proliferation stimulated by concanavalin A (Con A) in a dose-dependent manner.