Rat Polymorphonuclear Leukocytes Research Articles

Enhancing intracellular delivery of protein kinase C beta II peptide inhibitor using myristic acid-trans-activator of transcription via N-terminus conjugation in isolated rat polymorphonuclear leukocytes

Introduction: Protein kinase C beta II (PKCβII) activation promotes polymorphonuclear (PMN) superoxide (SO) production by phosphorylating serine and threonine amino acid residues on NADPH oxidase (NOX-2). Previous studies have shown that cell permeable myristic acid-conjugated PKCβII inhibitor (myr-PKCβII-; SLNPEWNET) (20 μM) remarkably attenuated phorbol 12-myristate 13-acetate (PMA)-induced PMN SO release when compared to scrambled control peptide (myr-PKCβII- scram; WNPESLNTE), unconjugated peptides and nontreated controls by ~35%. This suggests an enhanced intracellular delivery of PKCβII-. Studies have also shown that SO release is attenuated via trans-activator of transcription-conjugated (Tat; YGRKKRRQRRR) NOX-2 inhibitor (Nox2ds-Tat) (80 μM) by ~37%. There have not been evaluations of Tat- or dual myr-Tat-conjugated PKCβII-. We hypothesize that dual myr-Tat-conjugation would enhance the intracellular delivery of PKCβII- and reduce SO release compared to myr-, Tat-, and myr-Tat-PKCβII- scram. Methods: This study focused on the effects of myr-Tat-PKCβII- on intracellular delivery compared to myr-PKCβII-, Tat -PKCβII-, and myr-Tat-PKCβII- scram, with 0.5% dimethyl sulfoxide (DMSO) vehicle as the control. Sprague-Dawley (SD) male rats (~400g) were anesthetized with isoflurane and given a 0.5% glycogen i.p. injection (16ml), and 16-18hrs later, PMNs were harvested from the peritoneal cavity and incubated for 15min at 37oC with 5μM myr-Tat-PKCβII-, myr-PKCβII-, Tat-PKCβII-, or myr-Tat-PKCβII- scram. PMN SO release was calculated spectrophotometrically by the change in absorbance at 550 nm over 390s via ferricytochrome c reduction after PMA stimulation (100nM). Data were analyzed with ANOVA Fisher’s PLSD post-hoc analysis. Results: Myr-Tat-PKCβII- (n=20, 0.338±0.024, p<0.05) and Myr-PKCβII- (n=8, 0.342±0.041, p<0.05) displayed significant attenuation of SO release by 28% and 27%, respectively, compared to 0.5% DMSO control (n=81, 0.470±0.013). Tat-PKCβII- (n=5, 0.404±0.049) showed attenuated SO release by 14% when compared to the vehicle control. Myr-Tat-PKCβII- scram (n=3, 0.542±0.081) showed an increase in SO release by 15% when compared to the vehicle control. Cell viability was > 85% in all groups. Conclusion: The results of the study suggest that intracellular delivery of PKCβII- cargo using myr-Tat dual conjugation is enhanced when compared to myr-, Tat-conjugated PKCβII-, and myr-Tat-PKCβII- scram. Future studies will utilize western blot analysis and immunohistochemistry to assess the translocation and activity of PKCβII- when conjugated with myr-Tat, myr-, or Tat- peptides. Funding: This study was funded by the National Heart, Lung & Blood Institute (1R43HL160338) SBIR phase I grant that was awarded to Young Therapeutics, LLC. Philadelphia College of Osteopathic Medicine, the Department of Biomedical Sciences, the Division of Research and the Center for Chronic Diseases of Aging. and Young Therapeutics, LLC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

New C9 -Monoterpenoid Alkaloids Featuring a Rare Skeleton with Anti-Inflammatory and Antiviral Activities from Forsythia suspensa.

Forsyqinlingines C (1) and D (2), two C9 -monoterpenoid alkaloids bearing a rare skeleton, were isolated from the ripe fruits of Forsythia suspensa. Their structures, including absolute configurations, were fully elucidated by extensive spectroscopic data and ECD experiments. The plausible biogenetic pathway for compounds 1 and 2 was also proposed. In vitro, two C9 -monoterpenoid alkaloids showed anti-inflammatory activity performed by the inhibitory effect on the release of β-glucuronidase in rat polymorphonuclear leukocytes (PMNs), as well as antiviral activity against influenza A (H1N1) virus and respiratory syncytial virus (RSV).

Autonomous regulation of inducible nitric oxide synthase and cytochrome P450 2E1-mediated oxidative stress in maneb- and paraquat-treated rat polymorphs

Maneb (MB)- and paraquat (PQ)-induced oxidative stress in rat polymorphonuclear leukocytes (PMNs) is regulated in parallel by cytochrome P450 2E1 (CYP2E1) and inducible nitric oxide synthase (iNOS). However, mechanism underlying their regulation is not yet understood. The study investigated the role of nuclear factor- kappa B (NF-κB) and mitogen-activated protein kinase/extracellular signal regulated kinase/protein kinase C (MEK/ERK/PKC) pathway in the regulation of iNOS- and CYP2E1-induced oxidative stress in PMNs. MB + PQ-induced changes in nitrite content, lipid peroxidation (LPO), iNOS expression/activity and inflammatory mediators were alleviated by aminoguanidine (AG), an iNOS inhibitor, without any change in CYP2E1. Alternatively, diallyl sulphide (DAS), a CYP2E1 inhibitor, rescued from MB + PQ-induced changes in CYP2E1 activity/expression, free radical generation, superoxide dismutase (SOD) activity, LPO and pro-inflammatory cytokines without any alterations in nitrite content and iNOS activity/expression. Pyrrolidine dithiocarbamate (PDTC), NF-κB inhibitor, did not alter CYP2E1 but mitigated free radical generation, SOD activity, LPO, nitrite content, iNOS activity/expression and levels of pro-inflammatory cytokines (tumor necrosis factor-α, interleukine-1β and interleukine-4). Ex-vivo treatment with MEK inhibitor (PD98059), ERK1/2 inhibitor (AG126) or PKC inhibitor (rottlerin) ameliorated MB + PQ-induced increase in free radical generation and CYP2E1 activity/expression in PMNs. While PD98059 and AG126 abated MB + PQ-induced increase in ERK1/2, PKC-α/δ and CYP2E1 levels, rottlerin restored PKC-α/δ and CYP2E1 towards normalcy without affecting ERK1/2 level in MB + PQ-treated group. The results suggest that iNOS and CYP2E1 contributing to MB + PQ-induced oxidative stress in rat PMNs exhibit differential regulatory mechanisms. The inflammatory mediators regulate iNOS expression while CYP2E1 expression is triggered via MEK-ERK1/2-PKC pathway.

Size-Dependent Phagocytic Uptake and Immunogenicity of Gliadin Nanoparticles.

The main objective of the present study was to investigate the hemo and immune compatibility of gliadin nanoparticles as a function of particle size. Gliadin nanoparticles of different size were prepared using a modified antisolvent nanoprecipitation method. The hemolytic potential of gliadin nanoparticles was evaluated using in vitro hemolysis assay. Phagocytic uptake of gliadin nanoparticles was studied using rat polymorphonuclear (PMN) leukocytes and murine alveolar peritoneal macrophage (J774) cells. In vivo immunogenicity of gliadin nanoparticles was studied following subcutaneous administration in mice. Gliadin nanoparticles were non-hemolytic irrespective of particle size and hence compatible with blood components. In comparison to positive control zymosan, gliadin nanoparticles with a size greater than 406 ± 11 nm showed higher phagocytic uptake in PMN cells, while the uptake was minimal with smaller nanoparticles (127 ± 8 nm). Similar uptake of gliadin nanoparticles was observed in murine alveolar peritoneal macrophages. Anti-gliadin IgG antibody titers subsequent to primary and secondary immunization of gliadin nanoparticles in mice were in the increasing order of 406 ± 11 nm < 848 ± 20 nm < coarse suspension). On the other hand, gliadin nanoparticles of 127 ± 8 nm in size did not elicit immunogenic response. Phagocytosis and immunogenicity of gliadin nanoparticles are strongly influenced by particle size. The results of this study can provide useful information for rational design of protein-based nanomaterials in drug delivery applications.

Abstract 447: Myristoylation of Protein Kinase C Beta II Peptide Inhibitor Facilitates Rapid Attenuation of Phorbol 12-myristate 13-acetate in Activated Superoxide Release in Isolated Rat Polymorphonuclear Leukocytes

Protein kinase C beta II (PKCβII) activates polymorphonuclear leukocyte (PMN) superoxide (SO) production via NADPH oxidase (NOX-2) phosphorylation to exacerbate myocardial ischemia/reperfusion (I/R) injury. In prior studies, myristoylation (myr) of PKCβII peptide inhibitor (N-myr-SLNPEWNET; myr-PKCβII-), which disrupts PKCβII translocation/phosphorylation of NOX-2, was shown to dose-dependently attenuate PMN SO release induced by phorbol 12-myristate 13-acetate (PMA), a broad-spectrum PKC agonist. However, the role of myr on the inhibitory effects of myr-PKCβII- has yet to be elucidated. We hypothesized that myr-PKCβII peptide activator (N-myr-SVEIWD; myr-PKCβII+) would augment, myr-PKCβII- would attenuate, and scrambled myr-PKCβII- (N-myr-WNPESLNTE; myr-PKCβII-scram), a control for myr, would not affect PMA-induced PMN SO release compared to unconjugated peptides and nontreated controls. Rat PMNs (5х10 6 ) were incubated for 15 min at 37 o C in the presence/absence of SO dismutase (SOD; 10 μg/mL), unconjugated PKCβII+/-, myr-PKCβII+/-, or myr-PKCβII-scram (all 20 μM). SO release was measured by the change in absorbance at 550 nm via ferricytochrome c reduction after PMA (100 nM) stimulation for 390 sec. Data were analyzed by ANOVA using Student-Newman-Keuls post hoc analysis. Myr-PKCβII- significantly attenuated SO release (0.30±0.02; n=27; p&lt;0.05) compared to nontreated controls (0.46±0.01; n=73), myr-PKCβII+ (0.46±0.03; n=25), unconjugated PKCβII+ (0.43±0.04; n=15), PKCβII- (0.43±0.02; n=22) and myr-PKCβII-scram (0.65±0.04; n=22). SOD (n=8), which rapidly converts SO to H 2 O 2 , significantly reduced absorbance by 94±7%, indicating that absorbance increased mainly due to PMA stimulation. Cell viability (trypan blue exclusion) was similar in all groups (94±2%). Unexpectedly, myr-PKCβII-scram significantly stimulated the highest increase in absorbance compared to all groups (p&lt;0.01). Future studies will determine whether myr-PKCβII-scram augments absorbance by a different mechanism. Results suggest that myr improves myr-PKCβII- delivery compared to unconjugated PKCβII- but does not affect inhibition of PMA-induced PMN SO release. Myr-PKCβII- may thus effectively limit inflammation-induced I/R injury.

Myristoylation of Novel Protein Kinase C Beta II Peptide Inhibitor is Required for the Attenuation of Phorbol 12‐myristate 13‐acetate‐induced Superoxide Release in Isolated Rat Polymorphonuclear Leukocytes

Polymorphonuclear leukocyte (PMN) superoxide (SO) production by NADPH oxidase (NOX‐2) activation contributes to myocardial ischemia‐reperfusion (I/R) injury. Protein kinase C beta‐II (PKC βII) is a principal mediator of NOX‐2 activation via phosphorylation of NOX‐2 cytosolic protein p47phox. Phorbol 12‐myristate 13‐acetate (PMA) is a known broad‐spectrum PKC agonist that induces PMN SO release. In prior studies, selective PKCβII inhibition with myristoylated PKCβII peptide inhibitor (N‐myr‐SLNPEWNET; myr‐PKCβII‐) attenuated PMA‐induced PMN SO release and myocardial I/R injury in a dose‐dependent manner. However, the role of myristoylation mediating the inhibitory effects of myr‐PKCβII‐ on PMN SO release needs to be determined. Therefore, we aim to confirm the role of PKCβII by using myristoylated PKCβII peptide activator (N‐myr‐SVEIWD; myr‐PKCβII+) and myr‐PKCβII‐ that influence PKCβII translocation. Whereas, myr‐scrambled PKCβII‐ (N‐myr‐WNPESLNTE; myr‐PKCβII‐scram) is a control for myristoylation. We hypothesize that myr‐PKCβII+ should augment, myr‐PKCβII‐should attenuate, and myr‐PKCβII‐scram should have no effect on PMA‐induced PMN SO release compared to non‐treated and unconjugated peptide controls. PMNs (5×106) isolated from male Sprague‐Dawley rats (~400g) were incubated for 15 min at 37°C in the presence/absence of SO dismutase (SOD; 10μg/mL, positive control), unconjugated PKCβII+/− (20 μM), myr‐PKCβII+/− (20 μM), or myr‐PKCβII‐scram (20 μM). SO release was evaluated by the absorbance change (at 550 nm) via ferricytochrome c reduction after PMA stimulation (100 nM) for 390 sec. Data were analyzed by ANOVA using Bonferroni‐Dunn post‐hoc analysis. Myr‐PKCβII‐ significantly attenuated PMA‐induced PMN SO release (0.29±0.02; n=36; p&lt;0.05) when compared to myr‐PKCβII+ (0.42±0.03; n=29), myr‐PKCβII‐scram (0.53±0.05; n=10), and non‐treated controls (0.41±0.02; n=55). Unconjugated PKCβII+ (0.41±0.04; n=16) and PKCβII‐(0.40±0.04; n=28) were similar to non‐treated controls. SOD (n=8) significantly reduced SO release by 94±7% compared to all groups (p&lt;0.01). Cell viability determined by 0.2% trypan blue exclusion was similar in all groups, 94±2%. Unexpectedly, myr‐PKCβII‐scram rather than myr‐PKCβII+ PMNs exhibited the highest PMA‐induced PMN SO release but was not significantly different from untreated controls. Additional experiments will determine whether myr‐PKCβII‐scram significantly enhances SO release. Results suggest myr‐ conjugation improved myr‐PKCβII‐ delivery compared to unconjugated PKCβII‐ but does not contribute to the inhibitory effects of PMA‐induced PMN SO release. Therefore, myr‐PKCβII‐ may be an effective therapeutic intervention to limit inflammation‐induced I/R injury.Support or Funding InformationThis research was supported by the Division of Research, Department of Biomedical Sciences, and the Center for Chronic Disorders of Aging at Philadelphia College of Osteopathic Medicine. Current license is supported by Young Therapeutics, LLC.

Labdane diterpenoids from Forsythia suspensa with anti-inflammatory and anti-viral activities

Five previously undescribed labdane diterpenoids, named Forsypensins A-E, were isolated from the fruits of Forsythia suspensa. The structures and relative configurations of the compounds were elucidated via extensive spectroscopic methods, and their absolute configurations were fully confirmed by single crystal X-ray diffraction analyses using Cu Kα radiation and electronic circular dichroism data. The five labdane diterpenoids showed in vitro anti-inflammatory activity in rat polymorphonuclear leukocytes, inhibiting the rates of β-glucuronidase release by 43.6%–49.2% at concentrations of 10 μM. The compounds also had anti-viral activity against influenza A (H1N1) virus and respiratory syncytial virus (RSV), with IC50 values in the range 21.8–27.4 μM, and EC50 values in the range 10.5–15.4 μM, respectively.

Three new secoiridoid glycosides from the flower buds of Lonicera japonica.

Three new secoiridoid glycosides, named lonijapoglycol A (1), aldosecolohanin C (2) and aldosecolohanin B (3), together with three known ones (4-6), have been isolated from the flower the buds of Lonicera japonica. All the structures were identified by spectroscopic analyses. Lonijapoglycol A (1) expressed significant anti-inflammatory activity to inhibit the release of β-glu-curonidase induced by platelet-activating factor in rat polymorphonuclear leukocytes with an IC50 value of 3.76 μmol·L-1.

Correction to: CYP2E1-mediated oxidative stress regulates HO-1 and GST expression in maneb- and paraquat-treated rat polymorphonuclear leukocytes.

In the original publication of the article, the wrong β-actin blots were pasted in Figs. 1b and 2c. The correct versions of Figs. 1b and 2c are given in this correction.

Protein Kinase C Beta II Peptide Modulation of Superoxide Release in Rat Polymorphonuclear Leukocytes

Previous studies have shown that protein kinase C (PKC) alpha, beta II (βII) and zeta inhibition attenuates polymorphonuclear leukocyte (PMN) superoxide (SO) release, whereas PKC delta inhibition augments this response via inhibiting phosphorylation of PMN NADPH oxidase (NOX‐2). However, to date, there is no information regarding the role of PKCβII peptide activator on regulating PMN SO release. PKCβII activator and inhibitor peptides work by augmenting or attenuating PKCβII translocation after stimulation by N‐formyl‐L‐methionyl‐Lleucyl‐L‐phenylalanine (fMLP; a PMN chemotactic receptor agonist) or phorbol 12‐myristate 13‐acetate (PMA; a diacylglycerol mimetic). It is known that myristic acid (myr‐) conjugation is an effective means to facilitate intracellular delivery of the cargo sequence to regulate PKCβII activity. We hypothesize that myr‐PKCβII peptide‐activator (N‐myr‐SVEIWD; myr‐PKCβ+) would increase PMA/fMLP‐induced rat PMN SO release, whereas, myr‐PKCβII peptideinhibitor (N‐myr‐SLNPEWNET; myr‐PKCβ−) would attenuate this response compared to non‐drug treated controls or unconjugated native PKCβ+/− peptide sequences. PMNs were isolated via peritoneal lavage from male Sprague‐Dawley rats (~500g) and were incubated (5x106) for 15min at 37°C in the presence/absence of native/myr‐PKCβ+/− (20 mM; n=8[fMLP]) or SO dismutase (SOD;10mg/mL; n=8) as positive control. fMLP or PMA induced PMN SO release was measured spectrophotometrically at 550nm via reduction of ferricytochrome c for 90 sec (fMLP;1mM; n=19) or 360 sec (PMA;100nM; n=17). fMLP‐induced PMN SO release increased absorbance to 0.155±0.018 in non‐drug controls, 0.162±0.037 in myr‐PKCβ+, 0.136±0.025 in native PKCβ+, 0.070±0.012 in myr‐PKCβ− and 0.146±0.018 in native PKCβ− treated PMNs at 30 sec. Myr‐PKCβ− significantly decreased fMLP‐induced PMN SO release compared to nondrug controls, myr‐PKCβ+ and native PKC β+/− peptides (p&lt;0.05). PMA‐induced PMN SO release increased absorbance to 0.41±0.039 in non‐drug controls, 0.517±0.047(n=7) in myr‐PKCβ+, 0.345±0.071(n=5) in native PKCβ+, 0.241±0.055(n=6) in myr‐PKCβ−, and 0.308±0.052(n=6) in native PKC β− at 360 sec. Myr‐PKCβ‐significantly attenuated PMA‐SO release compared to non‐drug controls and myr‐PKCβ+ (p&lt;0.05). SOD‐treated samples showed &gt;90% reduction of fMLP or PMA‐induced SO release and native PKCβ+/− was not different from non‐drug controls. Cell viability ranged between 94±2% and 98±2% in all groups as determined by 0.2% trypan blue exclusion. Preliminary results suggest that myr‐PKCβ‐significantly attenuates fMLP/PMA‐induced SO release, whereas myr‐PKCβ+ only shows a trend to augment fMLP/PMA‐induced SO release. Additional studies will be conducted to determine if myr‐PKCβ+ will significantly augment PMN SO release.Support or Funding InformationThis research was supported by the Department of Bio‐Medical Sciences and the Division of Research at Philadelphia College of Osteopathic Medicine (PCOM) and by Young Therapeutics, LLC. 4170 City Avenue, Philadelphia, PA 19131This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A new anti-inflammatory lignan from Lonicerae Japonicae flos

One new lignan, loniceralanside A (1), together with three known compounds (2–4), were purified from Lonicerae Japonicae Flos. Their structures were determined by HR-ESI-MS, 1 D and 2 D NMR data. Compounds 2–4 were separated from the plant for the first time. The biological test showed that compound 1 had significant anti-inflammatory activity with inhibiting the release of β-glucuronidase induced by platelet-activating factor (PAF) in rat polymorphonuclear leukocytes (PMNs) (IC50 = 3.05 µM).

Separation of Five Iridoid Glycosides from Lonicerae Japonicae Flos Using High-Speed Counter-Current Chromatography and Their Anti-Inflammatory and Antibacterial Activities.

A high-speed counter-current chromatography (HSCCC) method, using a two-phase solvent system composed of ethyl acetate/n-butanol/methanol/water (5:1:1:5, v/v/v/v), was successfully established to separate the five iridoid glucosides 7-O-ethyl sweroside (1), secologanin dimethylacetal (2), adinoside F (3), (7R)-secologain n-butyl methyl acetal (4) and adinoside G (5) from Lonicerae Japonicae Flos. Their purities were 96.8%, 98.5%, 93.3%, 98.0% and 99.9%, respectively. All the iridoid glucosides were identified by HR-ESI-MS, 1D and 2D NMR. Compounds 3 and 5 are new iridoid glucosides. The anti-inflammatory tests showed that compounds 1–5 all expressed moderate inhibitory effects on β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor (PAF) with IC50 values ranging from 4.52 to 6.50 µM, while the antibacterial assays demonstrated that all the compounds displayed mild inhibitory activities against Staphylococcus aureus ATCC 25923 with MIC values ranging from 13.7 to 26.0 µg/mL.

Two new polyketides from the roots of Stemona tuberosa

Two polyketides, stemonones A (1) and B (2) with new skeletons, were isolated from the roots of Stemona tuberosa. Their absolute structures were fully characterized by comprehensive spectroscopic analyses and comparison of experimental electronic circular dichroism (ECD) spectra with calculated ones. The plausible biosynthetic pathways for 1 and 2 were also proposed. Anti-inflammatory assay confirmed that the two compounds showed moderate inhibitory effects on β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor.

Novel sesquilignan and lignan glycoside from the twigs and leaves of Illicium majus

A novel sesquilignan compound (1), possesing an unusual carbon skeleton of aryltetralin unit linked with a C6-C3 unit and a five-membered ring by a C-7″ and C-4 linkage pattern via an oxygen atom, and a new lignan glycoside (2) have been isolated from the twigs and leaves of Illicium majus. Their structures were determined by spectroscopic analysis and chemical methods. The absolute configurations of 1 and 2 are confirmed by observing the circular dichroism. At 10 μM, Compounds 1 and 2 showed in Vitro inhibitory activity against the release of β-glucuronidase in rat polymorphonuclear leukocytes induced by platelet-activating factor.

Anti-inflammatory lignans from Melodinus suaveolens

Three new lignans, melodinins A–C (1–3), together with four known analogues (4–7), were isolated from the stems of Melodinus suaveolens. Their structures including relative configurations were determined by spectroscopic methods, including 1D and 2D NMR, and HRESIMS. Their absolute configurations were unambiguously assigned by electronic circular dichroism (ECD) experiments, especially the application of ECD exciton chirality method. Anti-inflammatory evaluation revealed that compounds 1, 2, 4, and 5 exhibited moderate inhibitory effects on β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor, with IC50 values ranging from 1.68 to 9.56 μM.

New Flavonoid Glucuronate Esters with Anti‐inflammatory Activities from Scutellaria regeliana

Two new flavonoid glucuronate esters, named scuregeliosides A and B (1 and 2), as well as three known ones, chrysin-7-O-β-d-glucuronic acid methyl ester (3), 5,7,4'-trihydroxyflavone-8-O-β-d-glucuronic acid methyl ester (4) and apigenin-7-O-β-d-glucuronic acid ethyl ester (5), were isolated from the ethanolic extract of the whole plant of Scutellaria regeliana. Their chemical structures were elucidated on the basis of comprehensive spectroscopic analyses. Five compounds were screened for anti-inflammatory activity in vitro. As the results, the inhibition rates of release of β-glucuronidase from rat polymorphonuclear leukocytes were in the range of 42.2 - 47.1% at a concentration of 10 μm.

Scumoniliosides A and B, two new flavanone glucuronate esters from Scutellaria moniliorrhiza Komarov with anti-inflammatory activities

Two new flavanone glucuronate esters, named scumoniliosides A and B (1-2), along with two known flavonoid glucuronate esters, 5,4′-dihydroxyflavonoid-7-O-β-d-glycuronate methyl ester (3) and 5,4′-dihydroxyflavonoid-7-O-β-d-glycuronate butyl ester (4), were isolated from the ethanolic extract of the whole plant of Scutellaria moniliorrhiza. Their chemical structures including absolute configurations were determined by means of integrated spectroscopic techniques. In vitro, four compounds showed anti-inflammatory activities, with the inhibition rates of release of β-glucuronidase from rat polymorphonuclear leukocytes being in the range 43.5%-48.1% at concentrations of 10 μM.

Isolation and Purification of Three Ecdysteroids from the Stems of Diploclisia glaucescens by High-Speed Countercurrent Chromatography and Their Anti-Inflammatory Activities In Vitro.

High-speed counter-current chromatography was used to separate and purify ecdysteroids for the first time from the stems of Diploclisia glaucescens using a two-phase solvent system composed of ethyl acetate–n-butanol–ethanol–water (3:0.2:0.8:3, v/v). Three ecdysteroids were obtained from 260 mg of ethyl acetate extract of the residue obtained after evaporation of the crude ethanolicextractof D. glaucescens in one-step separation, which were identified as paristerone (I, 30.5 mg), ecdysterone (II, 7.2 mg), and capitasterone (III, 8.1 mg) by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). Their anti-inflammatory activities were evaluated by measuring the inhibitory ratios of β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor. Compounds I–III showed significant anti-inflammatory activities with IC50-values ranging from 1.51 to 11.68 μM, respectively.

IFN-γ regulates xanthine oxidase-mediated iNOS-independent oxidative stress in maneb- and paraquat-treated rat polymorphonuclear leukocytes.

Maneb (MB) and paraquat (PQ) provoke oxidative stress-mediated cell damage. Role of xanthine oxidase (XO) in oxidative stress and its association with nitric oxide (NO)/NO synthase (NOS) have been widely reported. While inducible NOS (iNOS) is implicated in MB+PQ-induced toxicity in rat polymorphonuclear leukocytes (PMNs), role of XO and its alliance with iNOS have not yet been established. The study investigated the role of XO in MB+PQ-induced oxidative stress in rat PMNs and its regulation by iNOS and inflammatory cytokines. MB+PQ-augmented reactive oxygen species (ROS), superoxide, nitro-tyrosine, lipid peroxidation (LPO), and nitrite levels along with the catalytic activity of iNOS, superoxide dismutase (SOD), and XO. XO inhibitor, allopurinol (AP), alleviated MB+PQ-induced changes except nitrite content and iNOS activity. Conversely, an iNOS inhibitor, aminoguanidine, mitigated MB+PQ-induced LPO, nitrite, iNOS, and nitro-tyrosine levels; however, no change was observed in ROS, SOD, and XO. Nuclear factor-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), tumor necrosis factor-alpha (TNF-α) inhibitor, pentoxyfylline, and an anti-inflammatory agent, dexamethasone, attenuated MB+PQ-induced increase in XO, superoxide, and ROS with parallel reduction in the expression of interferon-gamma (IFN-γ), TNF-α, and interleukin-1β (IL-1β) in rat PMNs. Exogenous IFN-γ, TNF-α, and IL-1β enhanced superoxide, ROS, and XO in the PMNs of control and MB+PQ-treated rats; however, IFN- γ was found to be the most potent inducer. Moreover, AP ameliorated cytokine-induced free radical generation and restored XO activity towards normalcy. The results thus demonstrate that XO mediates oxidative stress in MB+PQ-treated rat PMNs via iNOS-independent but cytokine (predominantly IFN-γ)-dependent mechanism.

Melaxillines A and B, monoterpenoid indole alkaloids from Melodinus axillaris

Two new monoterpenoid indole alkaloids, melaxillines A (1) and B (2), together with four known alkaloids (3–6), were isolated from the roots of Melodinus axillaris. The structures were determined by extensive spectroscopic methods, including 1D and 2D-NMR spectroscopy, high resolution mass spectrometric data, and by comparison to literature data. New compounds 1–2 might be derived from a common precursor (3) by proposing their biogenetic route, and compound 1 represents the first Melodinus alkaloid featuring an ethyl acetate group skeleton at C-18. The anti-inflammatory effects of all the isolated compounds were evaluated by measuring the inhibitory ratios of β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor. Compounds 1–4 showed significant anti-inflammatory activities with IC50 values ranging from 1.51 to 21.56μM, respectively.