Immunomodulatory role of Withania somnifera root powder on experimental induced inflammation: An in vivo and in vitro study

The aqueous suspension of Withania somnifera root powder was investigated for their in vivo and in vitro immunomodulatory properties. W. somnifera showed potent inhibitory activity towards the complement system, mitogen induced lymphocyte proliferation and delayed-type hypersensitivity reaction. Administration of W. somnifera root powder did not have a significant effect on humoral immune response in rats. Our results report immunosuppressive effect of W. somnifera root powder, thus it could be a candidate for developing as an immunosuppressive drug for the inflammatory diseases.     

舟山眼镜蛇毒细胞毒素的分离纯化及其体外抗肿瘤活性

目的从眼镜蛇毒中分离纯化细胞毒素 F(CTX F)并鉴定其活性。方法应用凝胶过滤、离子交换柱色谱及疏水柱色谱等方法从舟山眼镜蛇毒中分离纯化CTX F ,以SRB法观察CTX F对体外培养癌细胞的杀伤作用。结果眼镜蛇毒粗毒经凝胶过滤获得 4个蛋白峰 ,将CTX所在第Ⅳ峰用阳离子交换柱色谱获A、B、C、D、E、F和G等7个组分 ,其中E、F和G具CTX活性 ,将F组分再经凝胶过滤和疏水色谱进一步纯化得不含磷酯酶A2 (PLA2 )的CTX纯品 ,暂定名为CTX F ,它对多种癌细胞株有杀伤作用。结论应用凝胶过滤、离子交换和疏水色谱等方法可从眼镜蛇毒中获得不含PLA2 的CTX ,其组分F有抗肿瘤活性     

In vitro potential modulation of baicalin and baicalein on P-glycoprotein activity and expression in Caco-2 cells and rat gut sacs

Context Previous studies have shown that Scutellariae Radix, the dried root of Scutellaria baicalensis Georgi (Labiatae), has a certain inhibitory effect on P-glycoprotein (P-gp), but the effects of its main active constituents on P-gp are still ambiguous.

Objectives In vitro studies were performed to investigate the effects of its main active constituents (baicalin and its aglycone, baicalein) on the activity and expression of P-gp in intestine using Caco-2 cells and rat gut sacs.

Materials and methods In Caco-2 cell experiments, the effects of baicalin and baicalein on P-gp activity were investigated using a P-gp substrate, rhodamine 123 and non-substrate fluorescein Na, by determining their intracellular fluorescence accumulation, and their effects on P-gp expression were determined using flow cytometry. In addition, rat gut sac model was selected to investigate the effects of baicalin and baicalein on the transport of verapamil, a classical P-gp substrate. The gut sacs of male Sprague–Dawley rats were filled with 0.4?mL the test solution contained verapamil (0.2575?mg/mL) and the drugs [baicalin and baicalein, at concentrations of 1/8 IC₅₀ (59.875, 41.5?μg/mL), 1/4 IC₅₀ (119.75, 83?μg/mL) and 1/2 IC₅₀ (239.5, 166?μg/mL)], and then incubated in Tyrode’s solution for a period of time. After termination of the incubation, the incubated solution was processed for the subsequent detection.

Results According to the results of MTT assay, the IC₅₀ values of verapamil, baicalin and baicalein were 104, 479, 332?μg/mL, respectively. The obtained results from the two models were confirmed mutually. As a result, baicalin exhibited no obvious effect on intracellular accumulation of Rh-123, and almost had no effect on P-gp expression and verapamil transportation, while baicalein significantly increased intracellular accumulation of Rh-123 (p?<?0.01), down-regulated P-gp expression (p?<?0.01) and increased the transport of verapamil (p?<?0.05).

Discussion and conclusion The results indicated that baicalein may be a P-gp inhibitor, which presented obvious inhibitory effects on P-gp activity and expression level. A comparison of the structures of baicalin and baicalein indicates that the existence of glucosyl plays a decisive role in influencing the activity and expression of P-gp.     

Lack of effect of 5-aminosalicylic acid on platelet aggregation and fibrinolytic activity in vivo and in vitro

Summary We have studied platelet aggregation and fibrinolytic activity in six patients with chronic inflammatory bowel disease treated with 5-aminosalicylic acid (mesalazine).There were no changes in these measurements during normal treatment, i.e. 1.5 g per day with a slow-release formulation, nor after an intravenous dose of 250 mg. Also in vitro tests were negative, in contrast to the inhibition seen with aspirin (acetylsalicylic acid).We conclude that treatment with mesalazine does not constitute a hazard to these patients in regard to prolonged bleeding time caused by an influence on platelet aggregation or fibrinolytic activity.     

Non‐peptide‐based new class of platelet aggregation inhibitors: Design,synthesis, bioevaluation,SAR, and in silico studies

A series of 2‐oxo‐2‐phenylethylidene linked 2‐oxo‐benzo[1,4]oxazine analogues 17a–x and 18a–o , incorporated with a variety of electron‐withdrawing as well as electron‐donating groups at ring A and ring C, were synthesized under greener conditions in excellent yields (up to 98%). These analogues 17a–x and 18a–o were evaluated for their arachidonic acid (AA)‐induced platelet aggregation inhibitory activities in comparison with the standard reference aspirin (IC₅₀ = 21.34 ± 1.09 µg/mL). Among all the screened compounds, eight analogues, 17i , 17x , 18f , 18g , 18h , 18i , 18l , and 18o , were identified as promising platelet aggregation inhibitors as compared to aspirin. In addition, cytotoxic studies in 3T₃ fibroblast cell lines by MTT assay of the promising compounds ( 17i , 17x , 18f–18i , 18l , and 18o ) were also performed and the compounds were found to be non‐toxic in nature. Furthermore, the results on the AA‐induced platelet aggregation inhibitory activities of these compounds ( 17i , 17x , 18f–18i , 18l , and 18o ) were validated via in silico molecular docking simulation studies. To the best of our knowledge, this is the first report of the identification of non‐peptide‐based functionalized 2‐oxo‐benzo[1,4]oxazines as platelet aggregation inhibitors.

     

Effect of 5-HT2 receptor antagonist ergolines and their desisopropyl metabolites on rabbit platelet aggregation in vitro and ex vivo

Amesergide and LY215840 are potent and long-lasting 5-HT₂ receptor antagonists after oral administration to animals. In animals, these ergolines are metabolized to their desisopropyl ergoline congeners which have lower affinity (40–60 nM) at 5-HT₂ receptors in the rat relative to higher 5-HT₂ receptor affinity (2–3 nM) at the cloned human 5-HT₂ receptor. Because amesergide and LY215840 are effective in rabbit models of thrombosis, we asked whether their efficacy in the rabbit was related in part to the activity of both the parent and desisopropyl metabolites at rabbit platelet 5-HT₂ receptors. Platelet aggregation responses were first optimized to ADP and the combination of ADP and serotonin with regard to platelet number (300,000 platelets/μl of plasma) and time (70 to 140 min after platelet harvest). In ex vivo studies, both amesergide and LY215840 (3.0 mg/kg p.o.) showed similar and marked antagonism of rabbit platelet 5-HT₂ receptors at 1 and 24 h after their oral administration to rabbits. Furthermore, the desisopropyl ergoline metabolites of both amesergide and LY215840 inhibited serotonin-amplified platelet aggregation responses in vitro as did amesergide and LY215840. Thus, these studies add support to the hypothesis that the desisopropyl metabolites of amesergide and LY215840 may contribute to the oral antithrombotic efficacy of the parent molecules in rabbits.     

Ameliorative effects of curcumin towards cyclosporine-induced genotoxic potential: an in vitro and in silico study

Several studies documented the ameliorative effects of curcumin which plays a pivotal role in radical scavenging activities. It also participates in various cellular pathways and interacts with multiple targets. In the present study, we investigated the ameliorative effect of curcumin upon chromosomal genotoxicity induced by cyclosporine, an immunosuppressant, using in vitro approaches. A plausible mechanism of how curcumin mitigates the genotoxic implications of cyclosporine was ascertained using in silico tools. We observed that the curcumin reduces the genotoxic consequences made by cyclosporine upon cell cycle checkpoints and associated chromosomal/DNA manifestations. In addition, we presented the mechanistic details of curcumin interaction with various biomacromolecule types using docking experiments which showed that the possible radical scavenging activities can only be emerged by inducing the expression of antioxidant enzymes, supported by available experimental evidences. We anticipate that the induction of antioxidant enzymes by curcumin would activate Nrf2-Keap1 pathway as the plausible mechanism to exert anti-inflammatory response as demonstrated in renal epithelial cells.     

Advances in the pathophysiology of constitutive and inducible cyclooxygenases: two enzymes in the spotlight

The aim of this commentary is to discuss recent data on the role of prostaglandins generated by both constitutive and inducible cyclooxygenases (COXs). According to a popular hypothesis, COX-1 generates 'good' prostaglandins for physiological 'housekeeping' functions like gastrointestinal (GI) mucosal integrity and regulation of renal blood flow, while COX-2 forms the 'bad' prostaglandins responsible for inflammatory symptoms. However, recent data show that the biological functions of prostanoids formed by the two enzymes are much more complex and interrelated than previously appreciated. Experimental evidence indicates that a full inflammatory response is likely sustained by prostanoids generated by both enzymes, and an effective anti-inflammatory effect requires the inhibition of the two enzymes. Similarly, the selective inhibition of either COX-1 or COX-2 does not elicit GI damage, but inhibition of both enzymes is necessary for GI mucosal damage to develop. Prostaglandins generated by both enzymes contribute to normal renal function by regulating the vascular tone and the normal blood flow. The synthesis of endothelial prostacyclin is mainly driven by COX-2, so that the selective COX-2 inhibition may bias vascular prostaglandin synthesis in favour of COX-1-derived thromboxane A(2) in platelets, leading to a prothrombotic outcome. Moreover, prostaglandins formed by COX-2 appear to have a major role in myocardial protection. We propose that the complexity of the situation in the field of COX-derived mediators should be borne in mind when anti-inflammatory therapy is required.     

Synthesis,in-vitro and in-silico study of novel thiazoles as potent antibacterial agents and MurB inhibitors

Efficient procedures are herein reported for the synthesis of novel hybrid thiazoles via a one-pot three-component protocol. The protocol involves the reaction of novel aldehyde, thiosemicarbazide and halogen-containing reagents in solvent- and catalyst-free conditions. The structures of the new thiazoles were elucidated by elemental analyses and spectroscopic data. The in-vitro antibacterial screening and MurB enzyme inhibition assays were performed for the novel thiazoles. The thiazol-4(5H)-one derivative 6d , with p-MeO, exhibits the best antibacterial activities with minimum inhibitory concentration values of 3.9, 3.9, 7.8, and 15.6 μg/ml against Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus mutans, and Escherichia coli, respectively, as compared to the reference antibiotic drugs. It also exhibits the highest inhibition of the MurB enzyme with an IC₅₀ of 8.1 μM. The structure–activity relationship was studied to determine the effect of the structures of the newly prepared molecules on the strength of the antibacterial activities. Molecular docking was also performed to predict the binding modes of the new thiazoles in the active sites of the E. coli MurB enzyme.     

Inhibition of key enzymes in the inflammatory pathway by hybrid molecules of terpenes and synthetic drugs: In vitro and in silico studies

The aim of this work was to compare the anti‐inflammatory activity of compounds prepared from terpenes and the synthetic drugs ibuprofen and naproxen. The anti‐inflammatory activity of the hybrid compounds was compared with the activity of the parent compounds. This was accomplished using in vitro inhibition of lipoxygenases (LOX) and COX‐2, and in silico docking studies in 15‐LOX and COX‐2. The synthesized hybrids showed an inhibition of COX‐2 and LOX between 9.8%–57.4% and 0.0%–97.7%, respectively. None of the hybrids showed an improvement in the inhibitory effect toward these pro‐inflammatory enzymes, compared to the parent terpenes and non‐steroidal anti‐inflammatory drugs. The docking studies allowed us to predict the potential binding modes of hybrids 6 – 15 within COX‐2 and 15‐LOX active sites. The relative affinity of the compounds inside the binding sites could be explained by forming non‐covalent interactions with most important and known amino acids reported for those enzymes. A good correlation (r² = 0.745) between docking energies and inhibition percentages against COX‐2 was found. The high inhibition obtained for compound 10 against COX‐2 was explained by hydrogen bond interactions at the enzyme binding site. New synthetic possibilities could be obtained from our in silico models, improving the potency of these hybrid compounds.     

Correlation between inhibitory effect on platelet aggregation and disposition of sulfinpyrazone and its metabolites in rabbits. Part II: Multiple dose study

In a crossover study rabbits were given perorally sulfinpyrazone (SO) and the sulfide metabolite (S) every 24 h for 5 days on separate occasions and inhibition of aggregation was measured. The results showed: the dosage regimen is effective if the minimum effective concentration of S is defined to be between 0.5-1.0 microgram ml-1, and the repeated dosing did not cause changes in disposition kinetics except that the terminal half-life of S was reduced after dosing with S. No significant accumulations in trough concentration and inhibition of aggregation were observed. The results obtained in this study could provide some useful information for design of dosage regimen and blood level monitoring for humans.     

Correlation between inhibitory effect on platelet aggregation and disposition of sulfinpyrazone and its metabolites in rabbits. Part I: Single dose study

Simultaneous evaluation of inhibition of the sodium arachidonate-induced platelet aggregation and drug disposition was studied in rabbits receiving single doses of sulfinpyrazone (SO) and its sulfide metabolite (S). The metabolism of SO was found to be interconversible with that of S. Due to the parallelism of disposition profiles, the observed concentration-related inhibition not only strongly correlated with the much more potent sulfide, but also correlated with the p-OH-sulfide (OH-S) or with a summation of two substances. Exaggeration of inhibition at 24-30 h and rebound effect at 48 h were found after the substances were administered. There may exist a circadian rhythm of platelet aggregation.     

A comparative study of the effects of aspirin and paracetamol (acetaminophen) on platelet aggregation and bleeding time

Summary In a double blind, randomised trial, the effects of 1 g aspirin and 1 g paracetamol were compared on bleeding time and platelet aggregation in 40 volunteers (20 females). Also investigated was the relationship between plasma aspirin esterase activity and both bleeding time and platelet aggregation after aspirin. Following 1 g aspirin there was a significant increase in bleeding time at 24 h (p<0.01). A significant reduction (P<0.01) in platelet aggregation with collagen was observed at 1, 6 and 24 h after aspirin, but no significant reduction (P>0.05) was observed with ADP. Paracetamol had no effect on bleeding time or platelet aggregation. Plasma aspirin esterase activity ranged from 0.26–0.6 µmol/ml/min. A significant negative correlation (R=–0.55, P<0.001) was observed between percentage increase in bleeding time (24 h) and plasma aspirin esterase activity. Further significant correlations were observed between plasma aspirin esterase activity and change in platelet aggregation with collagen at 1 h (R=0.68, P<0.001), 6 h (R=–0.73, P<0.001) and 24 h (R=–0.67, P<0.001). These results suggest that it might be possible to predict an individual's haemostatic response to aspirin from knowledge of their plasma aspirin esterase activity.     

The potential role of nicotinamide on Leishmania tropica: An assessment of inhibitory effect,cytokines gene expression and arginase profiling

Leishmaniasis represents a major health concern worldwide which has no effective treatment modality. Nicotinamide (NAm) has been used for a wide range of applications from anticancer to antimicrobial usage. This study aimed to assess the effect of NAm combination on Leishmania tropica Inhibition, as well as on cytokines gene expression and arginase (ARG) activity in L. tropica-infected macrophages in an in vitro model. The leishmanicidal effects of NAm and Glucantime (meglumine antimoniate, MA) alone and in combination (NAm/MA) were evaluated using a colorimetric assay and macrophage model. Additionally, immunomodulatory effects and enzymatic activity were assessed by analyzing Th1 and Th2 cytokines gene expression and ARG level, respectively, in infected macrophages treated with NAm and MA, alone and in combination. Findings indicated that the NAm/MA combination demonstrated greater inhibitory effects on L. tropica promastigotes and amastigotes compared with each drug individually. Docking results proved the affinity of NAm to IFN-γ, which can affirm the increased levels of IFN-γ, IL-12p40 and TNF-α as well as reductions in IL-10 secretion with a dose-response effect, especially in the combination group. The NAm/MA combination also showed a significant reduction in the level of ARG activity at all concentrations used compared to each drug individually. These findings indicate higher effectiveness of NAm plus MA in reducing parasite growth, promoting immune response and inhibiting ARG level. This combination should be considered as a potential therapeutic regimen for treatment of volunteer patients with anthroponotic cutaneous leishmaniasis (ACL) in future control programs.     

Effect of Ficus racemosa stem bark on the activities of carbohydrate hydrolyzing enzymes: An in vitro study

Herbal medicines have been used since prehistoric times by different cultures worldwide for the treatment of diabetes. The present investigation evaluated the effect of Ficus racemosa Linn. (Moraceae) stem bark on carbohydrate hydrolyzing enzymes, viz., porcine pancreatic α-amylase, rat intestinal α-glucosidase, sucrase, and almond β-glucosidase, using in vitro model systems. In addition, the effect of heat treatment was also studied. Untreated F. racemosa bark (FRB) significantly inhibited (p?≤?0.05) α-amylase, α-glucosidase, β-glucosidase, and sucrase in a dose-dependent manner. Heat treatment of the sample comparably increased α-amylase, α-glucosidase, and sucrase inhibitory activities, while a marginal decrease in β-glucosidase inhibitory activity was observed; however, no statistical differences were noted. Untreated FRB showed IC₅₀ values of 0.94% and 280, 212, and 367 μg/mL for α-amylase, α-glucosidase, β-glucosidase, and sucrase, respectively, while the IC₅₀ values for heat treated FRB were 0.58% and 259, 223, and 239 μg/mL, respectively. Further, a significant correlation (p?≤?0.01; r?=?0.791) was observed between α-amylase, α-glucosidase, β-glucosidase, and sucrase inhibitory activities of both untreated and heat treated FRB. The results clearly demonstrate that inhibition of carbohydrate hydrolyzing enzymes is one mechanism through which F. racemosa stem bark exerts its hypoglycemic effect in vivo. Therefore, the potential exists to explore the utilization of F. racemosa stem bark in the development of nutraceuticals and functional foods for the management of diabetes and related symptoms/disorders.     

Effects of propofol on the leukocyte nitric oxide pathway: in vitro and ex vivo studies in surgical patients

This study was designed to evaluate the mechanism by which propofol modifies leukocyte production of nitric oxide (NO) in humans. In vitro experiments used whole blood from healthy volunteers (n = 10 samples/experiment). Ex vivo experiments studied the effects of an intravenous dose of 2.5 mg propofol per kilogram body weight followed by intravenous infusion of 4 mg kg⁻¹ h⁻¹ in surgical patients in ASA class I or II (n = 20). In whole blood, neutrophils and plasma, we measured NO production and the activities of the enzymes nitric oxide synthase [inducible (iNOS) and constitutive (cNOS)] and cyclooxygenase [constitutive (COX-1) and inducible (COX-2)]. Concentrations of interleukins (IL-1β, IL−6, and IL−10) and tumor necrosis factor-alpha (TNFα) were measured in plasma. In blood from healthy donors, propofol increased NO production and cNOS activity. The concentration of propofol that increased NO production by 50% (EC₅₀) was 23.5 μM, and the EC₅₀ of propofol for cNOS was 18.6 μM. In blood from surgical patients, propofol increased NO production by 52% and cNOS activity by 57%. Propofol inhibited iNOS activity in vitro; the concentration that reduced activity by 50% (IC₅₀) was 19.9 μM. In surgical patients propofol inhibited iNOS activity by 53%. COX-1 and COX-2 activities were inhibited in vitro (IC₅₀ 32.6 and 187 μM, respectively) and in surgical patients (53 and 81% inhibition, respectively). Plasma concentrations of IL-1β, IL-6, and TNFα were significantly reduced in surgical patients (32, 23, and 21% inhibition, respectively). None of these parameters were modified in a group of patients (n = 10) anesthetized with sevoflurane. We conclude that propofol stimulated constitutive NO production and inhibited inducible NO production, possibly by curtailing the stimulation of iNOS by inflammatory mediators in surgical patients.