Cyclooxygenase-2 inhibitors and cardiovascular risk

Zanthoxylum Species: A Comprehensive Review of Traditional Uses, Phytochemistry, Pharmacological and Nutraceutical Applications

Zanthoxylum species (Syn. Fagara species) of the Rutaceae family are widely used in many countries as food and in trado-medicinal practice due to their wide geographical distribution and medicinal properties. Peer reviewed journal articles and ethnobotanical records that reported the traditional knowledge, phytoconstituents, biological activities and toxicological profiles of Z. species with a focus on metabolic and neuronal health were reviewed. It was observed that many of the plant species are used as food ingredients and in treating inflammation, pain, hypertension and brain diseases. Over 500 compounds have been isolated from Z. species, and the biological activities of both the plant extracts and their phytoconstituents, including their mechanisms of action, are discussed. The phytochemicals responsible for the biological activities of some of the species are yet to be identified. Similarly, biological activities of some isolated compounds remain unknown. Taken together, the Z. species extracts and compounds possess promising biological activities and should be further explored as potential sources of new nutraceuticals and drugs.

Antiinflammatory Medicinal Plants from the Ugandan Greater Mpigi Region Act as Potent Inhibitors in the COX-2/PGH2 Pathway

Our study investigates 16 medicinal plants via assessment of inhibition of proinflammatory enzymes such as cyclooxygenases (COX). The plants are used by traditional healers in the Greater Mpigi region in Uganda to treat inflammation and related disorders. We present results of diverse in vitro experiments performed with 76 different plant extracts, namely, (1) selective COX-2 and COX-1 inhibitor screening; (2) 15-LOX inhibition screening; (3) antibacterial resazurin assay against multidrug-resistant Staphylococcus aureus, Listeria innocua, Listeria monocytogenes, and Escherichia coli K12; (4) DPPH assay for antioxidant activity; and (5) determination of the total phenolic content (TPC). Results showed a high correlation between traditional use and pharmacological activity, e.g., extracts of 15 out of the 16 plant species displayed significant selective COX-2 inhibition activity in the PGH₂ pathway. The most active COX-2 inhibitors (IC₅₀ < 20 µg/mL) were nine extracts from Leucas calostachys, Solanum aculeastrum, Sesamum calycinum subsp. angustifolium, Plectranthus hadiensis, Morella kandtiana, Zanthoxylum chalybeum, and Warburgia ugandensis. There was no counteractivity between COX-2 and 15-LOX inhibition in these nine extracts. The ethyl acetate extract of Leucas calostachys showed the lowest IC₅₀ value with 0.66 µg/mL (COX-2), as well as the most promising selectivity ratio with 0.1 (COX-2/COX-1). The TPCs and the EC₅₀ values for DPPH radical scavenging activity showed no correlation with COX-2 inhibitory activity. This led to the assumption that the mechanisms of action are most likely not based on scavenging of reactive oxygen species and antioxidant activities. The diethyl ether extract of Harungana madagascariensis stem bark displayed the highest growth inhibition activity against S. aureus (MIC value: 13 µg/mL), L. innocua (MIC value: 40 µg/mL), and L. monocytogenes (MIC value: 150 µg/mL). This study provides further evidence for the therapeutic use of the previously identified plants used medicinally in the Greater Mpigi region.

Endothelial cell prostaglandin E2 receptor EP4 is essential for blood pressure homeostasis

Prostaglandin E2 and its cognate EP1-4 receptors play important roles in blood pressure (BP) regulation. Herein, we show that endothelial cell-specific (EC-specific) EP4 gene-knockout mice (EC-EP4-/-) exhibited elevated, while EC-specific EP4-overexpression mice (EC-hEP4OE) displayed reduced, BP levels compared with the control mice under both basal and high-salt diet-fed conditions. The altered BP was completely abolished by treatment with l-NG-nitro-l-arginine methyl ester (l-NAME), a competitive inhibitor of endothelial nitric oxide synthase (eNOS). The mesenteric arteries of the EC-EP4-/- mice showed increased vasoconstrictive response to angiotensin II and reduced vasorelaxant response to acetylcholine, both of which were eliminated by l-NAME. Furthermore, EP4 activation significantly reduced BP levels in hypertensive rats. Mechanistically, EP4 deletion markedly decreased NO contents in blood vessels via reducing eNOS phosphorylation at Ser1177. EP4 enhanced NO production mainly through the AMPK pathway in cultured ECs. Collectively, our findings demonstrate that endothelial EP4 is essential for BP homeostasis.

Platelet Function: Meloxicam Intravenous in Whole Blood Samples From Healthy Volunteers

Nonsteroidal anti‐inflammatory drugs (NSAIDs) are effective treatments for pain but may induce bleeding events due to platelet dysfunction associated with inhibition of cyclooxygenase (COX)‐1 impairing thromboxane production. An intravenous nanocrystal formulation of meloxicam, a COX‐2 preferential nonsteroidal anti‐inflammatory drug, is under development for the treatment of moderate to severe pain. This single‐center ex vivo study evaluated the effect of meloxicam intravenous and ketorolac on platelet function in whole blood samples from healthy volunteers. Each whole blood sample was aliquoted to allow analysis using a platelet function analyzer under negative control (untreated), positive control (2 therapeutic ketorolac concentrations), and meloxicam intravenous (1 therapeutic, 3 supratherapeutic concentrations) using both collagen with epinephrine and collagen with adenosine diphosphate reagent cartridges. The platelet function analyzer determines closure time by simulating platelet adhesion and aggregation following vascular injury. The final analysis set included data from 8 subjects. The collagen with adenosine diphosphate analysis (sensitive to thrombocytopathies) showed no significant differences in closure time for meloxicam‐ or ketorolac‐treated samples and untreated control. The collagen with epinephrine analysis (sensitive to aspirin‐induced platelet abnormalities) produced no significant difference in closure time between any meloxicam concentration and untreated control. Ketorolac was associated with significantly longer closure times vs untreated control at both the 2.5‐ and 5‐µg/mL concentrations (P = .003 and .0257, respectively) and vs meloxicam at several concentrations. Similar results were observed when all analyzed samples were included. Meloxicam intravenous had no significant effect on closure times at therapeutic or supratherapeutic concentrations in this ex vivo study.

Ellagitannin-rich cloudberry inhibits hepatocyte growth factor induced cell migration and phosphatidylinositol 3-kinase/AKT activation in colon carcinoma cells and tumors in Min mice

Berries have been found to inhibit colon carcinogenesis in animal models, and thus represent a potential source of compounds for prevention and treatment of colorectal cancer. The mechanistic basis for their effects is not well understood. We used human colon carcinoma cells and Min mice to investigate the effects of ellagitannin-rich cloudberry (Rubus chamaemorus) extract on cancer cell migration and underlying cell signaling. Intrinsic and hepatocyte growth factor (HGF) -induced cell motility in human HT29 and HCA7 colon carcinoma cells was assessed carrying out cell scattering and scratch wound healing assays using time-lapse microscopy. Activation of Met, AKT, and ERK in cell lines and tumors of cloudberry-fed Min mice were determined using immunoprecipitation, Western blot and immunohistochemical analyses. Cloudberry extract significantly inhibited particularly HGF-induced cancer cell migration in both cell lines. Cloudberry extract inhibited the Met receptor tyrosine phosphorylation by HGF and strongly suppressed HGF-induced AKT and ERK activation in both HT29 and HCA7 cells. Consistently, cloudberry feeding (10% w/w freeze-dried berries in diet for 10 weeks) reduced the level of active AKT and prevented phosphoMet localization at the edges in tumors of Min mice. These results indicate that cloudberry reduces tumor growth and cancer cell motility by inhibiting Met signaling and consequent activation of phosphatidylinositol 3-kinase/AKT in vitro and in tumors in vivo. As the Met receptor is recognized to be a major target in cancer treatment, our results suggest that dietary phytochemicals may have therapeutic value in reducing cancer progression and metastasis.

Anti-inflammatory effects of Polygonum minus (Huds) extract (Lineminus™) in in-vitro enzyme assays and carrageenan induced paw edema

Background

The study was aimed to evaluate the anti-inflammatory activity of ethanolic and aqueous extracts of Polygonum minus (Huds) using in vitro and in vivo approaches.

Methods

The in vitro tests used to evaluate ethanolic extract are cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), lipooxygenase (5-LOX), secretory phospholipase-A2 (sPLA2) inhibition assay whilst the in-vivo effect was measured by the ability of aqueous extracts to reduce paw edema induced by λ-carrageenan, in rats.

Results

The ethanolic extract inhibited the activities of 5-LOX and COX-1(p < 0.05) whilst the inhibitory effect on COX-2 was only moderate. A marked inhibition of 5-LOX was observed at 30 μg/ ml. The extract did not inhibit the activity of sPLA2. The ability of the ethanolic extracts of Polygonum minus to inhibit both 5-LOX and COX, prompted a study to evaluate the effects of using an aqueous extract of Polygonum minus(Lineminus^TM); as this would be more suitable for future clinical testing. The anti-inhibitory activity of the aqueous extract from this plant was evaluated using a rat model where inflammation was induced in the paws by injection of λ-carrageenan. The aqueous extracts from Polygonum minus administered at doses of 100 and 300 mg/kg body weight (b.w.), significantly (p < 0.01) reduced paw edema induced by λ-carrageenan in the experimental model, at 4 h compared to the vehicle control. Furthermore, administration of 100 mg/kg b.w. or 300 mg/kg b.w. completely reduced inflammation of the paw 4 h after injection.

Conclusion

These findings suggest that aqueous extract of Polygonum minus possesses potent anti-inflammatory activities.

Cardiovascular risks of COX inhibition: current perspectives

BACKGROUND

NSAIDs are among the most commonly used pharmacotherapeutic agents worldwide. As the long-term use of these drugs is associated with serious gastrointestinal side effects, a new subgroup of COX-2 selective NSAIDs was developed. It was thought that the therapeutic strategy underlying the development of these newer compounds would enable them to provide the same analgesic and anti-inflammatory benefits as those of their traditional counterparts but perhaps offer a much safer gastrointestinal profile. Much scientific data has accumulated over the last few years, however, raising concerns regarding the increased cardiovascular complications associated with the use of COX-2 selective NSAIDs, and perhaps of the traditional NSAIDs as well.

OBJECTIVE

To review current and emerging evidence related to the cardiovascular effects of COX inhibitors and examine the clinical implications.

METHOD

We studied data from basic clinical research, non-randomized analyses, and randomized trials of COX inhibitors that investigated their cardiovascular effects.

CONCLUSION

Both COX-2 selective and traditional NSAIDs are associated with a moderately increased risk of cardiovascular events.

Prescription of nonsteroidal anti-inflammatory drugs and co-prescribed drugs for mucosal protection: analysis of the present status based on questionnaires obtained from orthopedists in Japan

OBJECTIVE

Recently guidelines for the treatment and prevention of ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) have been established. The aim of the present study was to examine factors influencing orthopedists in Japan in the use of cytoprotective drugs to prevent NSAID-associated gastrointestinal adverse events.

METHODS

We sent a questionnaire to 402 orthopedists in Hyogo Prefecture. A standardized 10-item questionnaire was used to collect information on NSAID prescriptions (drug name, pharmaceutical form, doses, and duration of use) and associated drugs, especially gastroprotective drugs.

RESULTS

Two hundred eight (51.7%) orthopedists returned the questionnaire. The most frequently used NSAIDs, in descending order, were loxoprofen sodium, diclofenac sodium, and etodolac. Most doctors (80%) reported patients with abdominal symptoms associated with NSAIDs. Of these doctors, 59% treated the symptoms by themselves, and prescribed gastroprotective agents (32.2%), histamine H2-receptor antagonists (H2RAs) (26.4%), prostaglandin analogues (PAs) (17.0%), or proton pump inhibitors (PPIs) (16.2%). Sixty-seven percent of doctors reported that those drugs reduced the symptoms. Most orthopedists (96%) prescribed some type of drug to prevent NSAID-associated gastrointestinal events, including gastroprotective drugs (44.6%), H2RAs (19.5%), PAs (17.4%), and PPIs (10.8%). The doctors reported that they prescribed medicines for NSAID-associated gastrointestinal events on the basis of their experience (23%), by considering medical insurance restrictions (17%), and by referring to information provided by pharmaceutical company representatives (16%).

CONCLUSION

Most orthopedists prescribe some type of drug to prevent NSAID-induced ulcers but do not refer to the guidelines. We therefore strongly recommend that the guidelines be made more widely known to gastroenterologists and to physicians in every field of clinical practice, including orthopedics.