GOAL: multicenter, open-label, post-marketing study of flavocoxid, a novel dual pathway inhibitor anti-inflammatory agent of botanical origin

Druggable Prostanoid Pathway

Prostanoids (prostaglandins, prostacyclin and thromboxane) belong to the oxylipin family of biologically active lipids generated from arachidonic acid (AA). Protanoids control numerous physiological and pathological processes. Cyclooxygenase (COX) is a rate-limiting enzyme involved in the conversion of AA into prostanoids. There are two COX isozymes: the constitutive COX-1 and the inducible COX-2. COX-1 and COX-2 have similar structures, catalytic activities, and subcellular localizations but differ in patterns of expression and biological functions. Non-selective COX-1/2 or traditional, non-steroidal anti-inflammatory drugs (tNSAIDs) target both COX isoforms and are widely used to relieve pain, fever and inflammation. However, the use of NSAIDs is associated with various side effects, particularly in the gastrointestinal tract. NSAIDs selective for COX-2 inhibition (coxibs) were purposefully designed to spare gastrointestinal toxicity, but predisposed patients to increased cardiovascular risks. These health complications from NSAIDs prompted interest in the downstream effectors of the COX enzymes as novel drug targets. This chapter describes various safety issues with tNSAIDs and coxibs, and discusses the current development of novel classes of drugs targeting the prostanoid pathway, including nitrogen oxide- and hydrogen sulfide-releasing NSAIDs, inhibitors of prostanoid synthases, dual inhibitors, and prostanoid receptor agonists and antagonists.

Natural products as a potential modulator of microglial polarization in neurodegenerative diseases

Neurodegenerative diseases (NDs) are characterized by the progressive loss of structure and function of neurons most common in elderly population, mainly including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). Neuroinflammation caused by microglia as the resident macrophages of the central nervous system (CNS) plays a contributory role in the onset and progression of NDs. Activated microglia, as in macrophages, to be heterogeneous, can polarize into M1 (pro-inflammatory) and M2 (anti-inflammatory) functional phenotypes. The former elaborate pro-inflammatory mediators promoting neuroinflammation and neuronal damage. In contrast, the latter generate anti-inflammatory mediators and neurotrophins that inhibit neuroinflammation and promote neuronal healing. Consistently, the regulation of microglial polarization from M1 to M2 phenotype appears as an outstanding therapeutic and preventive approach for NDs treatment. Although non-steroidal anti-inflammatory drugs (NSAIDs) currently used to alleviate M1 microglia-associated neuroinflammation responsible for the development of NDs, these drugs have different degrees of adverse effects and limited efficacy. As the advantages of novel structure, multi-target, high efficiency and low toxicity, natural products as the modulators of microglial polarization have attracted considerable concerns in the therapeutic areas of NDs. In this review, we mainly summarized the therapeutic potential of natural products and their various molecular mechanisms for NDs treatment through modulating microglial polarization. The aim of the current review is expected to be useful to develop innovative modulators of microglial polarization from natural products for the amelioration and treatment of NDs.

Nonsteroidal Anti-Inflammatory Therapy: A Journey Toward Safety

The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) against inflammation, pain, and fever has been supporting their worldwide use in the treatment of painful conditions and chronic inflammatory diseases until today. However, the long-term therapy with NSAIDs was soon associated with high incidences of adverse events in the gastrointestinal tract. Therefore, the search for novel drugs with improved safety has begun with COX-2 selective inhibitors (coxibs) being straightaway developed and commercialized. Nevertheless, the excitement has fast turned to disappointment when diverse coxibs were withdrawn from the market due to cardiovascular toxicity. Such events have once again triggered the emergence of different strategies to overcome NSAIDs toxicity. Here, an integrative review is provided to address the breakthroughs of two main approaches: (i) the association of NSAIDs with protective mediators and (ii) the design of novel compounds to target downstream and/or multiple enzymes of the arachidonic acid cascade. To date, just one phosphatidylcholine-associated NSAID has already been approved for commercialization. Nevertheless, the preclinical and clinical data obtained so far indicate that both strategies may improve the safety of nonsteroidal anti-inflammatory therapy.

Flavocoxid, a nutraceutical approach to blunt inflammatory conditions

Flavonoids, from Scutellaria baicalensis (Chinese skullcap) and Acacia catechu (black catechu), have been shown to exert a variety of therapeutic effects, including anti-inflammatory, antiviral, antibacterial, and anticancer activities. Flavocoxid is a mixed extract containing baicalin and catechin and it acts as a dual balanced inhibitor of cyclooxygenase-1 (COX-1) and COX-2 peroxidase enzyme activities with a significant inhibition of 5-lipoxygenase (5-LOX) enzyme activity in vitro. Flavocoxid downregulates gene or protein expression of several inflammatory markers and exerts also strong antioxidant activity in several experimental models. Controlled clinical trials and a postmarketing study have clearly shown that flavocoxid is as effective as naproxen in managing the signs and symptoms of osteoarthritis of the knee and it has better upper gastrointestinal, renal, and respiratory safety profile than naproxen. Flavocoxid may therefore provide a potential therapeutic approach to the treatment of chronic inflammatory conditions.

Herbs and liver injury: a clinical perspective

Despite a perception that herbal and dietary supplements are safe, devastating liver injury has been reported to result from their use. The difficulty in characterizing liver injury attributable to herbal and dietary supplements stems from the permissive regulatory environment, the complexity of marketed products, and underreporting by the patients who use them. Despite these limitations, researchers, clinicians, and regulators have increasing awareness of the need for study in this area.

Nutritional interventions to prevent and treat osteoarthritis. Part II: focus on micronutrients and supportive nutraceuticals

Osteoarthritis (OA) is the most common cause of musculoskeletal disability in the elderly, and it places an enormous economic burden on society, which will remain a major health care challenge with an aging population. Management of OA is primarily focused on palliative relief using agents such as nonsteroidal anti-inflammatory drugs (NSAID) and analgesics. However, such an approach is limited by a narrow therapeutic focus that fails to address the progressive and multimodal nature of OA. Given the favorable safety profile of most nutritional interventions, identifying disease-modifying pharmaconutrients capable of improving symptoms and also preventing, slowing, or even reversing the degenerative process in OA should remain an important paradigm in translational and clinical research. The goals of pharmaconutrition for metabolic optimization are to drive biochemical reactions in a desired direction and to meet health condition-specific metabolic demands. Applying advances in nutritional science to musculoskeletal medicine remains challenging, given the fluid and dynamic nature of the field, along with a rapidly developing regulatory climate over manufacturing and commerce requirements. The purpose of this article is to review the available literature on effectiveness and potential mechanism for OA of micronutrient vitamins; minerals; glycosaminoglycans; avocado-soybean unsaponifiable fractions; methylsulfonylmethane; s-adenosylmethionine; undenatured and hydrolyzed collagen preparations; phytoflavonoid compounds found in fruits, vegetables, spices, teas, and nuts; and other nutrients on the horizon. There also is a discussion on the concept of rational polysupplementation via the strategic integration of multiple nutraceuticals with potential complementary mechanisms for improving outcomes in OA. As applied nutritional science evolves, it will be important to stay on the forefront of proteomics, metabolomics, epigenetics, and nutrigenomics, because they hold enormous potential for developing novel therapeutic and prognostic breakthroughs in many areas of medicine, including OA.

Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series

BACKGROUND

Flavocoxid is a prescription medical food that is used to treat osteoarthritis. It is a proprietary blend of 2 flavonoids, baicalin and catechins, which are derived from the botanicals Scutellaria baicalensis and Acacia catechu, respectively.

OBJECTIVE

To describe characteristics of patients with acute liver injury suspected of being caused by flavocoxid.

DESIGN

Case series.

SETTING

Drug-Induced Liver Injury Network Prospective Study ongoing at multiple academic medical centers since 2004.

PATIENTS

Four adults with liver injury.

MEASUREMENTS

Clinical characteristics, liver biochemistry values, and outcomes.

RESULTS

Among 877 patients enrolled in the prospective study, 4 had liver injury suspected to have been caused by flavocoxid. All were women; ages ranged from 57 to 68 years. All developed symptoms and signs of liver injury within 1 to 3 months after initiating flavocoxid. Liver injury was characterized by marked elevations in levels of alanine aminotransferase (mean peak, 1268 U/L; range, 741 to 1540 U/L), alkaline phosphatase (mean peak, 510 U/L; range, 286 to 770 U/L), and serum bilirubin (mean peak, 160.7 µmol/L [9.4 mg/dL]; range, 34.2 to 356 µmol/L [2.0 to 20.8 mg/dL]). Liver biochemistry values decreased to the normal range within 3 to 12 weeks after flavocoxid was stopped, and all patients recovered without experiencing acute liver failure or chronic liver injury. Causality was adjudicated as highly likely in 3 patients and as possible in 1 patient.

LIMITATION

The frequency and mechanism of liver injury could not be assessed.

CONCLUSION

Flavocoxid can cause clinically significant liver injury, which seems to resolve within weeks after cessation.

5-Lipoxygenase metabolic contributions to NSAID-induced organ toxicity

Cyclooxygenase (COX)-1, COX-2, and 5-lipoxygenase (5-LOX) enzymes produce effectors of pain and inflammation in osteoarthritis (OA) and many other diseases. All three enzymes play a key role in the metabolism of arachidonic acid (AA) to inflammatory fatty acids, which contribute to the deterioration of cartilage. AA is derived from both phospholipase A(2) (PLA(2)) conversion of cell membrane phospholipids and dietary consumption of omega-6 fatty acids. Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the COX enzymes, but show no anti-5-LOX activity to prevent the formation of leukotrienes (LTs). Cysteinyl LTs, such as LTC(4), LTD(4), LTE(4), and leukoattractive LTB(4) accumulate in several organs of mammals in response to NSAID consumption. Elevated 5-LOX-mediated AA metabolism may contribute to the side-effect profile observed for NSAIDs in OA. Current therapeutics under development, so-called "dual inhibitors" of COX and 5-LOX, show improved side-effect profiles and may represent a new option in the management of OA.

Flavocoxid inhibits phospholipase A2, peroxidase moieties of the cyclooxygenases (COX), and 5-lipoxygenase, modifies COX-2 gene expression, and acts as an antioxidant

The multiple mechanisms of action for flavocoxid relating to arachidonic acid (AA) formation and metabolism were studied in vitro. Flavocoxid titrated into rat peritoneal macrophage cultures inhibited cellular phospholipase A2 (PLA(2)) (IC(50) = 60 μg/mL). In in vitro enzyme assays, flavocoxid showed little anti-cyclooxygenase (CO) activity on COX-1/-2 enzymes, but inhibited the COX-1 (IC(50) = 12.3) and COX-2 (IC(50) = 11.3 μg/mL) peroxidase (PO) moieties as well as 5-lipoxygenase (5-LOX) (IC(50) = 110 μg/mL). No detectable 5-LOX inhibition was found for multiple traditional and COX-2 selective NSAIDs. Flavocoxid also exhibited strong and varied antioxidant capacities in vitro and decreased nitrite levels (IC(50) = 38 μg/mL) in rat peritoneal macrophages. Finally, in contrast to celecoxib and ibuprofen, which upregulated the cox-2 gene, flavocoxid strongly decreased expression. This work suggests that clinically favourable effects of flavocoxid for management of osteoarthritis (OA) are achieved by simultaneous modification of multiple molecular pathways relating to AA metabolism, oxidative induction of inflammation, and neutralization of reactive oxygen species (ROS).

Cost analysis of flavocoxid compared to naproxen for management of mild to moderate OA

OBJECTIVE

Flavocoxid is a medical food used for the clinical dietary management of osteoarthritis (OA). The acquisition cost of flavocoxid is higher than most traditional, generic NSAIDs. However, flavocoxid may have more favorable gastrointestinal (GI) toxicity resulting in lower overall costs. These costs have not been previously examined. This study provides a decision analytic model to assess the net costs of using flavocoxid for OA from a Medicare perspective.

RESEARCH DESIGN AND METHODS

A decision model was developed to estimate the total costs associated with flavocoxid versus naproxen for the management of Medicare patients with mild to moderate OA. Probabilities were obtained from literature and expert opinion, and costs were obtained from Medicare. Sensitivity analyses were conducted by varying probabilities and costs within clinically relevant ranges.

RESULTS

The base case resulted in flavocoxid having lower total annual costs ($1482 per patient) compared to naproxen ($1592). Flavocoxid remained the lowest cost option when the cost inputs were varied by 25% (above and below the base case), and when the probability of GI events with flavocoxid were varied by 25%. However, when GI rates from the literature and implied relative risks from the expert panel were used, or if the cost of PPIs was $0, then naproxen was the less costly alternative, though saving less than the annual cost of flavocoxid. Key limitations were the limited outcomes in the model (only GI events), lack of consideration of adherence or combination therapy, and the reliance on expert opinion due to a lack of data for flavocoxid.

CONCLUSIONS

In patients over 65 years of age who suffer from mild to moderate OA, flavocoxid may result in lower overall costs, despite a higher acquisition cost. Managed care organizations should consider total health care costs in the decision to include flavocoxid as a covered benefit.

Flavocoxid, an anti-inflammatory agent of botanical origin, does not affect coagulation or interact with anticoagulation therapies

INTRODUCTION

Flavocoxid, a botanical, anti-inflammatory agent, nonspecifically inhibits the peroxidase activity of cyclooxygenase (COX-1 and COX-2) enzymes and 5-lipooxygenase (5-LOX). Due to the concomitant use of aspirin or warfarin in many osteoarthritis (OA) patients with increased cardiovascular risk, we felt it necessary to assess the anticoagulation properties of flavocoxid.

METHODS

Three different studies were used: 1) a mouse model to assess effects on bleeding times when combined with aspirin; 2) the effect on platelet function as evaluated by platelet aggregation and bleed times in healthy human subjects; and 3) the effect on international normalized ratio in previously warfarinized patients with OA.

RESULTS

Flavocoxid at a human equivalent dose (HED) of 569 mg (within the standard human dosing range of 500 mg) produced no significant increases in bleeding time in mice. There was also no inhibition or synergistic increase in bleed times when flavocoxid was combined with aspirin (370 mg HED). Flavocoxid did not significantly inhibit thromboxane production or platelet aggregation, and did not increase bleeding times in healthy volunteers. Finally, flavocoxid did not inhibit or potentiate the anticoagulant effect of warfarin.

CONCLUSION

These results suggest that flavocoxid does not affect the primary or extrinsic pathways of secondary hemostasis and, by not inhibiting the anticoagulation effects of aspirin, may have utility in cardiovascular patients with OA.