Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

Curcumin: The Indian solid gold

Turmeric (Curcuma longa) is extensively used as a spice, food preservative and colouring material in India, China and South East Asia. It has been used in traditional medicine as a household remedy for various diseases, including biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism and sinusitis. For the last few decades, extensive work has been done to establish the biological activities and pharmacological actions of turmeric and its extracts. Curcumin (diferuloylmethane), the main yellow bioactive component of turmeric has been shown to have a wide spectrum of biological actions. These include its antiinflammatory, antioxidant, anticarcinogenic, antimutagenic, anticoagulant, antifertility, antidiabetic, antibacterial, antifungal, antiprotozoal, antiviral, antifibrotic, antivenom, antiulcer, hypotensive and hypocholesteremic activities. Its anticancer effect is mainly mediated through induction of apoptosis. Its antiinflammatory, anticancer and antioxidant roles may be clinically exploited to control rheumatism, carcinogenesis and oxidative stress-related pathogenesis. Clinically, curcumin has already been used to reduce post-operative inflammation. Safety evaluation studies indicate that both turmeric and curcumin are well tolerated at a very high dose without any toxic effects. Thus, both turmeric and curcumin have the potential for the development of modern medicine for the treatment of various diseases.

Turmeric and curcumin: Biological actions and medicinal applications

Regulation of inflammation and redox signaling by dietary polyphenols

Reactive oxygen species, either directly or via the formation of lipid peroxidation products, may play a role in enhancing inflammation through the activation of stress kinases (c-Jun activated kinase, extracellular signal-regulated kinase, p38) and redox-sensitive transcription factors, such as nuclear factor (NF)-kappaB and activator protein-1. This results in increased expression of a battery of distinct pro-inflammatory mediators. Oxidative stress activates NF-kappaB-mediated transcription of pro-inflammatory mediators either through activation of its activating inhibitor of kappaB-alpha kinase or the enhanced recruitment and activation of transcriptional co-activators. Enhanced NF-kappaB-co-activator complex formation results in targeted increases in histone modifications, such as acetylation leading to inflammatory gene expression. Emerging evidence suggests the glutathione redox couple may entail dynamic regulation of protein function by reversible disulphide bond formation on kinases, phosphatases and transcription factors. Oxidative stress also inhibits histone deacetylase activity and in doing so further enhances inflammatory gene expression and may attenuate glucocorticoid sensitivity. The antioxidant/anti-inflammatory effects of thiol molecules (glutathione, N-acetyl-L-cysteine and N-acystelyn, erdosteine), dietary polyphenols (curcumin-diferuloylmethane, cathechins/quercetin and reserveratol), specific spin traps, such as alpha-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (extracellular superoxide dismutase (SOD) mimetic, SOD mimetic M40419 and SOD, and catalase manganic salen compound, eukarion-8), porphyrins (AEOL 10150 and AEOL 10113) and theophylline have all been shown to play a role in either controlling NF-kappaB activation or affecting histone modifications with subsequent effects on inflammatory gene expression in lung epithelial cells. Thus, oxidative stress regulates both key signal transduction pathways and histone modifications involved in lung inflammation. Various approaches to enhance lung antioxidant capacity and clinical trials of antioxidant compounds in chronic obstructive pulmonary disease are also discussed.

https://erj.ersjournals.com/content/erj/28/1/219.full.pdf

Oxidative stress and redox regulation of lung inflammation in COPD

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.

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Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

Oxidants and tumor necrosis factor-α (TNF-α) activate transcription factors such as nuclear factor-κB (NF-κB), which is involved in the transcription of proinflammatory mediators, including interleukin-8 (IL-8). Curcumin (diferuloylmethane) is a naturally occurring flavonoid present in the spice turmeric, which has a long traditional use as a chemotherapeutic agent for many diseases. We hypothesize that curcumin may possess both antioxidant and antiinflammatory properties by increasing the glutathione levels and inhibiting oxidant- and cytokine-induced NF-κB activation and IL-8 release from cultured alveolar epithelial cells (A549). Treatment of A549 cells with hydrogen peroxide (H2O2; 100 µM) and TNF-α (10 ng/ml) significantly increased NF-κB and activator protein-1 (AP-1) activation, as well as IL-8 release. Curcumin inhibited both H2O2- and TNF-α-mediated activation of NF-κB and AP-1, and IL-8 release. Furthermore, an increased level of GSH and glutamylcysteine ligase catalytic subunit mRNA expression ...

Curcumin induces glutathione biosynthesis and inhibits NF-kappaB activation and interleukin-8 release in alveolar epithelial cells: mechanism of free radical scavenging activity.

Prostaglandin H2 synthase (PGHS) is the enzyme that catalyses the two-stage conversion of arachidonic acid to prostaglandin H2 (PGH2) prior to formation of prostanoids that are important in inflammation. PGHS isozymes (-1 and -2) are the target for nonsteroidal anti-inflammatory drugs (NSAIDs). Given the rekindled interest in specific anti-inflammatory PGHS inhibitors with reduced unwanted side effects, it is of paramount importance that there are reliable and efficient techniques to test new inhibitors. Here, we describe a novel in vitro electron paramagnetic resonance (EPR)-based assay for measuring the activity of PGHS-1. We validated a novel in vitro PGHS-1 activity assay based on the oxidation of spin-trap agent, 1-hydroxy-3-carboxy-pyrrolidine (CPH) to 3-carboxy-proxy (CP) under the action of the peroxidase element of PGHS-1. This quantifiable spin-adduct, CP, yields a characteristic 3-line electron paramagnetic (EPR) spectrum. The assay is simple, reproducible and facilitates rapid screening of inhibitors of PGHS-1. Aspirin (100 μM, 1 mM) caused significant inhibition of spin-adduct formation (72 ± 11 and 100 ± 16% inhibition of control respectively; P 0.05). We have demonstrated and validated a simple, reproducible, quick and specific assay for detecting PGHS-1 activity and inhibition. The EPR-based assay described represents a novel approach to measuring PGHS activity and provides a viable and competitive alternative to existing assays.

/pdf/a-novel-electron-paramagnetic-resonance-based-assay-for-1wk4nedmta.pdf

Danny McClure

Papers

Curcumin induces glutathione biosynthesis and inhibits NF-kappaB activation and interleukin-8 release in alveolar epithelial cells: mechanism of free radical scavenging activity.

A novel electron paramagnetic resonance-based assay for prostaglandin H synthase-1 activity