Oxidative stress is viewed as an imbalance between the production of reactive oxygen species (ROS) and their elimination by protective mechanisms, which can lead to chronic inflammation. Oxidative stress can activate a variety of transcription factors, which lead to the differential expression of some genes involved in inflammatory pathways. The inflammation triggered by oxidative stress is the cause of many chronic diseases. Polyphenols have been proposed to be useful as adjuvant therapy for their potential anti-inflammatory effect, associated with antioxidant activity, and inhibition of enzymes involved in the production of eicosanoids. This review aims at exploring the properties of polyphenols in anti-inflammation and oxidation and the mechanisms of polyphenols inhibiting molecular signaling pathways which are activated by oxidative stress, as well as the possible roles of polyphenols in inflammation-mediated chronic disorders. Such data can be helpful for the development of future antioxidant therapeutics and new anti-inflammatory drugs.

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Oxidative Stress and Inflammation: What Polyphenols Can Do for Us?

Chronic inflammation is being shown to be increasingly involved in the onset and development of several pathological disturbances such as arteriosclerosis, obesity, diabetes, neurodegenerative diseases and even cancer. Treatment for chronic inflammatory disorders has not been solved, and there is an urgent need to find new and safe anti-inflammatory compounds. Flavonoids belong to a group of natural substances occurring normally in the diet that exhibit a variety of beneficial effects on health. The anti-inflammatory properties of flavonoids have been studied recently, in order to establish and characterize their potential utility as therapeutic agents in the treatment of inflammatory diseases. Several mechanisms of action have been proposed to explain in vivo flavonoid anti-inflammatory actions, such as antioxidant activity, inhibition of eicosanoid generating enzymes or the modulation of the production of proinflammatory molecules. Recent studies have also shown that some flavonoids are modulators of proinflammatory gene expression, thus leading to the attenuation of the inflammatory response. However, much work remains to be done in order to achieve definitive conclusions about their potential usefulness. This review summarizes the known mechanisms involved in the anti-inflammatory activity of flavonoids and the implications of these effects on the protection against cancer and cardiovascular disease.

Flavonoids as anti-inflammatory agents: implications in cancer and cardiovascular disease.

Antioxidants are substances that may protect cells from the damage caused by unstable molecules such as free radicals. Flavonoids are phenolic substances widely found in fruits and vegetables. The previous studies showed that the ingestion of flavonoids reduces the risk of cardiovascular diseases, metabolic disorders, and certain types of cancer. These effects are due to the physiological activity of flavonoids in the reduction of oxidative stress, inhibiting low-density lipoproteins oxidation and platelet aggregation, and acting as vasodilators in blood vessels. Free radicals are constantly generated resulting in extensive damage to tissues leading to various disease conditions such as cancer, Alzheimer's, renal diseases, cardiac abnormalities, etc., Medicinal plants with antioxidant properties play a vital functions in exhibiting beneficial effects and employed as an alternative source of medicine to mitigate the disease associated with oxidative stress. Flavonoids have existed over one billion years and possess wide spectrum of biological activities that might be able to influence processes which are dysregulated in a disease. Quercetin, a plant pigment is a potent antioxidant flavonoid and more specifically a flavonol, found mostly in onions, grapes, berries, cherries, broccoli, and citrus fruits. It is a versatile antioxidant known to possess protective abilities against tissue injury induced by various drug toxicities.

Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid.

The contemporary scientific community has presently recognized flavonoids to be a unique class of therapeutic molecules due to their diverse therapeutic properties. Of these, rutin, also known as vitamin P or rutoside, has been explored for a number of pharmacological effects. Tea leaves, apples, and many more possess rutin as one of the active constituents. Today, rutin has been observed for its nutraceutical effect. The present review highlights current information and health-promoting effects of rutin. Along with this, safety pharmacology issues and SAR of the same have also been discussed.

The Pharmacological Potential of Rutin.

Inflammation and oxidative stress are two major causes of various life-threatening diseases. Hesperidin (Hsd) and its aglycone, hesperetin (Hst), are two flavonoids from citrus species that have numerous biological properties, particularly antioxidant and anti-inflammatory. New findings showed that the antioxidant activity of Hsd/Hst was not only limited to its radical scavenging activity, but it augmented the antioxidant cellular defenses via the ERK/Nrf2 signaling pathway as well. Various in vitro and in vivo studies have been conducted to evaluate Hsd, its metabolites, or its synthetic derivatives at reducing inflammatory targets including NF-κB, iNOS, and COX-2, and the markers of chronic inflammation. In this review, new findings regarding the molecular targets of Hsd and Hst in the reduction of oxidative stress are discussed. Also, in the anti-inflammatory section, we provide a summary of significant investigations concerning the mechanisms of action based on the studied inflammation models.

Antioxidant and anti-inflammatory properties of the citrus flavonoids hesperidin and hesperetin: an updated review of their molecular mechanisms and experimental models.

Some plant proteases (e. g., papain, bromelain, ficin) have been used as anti-inflammatory agents for some years, and especially bromelain is still being used as alternative and/or complementary therapy to glucocorticoids, nonsteroidal antirheumatics, and immunomodulators. Bromelain is an extract rich in cysteine endopeptidases obtained from Ananas comosus. In this study the anti-inflammatory action of a partially purified extract of Bromelia hieronymi fruits, whose main components are cysteine endopeptidases, is presented. Different doses of a partially purified extract of B. hieronymi were assayed on carrageenan-induced and serotonine-induced rat paw edema, as well as in cotton pellet granuloma model. Doses with equal proteolytic activity of the partially purified extract and bromelain showed significantly similar anti-inflammatory responses. Treatment of the partially purified extract and bromelain with E-64 provoked loss of anti-inflammatory activity on carrageenan-induced paw edema, a fact which is consistent with the hypothesis that the proteolytic activity would be responsible for the anti-inflammatory action.

Anti-inflammatory activity of Bromelia hieronymi: comparison with bromelain.

Chemical components and anti-inflammatory activity from Bidens subalternans.

Traditional knowledge available on 148 plant species used in Argentina for gastroprotection and treating gastrointestinal ulcers, gastritis, and heartburn, was compiled to analyze their taxonomic grouping, floristic richness, the life form, and organs used, and to determine their susceptibility to over-collection.

Records of Medicinal Plants Utilized as Gastroprotective and for Treatment of Gastrointestinal Ulcers, Gastritis, and Heartburn in Argentina: A Survey of the Literature

SUMMARY. Melatonin influence (4 mg/kg) was investigated on acute inflammation using rat paw edema and on chronic inflammation through granuloma test and adjuvant arthritis. Melatonin inhibited the edema produced by carrageenan in acute model. However, failed to inhibit the proliferative phase in the granuloma test and the acute and chronic phase in the adjuvant arthritis. These results suggest melatonin shows different activity on the tested inflammatory models at the same doses. RESUMEN. “ Efecto de melatonina exo gena en procesos inflamatorios agudos y cr o nicos en ratas” . Se investigo la influencia de melatonina (4 mg/kg) en la inflamaci o n aguda usando el modelo de edema de pata en rata y en la inflamacio n cro nica mediante la prueba del granuloma y artritis inducida por adyuvante. Melatonina inhibi o el edema producido por carragenina en el modelo agudo, pero no present o accio n inhibitoria en la fase proliferativa de la prueba del granuloma y en la fase aguda y cr o nica de la artritis inducida por adyuvante. Estos resultados sugieren que melatonina, a la misma dosis, muestra diferentes comportamientos en los modelos inflamatorios ensayados.

http://www.latamjpharm.org/trabajos/21/4/LAJOP_21_4_1_9_006RHCAB15.pdf

Effect of exogenous melatonin on acute and chronic inflammatory process in rats

Several species of the family Bromeliaceae are characterized by the production of proteases in unusual amounts, especially in fruits. Bromelain, an extract rich in cysteine endopeptidases obtained from Ananas comosus L., and a few other proteases have been used as anti-inflammatory agents for some years, but bromelain is still mainly being used as alternative and/or complementary therapy to the treatment with glucocorticoids, nonsteroidal antirheumatics, and immunomodulators. In this study, the anti-inflammatory action of a partially purified extract from Pseudananas macrodontes (Morr.) Harms fruits (PPE(Pm)) is presented, whose main components are cysteine endopeptidases. The effect of PPE(Pm) was assessed in carrageenan-induced and serotonin-induced rat paw edema, as well as in the cotton pellet granuloma model. Doses with equal proteolytic activity of PPE(Pm) and bromelain produced significantly similar anti-inflammatory responses in the acute inflammatory models assayed, supporting the hypothesis that proteolytic activity could be responsible for the anti-inflammatory action. On the contrary, comparable anti-inflammatory effects of PPE(Pm) and bromelain in the chronic inflammatory assay required a much lower proteolytic activity content of PPE(Pm), which could be due to a differential affinity for the protein target involved in this process.

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Alejandra Ester Rotelli

Papers

Anti-inflammatory activity of Bromelia hieronymi: comparison with bromelain.

Chemical components and anti-inflammatory activity from Bidens subalternans.

Records of Medicinal Plants Utilized as Gastroprotective and for Treatment of Gastrointestinal Ulcers, Gastritis, and Heartburn in Argentina: A Survey of the Literature

Effect of exogenous melatonin on acute and chronic inflammatory process in rats

Evaluation of anti-inflammatory activity of Pseudananas macrodontes (Morr.) Harms (Bromeliaceae) fruit extract in rats.