Vidushi S. Neergheen

Targeting specific cell signaling transduction pathways by dietary and medicinal phytochemicals in cancer chemoprevention

Natural phytochemicals derived from dietary sources or medicinal plants have gained significant recognition in the potential management of several human clinical conditions. Much research has also been geared towards the evaluation of plant extracts as effective prophylactic agents since they can act on specific and/or multiple molecular and cellular targets. Plants have been an abundant source of highly effective phytochemicals which offer great potential in the fight against cancer by inhibiting the process of carcinogenesis through the upregulation of cytoprotective genes that encode for carcinogen detoxifying enzymes and antioxidant enzymes. The mechanistic insight into chemoprevention further includes induction of cell cycle arrest and apoptosis or inhibition of signal transduction pathways mainly the mitogen-activated protein kinases (MAPK), protein kinases C (PKC), phosphoinositide 3-kinase (PI3K), glycogen synthase kinase (GSK) which lead to abnormal cyclooxygenase-2 (COX-2), activator protein-1 (AP-1), nuclear factor-kappaB (NF-κB) and c-myc expression. Effectiveness of chemopreventive agents reflects their ability to counteract certain upstream signals that leads to genotoxic damage, redox imbalances and other forms of cellular stress. Targeting malfunctioning molecules along the disrupted signal transduction pathway in cancer represent a rational strategy in chemoprevention. NF-κB and AP-1 provide mechanistic links between inflammation and cancer, and moreover regulate tumor angiogenesis and invasiveness, indicating that signaling pathways that mediate their activation provide attractive targets for new chemotherapeutic approaches. Thus cell signaling cascades and their interacting factors have become important targets of chemoprevention and phenolic phytochemicals and plant extracts seem to be promising in this endeavor.

Free Radicals, Antioxidants and Diabetes: Embryopathy, Retinopathy, Neuropathy, Nephropathy and Cardiovascular Complications

The metabolic disturbances in the insulin-dependent diabetes mellitus or type 1 and noninsulin-dependent diabetes mellitus or type 2 are associated with a number of complications including cardiovascular diseases, nephropathy, neuropathy, retinopathy leading to blindness and embryopathy or congenital malformations. Maternal diabetes is associated with a high incidence of congenital malformations and fetal abortions. Heart and kidney anomalies, along with central nervous system defects are frequent manifestations of a maternal diabetic environment. Glycation products from excess glucose can chemically modify DNA causing mutations and complex DNA rearrangements. Therefore, DNA damage in fetal tissues as a result of maternal diabetes may reflect a level of genomic injury sufficient to affect embryonic development. The formation of advanced glycation end products can accelerate vascular occlusion by quenching the vasodilating agent nitric oxide. Interaction with high-affinity receptors located on monocytes and macrophages can enhance the production of free radicals and reactive oxygen/nitrogen species, the secretion of tumor necrosis factor-α, interleukin-1 and insulin-like growth factor 1 which can proliferate endothelial, mesangial and smooth muscle cells and hence contribute significantly to the pathogenesis of cardiovascular complications. Retinopathy is characterized by increased vascular permeability, by vascular closure, together with the growth of new blood vessels on the retina and posterior surface of the vitreous. Reactive oxygen species are involved in decreased retinal blood flow, increased vascular permeability and disruption of blood-retinal barrier. The involvement of oxidative stress in the pathology of diabetes from its associated cardiovascular dysfunctions, nephropathy, neuropathy, retinopathy (leading to blindness) and embryopathy or congenital malformations, suggests that potential management of diabetes could benefit from use of dietary biofactors in medicinal and food plants. There is therefore a requirement for research to focus on the molecular mechanisms of action of extracts and/or the biofactors flavonoids, proanthocyanidins, alkaloids, etc. derived from these plants.

Bioefficacy of Mauritian Endemic Medicinal Plants: Assessment of Their Phenolic Contents and Antioxidant Potential

Abstract The role of free radicals in the etiology and development of a wide range of clinical disorders has continued to fuel the suggestion that phenolic antioxidants can offer a realistic promise to reduce the incidence of a number of pathologies involving oxidative stress. In this study, the total phenol, flavonoid, and proanthocyanidin contents of the Mauritian medicinal plants Crinum mauritianum. Lodd. (Asteraceae), Gaertnera psychotroides. DC (Rubiaceae), Psidia terebinthina. A.J. Scott (Asteraceae), and Tylophora coriacea. Marais. (Monimiaceae) were assessed and contrasted with their antioxidant potential. The antioxidant propensity was evaluated by the ability of the extracts to scavenge hypochlorous acid and hydroxyl radical and the ABTS⋅ + radical including their abilities to inhibit microsomal lipid peroxidation. The endemic plants Badula multiflora. A. DC. (Myrsinaceae), Croton vaughanii. L. (Euphorbiaceae), Erythroxylum macrocarpum. Lam. (Erythroxylaceae), Ochna mauritiana. Lam. (Ochnaceae), Tambourissa cordifolia. Lorence. (Monimiaceae), and Turraea rigida. Vent. (Meliaceae) were similarly investigated. Badula multiflora. and Erythoxylum macrocarpum. showed highest antioxidant activity in the TEAC and FRAP assay. Badula multiflora., Ochna mauritiana., and Gaertnera psychotroides. were very potent scavengers of hypochlorous acid and inhibited microsomal lipid peroxidation induced by 2,2′-azobis.(2-amidinopropane) hydrochloride (AAPH), suggesting that the inhibition was intrinsically linked to peroxyl radical scavenging. The antioxidant activity of Gaertnera psychotroides., Tylophora coriacea., Psidia terebinthina., and Crinum mauritianum. may account for the therapeutic effects of these extracts, in particular, in conditions characterized by inflammation and oxidative mechanisms. While these polyphenolic-rich endemics are good sources of natural prophylactic antioxidants, there is an urgent need for sustainable conservation programs for their protection.

Botanical Drugs, Nutraceuticals and Functional Foods: The Context of Africa

Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).

Chapter 22 – Botanical Drugs, Nutraceuticals and Functional Foods: The Context of Africa

Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).

Botanical Drugs, Nutraceuticals and Functional Foods

Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).Publisher Summary The involvement of developing countries in international food trade has transcended ideology from the traditional production of cash crops and raw materials to producing processed or semiprocessed food products. The African continent is endowed with a great variety of plant species and their use for achieving nutritional and therapeutic effects is strongly anchored in African culture. There is need for pharmacological, toxicological studies which complement the strict regulatory framework governing the sale, manufacture, packaging, labeling, importation, distribution, and storage of natural health products. For the products (botanical drugs, nutraceuticals and functional foods) emanating from the endemic plants, these important determinants anchor the supply chain and regulation of botanical drugs, nutraceuticals, and functional foods. The various factors that determine the supply of botanical drugs and functional nutraceuticals include bioprospecting for new products, low cost sources of existing products, standards that govern the introduction of new products, and enhancement of the acceptance of existing products, differentiating products based on the physicochemical properties of the products, product innovation (e.g. new additives to foods, drinks, and/or cosmetics). Functional foods have generally been defined to include products that influence specific functions in the body (thereby offering benefits for health, well-being or performance). Functional foods result from technological innovation (e.g. cholesterol lowering products, sweeteners in chewing gums, fermentation products, and genetically modified products).