The role of natural antioxidants in cancer disease

Abstract

Cell oxidation can lead to the onset and development of a wide range of diseases including Alzheimer, Parkinson, the pathologies caused by diabetes, rheumatoid arthritis, neurodegeneration in motor neuron diseases, and cancer. Reactive species (RS) of various types are powerful oxidizing agents, capable of damaging DNA and other biomolecules. Increased formation of RS can promote the development of malignancy, and the ?normal? rates of RS generation may account for the increased risk of cancer development. Oxidants and free radicals are inevitably produced during most physiological and metabolical processes, and the human body has defensive antioxidant mechanisms, these mechanisms vary according to the cell and tissue type and they may act antagonistically or synergistically. They include synthetic antioxidants and natural antioxidant as enzymes such as superoxide dismutase, catalase, and glutathione peroxidase, as well as antioxidant such as vitamins, carotenoids, poliphenols and other naturals antioxidants which have taken great interest in last years. There has been a great deal of interest recently in the role of complementary and alternative medicines for the treatment of various acute and chronic diseases. Of the various classes of phytochemicals, interest has focused on the anti-inflammatory and antioxidant properties of polyphenols found in various botanical agents. Plants vegetables and spices used in folk and traditional medicine have gained wide acceptance as one of the main sources of prophylactic and chemopreventive drug discovery and development. Recently researches on medicinal plants has drawn global attention; large bodies of evidence have accumulated to demonstrate the promising potential of medicinal plants used in various traditional, complementary and alternate systems of treatment of human diseases. The plants are rich in a wide variety of secondary metabolites such as tannins, terpenoids, alkaloids, flavonoids, etc., which have been screened in vivo and in vitro and indicated antioxidant, and anticarcinogenic properties are used to developed drugs or dietary supplements. Evidence suggests that plant kingdom is considered as a good candidate for chemoprevention and cancer therapy, due to the high concentration and wide variety of antioxidants such as resveratrol, genestein, beicalein, vitamin A, vitamin C, polyphenols, (-)-Epigallocatechin 3-gallate, flavonoids, polyphenols, gallic acid, glycosides, verbascoside, calceorioside, epicatechin, quersetin, curcumin, lovastatin, and many other kinds of compounds with capability to inhibit cell proliferation of different cancer cells in vitro and in vitro, such as colon cancer cells (HT-29, SW48, HCT116), breast (MCF7, MDA), cervix (HeLa, SiHa, Ca-Ski,C33-A), liver (Hep G2), skin (A 431), fibroblasts (3T3 SV40) and many others malignant cells; the studies had indicated that the antioxidants can be used efficiently as chemopreventive and as an effective inhibitor of cell proliferation, promoting cell apoptosis, increasing detoxification enzymes, inhibiting gene expression, and scavenger reactive oxygen species (ROS). For this reason many researchers are working with different kinds of natural antioxidants with the aim of finding those with greater capacity to inhibit the development of cancer, both in vitro as in vivo, since these compounds have submitted a high potential to be used not only in the treatment of this disease, if not also act as a good chemoprotective agents