Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

结节病易误诊,据王洪武等~([1])收集国内18篇关于此病误诊的文献,误诊率高达63.2%,当然有误诊就会有误治,如孙永昌等~([2])报道26例结节病在影像学检查诊断的第一印象中拟诊结核5例,其中就有2例完成规范的抗结核治疗,为此应引起临床对本病诊治的重视。

Sarcoidosis

Review of the biological properties and toxicity of bee propolis (propolis)

International variations in cancer rates have been attributed, at least in part, to differences in dietary intake. Recently, it has been suggested that consumption of soyfoods may contribute to the relatively low rates of breast, colon, and prostate cancers in countries such as China and Japan. Soybeans contain a number of anticarcinogens, and a recent National Cancer Institute workshop recommended that the role of soyfoods in cancer prevention be investigated. In this review, the hypothesis that soy intake reduces cancer risk is considered by examining relevant in vitro, animal, and epidemiological data. Soybeans are a unique dietary source of the isoflavone genistein, which possesses weak estrogenic activity and has been shown to act in animal models as an antiestrogen. Genistein is also a specific inhibitor of protein tyrosine kinases; it also inhibits DNA topoisomerases and other critical enzymes involved in signal transduction. In vitro, genistein suppresses the growth of a wide range of can...

Soy intake and cancer risk: A review of the in vitro and in vivo data

Plants consumed by humans contain thousands of phenolic compounds. The effects of dietary polyphenols are of great current interest due to their antioxidative and possible anticarcinogenic activities. A popular belief is that dietary polyphenols are anticarcinogens because they are antioxidants, but direct evidence for this supposition is lacking. This chapter reviews the inhibition of tumorigenesis by phenolic acids and derivatives, tea and catechins, isoflavones and soy preparations, quercetin and other flavonoids, resveratrol, and lignans as well as the mechanisms involved based on studies in vivo and in vitro. Polyphenols may inhibit carcinogenesis by affecting the molecular events in the initiation, promotion, and progression stages. Isoflavones and lignans may influence tumor formation by affecting estrogen-related activities. The bioavailability of the dietary polyphenols is discussed extensively, because the tissue levels of the effective compounds determine the biological activity. Understanding the bioavailability and blood and tissue levels of polyphenols is also important in extrapolating results from studies in cell lines to animal models and humans. Epidemiological studies concerning polyphenol consumption and human cancer risk suggest the protective effects of certain food items and polyphenols, but more studies are needed for clear-cut conclusions. Perspectives on the application of dietary polyphenols for the prevention of human cancer and possible concerns on the consumption of excessive amounts of polyphenols are discussed.

Inhibition of carcinogenesis by dietary polyphenolic compounds

Antioxidant and antipromotional effects of the soybean isoflavone genistein have been studied in HL-60 cells and the mouse skin tumorigenesis model Effects of structure-related flavone/iso

Antioxidant and antipromotional effects of the soybean isoflavone genistein.

Here we report that genistein, a soybean isoflavone, strongly inhibits tumor promoter‐induced H2O2 formation both in vivo and in vitro. Genistein suppressed H2O2 production by 12‐O‐tetrade‐canoylphorbol‐13‐acetate‐ (TPA) stimulated human polymorphonuclear leukocytes (PMNs) and HL‐60 cells in a dose‐dependent manner over the concentration range 1–150 μM. Human PMNs were more sensitive to the inhibitory effect of genistein than HL‐60 cells (50% inhibitory concentration 14.8 and 30.2 μM, respectively). In addition, genistein moderately inhibited Superoxide anion formation by HL‐60 cells and scavenged exogenously added H2O2 under the same conditions as in cell culture. However, the H2O2‐scavenging effect of genistein was about 50% lower than its inhibition of cell‐derived H2O2 formation at all concentrations. In the CD‐1 mouse skin model, genistein strongly inhibited TPA‐induced oxidant formation, edema, and PMN infiltration in mouse skin. Inhibition of TPA‐mediated H2O2 in vivo may result from decre...

Inhibition of tumor Promoter‐induced hydrogen peroxide formation in vitro and in vivo by genistein

Alterations of antioxidant enzymes and oxidative damage to macromolecules in different organs of rats during aging.

Caffeic acid phenethyl ester (CAPE) was isolated from propolis (a product of honeybee hives) that has been used in folk medicine as a potent antiinflammatory agent. CAPE is cytotoxic to tumor and virally transformed but not to normal cells. Our main goal was to establish whether CAPE inhibits the tumor promoter (12-O-tetradecanoylphorbol-13-acetate)-induced processes associated with carcinogenesis. Topical treatment of SENCAR mice with very low doses (0.1–6.5 nmol/topical treatment) of CAPE strongly inhibits the following 12-O-tetradecanoylphorbol-13-acetate-mediated oxidative processes that are considered essential for tumor promotion: (a) polymorphonuclear leukocyte infiltration into mouse skin and ears, as quantified by myeloperoxidase activity; (b) hydrogen peroxide (H2O2) production; and (c) formation of oxidized bases in epidermal DNA, as measured by 5-hydroxymethyluracil and 8-hydroxylguanine. A 0.5-nmol dose of CAPE suppresses the oxidative burst of human polymorphonuclear leukocytes by 50%. At higher doses (1–10 µmol), CAPE inhibits edema and ornithine decarboxylase induction in CD-1 and SENCAR mice. Interestingly, we discovered that 12-O-tetradecanoylphorbol-13-acetate-induced H2O2 production in bovine lenses also is inhibited by CAPE. Cumulatively, these findings point to CAPE as being a potent chemopreventive agent, which may be useful in combatting diseases with strong inflammatory and/or oxidative stress components, i.e., various types of cancer and possibly cataract development.

http://cancerres.aacrjournals.org/content/canres/53/6/1255.full.pdf

Inhibition of Tumor Promoter-mediated Processes in Mouse Skin and Bovine Lens by Caffeic Acid Phenethyl Ester

Dietary administration of the soybean isoflavone genistein (50 and 250 ppm) for 30 days significantly increases the activities of antioxidant enzymes in various organs of SENCAR mice. Feeding a 250-ppm genistein diet to SENCAR mice significantly increases the activities of catalase in small intestine, liver, and kidney, the activities of superoxide dismutase and glutathione peroxidase in skin, and the activity of glutathione reductase in skin and small intestine. Feeding 50 ppm genistein to SENCAR mice results in elevated catalase activity in the small intestine and increases glutathione-S-transferase activities in skin, small intestine, liver, kidney, and lung. Dietary genistein's greatest enhancement of antioxidant enzyme activities occurred in skin and small intestine. Our results suggest that dietary genistein enhances the activities of antioxidant enzymes in various organs, which may be a mechanism(s) of genistein's chemopreventive action.

Huachen Wei

Papers

Antioxidant and antipromotional effects of the soybean isoflavone genistein.

Inhibition of tumor Promoter‐induced hydrogen peroxide formation in vitro and in vivo by genistein

Alterations of antioxidant enzymes and oxidative damage to macromolecules in different organs of rats during aging.

Inhibition of Tumor Promoter-mediated Processes in Mouse Skin and Bovine Lens by Caffeic Acid Phenethyl Ester

Effect of dietary genistein on antioxidant enzyme activities in SENCAR mice