The biochemistry and medical significance of the flavonoids.

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

Dietary agents in cancer prevention: flavonoids and isoflavonoids.

Flavonoids are polyphenolic compounds that are ubiquitously in plants. They have been shown to possess a variety of biological activities at nontoxic concentrations in organisms. The role of dietary flavonoids in cancer prevention is widely discussed. Compelling data from laboratory studies, epidemiological investigations, and human clinical trials indicate that flavonoids have important effects on cancer chemoprevention and chemotherapy. Many mechanisms of action have been identified, including carcinogen inactivation, antiproliferation, cell cycle arrest, induction of apoptosis and differentiation, inhibition of angiogenesis, antioxidation and reversal of multidrug resistance or a combination of these mechanisms. Based on these results, flavonoids may be promising anticancer agents.

Flavonoids: Promising anticancer agents

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.

Although studies of bacteriology of closed oral abscesses have been extensively done, there are few studies on microorganisms involving open oral abscesses. We examined bacteriologically three open abscesses with precaution against bacterial contamination with oral normal flora and saliva, when sampling. The specimens were subjected to aerobic and anaerobic cultures within 2 hours after sampling. All three cases were infected with 5 to 14 species of aerobic and anaerobic bacteria; Streptococcus spp., Prevotella intermedia and other Prevotella spp. were predominant in all three cases. All six Prevotella spp. isolated were beta-lactamase producers, being resistant to beta-lactam antibiotics. These results emphasize the importance of prompt anaerobic culture for the bacteriological study of open oral abscess and the significance of nitrocefin test to detect beta-lactamase produced by oral isolates, especially Prevotella spp.

Bacteriological study of oral open abscesses

https://www.jstage.jst.go.jp/article/jjoms1967/24/2/24_2_287/_pdf

Chondrosarcoma of the mandible: report of a case

The distribution of subunit A of blood coagulation factor XIII (FXIIIa) was investigated in human pulmonary tissues by the avidin-biotin-peroxidase complex (ABC) method. FXIIIa was detected in certain connective tissue cells, including dust-laden cells of the subpleural areas and alveolar septa as well as in alveolar macrophages, but not in type I or type II alveolar epithelial cells. These findings agree well with the widely accepted conception that pulmonary macrophages are part of the general mononuclear phagocyte system (MPS). The biological role of the FXIIIa-positive pulmonary cells is also discussed in this paper.

Factor XIIIa-positive cells in the human pulmonary tissues : an immunohistochemical study

A case of recurrent pleomorphic adenoma with multicentric satellites is reported in this paper. The tumor occurred in a minor salivary gland in the right buccal mucosa in a 67-year-old man. It was diagnosed on the basis of histopathological examinations of the mass and a swollen cervical lymph node. The diagnosis was recurrent pleomorphic adenoma with malignant transformation 36 years after primary surgery. In this report, the clinical course and histopathological findings are described and discussed.

Norichika Tatematsu

Papers

Bacteriological study of oral open abscesses

Chondrosarcoma of the mandible: report of a case

Factor XIIIa-positive cells in the human pulmonary tissues : an immunohistochemical study

Recurrent pleomorphic adenoma of the buccal mucosa with multicentric satellites. Report of a case with a review of the literature

Congenital epulis: Report of a case