Effect of curcumin on the production of nitric oxide by cultured rat mammary gland

Downregulation of COX-2 and iNOS by amentoflavone and quercetin in A549 human lung adenocarcinoma cell line

Flavonoids are natural polyphenolic compounds ubiquitously present in the plant kingdom. They are reported to exhibit numerous beneficial health effects. In the present study, we demonstrate the potential effects of different flavonoids on cytokines mediated cyclooxygenase-2 and inducible nitric oxide synthase expression and activities in A549 cell line using quercetin, amentoflavone and flavanone. Our data revealed that quercetin, at 50 micro M concentration inhibited PGE(2) biosynthesis by A549 very strongly with little effect on COX-2 mRNA and protein expression. Unlike quercetin, amentoflavone inhibited both PGE(2) biosynthesis and COX-2 mRNA and protein expression strongly. In another set of experiment, quercetin inhibited iNOS protein expression completely without affecting iNOS mRNA expression. In contrast, amentoflavone although exerted no inhibitory effect on iNOS mRNA expression, did inhibit weakly iNOS protein expression. Flavanone had no inhibitory effect on either enzyme at the same concentration. Taken together, our data indicated that amentoflavone and quercetin differentially exerted supression of PGE(2) biosynthesis via downregulation of COX-2/iNOS expression.

Prevention of radiation-induced mammary tumors

The radiation-induced rat mammary tumor model is useful for studying tumor prevention by treatment in the initiation or promotion stage. In anti-initiation experiments, the administration of radical scavengers or spin-trapping agents before or immediately after irradiation reduced the incidence of mammary tumors, suggesting that free radicals produced by exposure are a potent initiator. To evaluate the role of nitric oxide (NO) in the initiation, NO-specific scavengers or NO synthase inhibitors were administered during the initiation. These agents partially prevented the tumorigenesis, suggesting that radiation-induced NO contributes to tumor initiation. The administration of curcumin during irradiation reduced the incidence of the tumors in the presence of tumor promotor. In anti-promotion experiments on preventing diethylstilbestrol (DES)-dependent tumor development from mammary primodial cells exposed to radiation, tamoxifen decreased the tumor incidence. From the results, estrogen itself or prolactin induced by estrogen may be a promoter for the tumorigenesis. Bezafibrate and simvastatin, agents inducing hypolipidemia and hypocholesterolemia respectively, cause a decrease in the DES-dependent promotion of radiation-induced tumorigenesis. The simultaneous administration of curcumin and DES significantly reduces the development of mammary tumors in irradiated rats. In this review, the endocrinologic and pharmacologic significance of the anti-initiation and anti-promotion is discussed.

[A rare cause of neonatal exudative enteropathy: congenital Langerhans cell histiocytosis (histiocytosis X)]

A case of Langerhans cell histiocytosis is reported in a neonate. Intestinal involvement was especially diffuse and severe, presenting as a protein-losing enteropathy secondary to massive mucosal infiltration by histiocytic cells. The infant died at the age of 3 1/2 months despite therapy with corticosteroids and vinblastine then etoposide and interferon. Such an outcome confirmed the severity of forms with neonatal onset and digestive involvement.