Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a major pungent ingredient of red pepper, is reported to have antimutagenic and anticarcinogenic properties. However, the mechanisms underlying its chemoprotective effects remain largely unresolved. In the present study, we found that capsaicin induced expression of heme oxygenase-1 (HO-1) in HepG2 cells. Capsaicin treatment resulted in a transient increase in the phosphorylation of Akt and subsequently nuclear translocation of NF-E2-related factor 2 (Nrf2), enhancing its binding to antioxidant response element (ARE). HepG2 cells treated with capsaicin exhibited increased production of reactive oxygen species (ROS). Prior exposure of cells to N-acetyl-L -cysteine blocked not only the ROS production but also the nuclear translocation of Nrf2 and its ARE binding, as well as HO-1 induction by capsaicin. Immunoblot analysis showed that whereas the level of HO-1 protein was elevated, that of NAD(P)H:quinone oxidoreductase (NQO1) was decreased after the treatment with capsaicin or the inhibitor of NQO1, dicumarol. We hypothesize that quinone metabolites or other reactive forms of capsaicin may bind covalently to NQO1 and thereby inhibit its activity, leading to production of ROS. This, in turn, would trigger the activation of Akt via phosphorylation, increase the nuclear translocation and ARE binding of Nrf2, and upregulate the expression of HO-1.

This study tests the hypothesis that perinatal taurine supplementation prevents diabetes mellitus and hypertension in adult offspring of maternal diabetic rats. Female Wistar rats were fed normal rat chow and tap water with (Diabetes group) or without diabetic induction by intraperitoneal streptozotocin injection (Control group) before pregnancy. Then, they were supplemented with 3% taurine in water (Control+T and Diabetes+T groups) or water alone from conception to weaning. After weaning, both male and female offspring were fed normal rat chow and tap water throughout the study. Blood chemistry and cardiovascular parameters were studied in 16-week old rats. Body, heart, and kidney weights were not significantly different among the eight groups. Further, lipid profiles except triglyceride were not significantly different among male and female groups, while male Diabetes displayed increased fasting blood glucose, decreased plasma insulin, and increased plasma triglyceride compared to other groups. Compared to Control, mean arterial pressures significantly increased and baroreflex control of heart rate decreased in both male and female Diabetes, while heart rates significantly decreased in male but increased in female Diabetes group. Although perinatal taurine supplementation did not affect any measured parameters in Control groups, it abolished the adverse effects of maternal diabetes on fasting blood glucose, plasma insulin, lipid profiles, mean arterial pressure, heart rate, and baroreflex sensitivity in adult male and female offspring. The present study indicates that maternal diabetes mellitus induces metabolic and cardiovascular defects more in male than female adult offspring, and these adverse effects can be prevented by perinatal taurine supplementation.

Thalassemia major is characterized by anemia, iron overload, and oxidant damage to major organs, especially the cardiovascular system. Oxidative stress is ultimately involved in endothelial dysfunction, a condition which is evident in adults suffering from various cardiovascular diseases including thalassemia. We investigated endothelial function in pediatric patients with hemoglobin E-beta thalassemia (HbE-beta thalassemia), who have been exposed to excessive iron and oxidative stress for much shorter period than adults with thalassemia. We recruited 22 blood transfusion-dependent HbE-beta thalassemia patients aged 11.8 +/- 2.9 years and 20 healthy controls aged 12.1 +/- 1.7 years. Oxidant status was determined, and endothelial function was assessed by a forearm blood flow technique. Oxidative stress was increased in the thalassemic patients, as blood glutathione (GSH) and ratios of reduced GSH to GSH disulfide were markedly reduced, and superoxide anion released from blood cells was highly elevated. Oxidative stress response, assessed by gamma-glutamylcysteine ligase activity, was increased approximately twofold in thalassemia patients. Basal forearm blood flow was significantly increased in patients compared with controls (7.3 +/- 1.8 vs 6.0 +/- 1.8 ml/100 ml tissue/min, respectively), whereas forearm vasodilatory response to reactive hyperemia was depressed by 50% in patients compared with controls. Endothelial function is impaired in young thalassemia patients, and impaired endothelial function is associated with oxidant stress.

Cymbopogon citratus (DC) Stapf., commonly known as lemongrass, possesses strong antioxidant and cardiotonic properties. Lemongrass water extract contains several polyphenolic compounds including gallic acid, isoquercetin, quercetin, rutin, catechin and tannic acid. Rutin, isoquercetin catechin and quercetin are the flavonoids most abundantly found in the extract. The extract significantly decreased total cholesterol, low-density lipoprotein and atherogenic index in rats after treatment (p < 0.05). Expression of genes and protein of sterol regulatory element binding protein-1c (SREBP1c) and HMG-CoA reductase (HMGR) was also lowered significantly in treated groups (p < 0.05). Moreover, serum antioxidant capacity increased in treated rats in comparison with untreated ones (p < 0.05) and was associated with decreased serum lipid peroxidation.