Quercetin induces apoptosis of Trypanosoma brucei gambiense and decreases the proinflammatory response of human macrophages.

In addition to parasite spread, the severity of disease observed in cases of human African trypanosomiasis (HAT), or sleeping sickness, is associated with increased levels of inflammatory mediators, including tumor necrosis factor (TNF)-alpha and nitric oxide derivatives. In the present study, quercetin (3,3',4',5,7-pentahydroxyflavone), a potent immunomodulating flavonoid, was shown to directly induce the death of Trypanosoma brucei gambiense, the causative agent of HAT, without affecting normal human cell viability. Quercetin directly promoted T. b. gambiense death by apoptosis as shown by Annexin V binding. In addition to microbicidal activity, quercetin induced dose-dependent decreases in the levels of TNF-alpha and nitric oxide produced by activated human macrophages. These results highlight the potential use of quercetin as an antimicrobial and anti-inflammatory agent for the treatment of African trypanomiasis.

Increase in total blood antioxidant status and selenium levels in black patients with active vitiligo.

BACKGROUND: Oxidative stress could be an important phenomenon leading to melanocyte death in vitiligo. The accumulation of hydrogen peroxide (H2O2) and low catalase levels have recently been demonstrated in the epidermis of vitiligo patients. Few abnormalities of antioxidants have been found in the blood of patients with vitiligo, except for an elevation of selenium. No studies on oxidative stress have been performed so far on patients with skin phototype VI (Fitzpatrick classification). AIM: To study the blood antioxidant status of black patients with active generalized vitiligo. METHODS: Randox total antioxidant status, selenium, ferritin, transferrin, ceruloplasmin, tocopherol, and retinol levels were evaluated in blood samples obtained from 11 dark-skinned patients from the French West Indies (Isle of Martinique) with recent active lesions of vitiligo and from 11 age- and sex-matched healthy volunteers. RESULTS: Total blood antioxidant status and selenium levels were significantly increased in vitiligo patients, compared to those in sex- and age-matched controls (P < 0.01 and P < 0.02, respectively). Blood levels of ferritin, transferrin, ceruloplasmin, retinol, and tocopherol were not significantly modified. CONCLUSIONS: This is the first report on the global blood antioxidant status in vitiligo. The increase in total blood antioxidant status observed in black patients was an unexpected result that needs to be confirmed and explained by further studies. The spontaneous increase in selenium levels could be of interest, as it has been recommended in the treatment of vitiligo.