ABSTRACT
In this study, for the first time, the anti-inflammatory, antioxidant, anti-tyrosinase and antimicrobial property of P. atlantica Desf. subsp. atlantica leaf-bud extract have been investigated. The anti-inflammatory activity was determined in vivo by reducing carrageenan-induced hind paw edema in mice, while the antiradical function was evaluated using DPPH, total antioxidant capacity (TAC) and reduction power assays. The extract induced a significant reduction of the edema, from 1 to 6 h in a dose-dependent manner (150, 200 and 300 mg/kg). Histological observations of the inflamed tissues also confirmed this. An effective antioxidant activity of the plant samples was demonstrated, showing an EC50 = 0.183 ± 0.005 mg/mL for the DPPH test, a value of 28.776 ± 2.541 mg AAE/g for the TAC and an EC50 = 0.136 ± 0.003 mg/mL for reducing power. The leaf-bud extract also revealed a good antimicrobial activity against S. aureus and L. monocytogenes (mean diameter of inhibition zones of 13.2 and 17.0 mm, respectively), while a slight antifungal effect was observed. The plant preparation was then documented to inhibit tyrosinase activity, with an EC50 value of 0.098 ± 0.00 mg/mL in a dose-dependent manner. HPLC-DAD analysis revealed that dimethyl-allyl caffeic acid and rutin were the most abundant molecules. The current data documented that P. atlantica leaf-bud extract has strong biological properties and constitutes a potential source of pharmacological molecules.
ABSTRACT
BACKGROUND: Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus. METHODS: Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium. RESULTS: Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05). A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p < 0.001). The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001) and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001). CONCLUSIONS: Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus.
