Protective effect of a vitamin E analog, phosphatidylchromanol, against oxidative hemolysis of human erythrocytes

Abstract

The protective effect of a vitamin E analog, phosphatidylchromanol [1,2-diacyl-sn-glycero-3-phospho-2'-(hydroxyethyl)-2',5',7',8'-tetrameth yl-6'-hydroxychroman; PCh], against oxidative hemolysis of human erythrocytes was examined and was compared with those of vitamin E (alpha-tocopherol) and 2,2,5,7,8-pentamethyl-6-chromanol (PMC). These three compounds at 50 microM protected the erythrocytes from hemolysis, when erythrocyte suspension (10%, vol/vol) was incubated with a water-soluble radical generator, 2,2'-azobis(2-amidinopropane)-dihydrochloride (75 mM). When erythrocyte suspension was oxidized after pretreatment with these compounds (50 microM) for 30 min followed by washing, PCh protected about 54% of erythrocytes from the hemolysis, while alpha-tocopherol protected only about 16% of the cells and PMC did not show any protective effect. During preincubation, alpha-tocopherol, PMC, and PCh were incorporated into the cells at the concentration of 12.6, 3.7, and 16.3 nmol/mg protein, respectively. Moreover, PCh was found in the ghost membrane fraction at a 20% higher level than alpha-tocopherol, and no PMC was detected in this fraction. These results indicate that phosphatidyl group in PCh acts as an excellent carrier of chromanol moiety into cells as well as an anchor within membranes more efficiently than phytyl group in alpha-tocopherol. PMC seems to be slightly anchored within membranes because of the lack of hydrophobic side chain. The excellent antihemolytic activity of PCh is likely to be caused by its accumulation within erythrocyte membranes.

Quercetin and rutin as potential agents antifungal against Cryptococcus spp

“…The pelleted erythrocytes were washed three times with isotonic PBS (pH7.4), and the supernatant was carefully removed after each wash. After the final wash, the packed cells were re-suspended in PBS, and the hematocrit was determined (Koga et al, 1998)…”

“…The treatment regimens for cryptococcal meningitis are focused on amphotericin B (amB) alone or associated with azoles, especially fluconazole (Negroni, 2012). However, the therapy with amB has been limited by severe toxic side effects especially nephrotoxicity (Laniado-Laborín and Cabrales-Vargas, 2009). Attempts have been made to reduce amB toxicity by combination with other antifungal agents or natural products because combination therapy can promote synergistic antifungal effect with the advantage of reduced toxicity.…”

Hydroxytamoxifen interaction with human erythrocyte membrane and induction of permeabilization and subsequent hemolysis

“…The sediment of erythrocytes was washed three times with 6 volumes of isotonic phosphate buffered saline (PBS) (150 mm NaCl, 10 mm sodium phosphate, pH 7.4) and the buffy coat was removed with each wash, according to previous reports Dwight and Hendry, 1996;Koga et al, 1998). The retrieved cells were resuspended in PBS and the hematocrit determined.…”

“…After the incubation periods, the erythrocyte suspensions were centrifuged at 3000 rpm for 10 min and the hemolysis degree was estimated by visible spectroscopy at 540 nm from the hemoglobin released into the supernatant, as described elsewhere (Koga et al, 1998). The results were expressed as percent hemolysis.…”

Black and white teas as potential agents to combine with amphotericin B and protect red blood cells from amphotericin B-mediated toxicity

“…The suspensions were incubated for 7 hours at 37 °C with continuous shakingin the dark. After incubation, the erythrocyte suspensions were centrifuged at 2500rpm for 5 min and the hemolysis degree was estimated by visible spectroscopy at 540nm from the hemoglobin released into the supernatant (Koga et al, 1998). The results are expressed as the percentage of inhibition of amB-induced hemolysis, calculated according to the following formula: hemolysis inhibition % = [(Ab-Aa)/Ab]×100, where Ab is the absorption of the control and Aa is the absorption of the sample (Dypbukt et al, 2005).…”