Antiplasmodial 9-anilinoacridine derivatives exert their effects either by inhibiting DNA topoisomerase (topo) II or by interfering with heme crystallization within the parasite acidic food vacuole. Previous studies have shown that analogs of 9-anilinoacridine containing 3,6-diamino substitutions (in the acridine ring) inhibit Plasmodium falciparum DNA topo II in situ, whereas those with a 3,6-...

Oxyhemoglobin in erythrocyte hemolysates interferes with the Jendrassik-Grof assay. Destruction of azobilirubin occurs when oxyhemoglobin is oxidized to methemoglobin during diazotization or to alkaline hematin with addition of alkaline tartrate. The most probable mechanism is by oxidation with an agent such as hydrogen peroxide or a related species resulting from hemoglobin oxidation. Methemog...

Malaria parasite metabolizes hemoglobin and detoxifies the resulting toxic ferriprotoporphyrin IX by polymerization into a crystal insoluble pigment, known as hemozoin. A polymer identical to hemozoin, β-hematin, can be obtained in vitro from hematin at acidic pH. Quinoline-containing antimalarials (e.g. chloroquine) inhibit the formation of polymer. Thus, heme polymerization is an essensial an...

Heme formation in reticulocytes from rabbits and rodents is subject to end product negative feedback regulation: intracellular “free” heme has been shown to control acquisition of transferrin iron for heme synthesis. To identify the site of control of heme biosynthesis in the human erythron, immature erythroid cells were obtained from peripheral blood and aspirated bone marrow. After incubation...

Trioxaquines, potential antimalarial agents, and heme-artemisinin adducts, resulting from the alkylation of heme by artemisinin, were evaluated as inhibitors of beta-hematin formation in 10 M acetate medium at pH 5.

A series of phenylsubstituted pyrazolo and pyrimido benzothiazine dioxide derivatives were synthesized and investigated for their abilities to inhibit beta-hematin formation, hemoglobin hydrolysis and in vivo for their antimalarial efficacy in rodent Plasmodium berghei. Compounds 3-amino-7-chloro-9-(2'-methylphenyl)-1,9-dihydro-pyrazolo-[4,3-b]benzothiazine 4,4-dioxide 2b and 2,4-diamino-8-chlo...

Prolongation of clotting times produced by hematin was investigated both in vitro and in vivo. Hematin-derived anticoagulant (HDA) was found to be due to a degradative product or derivative of hematin, and was generated in vitro in standing (aging) aqueous solutions of the parent compound. Generation of HDA in vitro was inhibited by antioxidants. The anticoagulant effect of HDA was inhibited by...

background and objectives:the plants of genus artemisia (asteraceae) have been conventionally used for prevention and medication of a number of ailments. in the present research, ten extracts with different polarities from aerial parts of two artemisia species, a. kopetdaghensis and a. turcomanica were evaluated for their potential anti-malarial properties. methods: the plant materials were ext...

Scrophularia umbrosa is a medicinal plant used as a traditional herb. This study was designed to investigate the phytochemical analysis of methanol (MeOH), DCM, and n-Hexane extracts of rhizome as well as total phenol and total flavonoid contents (TPC and TFC). In-vitro β-hematin formation assay and DPPH method were applied for analyzing antimalarial and free-radical scavenging activities of th...