Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus.

Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.

Comparative evaluation of oxidative and antioxidative capacity during high-flux hemodialysis using two different membranes.

AIM: In patients with end-stage renal disease (ESRD) cardiovascular morbidity and mortality are increased. Apart from traditional and uremia-specific factors oxidative stress has been implicated as a main risk factor. This study investigated the influence of two different high-flux hemodialysis membranes on parameters of oxidative stress during a dialysis session. PATIENTS AND METHODS: 14 stable ESRD patients were enrolled in the study and randomly assigned to high-flux hemodialysis using either a polyamide membrane (Polyflux 14; PA group) or a new polysulfone membrane (Diacap Polysulfone HI PS 15; PS group). All patients received 6 treatments with the same membrane. During the 5th treatment parameters of dialysis efficiency, biocompatibility (cell counts, complement C3a, thrombin-antithrombin complex) and oxidative stress (lipid peroxides, total antioxidative capacity) were measured. RESULTS: Parameters of dialysis efficiency and biocompatibility were similar in both treatment groups. At the beginning of the dialysis session both groups showed a low to moderate level of oxidative stress and a reduced total antioxidative capacity as compared to healthy controls. Both parameters deteriorated significantly during the extracorporeal procedure with a similar magnitude in both membrane groups. No correlation between oxidative or antioxidative capacity and parameters of biocompatibility or dialysis efficiency could be found. CONCLUSIONS: Dialysis with synthetic high-flux membranes induces a temporary deterioration of oxidative stress parameters in ESRD patients despite good dialysis efficiency and biocompatibility.

In-vivo antimalarial activity of some oxygenated xanthones.

A series of oxygenated xanthones was prepared so that the antimalarial activity of each compound could be evaluated in vivo, using 4-day suppressive assays against Plasmodium berghei ANKA in BALB/c mice. When given in a dose of 20 mg/kg.day for 4 days, most of the compounds produced significant chemosuppression of parasitaemia. The most active compound was 1,3,6,8-tetrahydroxyxanthone, which reduced the percentage of erythrocytes infected by 70.5%, followed by norlichexanthone (44.3%) and its isomer, 1,3,8-trihydroxy-6-methylxanthone (37.0%). Whereas di-C-allyl-dihydroxyxanthone showed lower but still notable activity (33.4%), 1,3-dihydroxyxanthone was much less active (15.1%). This appears to be the first demonstration of the antimalarial activity of some hydroxyxanthones in vivo.

Two isoflavanones from the stem bark of Erythrina sacleuxii.

From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2',4',5'-trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy-2',4',5'-trimethoxy-2",2"-dimethylpyrano[5",6":6,7]isoflavanone (trivial name, (R)-saclenone) were isolated. In addition the known compounds shinpterocarpin, 2,3-dehydrokievitone, abyssinone V, abyssinone V-4'-methyl ether, erythrinasinate and 4'-O-methylsigmoidin B were isolated. The structures were determined on the basis of spectroscopic evidence.