Chemical constituents of the new endophytic fungus Mycosphaerella sp. nov. and their anti-parasitic activity

Chemical investigation of a new endophytic fungus, Mycosphaerella sp. nov. strain F2140, associated with the foliage of the plant Psychotria horizontalis (Rubiaceae) in Panama, resulted in the isolation of cercosporin (1) and a new cercosporin analog (3) as the major components. The structures of minor compounds in the extract were elucidated by detailed spectroscopic analysis as 2-(2-butyl)-6-ethyl-3-hydroxy-6-methylcyclohex-2-ene-1,5-dione (4), 3-(2-butyl)-6-ethyl-5-hydroxy-2-methoxy-6-methyl-cyclohex-2-enone (5), and an isomer of 5 (6). To study the influence of the hydroxy groups on the anti-parasitic activity of cercosporin, compound 1 was acetylated to obtain derivative 2. The isolated compounds 1- 6 were tested in vitro to determine their anti-parasitic activity against the causal agents of malaria (Plasmodium falciparum), leishmaniasis (Leishmania donovani), and Chagas disease (Trypanosoma cruzi). Cytotoxicity and potential anticancer activity of these compounds were evaluated using mammalian Vero cells and MCF7 cancer cell lines, respectively. Compounds 1 and 2 displayed high potency against L. donovani (IC50 0.46 and 0.64 microM), T. cruzi (IC50 1.08 and 0.78 microM), P. falciparum (IC50 1.03 and 2.99 microM), and MCF7 cancer cell lines (IC50 4.68 and 3.56 microM). Compounds 3-6 were not active in these assays at a concentration of 10 microg/mL.     

Positively and negatively charged ionic modifications to cellulose assessed as cotton-based protease-lowering and hemostatic wound agents

Recent developments in cellulose wound dressings targeted to different stages of wound healing have been based on structural and charge modifications that function to modulate events in the complex inflammatory and hemostatic phases of wound healing. Hemostasis and inflammation comprise two overlapping but distinct phases of wound healing wherein different dressing material properties are required to bring pathological events under control when they present as a result of trauma or chronic wounds. Thus, we have designed cellulose wound dressings with properties that function through modified fiber surface properties to lower protease levels in the chronic wound and promote clotting in hemorrhaging wounds. With this in mind three finishing chemistries utilizing traditional pad-dry-cure approaches were explored for their potential to confer charged properties to cotton dressings. Cellulose dressings designed to remove cationic serine proteases from highly exudative chronic wounds were created to present negatively charged fibers as an ion exchange mechanism of protease-lowering. Phosphorylated cotton and polycarboxylic acid crosslinked cotton were prepared to examine their ability to remove human neutrophil elastase (HNE) from surrogate wound fluid. A cellulose phosphorylation reaction utilizing sodium hexametaphosphate: urea was explored to optimize cellulose phosphorylation as a function of HNE sequestration efficacy. Acid catalyzed cross linking of cellulose with butane-tetracarboxylic acid also resulted in a negatively charged dressing that removed HNE from solution more effectively than phosphorylated cellulose. Collagenase sequestration was also assessed with phosphorylated cellulose and polycarboxylic acid cross linked cellulose derivatives. Butanetetracarboxylic acid and phosphorylated cellulose functioned to remove collagenase from solution most effectively. Cellulose dressings designed to accelerate thrombosis and aggregation of blood platelets were prepared with a view to examining derivatized cotton fibers bearing a net positive charge to promote hemostasis. Cellulose and chitosan dressings bearing an aminoglucan functionality were created by grafting chitosan on cotton and preparing aminized cotton. The preparation of chitosan-grafted cotton dressings was completed with a citric acid grafting onto cellulose. Aminized cotton was functionalized as an ethylamino-ether cellulose derivative. The chitosan-grafted and aminized cotton demonstrated a dose response gelling of citrated sheep blood.     

Thermal isomerization of cis,anti,cis-tricyclo[6.3.0.0(2,7)]undec-3-ene to endo-tricyclo[5.2.2.0(2,6)]undec-8-ene

[reaction: see text] The gas-phase thermal isomerization of cis,anti,cis-tricyclo[6.3.0.0(2,7)]undec-3-ene (1) to endo-tricyclo[5.2.2.0(2,6)]undec-8-ene (2) at 315 degrees C occurs cleanly through a symmetry-forbidden [1,3] suprafacial,retention (sr) pathway.