This model involves the inhibition of hemozoin biocrystallization in the heme detoxification pathway, which facilitates the aggregation of cytotoxic heme. Free cytotoxic heme accumulates in the parasites, causing their deaths. Quinine may target the malaria purine nucleoside phosphorylase enzyme. Chemistry
The UV absorption of quinine peaks around 350 nm (in UVA). Fluorescent emission peaks at around 460 nm (bright blue/cyan hue). Quinine is highly fluorescent (quantum yield ~0.58) in 0.1 M sulfuric acid solution. Synthesis
Cinchona trees remain the only economically practical source of quinine. However, under wartime pressure during World War II, research towards its synthetic production was undertaken. A formal chemical synthesis was accomplished in 1944 by American chemists R.B. Woodward and W.E. Doering. Since then, several more efficient quinine total syntheses have been achieved, but none of them can compete in economic terms with isolation of the alkaloid from natural sources. The first synthetic organic dye, mauveine, was discovered by William Henry Perkin in 1856 while he was attempting to synthesize quinine. Biosynthesis
In the first step of quinine biosynthesis, the enzyme strictosidine synthase catalyzes a stereoselective Pictet–Spengler reaction between tryptamine and secologanin to yield strictosidine. Suitable modification of strictosidine leads to an aldehyde. Hydrolysis and decarboxylation would initially remove one carbon from the iridoid portion and produce corynantheal. Then the tryptamine side-chain were cleaved adjacent to the nitrogen, and this nitrogen was then bonded to the acetaldehyde function to yield cinchonaminal. Ring opening in the indole heterocyclic ring could generate new amine and keto functions.
Calfactant, also known as Infasurf, is an intratracheal suspension derived from the natural surfactant in calf lungs. It is used in premature infants with lung surfactant deficiency that causes infant respiratory distress syndrome (IRDS). Mechanism of action
Lung surfactant is essential for effective ventilation as it modifies alveolar surface tension. IRDS is caused by a lung surfactant deficiency. Calfactant serves as a substitute for the natural surfactant. == References ==