Resolution of parasitemia was inadequate with monotherapy with either azithromycin or chloroquine, but combination therapy provided substantially improved clinical and parasitologic outcomes. The combination of azithromycin and chloroquine may be an effective alternative treatment for falciparum malaria and deserves further study.

A detailed photophysical study of the plant flavonoid fisetin in a dimyristoylphosphatidylcholine (DMPC) bilayer membrane has been carried out. Fisetin is found to partition well into the membrane (K(p) = (4.6 ± 0.5) × 10(5) in solid gel phase and (5.1 ± 0.5) × 10(5) in liquid crystalline phase). A fluorescence quenching study using cetylpyridinium chloride (CPC) as the quencher suggests that fisetin molecules are generally present near the head group region of the lipid bilayer membrane. The temperature dependence of the fluorescence lifetime indicates a local heterogeneity in the distribution of fisetin within the bilayer membrane. The phototautomer form of fisetin, which is the primary emitting species from the lipid membrane, has a large Stoke's shift (175 nm) and fluoresces with an intense green fluorescence, which can make the molecule a good dye for marker and bioimaging applications. Membrane-bound fisetin shows sensitive variations of fluorescence intensity, lifetime, and anisotropy parameters in cholesterol-containing DMPC membranes, in mixed phospholipids, and as a function of temperature. This suggests that fisetin can be an efficient fluorescent molecular probe for sensing lipid bilayer membrane related changes. The location of fisetin in the membrane and the observed cholesterol-induced expulsion of fisetin may possibly have implications in the antioxidant activity of fisetin.

In this study, 1-naphthol has been used as a sensitive ESPT fluorescent molecular probe to investigate the interaction of submicellar concentrations of two physiologically important bile salts, sodium deoxycholate and sodium cholate, with dipalmitoylphosphatidylcholine small unilamellar vesicles in solid gel and liquid crystalline phases. Steady-state and time-resolved fluorescence of the two excited state prototropic forms of 1-naphthol indicate that the incorporation of monomeric bile salt molecules in the lipid bilayer membrane induces appreciable wetting of the bilayer up to the hydrocarbon core region, even at very low (≤1 mM) concentrations of the bile salts.

The interaction of submicellar concentrations of various physiologically important unconjugated [sodium deoxycholate (NaDC), sodium cholate (NaC)] and conjugated [sodium glycodeoxycholate (NaGDC), sodium glycocholate (NaGC), sodium taurodeoxycholate (NaTDC), sodium taurocholate (NaTC)] bile salts with dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles in solid gel (SG) and liquid crystalline (LC) phases was investigated using the excited-state prototropism of 1-naphthol. Steady-state and time-resolved fluorescence of the two excited-state prototropic forms of 1-naphthol indicate that submicellar bile salt concentration induces hydration of the lipid bilayer membrane into the core region. This hydration effect is a general phenomenon of the bile salts studied. The bilayer hydration efficiency of the bile salt follows the order NaDC > NaC > NaGDC > NaTDC > NaGC > NaTC for both DPPC and DMPC vesicles in their SG and LC phases.

The present work focuses on the current interest in diyne bridged chromophores necessitating a clearer understanding of the photophysics of such molecules. The significance of the diyne moiety in the photophysics has been investigated by synthesizing simple substituted diphenyl butadiynyl derivatives following a quick and efficient microwave assisted Eglinton coupling of terminal alkynes. Emission of the fluorophores is observed from the usual locally excited (LE) state and intramolecular charge transfer (ICT) state. Separation of pure ICT emission from pure LE emission has been carried out by Gaussian/Lorentzian curve fitting. The vibronic coupling in the local transitions appears to be confined to the normal mode involving the C-C triple bond stretching of the diyne moiety. This implies that the LE transition involves the diyne moiety, a conclusion supported by quantum chemical calculations. The resolved ICT emission follows double linear dependence on ET(30) solvent polarity scale. The important role of the diyne moiety in the photophysics of this class of molecules is clearly discernible in this study.