Combining Nuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations to Characterize Carvedilol Polymorphs.

The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations.

Anthelmintic effects of alkylated diamines and amino alcohols against Schistosoma mansoni.

Polyamines are substances involved in many aspects of cell growth, division, and differentiation. Because of the metabolic differences between host cells and parasite cells, polyamine metabolism has been considered as a potential target for the chemotherapy of parasitic diseases. The aim of this work was to evaluate the schistosomicidal activity of different N-alkylated diamines (3a-3h), amino alcohols (4a-4d), and glycosylated amino alcohols (10a-10d). Compounds were prepared by synthetic methods and submitted to in vitro evaluation against adult worms of Schistosoma mansoni. At 100 µM, 3b, 3e, and 3h as well as 4a, 4b, 4d, 10a, 10b, and 10d resulted in 100% mortality of adult schistosomes. Compound 3d (12.5 to 100 µM) caused the death of 100% of both male and female adult schistosomes, while 3f (12.5 to 100 µM) resulted in 100% mortality of only male adult worms, whereas no mortality in female worms was observed. Compounds 3d and 3f were also able to reduce viability and decrease production of developed eggs in comparison with the negative control group. Diamines 3d and 3f may represent useful lead compounds for further optimization in order to develop new schistosomicidal agents.

In vitro leishmanicidal activity of N-dodecyl-1,2-ethanediamine.

Polyamine biosynthesis and inhibition in parasites have been an attractive chemotherapeutic approach in the design of novel antiparasitic drugs. We study in this work the effect of N-dodecyl-1,2-ethylenediamine (NDDE) on the morphology and replication of Leishmania using macrophages cultured from the peritoneal exudate of mice infected in vitro with three species of Leishmania: Leishmania (Leishmania) amazonensis, Leishmania (Viannia) brasiliensis and Leishmania (Leishmania) chagasi. The results showed that NDDE inhibited Leishmania amastigotes multiplication into inflammatory peritoneal cells in concentrations which were not toxic to mammalian cells (0.5-1µg/mL). An intracellular disorganization of the promastigote forms was observed by transmission electron microscopy after 3 to 24h of treatment with 1µg/mL NDDE, suggesting that this compound affects the viability of the parasite by an autophagy pathway.

(1)H, (15)N and (13)C assignments of the Rhipicephalus (Boophilus) microplus anti-microbial peptide microplusin.

Microplusin, a Rhipicephalus (Boophilus) microplus anti-microbial peptide (AMP) is the first member of a new family of cysteine-rich AMPs with histidine-rich regions at the N- and C-termini, which is being fully characterized by biophysical and biochemical methods. Here we report the NMR resonance assignments for (1)H, (15)N, and (13)C nuclei in the backbone and side chains of the microplusin as basis for further studies of structure, backbone dynamics and interactions mapping.

Structure and mode of action of microplusin, a copper II-chelating antimicrobial peptide from the cattle tick Rhipicephalus (Boophilus) microplus.

Microplusin, a Rhipicephalus (Boophilus) microplus antimicrobial peptide (AMP) is the first fully characterized member of a new family of cysteine-rich AMPs with histidine-rich regions at the N and C termini. In the tick, microplusin belongs to the arsenal of innate defense molecules active against bacteria and fungi. Here we describe the NMR solution structure of microplusin and demonstrate that the protein binds copper II and iron II. Structured as a single alpha-helical globular domain, microplusin consists of five alpha-helices: alpha1 (residues Gly-9 to Arg-21), alpha2 (residues Glu-27 to Asn-40), alpha3 (residues Arg-44 to Thr-54), alpha4 (residues Leu-57 to Tyr-64), and alpha5 (residues Asn-67 to Cys-80). The N and C termini are disordered. This structure is unlike any other AMP structures described to date. We also used NMR spectroscopy to map the copper binding region on microplusin. Finally, using the Gram-positive bacteria Micrococcus luteus as a model, we studied of mode of action of microplusin. Microplusin has a bacteriostatic effect and does not permeabilize the bacterial membrane. Because microplusin binds metals, we tested whether this was related to its antimicrobial activity. We found that the bacteriostatic effect of microplusin was fully reversed by supplementation of culture media with copper II but not iron II. We also demonstrated that microplusin affects M. luteus respiration, a copper-dependent process. Thus, we conclude that the antibacterial effect of microplusin is due to its ability to bind and sequester copper II.