Ana Camila Micheletti

Immunostimulatory effects of the phenolic compounds from lichens on nitric oxide and hydrogen peroxide production

Departament of Clinical Analysis Faculdade de Ciencias Farmaceuticas de Araraquara Sao Paulo State University, Post Office Box 502, Araraquara-SP 14801-902

Synthesis, characterization, thermal behavior, and biological activity of ozonides from vegetable oils

In this work, we have synthesized ozonides from sunflower, flaxseed and baru oils. In addition, ozonolysis reaction of sunflower oil in the presence of water was performed, and the product obtained had high viscosity and a gel-like appearance. The ozonated products were investigated for their antimicrobial activity and cytotoxicity. The oleogel, with an MIC ≤ 3 mg mL−1, exhibited excellent antimicrobial activity against standard and clinical strains. All products showed no cytotoxicity when tested against NIH/3T3 murine fibroblast cells. Effects of ozonation time on the oils were analyzed by IR, 1H and 13C NMR spectroscopy. DSC analysis shows that the ozonides of vegetable oils decompose with a peak at about 150 °C and with a broad exotherm. The decomposition enthalpy is proportional to the degree of ozonation reached.

Ozonolysis of neem oil: preparation and characterization of potent antibacterial agents against multidrug resistant bacterial strains

Neem, Azadirachta indica A. Juss, is endowed with relevant biological properties and its oil contains unsaturated fatty acids that are susceptible to structural modification by oxidative processes such as ozonolysis to form peroxides. Therefore, the aim of this work was the synthesis, physicochemical characterization, study of thermal behavior, and evaluation of the antimicrobial potential of neem ozonated oils. The ozonolysis reaction was performed over different periods of time, in the presence or absence of water at an ozone concentration of 63 mg L−1 O3/O2. The samples were characterized by 1H and 13C NMR spectroscopy, acid and iodine values and, DSC and TG/DTG thermal analyses. Additionally, quantitative 1H NMR spectroscopy was a very successful and useful tool to determine the unsaturation degree of samples. The products showed excellent broad-spectrum antimicrobial activity in comparison to other ozonated oils reported in the literature, with an MIC of <0.5 mg mL−1 for standard E. faecalis and clinical vancomycin resistant E. faecium, 5.0 mg mL−1 for clinical multiresistant K. pneumoniae (KPC), 2 mg mL−1 for standard S. aureus, and 3 mg mL−1 for methicillin-resistant S. aureus (MRSA). This is the first report on the antimicrobial action of neem oil after the ozonation process. The ozonated neem oils were investigated for their cytotoxicity against two normal human cell lines (HaCaT and HCEC). And the results show the products possess low toxicity. Our studies suggest the compounds can find potential application in the treatment of chronic wounds and skin infections.

Synthesis, Antibacterial and Antitubercular Evaluation of Cardanol and Glycerol‑Based β-Amino Alcohol Derivatives

The synthesis of novel amino alcohol derivatives based on cardanol and glycerol were achieved in good yields and characterized by H and C NMR (nuclear magnetic resonance) and MS (mass spectrometry). In addition, we evaluated the in vitro antimicrobial activity against Gram-positive (Staphylococcus aureus, standard and clinical strains), Gram-negative (Escherichia coli) and M. tuberculosis bacterial strains. The bioassay results indicated that four compounds showed activity against S. aureus, including the clinical resistant strain, with MIC (minimum inhibitory concentration) ranging from 3.90 to 15.60 μg mL and M. tuberculosis, with MIC90 (minimum inhibitory concentration required to inhibit the growth of 90% of organisms) ranging from 3.18 to 7.36 μg mL.

Design, Synthesis and in vitro Antimicrobial Activity Evaluation of Novel Hybrids of Lichexantone-THC Derivatives

Two novel hybrid lichexantone-THC (benzopirane group) derivatives as potential antimicrobial agents were designed and prepared from norlichexanthone and (S)-cis-verbenol in two steps. The newly synthesized compounds were characterized by 1 H-NMR, 13 C-NMR and MS. In addition, we evaluated the in vitro antimicrobial activity against Gram-positive (Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium) and Gram- negative (Escherichia coli, Enterobacter cloacea, Klebisiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa) bacterial strains. The bioassay results indicate that the compounds namely 5 and 6 proved active against Gram-positive strains (standard and clinical) in comparison with reference drugs. DOI: http://dx.doi.org/10.17807/orbital.v7i4.788

Determination of the absolute configuration of 6 -Hydroxitricyclo[ 6.2.1.02,7]undeca-9-ene-3-one by chemical correlation

Biotransformation is one of the most efficient methods for production of high optical purity compounds and development of efficient routes for target molecules. Our research group is interested in testing the ability of the microorganisms to perform desymmetrizations of achiral molecules. Our goal is to devise methodologies in order to obtain optically active intermediates for use in biological and, NMR spectroscopy studies and as precursors of chiral compounds or chiral auxiliaries for asymmetric synthesis. 1,2,3