Antimicrobial Activity of Volatile Oils from Brazilian Stingless Bees Melipona quadrifasciata quadrifasciata and Tetragonisca angustula Propolis.

Few studies were performed on the volatile components' properties of propolis from native Brazilian stingless bees. This work sought to extract, chemically characterize, and evaluate of the antimicrobial properties of volatile oils from propolis of the stingless bees Melipona quadrifasciata quadrifasciata (MQ) and Tetragonisca angustula (TA). The volatile oils from the pulverized propolis samples were obtained in a Clevenger apparatus and characterized by gas chromatography coupled to mass spectrometry (GC/MS) and to flame ionization detector (GC-FID). All samples showed promising activity against Mycoplasma pneumoniae, with MICs from 103 to 224 µg mL-1 , nonetheless, they were less active against cell walled bacteria. Activity against Candida species was moderate, but one MQ sample showed a MIC value of 103 µg mL-1 against C. tropicallis. Oils' fractionation showed no improvement in antibacterial activity. The promising antibacterial effect against this microorganism is likely related to the synergism between the components of the volatile oils.

Poloxamer-enhanced solubility of griseofulvin and its related antifungal activity against Trichophyton spp

Abstract Poorly water-soluble drugs, such as the antifungal drug griseofulvin (GF), exhibit limited bioavailability, despite their high membrane permeability. Several technological approaches have been proposed to enhance the water solubility and bioavailability of GF, including micellar solubilization. Poloxamers are amphiphilic block copolymers that increase drug solubility by forming micelles and supra-micellar structures via molecular self-association. In this regard, the aim of this study was to evaluate the water solubility increment of GF by poloxamer 407 (P407) and its effect on the antifungal activity against three Trichophyton mentagrophytes and two T. rubrum isolates. The GF water solubility profile with P407 revealed a non-linear behavior, well-fitted by the sigmoid model of Morgan-Mercer-Flodin. The polymer promoted an 8-fold increase in GF water solubility. Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and 2D nuclear magnetic resonance (NMR Roesy) spectroscopy suggested a GF-P407 interaction, which occurs in the GF cyclohexene ring. These results were supported by an increase in the water solubility of the GF impurities with the same molecular structure. The MIC values recorded for GF ranged from 0.0028 to 0.0172 mM, except for T. Mentagrophytes TME34. Notably, the micellar solubilization of GF did not increase its antifungal activity, which could be related to the high binding constant between GF and P407.

Distribution and antifungal susceptibility of Candida species isolated from clinical samples in southern Brazil

Abstract Invasive infections caused by Candida species have been strongly associated with poor prognosis and high resistance rates to some antifungals. This study aimed to identify Candida species isolated from different anatomical sites and to describe their susceptibility profile to antifungals. Ninety-four clinical isolates of Candida were obtained from a Medical Laboratory of Santa Catarina/Brazil. Species identification was performed by MALDI-TOF MS. Susceptibility assays were performed as described by Clinical Laboratory Standard Institute (CLSI) microboth method. Among the analyzed samples, C. albicans was the pathogen most incident (59.9%) followed by C. parapsilosis complex (14.9%), C. glabrata complex (8.5%), and C. tropicalis (6.3%). 37 Candida strains were isolated from vaginal content (39.3%), 21 from the nail (22.4%), 8 from tracheal aspirates (8.5%), and 7 from urine (7.4%). Together, the Candida isolates presented decreased susceptibility to azole drugs, mainly to fluconazole and itraconazole. Amphotericin B showed sensibility in 95.7% of samples analyzed. Previous knowledge about etiology and antifungal susceptibility becomes indispensable to conduct an efficient treatment.

Biological activities of essential oils from six genotypes of four Ocotea species

Abstract Essential oils from four Ocotea species collected in southern Brazil were evaluated for chemical composition using gas chromatography coupled with mass spectrometry. The primary compound identified in O. acutifolia essential oil was an unsaturated tetracyclic diterpene, phyllocladene (67.7%), followed by a sesquiterpene hydrocarbon, ß-selinene (18.0%). The sesquiterpene fraction was predominant in oils from two collections of O. puberula; ß-caryophyllene (25.2%) and globulol (22.6%) were the major compounds identified in collections 1 and 2, respectively. O. silvestris essential oil contained predominantly germacrene D and bicyclogermacrene. These compounds were also predominant in essential oil from O. indecora leaves collected from shady habitats. By contrast, essential oil extracted from O. indecora grown under direct sunlight contained mainly oxygenated sesquiterpenes, such as guaiol (30.2%), α-eudesmol (27.6%), and ß-eudesmol (12.7%). Chemotaxis assays showed that Ocotea essential oils had no significant inhibitory activity on leukocyte migration compared with a chemotactic stimulant (lipopolysaccharide from Escherichia coli). However, the oils exhibited antifungal activity against Candida parapsilosis, with a minimum inhibitory concentration of 500 µg/mL. To our knowledge, this is the first study to investigate the in vitro antifungal and antichemotactic activities of essential oils from Ocotea species native to southern Brazil

Development of analytical method for the quality control of the fruit bark of Punica granatum L. (pomegranate) and antichemotatic activity of extract and rich fraction in punicalagins.

Pomegranate is of current interest owing to the existing potential for industrial uses of fruit peels. This includes its availability as a raw vegetable material, a byproduct that constitutes residue in the use of the species and is recognized as a functional product, and beneficial health properties, as will be demonstrated in the studies cited. Therefore, it is necessary to ensure its effectiveness and safety. Toward this end, the aim of this study was to develop and validate an analytical method for the separation and quantification of total punicalagin present in the bark of the fruit of Punica granatum by HPLC. Purity tests such as water determination and total ashes were also performed. The ability of the extract and enriched fraction of punicalagin to inhibit leukocyte migration in vitro was determined by the Boyden's chamber method. The developed HPLC method demonstrated good separation and quantification of the punicalagin α and ß anomers. The method is efficient and reliable, and can ultimately be used for the analysis of the extract of pomegranate. The crude extract and the fraction of punicalagins significantly inhibited leukocyte migration at concentrations of 1 and 10 µg/mL in relation to the negative control, indicating potential antichemotactic action.