In Vitro Antimycotic Activity and Structural Damage against Canine Malassezia pachydermatis Strains Caused by Mexican Stingless Bee Propolis.

This work describes the antimycotic activity of propolis from the stingless bees Scaptotrigona mexicana and Tetragonisca angustula, collected from two Mexican regions (Veracruz and Chiapas, respectively), against three clinical isolates and the reference strain ATCC 14522 of Malassezia pachydermatis, the causative agent of canine otitis. The chemical components of the ethanolic extracts of propolis were determined by gas chromatography coupled with mass spectrometry (GC-MS), and sesquiterpenes were the predominant compounds. The antimycotic activity was evaluated by plate microdilution. The induced changes in the yeasts were evaluated by fluorescence microscopy and staining with calcofluor white and propidium iodide. The minimum inhibitory concentration (MIC) was 7.11 mg/mL, and the minimum fungicidal concentration was 21.33 mg/mL for both extracts. The EPPs of Scaptotrigona mexicana and Tetragonisca angustula caused substantial damage to yeast morphology, where the propidium iodide staining of the yeasts treated with both EEPs revealed the penetration of this marker, which indicates the destruction of the cell wall and plasma membrane of the fungi. This result suggests that these types of propolis could be used as alternative treatments for canine external otitis. To the best of our knowledge, this seems to be the first scientific report that has demonstrated structural damage in Malassezia pachydermatis by Mexican stingless bee propolis.

Effect of Different Karyophilic Peptides on Physical Characteristics and In Vitro Transfection Efficiency of Chitosan-Plasmid Nanoparticles as Nonviral Gene Delivery Systems.

A strategy to increase the transfection efficiency of chitosan-based nanoparticles for gene therapy is by adding nuclear localization signals through karyophilic peptides. Here, the effect of the length and sequence of these peptides and their interaction with different plasmids on the physical characteristics and biological functionality of nanoparticles is reported. The karyophilic peptides (P1 or P2) were used to assemble nanoparticles by complex coacervation with pEGFP-N1, pQBI25 or pSelect-Zeo-HSV1-tk plasmids, and chitosan. Size, polydispersity index, zeta potential, and morphology, as well as in vitro nucleus internalization and transfection capability of nanoparticles were determined. The P2 nanoparticles resulted smaller compared to the ones without peptides or P1 for the three plasmids. In general, the addition of either P1 or P2 did not have a significant impact on the polydispersity index and the zeta potential. P1 and P2 nanoparticles were localized in the nucleus after 30 min of exposure to HeLa cells. Nevertheless, the presence of P2 in pEGFP-N1 and pQBI25 nanoparticles raised their capability to transfect and express the green fluorescent protein. Thus, karyophilic peptides are an efficient tool for the optimization of nonviral vectors for gene delivery; however, the sequence and length of peptides have an impact on characteristics and functionality of nanoparticles.

Activity of propolis from Mexico on the proliferation and virulence factors of Candida albicans.

BACKGROUND: This research evaluated the anti-Candida albicans effect of Mexican propolis from Chihuahua. Chemical composition of the ethanolic extract of propolis was determined by GC-MS, HPLC-DAD, and HPLC-MS. The presence of anthraquinone, aromatic acid, fatty acids, flavonoids, and carbohydrates was revealed. RESULTS: The anti-Candida activity of propolis was determined. The inhibitions halos were between 10.0 to 11.8 mm; 25% minimum inhibitory concentration (0.5 mg/ml) was fungistatic, and 50% minimum inhibitory concentration (1.0 mg/ml) was fungicidal. The effect of propolis on the capability of C. albicans to change its morphology was evaluated. 25% minimum inhibitory concentration inhibited to 50% of germ tube formation. Staining with calcofluor-white and propidium iodide was performed, showing that the propolis affected the integrity of the cell membrane. INT1 gene expression was evaluated by qRT-PCR. Propolis significantly inhibited the expression of the INT1 gene encodes an adhesin (Int1p). Chihuahua propolis extract inhibited the proliferation of Candida albicans, the development of the germ tube, and the synthesis of adhesin INT1. CONCLUSIONS: Given the properties demonstrated for Chihuahua propolis, we propose that it is a candidate to be considered as an ideal antifungal agent to help treat this infection since it would not have the toxic effects of conventional antifungals.

Effect of the Essential Oils of Bursera morelensis and Lippia graveolens and Five Pure Compounds on the Mycelium, Spore Production, and Germination of Species of Fusarium.

The genus Fusarium causes many diseases in economically important plants. Synthetic agents are used to control postharvest diseases caused by Fusarium, but the use of these synthetic agents generates several problems, making it necessary to develop new alternative pesticides. Essential oils can be used as a new control strategy. The essential oils of Bursera morelensis and Lippia graveolens have been shown to have potent antifungal activity against Fusarium. However, for the adequate management of diseases, as well as the optimization of the use of essential oils, it is necessary to know how essential oils act on the growth and reproduction of the fungus. In this study, the target of action of the essential oils of B. morelensis and L. graveolens and of the pure compounds present in the essential oils (carvacrol, p-cymene, α-phellandrene, α-pinene, and Υ-terpinene) was determined by evaluating the effect on hyphal morphology, as well as on spore production and germination of three Fusarium species. In this work, carvacrol was found to be the compound that produced the highest inhibition of radial growth. Essential oils and pure compounds caused significant damage to hyphal morphology and affected spore production and germination of Fusarium species.

Comparison between In Vitro Antiviral Effect of Mexican Propolis and Three Commercial Flavonoids against Canine Distemper Virus.

Propolis is a resin that honey bees (Apis mellifera) produce by mixing wax, exudates collected from tree shoots, pollen, and enzymes. It has been used for its biological properties against pathogenic microorganisms including those of viral origin. In the present study, we demonstrate the antiviral effect of Mexican propolis, as well as of the three commercial flavonoids (quercetin, naringenin, and pinocembrin) present in its composition, in cell cultures infected with Canine Distemper Virus. The treatments were carried out with propolis, flavonoids individually, and a mixture of the three flavonoids at three different times. Antiviral activity was evaluated by the inhibition of the relative expression of the virus nucleoprotein gene (Real-Time qPCR) and by the determination of cellular viability (MTT assay). Propolis applied before infection decreased viral expression (0.72 versus 1.0, 1.65, and 1.75 relative expressions) and correlated with increased cell viability (0.314 versus 0.215, 0.259, and 0.237 absorbance units (AU)). The administration of a flavonoid mixture containing the three commercial flavonoids before infection induces a slight decrease in viral expression (0.93 versus 1, 1.42, and 1.82 relative expressions); however, it does not improve cellular viability (0.255 versus 0.247, 0.282, and 0.245 AU). Quercetin administrated at the same time of infection decreases viral expression (0.90 versus 1.0, 3.25, and 1.02 relative expressions) and improves cellular viability (0.294 versus 0.240, 0.250, and 0.245 AU). Pinocembrin and naringenin individually did not show any antiviral activity at the administration times evaluated in this study. The present work is the first in vitro study of the effect of propolis in Canine Distemper Virus and demonstrated the antiviral activity of Mexican propolis, in addition to the synergy that exists between the three flavonoids on cell viability and the expression of the nucleoprotein virus gene.

Proteinases in excretory-secretory products of Toxocara canis second-stage larvae: zymography and modeling insights.

Components released in excretory-secretory products of Toxocara canis larvae (TES) include phosphatidylethanolamine-binding proteins (TES26), mucins (TES120, MUC2-5), and C-type lectins (TES32, TES70) and their biochemical, immunological, and diagnostic properties have been extensively studied albeit proteinase activities towards physiological substrates are almost unknown. Proteolytic activities in TES samples were first analyzed by gel electrophoresis with gelatin as substrate. Major activities of ~400, 120, and 32 kDa in TES were relatively similar over a broad pH range (5.5-9.0) and all these were of the serine-type as leupeptin abolished gelatinolysis. Further, the ~400 kDa component degraded all physiological substrates tested (laminin, fibronectin, albumin, and goat IgG) and the 120 kDa component degraded albumin and goat IgG while proteinases of lower MW (45, 32, and 26 kDa) only degraded laminin and fibronectin, preferentially at alkaline pH (9.0). By protein modeling approaches using the known sequences of TES components, only TES26 and MUC4 displayed folding patterns significantly related to reference serine proteinases. These data suggest that most of serine proteinase activities secreted in vitro by infective larvae of T. canis have intriguing nature but otherwise help the parasite to affect multiple components of somatic organs and bodily fluids within the infected host.

[Effect of Mexican propolis extracts from Apis mellifera on Candida albicans in vitro growth]. / Efecto de extractos de propóleos mexicanos de Apis mellifera sobre el crecimiento in vitro de Candida albicans.

Propolis is a resinous substance collected by bees (Apis mellifera) from different trees and bushes. Due to its antifungal, antibacterial, antiviral and antiparasitic properties, it has continued to be very popular throughout the time showing variable activity depending on its geographical origin. In Mexico, information about this product is very limited. The aim of this work was to evaluate the antifungal activity of four propolis ethanolic extracts from three different Mexican states, and four commercial extracts on Candida albicans growth. A reference strain (ATCC 10231) and 36 clinical isolates of C. albicans were used. The Minimal Inhibitory Concentration (MIC) was determined by the dilution on agar method. Growth curves on Sabouraud Dextrose broth with and without different propolis ethanolic extracts concentrations were performed. In addition, whether the effect was fungistatic or fungicide was determined. The propolis ethanolic extract obtained from Cuautitlán Izcalli, State of Mexico, showed the best biological activity, inhibiting 94.4% from the clinical isolates at 0.8 mg/ml; the reference strain was inhibited at 0.6 mg/ml. The propolis effect was fungistatic in low concentrations and fungicide in concentrations higher to MIC. The Mexican propolis ethanolic extract could be further investigated for its alternative use for the treatment of some C. albicans infections.

Efecto de extractos de propóleos mexicanos de Apis mellifera sobre el crecimiento in vitro de Candida albicans / Effect of Mexican propolis extracts from Apis mellifera on Candida albicans in vitro growth

El propóleos es una sustancia resinosa recolectada por las abejas (Apis mellifera)a partir de diferentes árboles y arbustos. Sus propiedades medicinales hanmantenido su popularidad a través de los años debido a que posee actividadantifúngica, antibacteriana, antiviral y antiparasitaria, mostrando variación en suactividad biológica dependiendo de su origen geográfico. En México, lainformación respecto a la actividad de este producto es muy limitada. El objetivode este trabajo fue evaluar la actividad antifúngica de cuatro extractos etanólicosde propóleos de tres diferentes Estados de la República Mexicana, y de cuatroextractos comerciales sobre el crecimiento de Candida albicans. Se emplearonuna cepa de referencia (ATCC 10231) y 36 aislamientos clínicos de origenhumano de C. albicans. Se determinó la concentración mínima inhibitoria (CMI)por el método de dilución en agar. Se realizaron curvas de crecimiento en caldoglucosado de Sabouraud solo y con diferentes concentraciones de los extractosetanólicos de propóleos; además se determinó si el efecto era fungicida ofungistático. El extracto obtenido en Cuautitlán Izcalli, Estado de Méxicopresentó la mayor actividad biológica, inhibiendo el 94,4% de los aislamientosclínicos a una concentración de 0,8 mg/ml; la cepa de referencia fue inhibida auna concentración de 0,6 mg/ml. El efecto fue fungistático a bajasconcentraciones y fungicida a concentraciones superiores a la CMI. El extractoetanólico de propóleos mexicano podría ser investigado como un tratamientoalternativo en algunas infecciones causadas por C. albicans(AU)

Propolis is a resinous substance collected by bees (Apis mellifera) from differenttrees and bushes. Due to its antifungal, antibacterial, antiviral and antiparasiticproperties, it has continued to be very popular throughout the time showingvariable activity depending on its geographical origin. In Mexico, informationabout this product is very limited. The aim of this work was to evaluate theantifungal activity of four propolis ethanolic extracts from three different Mexicanstates, and four commercial extracts on Candida albicans growth. A referencestrain (ATCC 10231) and 36 clinical isolates of C. albicans were used.The Minimal Inhibitory Concentration (MIC) was determined by the dilution onagar method. Growth curves on Sabouraud Dextrose broth with and withoutdifferent propolis ethanolic extracts concentrations were performed. In addition,whether the effect was fungistatic or fungicide was determined. The propolisethanolic extract obtained from Cuautitlán Izcalli, State of Mexico, showed thebest biological activity, inhibiting 94.4% from the clinical isolates at 0.8 mg/ml;the reference strain was inhibited at 0.6 mg/ml. The propolis effect wasfungistatic in low concentrations and fungicide in concentrations higher to MIC.The Mexican propolis ethanolic extract could be further investigated for itsalternative use for the treatment of some C. albicans infections(AU)