Composition, Antibiofilm, and Antibacterial Potential of Volatile Oils from Geopropolis of Different Stingless Bees' Species.

We aimed to characterize and investigate the antibacterial potential of the native stingless bees geopropolis volatile oils (VO) for the search of potentially new bioactive compounds. Geopropolis samples from Melipona bicolor schencki, M. compressipes manaosensis, M. fasciculata, M. quadrifasciata, M. marginata and M. seminigra merrillae were collected from hives in South Brazil. VO were obtained by hydrodistillation and characterised by gas chromatography coupled to mass spectrometry (GC/MS). Antimicrobial activity was assessed by microplate dilution method. The lowest MIC against cell walled bacteria was 219±0 µg mL-1 from M. quadrifasciata geopropolis VO with Staphylococcus aureus. The M. b. schencki geopropolis VO minimal inhibition concentration (MIC) was 424±0 µg mL-1 against all the mycoplasma strains evaluated. Fractionation resulted in the reduction of 50 % of the MIC value from the original oil. However, its compounds' synergism seems to be essential to this activity. Antibiofilm assays demonstrated 15.25 % eradication activity and 13.20 % inhibition of biofilm formation after 24 h for one subfraction at 2× its MIC as the best results found. This may be one of the essential mechanisms by which geopropolis VOs perform their antimicrobial activity.

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.

Mollicute Anti-Adhesive and Growth Inhibition Properties of the Methanolic Extract of Propolis from the Brazilian Native Bee Melipona quadrifasciata.

Hydroalcoholic propolis extracts from the bee species Melipona quadrifasciata have been shown to possess antimicrobial activity against different mollicute strains, but a methanolic extract (ME) could contain an increased diversity of nonpolar bioactive components with a potentially higher antimicrobial activity. The ME obtained by maceration of the propolis sample was fractionated with solvents of different polarities and then, purified by silica gel column chromatography through biomonitoring of its antimicrobial activity against mollicute strains. Analysis by gas chromatography-mass spectrometry (GC/MS) enabled the identification of compounds using the NIST library. Minimum inhibitory concentrations (MICs) of the samples were determined by broth microdilution. Anti-adhesive assays were performed with Mycoplasma pneumoniae cells. The hexane (MIC=62.5 mg/L) and dichloromethane (MIC=125 mg/L) fractions presented the most promising results against M. pneumoniae. They were fractionated into 74 subfractions, and even the best ones did not show better results (MIC>250 mg/L) than their original fractions, likely due to the loss of terpene compounds that seem to act in synergy. The dichloromethane subfraction FD4 was highlighted in the anti-adhesive assay with an inhibitory activity of 21.6 %. A synergistic effect of the nonpolar compounds in M. quadrifasciata propolis may be responsible for its antibacterial activity, but several purified components can improve its anti-adhesive properties.

A Bioguided Approach for the Screening of Antibacterial Compounds Isolated From the Hydroalcoholic Extract of the Native Brazilian Bee's Propolis Using Mollicutes as a Model.

Nature is a vast source of medicinal substances, including propolis, which has been extensively investigated. Propolis is a resinous substance produced by bees from the exudates of plants that they collect and modify in their jaws; it is a rich and complex matrix with secondary metabolites of diverse botanical origins. The objective of this study was to apply an in vitro bioguided approach using as a model system the mollicutes with a sample of propolis from the Brazilian native bee Melipona quadrifasciata (mandaçaia) in order to identify potential new molecules with antimicrobial activity. A crude hydroalcoholic extract was obtained and submitted to liquid-liquid partitioning with solvents of different polarities, generating four different fractions: aqueous, dichloromethane, butanol, and ethyl acetate fractions. The antimollicute activity assays served as a basis for the bioguided fractionation. The dichloromethane fraction was the most promising, exhibiting a minimal inhibitory concentration (MIC) of 125 µg/mL against Mycoplasma pneumoniae. After purification by column liquid chromatography, a subfraction presenting MIC of 15.6 µg/mL against Mycoplasma genitalium was highlighted. The fractions were also tested against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Using gas chromatography coupled to a mass spectrometer (GC-MS), several volatile compounds were identified in the non-polar fractions of this propolis. However, the more purified molecules had no better antimollicute activity than their original subfraction. Apparently, the synergism among its compounds is largely responsible for the antibacterial activity of the propolis of this native Brazilian bee.

Antioxidant activity of the extracts from Pycnoporus sanguineus mycelium

The aim of this work was to study the production of compounds with antioxidant activity by Pycnoporus sanguineus when cultivated in submerged fermentation using a potato dextrose broth plus peptone medium. The study evaluated the biomass production, glucose consumption, variation of medium pH and antioxidant activity. The antioxidant potential was tested through the DPPH method and β-carotene / linoleic acid system with extracts obtained from the mycelium at different times of cultivation (5, 10, 15, 20, 25 and 30 days). Maximum kinetic values of specific growth rate (0.289 day-1), biomass productivity (0.698 g.L-1.day-1) and the yield of glucose conversion into biomass (26.24 g.g-1) were obtained during the exponential growth phase. The highest antioxidant activity was registered during the stationary phase, with a similar potential as the synthetic antioxidant BHT, in the extracts obtained at 30 days of cultivation.

Effects of flavonoids on α-glucosidase activity: potential targets for glucose homeostasis.

OBJECTIVE: Flavonoids are naturally occurring compounds widely distributed in plants, which have hypoglycemic potential and have been described as glucosidase inhibitors. This study evaluated the effect of flavonoids on intestinal glucosidase activity after in vivo and in vitro treatment. METHODS: For the in vivo studies animals received quercetin by gavage and for the in vitro assays a segment of the small intestine was used. To obtain the oral glucose tolerance curve fasted normal rats were loaded with glucose plus flavonoids. The glycemia was measured by the glucose oxidase method. RESULTS: Quercetin reduced the effect of sucrase and maltase in the in vivo and in vitro treatments. It was observed in the in vitro studies that the maximum inhibitory effect of kaempferitrin was around 23% for maltase activity. Also, for the sucrose substrate the specific enzyme activity was significantly decreased. Aglycone, flavonoids, and kaempferol decreased significantly the maltase activity at all concentrations assayed. Finally, rutin reduced maltase-specific activity at all concentrations studied. According to the oral glucose tolerance curve, rutin reduced the serum glucose levels at 15, 30, and 60 min when administered by oral gavage 30 min before glucose overload in rats. CONCLUSION: Based on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.

Análise da atividade antimicrobiana de extratos isolados de plantas nativas da flora brasileira frente a Mycoplasma arginini, M. hominis e Ureaplasma urealyticum / Evaluation of the antibacterial activity of extracts isolated from native plants of the Brazilian flora against Mycoplasma arginini, M. hominis and Ureaplasma urealyticum

Em vários grupos de microrganismos é crescente o número de cepas resistentes aos antibióticos utilizados no tratamento. Da mesma forma, o interesse nas espécies de molicutes vem aumentando constantemente, principalmente pelo fato de serem microorgansimos peculiares responsáveis pelo desenvolvimento de várias doenças e também pelos relatos constantes de aumento de resistências. Na busca de novos medicamentos,sabe-se que existem muitas plantas com excelentes potenciais medicinais e que vêm sendo utilizadas pela medicina popular. Estas propriedades terapêuticas necessitam de trabalhos científicos que comprovem suas atividades. Desta forma, neste trabalho procurou-se analisar frente às espécies de molicutes Mycoplasma arginini, M hominis e Ureaplasmaureaurealyticum, a atividade antibacteriana in vitro de sete plantas nativas da flora brasileira que apresentaram propriedade contra outros tipos de microrganismos. Extratos brutos de Hedyosmum brasiliense, Piper caldense, Piperlindbergii, Piper cernuum, Piper mollicomum, Serjania erecta e Rubus rosaefolius foram testados através do método de microdiluição em caldo para determinação de concentração minima inibitória (MIC). Todas as plantas apresentaram atividade inibindo o crescimento bacteriano com MICs variando de 5,0 mg /dL, sendo que a planta Serjania erecta do Paraná foi a que apresentou os melhores resultados.

Double mucosal and myocutaneous island flap: a one-stage reconstruction for full-thickness lower eyelid defect.

BACKGROUND: Basal cell carcinomas (BCCs) on the lower eyelid are not uncommon, and depending on their histological type, they can be highly aggressive and difficult to eradicate. Numerous techniques have been proposed for the reconstruction of the lower lid margin after surgical excision of the lesion. OBJECTIVE: To describe a double-flap technique consisting of a mucosal and myocutaneous V-Y advancement flap to repair full-thickness lower lid margin defects in a one-stage procedure under local anesthesia. METHODS: Over a 12-year period (1995-2007), 33 patients with BCC underwent lower eyelid reconstruction. After tumor excision, a triangular mucosal flap with a central pedicle was used to repair the inner layer. A similar triangular-shaped myocutaneous flap was obtained from the inferior orbicularis oculus muscle and sutured in a V-Y fashion to build the outer layer. RESULTS: All 33 patients achieved satisfactory functional and cosmetic results. Slight scleral show and discrete rounded lower eyelid were the main adverse effects. No additional surgery was needed. CONCLUSION: This double V-Y advancement flap is a simple, useful alternative procedure to close full-thickness defects in the lower lid margin. Aesthetic and functional outcome is good.

Topical anti-inflammatory activity of Serjania erecta Radlk (Sapindaceae) extracts.

Serjania erecta Radlk (Sapindaceae), commonly called cinco-folhas or cipó-cinco-folhas in Brazil, is thought to be effective for treating several inflammatory diseases. In order to verify the topical anti-inflammatory effect of Serjania erecta, hydroalcoholic extract and fractions were obtained by extraction in solvents of increasing polarity and were tested in mouse models using croton-oil-induced inflammation. Our findings showed that topical application of Serjania erecta hydroalcoholic extract (0.01-3.0 mg/ear), and the dichloromethane (0.03-1.0 mg/ear), ethyl acetate (0.03-1.0 mg/ear), and hexane (0.003-1.0 mg/ear) fractions revealed significant activity, causing a dose-dependent reduction of croton-oil ear edema (ID(50)=0.14 mg/ear, 0.23 mg/ear, 0.14 mg/ear, 0.04 mg/ear, respectively). The extract and all tested fractions also decreased tissue myeloperoxidase activity (indicative of polymorphonuclear leukocytes influx) in mouse-ears treated with croton oil with a maximum inhibition of 72% at 3.0 mg/ear for the hydroalcoholic extract and 81%, 78%, and 83% at 1.0mg/ear for dichloromethane, ethyl acetate and hexane fractions, respectively. As expected, dexamethasone (0.05 mg/ear) was effective in inhibiting both edema and myeloperoxidase activity (99% and 82%, respectively). In conclusion, our results indicate a topical anti-inflammatory effect for the species of Serjania studied.