Apolar Bioactive Fraction ofMelipona scutellarisGeopropolis onStreptococcus mutansBiofilm

Abstract

The aim of this study was to evaluate the influence of the bioactive nonpolar fraction of geopropolis on Streptococcus mutans biofilm. The ethanolic extract of Melipona scutellaris geopropolis was subjected to a liquid-liquid partition, thus obtaining the bioactive hexane fraction (HF) possessing antimicrobial activity. The effects of HF on S. mutans UA159 biofilms generated on saliva-coated hydroxyapatite discs were analyzed by inhibition of formation, killing assay, and glycolytic pH-drop assays. Furthermore, biofilms treated with vehicle control and HF were analyzed by scanning electron microscopy (SEM). HF at 250 μg/mL and 400 μg/mL caused 38% and 53% reduction in the biomass of biofilm, respectively, when compared to vehicle control (P < 0.05) subsequently observed at SEM images, and this reduction was noticed in the amounts of extracellular alkali-soluble glucans, intracellular iodophilic polysaccharides, and proteins. In addition, the S. mutans viability (killing assay) and acid production by glycolytic pH drop were not affected (P > 0.05). In conclusion, the bioactive HF of geopropolis was promising to control the S. mutans biofilm formation, without affecting the microbial population but interfering with its structure by reducing the biochemical content of biofilm matrix.

Comparison of SEM and VPSEM imaging techniques with respect toStreptococcus mutansbiofilm topography

“…85% EPS and 15% bacterial cells, and in S. mutans biofilm, the EPS strongly contributes to the antibiotic resistance, host evasion, hydration, maturation, adhesion, and structural support (Fulcher et al ., ; Rahim & Thurairajah, ; Xiao et al ., ). Although previous studies (Ishii et al ., ; Weimer et al ., ) have demonstrated the benefits of using VPSEM to visualize other biofilms under humid conditions as SEM protocol destroys the majority of the biofilm structure (Donlan & Costerton, ; Priester et al ., ), several studies analyze the matrix of S. mutans biofilm by SEM (da Cunha et al ., ; Fu et al ., ; Wang et al ., ). In addition, the biofilm matrix of S. mutans biofilm is commonly imaged by SEM during disruption experimentation, but our results indicated that VPSEM provided a more accurate image of the S. mutans biofilm morphology with respect to topography and EPS content.…”

Cardanols detected in non-polar propolis extracts from Scaptotrigona aff. postica (Hymenoptera, Apidae, Meliponini)

“…Some studies have demonstrated interesting biological activities exhibited by non-polar extracts of geopropolis. The hexane fractions of the geopropolis from Melipona scutellaris, harvested in the Atlantic forest of Bahia State (Northeastern Brazil), exhibited considerable antibacterial activity against Streptococcus mutans, antitumoral activities against human cancer cell lines (Cunha et al, 2013a) and antinociceptive activity (Franchin et al, 2012). The hexane extract of the geopropolis from Melipona mondury, which possesses anacardic acid derivatives as constituents, exhibited antioxidant, antibacterial and antiproliferative activities (Santos et al, 2017a).…”

“…Qualitative and quantitative differences in the chemical composition of propolis can influence its biological activity (Santos et al, 2017b;Franchin et al, 2012). However, the propolis produced by different species of stingless bees in different regions of the world, exhibit antimicrobial (Cunha et al, 2013a), anticancer, antioxidant (Ferreira et al, 2017), anti-inflammatory (Araújo et al, 2015;Santos et al, 2017aSantos et al, , 2017bSantos et al, , 2017c, gastroprotective (Ribeiro-Junior et al, 2015), and antiviral (Coelho et al, 2015) activities. The geopropolis produced by Melipona fasciculata Smith exhibited antimicrobial activity against Streptococcus mutans and Candida albicans (Liberio et al, 2011).…”

The Effect of Essential Oils and Bioactive Fractions onStreptococcus mutansandCandida albicansBiofilms: A Confocal Analysis

“…A starter culture of S. mutans was prepared using ultrafiltered (10 kDa cutoff membrane; Prep/Scale; Millipore, MA) tryptone yeast extract (UFTYE, pH 7.0) supplemented with 1% (w/v) glucose, incubated at 37°C, 5% CO 2 , overnight. This starter was used to prepare bacterial inoculum at midexponential growth phase for biofilm formation (OD 600 nm , 2 × 10 6 CFU/mL) (adapted from da Cunha et al [ 14 ]).…”

“…The glass slides were placed as much vertically as possible in 12-well plates and inoculated with S. mutans suspension in buffered ultrafiltered UFTYE medium supplemented with 1% (w/v) sucrose and incubated at 37°C, 5% CO 2 . S. mutans biofilms were grown undisturbed during 19 h, and later the culture medium was replaced daily until the end of the experimental period, which totalized 72 h (adapted from da Cunha et al [ 14 ]). To assess the effect of the bioactive fractions on S. mutans biofilm formation, the 19-hour-old biofilms were treated for two days (10 a.m. and 4 p.m., total of 4 treatments with 1 minute exposure per treatment) with the bioactive fractions or vehicle (propylene glycol) at the given concentrations ( Table 2 ), both diluted in sterile AB buffer.…”