Chemical Profile and Biological Potential of Scaptotrigona Bee Products (Hymenoptera, Apidae, Meliponini): An Review.

Stingless bees belong to the Meliponini tribe and are widely distributed in the tropics and subtropics, where they perform important ecological services. Among the best distributed groups of stingless bees is the genus Scaptotrigona, which includes 22 species distributed throughout the neotropical region, including the area from Mexico to Argentina. Bees of this genus are responsible for the production of products such as honey, propolis, geopropolis and fermented pollen ("saburá"). This review aimed to provide an overview of the chemical composition and biological activities associated with derived products from stingless bees of the genus Scaptotrigona. The bibliographic review was carried out through searches in the Scopus, Web of Science, ScienceDirect and PubMed databases, including publications from 2003 to January 2023. The study of the chemodiversity of products derived from Scaptotrigona demonstrated the mainly presence of flavonoids, phenolic acids, terpenoids and alkaloids. It was also demonstrated that products derived from bees of the genus Scaptotrigona exhibit a wide range of biological effects, such as antibacterial, antioxidant, anti-inflammatory and antifungal activities, among other bioactivities. This review provides an overview of phytochemical and pharmacological investigations of the genus Scaptotrigona. However, it is essential to clarify the toxicity and food safety of these products.

Chemical Characterization and Biological Activities of Jandaíra Stingless Bee Products (Melipona subnitida, Ducke, 1911): A Brief Review.

Melipona subnitida (Ducke, 1911), a species of stingless bee, popularly known as Jandaíra, has a wide distribution in the Brazilian Northeast region, being an important pollinator of the Caatinga biome. This bee produces products such as honey, geopropolis, pollen (saburá) and wax that are traditionally used for therapeutic purposes and some studies report the biological properties, as well as its chemical composition. This review aimed to select, analyze and gather data published in the literature focusing on the chemical profile and bioactivities described for M. subnitida products. Data collection was carried out through the Capes Journal Portal platform, using the following databases: Web of Science, Scopus, and PubMed. Original articles published in English and Portuguese were included, with no time limitation. The chemical composition of M. subnitida products has been investigated through chromatographic analysis, demonstrating the presence of a variety of phenolic compounds, such as flavonoids and phenylpropanoids, among other classes of secondary metabolites. These products also have several biological activities, including antioxidant, healing, antinociceptive, anti-inflammatory, antidepressant, antidyslipidemic, antiobesity, antifungal, antibacterial and prebiotic. Among the biological activities reported, the antioxidant activity was the most investigated. These data show that products derived from the stingless bee M. subnitida have promising bioactive compounds. This review provides useful information about the bioactivities and chemical profile of Melipona subnitida bee products, and a direction for future research, which should focus on understanding the mechanisms of action associated with the already elucidated pharmacological activities, as well as the bioactive properties of the main isolate's constituents identified in the chemical composition of these products.

Evaluation of the antibacterial and inhibitory activity of the MepA efflux pump of Staphylococcus aureus by riparins I, II, III, and IV.

The efflux pump mechanism contributes to the antibiotic resistance of widely distributed strains of Staphylococcus aureus. Therefore, in the present work, the ability of the riparins N-(4-methoxyphenethyl)benzamide (I), 2-hydroxy-N-[2-(4-methoxyphenyl)ethyl]benzamide (II), 2, 6-dihydroxy-N-[ 2-(4-methoxyphenyl)ethyl]benzamide (III), and 3,4,5-trimethoxy-N-[2-(4-methoxyphenethyl)benzamide (IV) as potential inhibitors of the MepA efflux pump in S. aureus K2068 (fluoroquinolone-resistant). In addition, we performed checkerboard assays to obtain more information about the activity of riparins as potential inhibitors of MepA efflux and also analyzed the ability of riparins to act on the permeability of the bacterial membrane of S. aureus by the fluorescence method with SYTOX Green. A molecular coupling assay was performed to characterize the interaction between riparins and MepA, and ADMET (absorption, distribution, metabolism, and excretion) properties were analyzed. We observed that I-IV riparins did not show direct antibacterial activity against S. aureus. However, combination assays with substrates of MepA, ciprofloxacin, and ethidium bromide (EtBr) revealed a potentiation of the efficacy of these substrates by reducing the minimum inhibitory concentration (MIC). Furthermore, increased EtBr fluorescence emission was observed for all riparins. The checkerboard assay showed synergism between riparins I, II, and III, ciprofloxacin, and EtBr. Furthermore, riparins III and IV exhibited permeability in the S. aureus membrane at a concentration of 200 µg/mL. Molecular docking showed that riparins I, II, and III bound in a different region from the binding site of chlorpromazine (standard pump inhibitor), indicating a possible synergistic effect with the reference inhibitor. In contrast, riparin IV binds in the same region as the chlorpromazine binding site. From the in silico ADMET prediction based on MPO, it could be concluded that the molecules of riparin I-IV present their physicochemical properties within the ideal pharmacological spectrum allowing their preparation as an oral drug. Furthermore, the prediction of cytotoxicity in liver cell lines showed a low cytotoxic effect for riparins I-IV.

Floral Visitation, Phytochemical and Biological Activities of Bioproducts from Tetragonisca angustula (Hymenoptera, Apidae, Meliponini): A Review.

Tetragonisca angustula (Latreille, 1811) is an indigenous neotropical stingless bee, popularly known as "Jataí", with a wide distribution in the Brazilian territory. T. angustula produces other derivatives such as propolis, geopropolis, fermented (saburá pollen), cerumen and resins, which are important in folk medicine. In this review, the objective was to gather research on the main plant species visited by T. angustula, as well as studies that verified the chemical composition and biological properties of T. angustula bioproducts. The bibliographic review was performed by searching the Scopus, Web of Science, ScienceDirect, and PubMed databases for publications from 2003 to February 2023. We found 78 studies that analyzed the interactions between T. angustula and floral species, with species from the botanical families Fabaceae, Asteraceae, Malvaceae, Bignoniaceae, Solanaceae, Myrtaceae and Lamiaceae being the most reported as the main food sources for this species. The presence of compounds belonging to the class of flavonoids, phenolic acids, terpenoids and alkaloids has been identified by studying the chemical composition of honey, propolis, geopropolis and fermented pollen (saburá) in 21 studies. The data collected in the literature emphasize that these T. angustula products have remarkable biological properties, especially their antibacterial and antioxidant activities.

Antibacterial and Toxic Activity of Geopropolis Extracts from Melipona subnitida (Ducke, 1910) (Hymenoptera: Apidae) and Scaptotrigona depilis (Moure, 1942) (Hymenoptera: Apidae).

Bacteria are associated with many infections that affect humans and present antibiotic resistance mechanisms, causing problems in health organisations and increased mortality rates. Therefore, it is necessary to find new antibacterial agents that can be used in the treatment of these microorganisms. Geopropolis is a natural product from stingless bees, formed by a mixture of plant resins, salivary secretions, wax and soil particles, the chemical composition of this natural product is diverse. Thus, this study aimed to evaluate antibacterial activity, antibiotic modulation and the toxicity of geopropolis extracts from the stingless bees, Melipona subnitida (Ducke, 1910) and Scaptotrigona depilis (Moure, 1942) against standard and multi-resistant Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacteria. Geopropolis samples were collected in a meliponary located in Camaragibe, Pernambuco, Brazil. To determine the Minimum Inhibitory Concentration (MIC) and antibiotic modulation we performed broth microdilution tests. Mortality tests were used to verify extract toxicity in the model Drosophila melanogaster. The microbiological tests showing that the M. subnitida extracts had better inhibitory effects compared to S. depilis, presenting direct antibacterial activity against standard and multi-resistant strains. The extracts potentialized antibiotic effects, suggesting possible synergy and did not present toxicity in the model used. The information obtained in this study highlights extracts as promising antibacterial agents and is the first study to evaluate bacterial activity in these extracts, in addition to verifying their modulating effects and determining toxicity in the model used.

Antibacterial activity of eugenol on the IS-58 strain of Staphylococcus aureus resistant to tetracycline and toxicity in Drosophila melanogaster.

The indiscriminate use of antibiotics contributes significantly to the selection of bacteria resistant to several antibiotics. Among the resistance mechanisms are the Efflux Pumps which are responsible for extruding solutes from the cell cytoplasm through proteins in the cell membrane. Because of this, new strategies are needed to control multidrug-resistant pathogenic strains. In this way, the objective of this study was to evaluate the antibacterial activity of eugenol by inhibition of TetK Efflux Pump in strains of Staphylococcus aureus resistant to Tetracycline, in addition to evaluating its toxicity in Drosophila melanogaster. To determine the Minimum Inhibitory Concentration (MIC), the broth microdilution method was used. The modulated effect of antibiotic and Ethidium Bromide associated with eugenol in subinhibitory concentrations (MIC/8) was evaluated. To evaluate the toxic effect of eugenol on D. melanogaster, fumigation tests were used, in which the parameters of mortality and damage to the locomotor system were evaluated. The results showed that eugenol has no direct activity in S. aureus, with an MIC ≥1024 µg/mL. However, it demonstrated that the synergistic potential when associated with Tetracycline, reducing the MIC of the antibiotic, already associated with Ethidium Bromide, had an antagonistic effect. When the toxicity in D. melanogaster was evaluated, eugenol demonstrated a non-toxic profile, since it presented EC50: 2036 µL/mL in 48 h of exposure. In conclusion, eugenol had no relevant direct effect against S. aureus, however, it potentialized the action of the antibiotic by decreasing its MIC.

Effect of Carvacrol and Thymol on NorA efflux pump inhibition in multidrug-resistant (MDR) Staphylococcus aureus strains.

Undue exposure to antimicrobials has led to the acquisition and development of sophisticated bacterial resistance mechanisms, such as efflux pumps, which are able to expel or reduce the intracellular concentration of various antibiotics, making them ineffective. Therefore, inhibiting this mechanism is a promising way to minimize the phenomenon of resistance in bacteria. In this sense, the present study sought to evaluate the activity of the Carvacrol (CAR) and Thymol (THY) terpenes as possible Efflux Pump Inhibitors (EPIs), by determining the Minimum Inhibitory Concentration (MIC) and the association of these compounds in subinhibitory concentrations with the antibiotic Norfloxacin and with Ethidium Bromide (EtBr) against strains SA-1199 (wild-type) and SA-1199B (overexpresses NorA) of Staphylococcus aureus. In order to verify the interaction of the terpenes with the NorA efflux protein, an in silico molecular modeling study was carried out. The assays used to obtain the MIC of CAR and THY were performed by broth microdilution, while the Efflux Pump inhibitory test was performed by the MIC modification method of the antibiotic Norfloxacin and EtBr. docking was performed using the Molegro Virtual Docker (MVD) program. The results of the study revealed that CAR and THY have moderate bacterial activity and are capable of reducing the MIC of Norfloxacin antibiotic and EtBr in strains of S. aureus carrying the NorA efflux pump. The docking results showed that these terpenes act as possible competitive NorA inhibitors and can be investigated as adjuvants in combined therapies aimed at reducing antibiotic resistance.

Inhibition of Staphylococcus aureus Efflux Pump by O-Eugenol and Its Toxicity in Drosophila melanogaster Animal Model.

Background: Efflux pumps are transmembrane proteins that expel drugs out of a bacterial cell contributing to microorganism drug resistance. Several studies addressing the use of natural products with medicinal properties have intensified given the above. Thus, the aim of the present study was to investigate the antibacterial activity and the O-eugenol potential in Staphylococcus aureus resistance reversal by efflux pump inhibition, as well as to evaluate its toxicity in the Drosophila melanogaster arthropod model. The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) and the O-eugenol efflux pump inhibition. For the D. melanogaster toxicity assays, mortality and locomotor system damage were performed using the fumigation method. Results: O-eugenol presented a MIC of 1024 µg/mL against S. aureus. The association of this compound with the antibiotic tetracycline demonstrated a synergistic effect (p < 0.0001), this also being observed when the antibiotic was associated with ethidium bromide (p < 0.0001); thus, these results may be attributable to an efflux pump inhibition. The D. melanogaster mortality and geotaxis assays revealed the compound is toxic, with an EC50 of 18 µg/mL within 48 hours of exposure. Conclusions: While we can conclude that the tested product has an efflux pump inhibitory effect, further studies are needed to elucidate its mechanisms of action, in addition to assays using other strains to verify whether the substance has the same inhibitory effect.

Evaluation of isoeugenol in inhibition of Staphylococcus aureus efflux pumps and their toxicity using Drosophila melanogaster model.

The Staphylococcus aureus bacteria is a pathogen considered opportunistic and that has been acquiring resistance to several classes of antibiotics, mainly due to the synthesis of efflux pumps, which are proteins that expel these drugs intracellularly, reducing their effectiveness. The objective of this study was to evaluate the ability of isoeugenol to inhibit S. aureus efflux pumps and to determine its toxicity against a eukaryotic model (Drosophila melanogaster). IS-58, K2068 and K4414 S. aureus strains were used in the study. Isoeugenol minimum inhibitory concentration (MIC) and antibiotic modulation were evaluated in efflux pump inhibitory tests as well as in ethidium bromide (EtBr) assays. Toxicity tests against D. melanogaster assessed mortality and negative geotaxis. Isoeugenol obtained a relevant MIC result and a synergism was observed when isoeugenol was associated with the antibiotics, mainly with ciprofloxacin. Isoeugenol was able to affect all three efflux pumps tested, especially in strain K4414. The mortality of D. melanogaster caused by isoeugenol administration started after 12 h of exposure, being volume dependent and having an LC50 of 81.69 µL/L. In the negative geotaxis test, a statistical difference was observed after 24h of exposure compared to the control, demonstrating that damage to the locomotor apparatus had occurred. Based on the results, isoeugenol is a putative efflux pump inhibitor, becoming an alternative in blocking these proteins, and demonstrated acute toxicity against D. melanogaster.

Effect of estragole over the RN4220 Staphylococcus aureus strain and its toxicity in Drosophila melanogaster.

Among the bacterial resistance mechanisms, efflux pumps are responsible for expelling xenobiotics, including bacterial cell antibiotics. Given this problem, studies are investigating new alternatives for inhibiting bacterial growth or enhancing the antibiotic activity of drugs already on the market. With this in mind, this study aimed to evaluate the antibacterial activity of Estragole against the RN4220 Staphylococcus aureus strain, which carries the MsrA efflux pump, as well as Estragole's toxicity in the Drosophila melanogaster arthropod model. The broth microdilution method was used to perform the Minimum Inhibitory Concentration (MIC) tests. Estragole was used at a Sub-Inhibitory Concentration (MIC/8) in association with erythromycin and ethidium bromide to assess its combined effect. As for Estragole's toxicity evaluation over D. melanogaster, the fumigation bioassay and negative geotaxis methods were used. The results were expressed as an average of sextuplicate replicates. A Two-way ANOVA followed by Bonferroni's post hoc test was used. The present study demonstrated that Estragole did not show a direct antibacterial activity over the RN4220 S. aureus strain, since it obtained a MIC ≥1024 µg/mL. The association of estragole with erythromycin demonstrated a potentiation of the antibiotic effect, reducing the MIC from 512 to 256 µg/mL. On the other hand, when estragole was associated with ethidium bromide (EtBr), an antagonism was observed, increasing the MIC of EtBr from 32 to 50.7968 µg/mL, demonstrating that estragole did not inhibited directly the MsrA efflux pump mechanism. We conclude that estragole has no relevant direct effect over bacterial growth, however, when associated with erythromycin, this reduced its MIC, potentiating the effect of the antibiotic.