Propolis ethanolic extract has double-face in vitro effect on the planktonic growth and biofilm formation of some commercial probiotics

Molecular and Cellular Mechanisms of Propolis and Its Polyphenolic Compounds against Cancer

In recent years, interest in natural products such as alternative sources of pharmaceuticals for numerous chronic diseases, including tumors, has been renewed. Propolis, a natural product collected by honeybees, and polyphenolic/flavonoid propolis-related components modulate all steps of the cancer progression process. Anticancer activity of propolis and its compounds relies on various mechanisms: cell-cycle arrest and attenuation of cancer cells proliferation, reduction in the number of cancer stem cells, induction of apoptosis, modulation of oncogene signaling pathways, inhibition of matrix metalloproteinases, prevention of metastasis, anti-angiogenesis, anti-inflammatory effects accompanied by the modulation of the tumor microenvironment (by modifying macrophage activation and polarization), epigenetic regulation, antiviral and bactericidal activities, modulation of gut microbiota, and attenuation of chemotherapy-induced deleterious side effects. Ingredients from propolis also "sensitize" cancer cells to chemotherapeutic agents, likely by blocking the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In this review, we summarize the current knowledge related to the the effects of flavonoids and other polyphenolic compounds from propolis on tumor growth and metastasizing ability, and discuss possible molecular and cellular mechanisms involved in the modulation of inflammatory pathways and cellular processes that affect survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.

In Vivo Therapeutic Effect of Some Medicinal Plants' Methanolic Extracts on the Growth and Development of Secondary Hydatid Cyst Infection

PURPOSE

The current study aimed to explore the in vivo therapeutic effects of the methanolic extracts of Citrullus colocynthis, Ruta graveolens, and Peganum harmala against hydatid cyst secondary infection.

METHODS

Aerial parts of P. harmala and R. graveolens, including leaves and stems, and seeds of C. colocynthis were collected and extracted using absolute methanol. Rats that are infected with secondary infection of hydatid cysts were treated orally and intraperitoneally according to the determined lethal doses for 30 days. Histological, hematological, and biochemical investigations were done 8 months after the infection.

RESULTS

Compared to Albendazole drug, C. colocynthis, and P. harmala, the methanol extract of R. graveolens showed higher and significant (P < 0.05) therapeutic effects on the secondary hydatid cysts growth. Those effects were represented by the reduction in the cysts' number, size, and weight; as well as the significant changes (P < 0.05) in values of hematological and biochemical parameters, the elevation of IFN-γ levels, and the decline of IL-10 and IL-4 cytokines, compared to the negative control group in both routes of treatment (oral and IP). Moreover, the histological sections showed that R. graveolens has a clear damaging effect on the hydatid cysts GL in the infected rats represented by the detachment of GL from LL and AL.

CONCLUSION

This study can open an avenue to find new therapeutics for secondary hydatid cyst infections using the studied plant extracts, especially the extract of R. graveolens.

Silver nanoparticles biosynthesis using an airborne fungal isolate, Aspergillus flavus: optimization, characterization and antibacterial activity

Background and Objectives

Nanoscience is one of the most important branches of modern science, which deals with the knowledge, structure, and properties of nanoparticles. This study aimed to investigate the ability of an airborne fungus (Aspergillus flavus) to synthesize silver nanoparticles (AgNPs) and to test the antibacterial activity of the synthesized AgNPs.

Materials and Methods

The confirmation of AgNPs synthesis and the characterization of their properties were done using UV-Vis spectrophotometer, Zeta potential, Zeta sizer, FT-IR, and XRD analyses. The antibacterial activity was determined using broth microdilution method.

Results

The findings showed that the average diameter of the resultant AgNPs was 474.2 nm with a PDI value of 0.27, and the zeta potential was -33.8 mV. Transmission electron microscopy (TEM) revealed that the AgNPs were regular and spherical in shape. TEM micrographs demonstrated that the AgNPs were smaller than those that were observed by DLS examination because the drying process resulted in particle shrinkage. The average size of AgNPs were less than 35 nm. The AgNPs exhibited a remarkable antibacterial activity against K. pneumoniae, E. coli, E. cloacae, S. aureus, S. epidermidis, and Shigella sp., and the MIC values ranged from 25 to 100 μg/mL. However, an exception was P. aeruginosa in which its MIC was >125 μg/mL.

Conclusion

The results suggest that, the biosynthesized AgNPs by A. flavus could be utilized as a source of potent antibacterial agents in medicine and biotechnological applications.

Evaluation of Total Phenolic and Flavonoid Contents, Antibacterial and Antibiofilm Activities of Hungarian Propolis Ethanolic Extract against Staphylococcus aureus

Propolis is a natural bee product that is widely used in folk medicine. This study aimed to evaluate the antimicrobial and antibiofilm activities of ethanolic extract of propolis (EEP) on methicillin-resistant and sensitive Staphylococcus aureus (MRSA and MSSA). Propolis samples were collected from six regions in Hungary. The minimum inhibitory concentrations (MIC) values and the interaction of EEP-antibiotics were evaluated by the broth microdilution and the chequerboard broth microdilution methods, respectively. The effect of EEP on biofilm formation and eradication was estimated by crystal violet assay. Resazurin/propidium iodide dyes were applied for simultaneous quantification of cellular metabolic activities and dead cells in mature biofilms. The EEP1 sample showed the highest phenolic and flavonoid contents. The EEP1 successfully prevented the growth of planktonic cells of S. aureus (MIC value = 50 µg/mL). Synergistic interactions were shown after the co-exposition to EEP1 and vancomycin at 108 CFU/mL. The EEP1 effectively inhibited the biofilm formation and caused significant degradation of mature biofilms (50-200 µg/mL), as a consequence of the considerable decrement of metabolic activity. The EEP acts effectively as an antimicrobial and antibiofilm agent on S. aureus. Moreover, the simultaneous application of EEP and vancomycin could enhance their effect against MRSA infection.

Antifungal and Anti-Biofilm Effects of Caffeic Acid Phenethyl Ester on Different Candida Species

This study investigated the effect of CAPE on planktonic growth, biofilm-forming abilities, mature biofilms, and cell death of C. albicans, C. tropicalis, C. glabrata, and C. parapsilosis strains. Our results showed a strain- and dose-dependent effect of CAPE on Candida, and the MIC values were between 12.5 and 100 µg/mL. Similarly, the MBIC values of CAPE ranging between 50 and 100 µg/mL highlighted the inhibition of the biofilm-forming abilities in a dose-dependent manner, as well. However, CAPE showed a weak to moderate biofilm eradication ability (19-49%) on different Candida strains mature biofilms. Both caspase-dependent and caspase-independent apoptosis after CAPE treatment were observed in certain tested Candida strains. Our study has displayed typical apoptotic hallmarks of CAPE-induced chromatin margination, nuclear blebs, nuclear condensation, plasma membrane detachment, enlarged lysosomes, cytoplasm fragmentation, cell wall distortion, whole-cell shrinkage, and necrosis. In conclusion, CAPE has a concentration and strain-dependent inhibitory activity on viability, biofilm formation ability, and cell death response in the different Candida species.

The Scent of Antifungal Propolis

Propolis contains many effective antifungal compounds that have not yet been identified and evaluated. In addition, distinguishing samples of propolis with high antifungal activity from less active ones would be beneficial for effective therapy. Propolis samples were collected from four different geographical regions in Hungary and used to prepare ethanol extracts for analysis. First, an antifungal susceptibility test was performed on Candida albicans. Then, gas chromatography-mass spectrometry (GC-MS) and an opto-electronic nose were applied for the classification of propolis samples. In three propolis samples, the IC₅₀ was measured between 72 and 134 µg/mL, but it was not calculable in the fourth sample. GC-MS analysis of the four propolis samples identified several compounds belonging to the various chemical classes. In the antifungal samples, the relative concentration of 11,14-eicosadienoic acid was the highest. Based on the opto-electronic electronic nose measurements, 98.4% of the original grouped antifungal/non-antifungal cases were classified correctly. We identified several molecules from propolis with potential antifungal properties. In addition, this is the first report to demonstrate the usefulness of a portable opto-electronic nose to identify propolis samples with high antifungal activity. These results may contribute to the rapid and efficient selection of new fungicide-candidate molecules and effective propolis samples for treatment.

Lactobacillus reuteri in Its Biofilm State Improves Protection from Experimental Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a devastating disease predominately found in premature infants that is associated with significant morbidity and mortality. Despite decades of research, medical management with broad spectrum antibiotics and bowel rest has remained relatively unchanged, with no significant improvement in patient outcomes. The etiology of NEC is multi-factorial; however, gastrointestinal dysbiosis plays a prominent role in a neonate's vulnerability to and development of NEC. Probiotics have recently emerged as a new avenue for NEC therapy. However, current delivery methods are associated with potential limitations, including the need for at least daily administration in order to obtain any improvement in outcomes. We present a novel formulation of enterally delivered probiotics that addresses the current limitations. A single enteral dose of Lactobacillus reuteri delivered in a biofilm formulation increases probiotic survival in acidic gastric conditions, increases probiotic adherence to gastrointestinal epithelial cells, and reduces the incidence, severity, and neurocognitive sequelae of NEC in experimental models.