Moroccan Propolis: A Natural Antioxidant, Antibacterial, and Antibiofilm against Staphylococcus aureus with No Induction of Resistance after Continuous Exposure

Abstract

This study was performed to evaluate the total phenols, flavonoids, and antioxidant activities of twenty-four propolis samples from different regions of Morocco. In addition, two samples were screened regarding the antibacterial effect against four Staphylococcus aureus strains. Gas chromatography coupled to mass spectra (GC-MS) analysis was done for propolis samples used in antibacterial tests. The minimum inhibitory and minimum bactericidal concentration (MIC, MBC) were determined. The potential to acquire the resistance after sequential exposure of bacterial strains and the impact of adaptation to propolis on virulence using the Galleria mellonella were evaluated. Additionally, the effects of propolis extract on the bacterial adherence ability and its ability to inhibit the quorum sensing activity were also examined. Among the twenty-four extracts studied, the samples from Sefrou, Outat el Haj, and the two samples marketed in Morocco were the best for scavenging DPPH, ABTS, NO, peroxyl, and superoxide radicals as well as in scavenging of hydrogen peroxide. A strong correlation was found between the amounts of phenols, flavonoids, and antioxidant activities. Propolis extract at the MIC value (0.36 mg/mL) significantly reduced (p < 0.001) the virulence potential of S. aureus ATCC 6538 and the MRSA strains without leading to the development of resistance in the sequence of continuous exposure. It was able to impair the bacterial biofilm formation. The results have revealed that sample 1 reduces violacein production in a concentration dependent manner, indicating inhibition of quorum sensing. This extract has as main group of secondary metabolites flavonoids (31.9%), diterpenes (21.5%), and phenolic acid esters (16.5%).

In VitroEvaluation of the Potential Use of Propolis as a Multitarget Therapeutic Product: Physicochemical Properties, Chemical Composition, and Immunomodulatory, Antibacterial, and Anticancer Properties

“…e results of bioactive compounds identified in this article are in agreement with other studies, which have found that propolis samples collected in different countries contain many phenolic and flavonoid components at different concentrations such as caffeic acid, p-coumaric acid, ferulic acid, gallic acid, chlorogenic acid, rutin, quercetin, cinnamic acid, naringenin, pinocembrin, chrysin, CAPE, galangin, apigenin, kaempferol, chrysin, cinnamyl caffeate, and aromatic acids [50,51]. Many studies documented the antimicrobial activity of these compounds against large number of bacteria [46,52,53]. e diameters of bacterial growth inhibited by disc agar diffusion method of the propolis sample are shown in Figure 2.…”

“…e total antioxidant capacity of the ethanol extract of PNM was 94.76 ± 1.91 mg AAE/g. ese results are within the range reported in other studies [21,46]. e capacity of the propolis samples to scavenge free radicals was evaluated and the results were expressed as IC50 mg/ml ( Table 2).…”

“…e results show a strong free radical scavenging with IC50 being 0.02 ± 0.002 for DPPH assay, 0.04 ± 0.001 for ABTS assay, and the same value for FRAP assay. e values of the IC50 are within the range reported in other propolis samples [46][47][48]. e pharmacologic properties of the phenolic compounds of propolis are documented in numerous scientific papers.…”

The impacts of water and ethanolic extracts of propolis on vacuum packaged sardine fillets inoculated with Morganella psychrotolerans during chilly storage

“…However, their chemical compounds can be variable depending on different reasons, such as plant origin, environmental origin, collection time and extraction method (Bankova, 2005a;Marcucci, 1995;Silva et al, 2017). They have antimicrobial, anti-inflammatory, antioxidant, antidiabetic, spasmolytic, anesthetic, anticancer, and immunomodulatory effects (El-Guendouz et al, 2018;Silva-Carvalho, Baltazar, & Almeida-Aguiar, 2015).…”

Insight on Propolis from Mediterranean Countries: Chemical Composition, Biological Activities and Application Fields

“…On the same insight of the results reported in this review, the authors related this activity to the bioactive compounds present in Moroccan propolis samples. [22,157] From above, we can conclude that propolis from Mediterranean basin is mainly active on Gram + bacteria and less effective regarding Gram À bacteria and yeast, as reported for other propolis with different geographical origins. Regardless the diversity of the chemical profile of propolis, generally all of them present antimicrobial activity.…”