Assessment of phenolic and flavonoid contents, antioxidant and antimicrobial activities of Moroccan propolis

Background

Despite the extensive literature focused on propolis extract, few data exists on the bioactive compounds and biological activities in the Moroccan propolis and its economic value is low.

Objective

In this research, the aim was to evaluate the total content of phenols and flavonoids as well as the antioxidant, antibacterial and antifungal activities of Moroccan propolis.

Material and Methods

The polyphenol and flavonoid content of the Moroccan propolis from three geographic regions, was quantified in the ethanolic extract by colorimetric methods using folin-ciocalteu and aluminum chloride. The antioxidant activity was evaluated by the DPPH test and expressed as IC50. Disk diffusion and broth microdilution methods were used to examine in vitro antimicrobial activity against known human microorganism pathogens.

Results

The obtained data revealed that Moroccan propolis samples presented significant variations in total polyphenols and flavonoids. All samples showed significant antioxidant activity with IC50 values ranging from 4.23±0.5 to 154±0.21 μg/ mL. A strong correlation between total phenolic activity, flavonoids and antioxidant activity was found. The in vitro study of antibacterial activity showed that the propolis samples exhibited a range of growth inhibitory actions against all bacterial strains tested with the highest activity against gram-positive bacteria. Only propolis from the Sidi Bennour region demonstrated an antifungal activity.

Conclusion

The study data show that Moroccan propolis extracts have a promising content of antioxidant and antimicrobial compounds that could be exploited to prevent certain diseases linked to oxidative stress and pathogenic infections.

Antibacterial activity of essential oils of Salvia Officinalis growing in Morocco

Background

The bacterial infections treatment is complicated by antibiotic resistance. In this fact, the need for new therapeutic approaches to control bacterial infections is crucial. Therefore, discovering new antibiotics from medicinal plants, able to kill drug-resistant bacteria, is essential to saving modern medicine.

Objective

This study was to evaluate the in vitro antibacterial activity of Salvia officinalis essential oil (SoEO) growing in Morocco.

Material and methods

The essential oil was extracted by hydro distillation, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by agar dilution method. The essential oil was analyzed by Fourier-transform infrared spectroscopy (FTIR) and fractionated/purified using column chromatography followed by thin-layer chromatography (TLC).

Results

The results revealed that SoEO showed higher antimicrobial activity against Enterococcus faecalis and Citrobacter freundii. Fourier-transform infrared spectroscopy (FTIR) analysis, and purification/fractionation of SoEO, indicates that the most polar fraction F6 is the active fraction of SoEO. This finding can be explained by the existence of polar compounds in this fraction including alcohols, and phenols as thymol, eugenol, globulol, and spathulenol.

Conclusions

It can be conclude that alcohols and phenols from Salvia officinalis essential oil (SoEO) have promising antibacterial activity. This action can offer a great possibility of the application of SoEO in the treatment of bacterial diseases.

Chemical composition, antioxidant and antimicrobial activities of Moroccan species of Psidium guajava extracts

Background

During the recent years, appropriate attention has been paid to the oxidative stress which damages the body's cells, proteins, and DNA. Therefore, the need of antioxidants becomes a therapeutic and preventive priority. In addition, microbial infections also constitute a public health problem.

Objective

To find efficient, reliable and safe alternatives sources to synthetic antioxidants, antibiotics and antifungals drugs.

Materials and methods

Extract and essential oil of Psidium guajava were screened for their antioxidant and antimicrobial activities against gram positive bacteria (Enterococcus faecalis and Staphylococcus aureus), gram negative bacteria (Citrobacter freundii, Escherichia coli and Pseudomonas sp) and fungi (Candida albicans,Candida tropicalis and Cryptococcus neoformans), as well as to determine the functional groups of phytochemicals present in the essential oil by Fourier transform infrared spectroscopy (FTIR).

Results

The results indicate that P. guajava leaves extract demonstrated very high antioxidant activity and P.guajava essential oil showed the highest polyphenols content. The antioxidant capacity showed a significant negative linear correlation to total polyphenolic content (TPC) with Pearson's correlation coefficients. P. guajava essential oil shows high antibacterial and antifungal activity against all the studied bacteria and fungi. The FTIR analysis of P. guajava essential oil showed the presence of several functional groups (ethers, esters, ketones, terpenes, alkanes, aldehydes, aromatic hydrocarbons, alcohols, and phenols). The relationship between the chemical composition and antimicrobial activity of P.guajava essential oil suggests that the attribution of its antimicrobial activity to a particular compound or a synergistic effects between its different constituents remains difficult.

Conclusions

The present study demonstrated that Psidium guajava is a valuable source of active compounds with antioxidant and antimicrobial activities. This finding suggests the new use of the fruits and the leaves extracts of this plant in the treatment of bacterial and fungal infections, as well as for the extraction of new antioxidants. Therefore, it is necessary to be carried out in another study to identify the active(s) compound(s) in P.guajava essential oil with respect to their mechanisms and synergistic actions.