Abstract:
This study focuses on the formulation of respiratory gums enriched with natural plant extracts,
specifically licorice (Glycyrrhiza glabra), propolis, rosemary (Rosmarinus officinalis L.), and
essential oil of Eucalyptus globulus, highlighting their antioxidant and antibacterial activities, as
well as the evaluation of total polyphenol content.
The antioxidant activity, assessed using the DPPH method, showed that rosemary extract
exhibited the strongest activity with an IC₅₀ of 0.004 mg/ml, followed by propolis (0.142 mg/ml)
and licorice (0.724 mg/ml). These results correlate with the total polyphenol contents, expressed
in mg of gallic acid equivalents per gram of dry matter (mg GAE/g DM): rosemary (336.6),
licorice (140.1), and propolis (106.6).
The antimicrobial activity study demonstrated that all extracts were effective against
Staphylococcus aureus at a minimum inhibitory concentration (MIC) of 25 mg/ml. Against
Klebsiella pneumoniae, rosemary was active at 25 mg/ml, licorice at 50 mg/ml, while propolis
showed no effect. Concerning Bacillus subtilis, both propolis and rosemary were active at 25
mg/ml, and licorice at 50 mg/ml. Finally, against Pseudomonas aeruginosa, only licorice showed
activity at 100 mg/ml, while the other two extracts were inactive.
These findings confirm the potential of using natural extracts in pharmaceutical formulations
such as gums, by combining strong antioxidant effects with targeted antimicrobial activity
