Background Plant species Robinia pseudoacacia L. (Fabaceae) has been used as a medicinal plant since ancient times, as its infusions and extracts have antacid, antibacterial, purgative and emenagogic properties. The volatile oil of the flowers is also used in perfumery and cosmetics.

Purpose Due to its high content of volatile oil phenolic compounds, flavonoids and tannins with antimicrobial properties, the present study proposed to investigate the antibacterial and antifungal effect of the species Robinia pseudoacacia.

Materials and methods The dry powdered flowers, leaves, bark and seeds of Robinia pseudoacacia were subjected to extraction in a Soxhlet extractor with 90% ethanol. The alcoholic extract obtained in the concentration of 100 mg / ml, was tested using sterile discs of Whatman No. 1 filter paper, impregnated with 100 mg extract. Antibacterial and antifungal effects was evaluated by the Kirby-Bauer disc diffusion method, in accordance with the NCCLS / CLSI standard, using the following infectious agents isolated from patients and the corresponding reference strains: methicillin-resistant Staphylococcus aureus and methicillin-sensitive haemolytic S. epidermidis, Streptococcus pyogenes, Enterococcus, Enterobacter aerogenes, Escherichia coli, Salmonella choleraesuis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus, Candida albicans.

Results Extracts from various different parts of the plant had different antibacterial activities. Extracts of flowers and seeds are efficient antibacterials for Gram positive cocci. Bark and leaf extracts were active against Escherichia coli, Pseudomonas, Proteus, Salmonella choleraesuis, Candida albicans.

Conclusions These results prove the antimicrobial or antifungal properties of certain extracts of Robinia pseudoacacia L., which offers an alternative treatment with a natural product with synergistic effects with conventional antibacterial treatment.