Chemical Composition and Antibacterial Activity of  Wild Rose (Rosa canina L.) Gall Extracts against Gram-Negative Pathogenic Bacteria

Treating infections due to antibiotic-resistant bacteria is a challenge and researchers are looking for new antimicrobial compounds. Galls are abnormal plant growths caused by biological agents and have active compounds. The present study was designed to examine the antibacterial effects of different extracts of wild rose gall (Rosa canina L.) against some pathogenic Gram-negative bacilli.

Methanol, acetone, and aqueous extracts from galls were prepared using Soxhlet apparatus. The antibacterial activity of the extracts was determined by agar well diffusion method, and the minimum inhibitory concentration and the minimum bactericidal concentration were assessed by  the microdilution method. The phytochemical composition of galls was investigated by Gas Chromatography-Mass Spectrometry (GC-MS) method.

The inhibition zones of 500 mg/ml methanol extract of wild rose gall against Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella pneumoniae, Acinetobacter bummani, Shigella sonei, and Salmonella typhi were 26.7, 25.0, 25.7, 25.7, 26.7, 23.7 and 18.3, respectively. The antimicrobial activity of the extracts was directly related to their concentration. The extracts were active against all the pathogenic bacteria with average MICs ranging from 15.6 to 31.3 mg/ml.  The methanol extract of wild rose gall showed the highest bactericidal effect on P. aeruginosa and A. bummani at 62.5 mg/ml, respectively. Moreover, oleic acid, palmitic acid, and octadecenoic acid were composed 36.66%, 14.40%, and 13.21% of total active compounds in wild rose gall.

All of the wild rose gall extracts showed significant antibacterial activities against Gram-negative bacilli. The antibacterial effects may be related to the high amounts of organic acids in wild rose gall extracts