Quantitative and Qualitative Analyses of the Constituents of the Hydroalcoholic Extract of Quercus infectoria Gall from Kermanshah and Evaluation of Its Antioxidant and Antibacterial Activities

Quercus infectoria is a species of Quercus genus (Fagaceae) whose galls are known in traditional medicine for their antibacterial, analgesic, anti-inflammatory, and astringent effects. The present study aimed to carry out quantitative and qualitative analyses of the constituents of the hydroalcoholic extract of the Q. infectoria galls from Kermanshah and to evaluate its antioxidant and antibacterial activities.

Following the extraction process using ethanol/water (70/30), phytochemical tests were done. Total phenol and flavonoid and antioxidant and antibacterial activities against specific strains of bacteria were evaluated. Some of the constituents of the extract were identified using high-performance liquid chromatography-photodiode array, and their amount was obtained.

The phytochemical tests proved that the extract contained alkaloid, flavonoid, tannin, saponin, and phenolic compounds. The amount of total phenolic and flavonoid compounds was 16.21 and 1.78 mg/g dried galls, respectively. The IC50 value of the antioxidant constituents of the extract was 47 µg/ mL. The results of the antimicrobial assay showed the high activity of the extract against Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and S. epidermidis. The quantitative analysis of the extract confirmed the presence of gallic acid, rutin, quercetin, benzoic acid, and caffeic acid (12.30, 10.72, 5.00, 9.25, and 3.94 mg/g dried galls, respectively).

Considering the results of this study, the extract of Q. infectoria galls could be used as a primary substance in treating bacterial infections and oxidative stress-related diseases.