Partial purification of tannins from Quercus infectoria galls and the study of its effect on some isolated skin pathogenic microorganisms.

Abstract

Five methods were used for the extraction of tannins from Quercus infectoria galls. Results revealed that extraction with acetone (70%) was the best.Biochemical detection showed the existence of tannins and glycosides in the gall extract, with no alkaloids and essential oils.As regards biological test, the gall extract was very efficient in inhibiting the growth of Staphylococcus aureus, Streptococcus pyogens, Pseudomonas auroginosa and the dermatophytic fungi: Trichophyton mentagrophytes.Minimal inhibitory concentrations (MIC) were 5 and 10 mg/ml for S. aureus and P. auroginosa, respectively.A partial purification for the above- mentioned extract was conducted. The purification steps included extraction with acetone (70%), extraction with ethanol (95%) and adsorption chromatography with Sephadex LH-20.