Dihydroquercetin, the bioactive substance, to be used against pathogenic microorganisms as an alternative to antibiotics

According to WHO reports, since 2000 a microorganism resistance to antimicrobials has become a serious threat to global public health. Thereby, more strict control for used antibiotics and novel antibacterial substances are considered helpful. Of that, the development of new antimicrobial compounds seems to be most perspective, seeing the high yielding animals are much more susceptible to diseases, and animal products are poorly stored because of microbial contamination. Among compounds possessing antimicrobial properties the dihydroquercetin, a bioflavonoid is of special interest due to wide range of biological activity, including antioxidant activity. Dihydroquercetin is used widely in food industry and medicine, but in animal farming its use is a novel project aimed to provide for animal welfare and quality of livestock products. We compared in vitro antimicrobial effect of different antibiotics (tetracycline, chloramphenicol, streptomycin, bacitracin, grisin, benzyl penicillin at 3.0, 5.0, 10.0, 16.0, 19.0, 24.0 and 48.0 mg/ml each) and 0.5, 1.0, 2,0 and 5.0 % dihydroquercetin to pathogenic, opportunistic, and probiotic microorganism Staphylococcus epidermidis АТСС 14990, Micrococcus luteus ( lysodeicticus ) АТСС 4698, M. luteus АТСС 10240, Escherichia coli VL-613, Pseudomonas aeruginosa 98. In gel diffusion test with a series of dilutions the diameters of growth inhibition zone (D) were measured. St. epidermidis was found to be high sensitive to 5.0 % dihydroquercetin (D of 21.33±0.82 mm) but low sensitive to all the tested concentrations of bacitracin at the Ds ranged from 14.40±0.27 to 18.80±0.42 mm, and to grisin at 3 to 10 mg per milliliter concentration with zone diameters of 18.30±0.22 to 19.80±0.22 mm. Probiotic E. coli and nonpathogenic M. luteus ( lysodeicticus ) АТСС 4698 и M. luteus АТСС 10240 of the gastrointestinal microflora seem to be insensitive to 0.5 до 2.0 % dihydroquercetin (D of 12.20±0.84 to 19.75±0.73 mm) but high sensitive to all tested antimicrobial drugs (D of 20.20±0.22 to 54.80±0.22 mm).