Document Type : Complete scientific research article
Authors
1
Assistant Professor, Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
2
Associate Professor, Department of Food Science and Technology, Ahar Faculty of Agriculture and Natural Resources, University of Tabriz, Tabriz, Iran
3
Associate Professor, Department of Food Science and Technology, Ahar Faculty of Agriculture and Natural Resources, University of Tabriz,
10.22069/fppj.2025.23171.1854
Abstract
Background and Objective: Biofilms are formed by various microorganisms that form a structural network and are surrounded by a layer of extracellular polymeric substances. These microorganisms may be attached to a surface or freely suspended in a liquid medium. Although chlorine-based disinfectants are commonly used , prolonged exposure to chlorine may lead to the emergence of bacterial resistance, often associated with antibiotic cross-resistance. The medicinal plant of Stachys is a diverse group of medicinal plants with a high capacity to synthesize a wide range of natural compounds such as phenolic acids, flavonoids, phenylethanoid and phenylpropanoid glycosides, saponins, iridoids, diterpenoids, and steroids. These compounds have a wide range of biological activities. This study was conducted to investigate the antimicrobial properties of Stachys schtschegleevii extract on biofilm producing Corynebacterium spp. .
Materials and Methods: Leaves and flowers of Stachys schtschegleevii were collected from the Arasbaran region. After drying in the shade and grinding, extraction was performed by cold maceration with hydroethanolic solvent (70% ethanol and 30% water) for four days with continuous stirring of the powder-solvent mixture using a laboratory shaker. The Stachys schtschegleevii extract was prepared at concentrations of 200 mg mL-1 and lower concentrations through serial dilution to evaluate its antimicrobial activity. The bioactive compounds of the extract were analyzed to determine the content of total phenols, total flavonoids, and antioxidant capacity. The biofilm production was evaluated using the tissue culture plate method.
Results: The optical density of the wells was obtained by the ELISA method. The average optical density of isolate S1-6A was 0.477, which showed high-strength biofilm production compared to the control well. The average optical density for isolate S2-4 was 0.281, which showed the medium strength of this isolate in biofilm production. Also, the average optical density results for isolates S1-7 and S2-3A were 0.108 and 0.138, respectively, indicating that these two isolates were weak in biofilm production. The hydroethanolic extract used in this study showed 12.5-100 mg mL-1 minimum inhibitory concentration for four Corynebacterium spp. The minimum bactericidal concentration was 25 mg mL-1 against Corynebacterium spp code S1-6A, 50 mg mL-1 against Corynebacterium spp code S1-7, 200 mg mL-1 against Corynebacterium spp code S2-3A, and 50 mg mL-1 against Corynebacterium spp coded S2-4, all of which were isolated from an industrial layer pullet farm.
Conclusion: Replacing harmful and hazardous chemical compounds with organic and plant compounds has significantly increased the inhibition of biofilm-forming bacteria and has been proven more effective than traditional disinfection methods. The poulk extract had a significant effect on Corynebacterium spp. in vitro compared to the conventional disinfectant (sodium hypochlorite) at a concentration of 3 mg L-1.
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