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In this investigation, we assessed the antibacterial properties of menthol using Escherichia coli strains, including a tetracycline-resistant (BN407) and a non-resistant reference (K12) strains. The disc-diffusion assay indicated remarkable antibacterial activity of menthol, warranting further exploration. The minimum inhibitory concentration (MIC) for menthol was determined to be 500 µg/ml for both strains. Despite identical MIC values, menthol exhibited different effects on the colony-forming units (CFUs) of the strains, reducing CFUs by 55% in E. coli K12 and 40% in E. coli BN407. Growth kinetics studies revealed that menthol extended the Lag phase by 50% and decreased the specific growth rate and mean generation time by nearly 50% for both strains. These findings illustrate menthol's significant impact on bacterial replication and adaptation processes. Additionally, menthol disrupted membrane-associated properties, as evidenced by reduced H+-flux through bacterial membranes, affecting both N,N-Dicyclohexylcarbodiimide (DCCD)-sensitive and non-sensitive proton flux rates. This indicates that menthol compromises the proton motive force critical for ATP synthesis and nutrient transport. In summary, menthol demonstrates potent antibacterial activity, influencing bacterial growth and survival. This activity is supposed to be due to the influence on membrane functionality. These effects are consistent across both tetracycline-resistant and non-resistant E. coli strains. [ABSTRACT FROM AUTHOR]

Compounds of plant origin are considered promising alternative approaches in the development of medicines for the prevention and treatment of cancer. The large diversity of herbal species still requires careful exploration as a source for new anticancer compounds. The goal of the study was to screen different herbal extracts traditionally used in Armenian folk medicine for their cytotoxic effect against some cancer cell lines, and to find the prospective plant species among them. The cytotoxicity of the plant ethanol extracts was evaluated with MTT test against HeLa (human cervical carcinoma) and A549 (human lung adenocarcinoma) cells. Antioxidant properties were assessed with DPPH free radical scavenging assay. Five of the tested ten herbal extracts exhibited significant growth-inhibiting activity on HeLa cells. Moreover, Alchemilla smirnovii and Hypericum alpestre extracts also showed potent cytotoxicity on human lung adenocarcinoma cells. These two plants possessed high antiradical activity as well. Their DPPH stoichiometric values were 0.4234 and 0.14437 respectively, meaning that 1 µg of plant extract brought the reduction of DPPH equal to the respective stoichiometric values in µg. Thus, A. smirnovii and H. alpestre extracts expressed themselves as potent cytotoxic and antioxidant agents and could have promising anticancer potential. Further evaluation of their in vivo anticancer properties has much interest. [ABSTRACT FROM AUTHOR]

In the presented work, we aimed to investigate the antioxidant and possible neuroprotective capacity of extract of the aerial parts of Hypericum alpestre, found in high altitude Armenian landscape. The neuroprotective activity was evaluated using BV-2 wild type (WT) cells and acyl-CoA oxidase 1 (ACOX1) deficient (Acox1-/-) microglial cell lines. In the chemical-based tests, H. alpestre extract showed high antioxidant activity, which was maintained even after heat treatment at 121 °C for 30 min. MTT test showed that the sub-cytotoxic concentration of investigated extracts for both microglial cell lines was 40 µg/mL. There were no significant changes in catalase activity during all period of treatment in both cell lines, meanwhile, SOD activity increased (up to 30%) in WT cells during the 48 h treatment. Increase of SOD activity (up to 50%) in Acox-/- cells was observed under the 24 h treatment. Significant modulation in activity of palmitoyl-CoA oxidase 1 was noticed only during the 48 h treatment of WT microglial cells. These results evidenced the pro-oxidant activity of the investigated extract. This finding can serve as a basis for further evaluation of plant extracts influence on cancer cell lines. [ABSTRACT FROM AUTHOR]