Evaluation of the phenolic contents and antibacterial activity of different concentrations of Onosma chlorotricum Boiss.

Because of side effects and increasing resistance to antibiotics, considerable attention hasbeen given to extract sand biologically active compounds isolated from medicinal plants. In the present study, phytochemical screening and antibacterial activities of different concentrations of various extracts of Onosma chlorotricum were evaluated and compared with those of vancomycin and amikacin. Total phenolic and flavonoid contents and the antibacterial activity of methanol, n-hexane, and aqueous extracts (5 mg/ml to 0.156 mg/ml final concentration) of O. chlorotricum against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were evaluated using disc diffusion and microdilution methods. Total phenolic and flavonoid contents were determined according to the Folin-Ciocalteu and aluminum chloride colorimetric assays, respectively. The results showed that the total phenolic and flavonoid contents of these extracts ranged from 56.10 ± 0.13 to 74.12 ± 0.05 mg GAE/g dry extract and from 19.3 ± 0.6 to 23.20 ± 0.41 mg QE/g dry extract, respectively. The methanol extract with the highest phenolic and flavonoid content showed the highest antibacterial activity against all the tested bacterial strains, with the highest inhibition zone of 21 ± 0.7 mm and the lowest MIC and MBC values of 78.12 µg/ml for S. aureus. The antibacterial effects and the total phenolic content of O. chlorotricum were remarkable. The results suggest that the effects of methanol extract on wound healing could be tested in an animal model.

Biosynthesis of zinc oxide nanoparticles using Fumaria parviflora extract and evaluation of their antibacterial and antioxidant activities.

Green synthesis is a biocompatible and stable method of producing zinc oxide nanoparticles (ZnONPs).In the present study, ZnONPs were biosynthesized using Fumaria parviflora extract by the green method, and the antibacterial and antioxidant properties of these NPs were evaluated. The characteristics of the synthesized ZnONPs were determined by ultraviolet-visible spectrophotometry (UV-VIS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antioxidant activity of the NPs was tested by the α-diphenyl-ß-picrylhydrazyl (DPPH) method. Antibacterial properties of the synthesized ZnONPs were evaluated against Staphylococcus aureus and Escherichia coli by disc diffusion and microdilution methods. The results of UV-VIS spectroscopy revealed an absorption peak at 370 nm. XRD results showed the formation of a hexagonal wurtzite structure, and SEM analyses demonstrated that ZnONPs had a spherical shape with an average size 42 to 60 nm. Free radical scavenging capacity of ZnONPs was assessed using the DPPH assay with varying concentrations of ZnONPs, and scavenging activity was observed with IC50 of 30.86 µg/ml. In the antibacterial assay, the inhibition zone of the synthesized NPs at 100 µg/ml concentration for S. aureus (24.6 ± 0.72) was greater than that of the antibiotics vancomycin (23 ± 0.51) and a mikacin (13 ± 0.40) and was greater for E. coli (13.2 ± 0.81)than that of vancomycin (12 ± 0.41) (P ≤ 0.05). The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of ZnONPs for S. aureus and E. coli were 1.56 and 3.125 µg/ml, and 6.25 and 12.5 µg/ml, respectively. The biosynthesized ZnONPs showed strong antibacterial and antioxidant activities.