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HPLC and GC–MS analyses of phytochemical compounds in Haloxylon salicornicum extract: Antibacterial and antifungal activity assessment of phytopathogens
Abstract The present study investigated the phytochemical constituents and antimicrobial effects of aqueous methanolic extract of Haloxylon salicornicum against some phytopathogenic bacterial and fungal strains. The selected bacterial strains were Pectobacterium carotovorum, Pectobacterium atrosepticum, Ralstonia solanacearum, and Streptomyces scabiei, while fungal strains were Fusarium oxysporum, Botrytis cinerea, and Rhizoctonia solani. The extract demonstrated significant efficacy against P. atrosepticum and P. carotovorum at a concentration of 1,000 µg/mL, resulting in inhibition zones measuring 12.3 and 11 mm, respectively. Furthermore, the extract demonstrated considerable effectiveness against fungal strains, achieving an impressive fungal growth suppression rate of 68.8% against R. solani at a concentration of 5,000 µg/mL. The high-performance liquid chromatography analysis identified nine notable phenolic compounds and six common flavonoid compounds in the extract. The identified phenolic compounds in the highest quantities were gallic acid (6427.5 µg/g), vanillin (1145.4 µg/g), chlorogenic acid (498.1 µg/g), and syringic acid (322.5 µg/g). Apigenin (1155.9 µg/g), daidzein (460.9 µg/g), quercetin (382.7 µg/g), and naringenin (160.4 µg/g) exhibited the most significant concentrations of flavonoid compounds. Gas chromatography–mass spectrometry analysis revealed that n-hexadecanoic acid (53.7%), 9-octadecenoic acid (26.9%), 9,12-octadecadienoic acid (Z,Z) (8.67%), palmitic acid, and TMS derivative (4.36%) were the predominant compounds in the extract. Consequently, the H. salicornicum aqueous methanolic extract could be used for the first time as an environmentally safe antimicrobial pesticide agent against plant pathogens to reduce the excessive use of chemical pesticides.
Copper oxide–ferric oxide nanocomposite: Synthesis, characterization, and antibacterial and antifungal properties
Abstract Recently, copper oxide–ferric oxide nanocomposites (CuO/Fe2O3-NCs) have gained popularity and are widely employed in various applications. However, their effectiveness against phytopathogens has not been studied yet. This study investigates the synthesis and characterization of CuO/Fe2O3-NCs using the hydrothermal technique. X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the produced nanocomposite (NC). EDX and TEM analyses revealed the presence of Cu, Fe, and O elements. The NC had a polygonal shape with sides around 12 nm, spherical CuO particles of 7–10 nm, and plate-like Fe2O3. XRD measurements confirmed the crystal and hexagonal structures of CuO and Fe2O3. The XRD patterns of CuO/Fe2O3 showed the characteristic peaks of (−111) and (004) reflections for CuO at 35.69° and 37.73°. The FTIR spectra showed characteristic lines at 525 and 567 cm−1 for the Cu–O bond and Fe–O stretching modes of Fe2O3, respectively. The antifungal activity of CuO/Fe2O3-NCs showed significant growth inhibition of Fusarium oxysporum, Rhizoctonia solani, and Botrytis cinerea by up to 71, 50, and 81%, respectively, at 100 µg/mL. At 50 µg/mL, the antibacterial test revealed inhibition zones of 12.33 mm for Pectobacterium carotovorum, 9.33 mm for Streptomyces scabies, 10.67 mm for Pectobacterium atrosepticum, and 14.67 mm for Ralstonia solanacearum. The results show that CuO/Fe2O3-NCs can efficiently suppress the growth of various fungal and bacterial strains, making them potential antimicrobial agents against phytopathogenic microorganisms.