RESUMO
Biologically active natural compounds are molecules produced by plants or plant-related microbes, such as endophytes. Many of these metabolites have a wide range of antimicrobial activities and other pharmaceutical properties. This study aimed to evaluate (in vitro) the antifungal activities of the secondary metabolites obtained from Paecilomyces sp. against the pathogenic fungus Rhizoctonia solani. The endophytic fungus Paecilomyces was isolated from Moringa oleifera leaves and cultured on potato dextrose broth for the production of the fungal metabolites. The activity of Paecilomyces filtrate against the radial growth of Rhizoctonia solani was tested by mixing the filtrate with potato dextrose agar medium at concentrations of 15%, 30%, 45%, and 60%, for which the percentages of inhibition of the radial growth were 37.5, 50, 52.5, and 56.25%, respectively. The dual culture method was conducted on PDA medium to observe the antagonistic nature of the antibiotic impacts of Paecilomyces sp. towards the pathogenic fungus. The strength of the antagonistic impacts was manifested by a 76.25% inhibition rate, on a scale of 4 antagonistic levels. Ethyl acetate extract of Paecilomyces sp. was obtained by liquid-liquid partition of the broth containing the fungus. Gas chromatography-mass spectrometry (GC-MS) analysis identified the presence of important chemical components e.g., (E) 9, cis-13-Octadecenoic acid, methyl ester (48.607), 1-Heptacosanol, 1-Nonadecene, Cyclotetracosane (5.979), 1,2-Benzenedicarboxylic acid, butyl 2-methylpropyl ester, di-sec-butyl phthalate (3.829), 1-Nonadecene, n-Nonadecanol-1, Behenic alcohol (3.298), n-Heptadecanol-1, 1-hexadecanol, n-Pentadecanol (2.962), Dodecanoic acid (2.849), 2,3-Dihydroxypropyl ester, oleic acid, 9-Octadecenal, and (Z)-(2.730). These results suggest that secondary metabolites of the endophytic Paecilomyces possess antifungal properties and could potentially be utilized in various applications, such as environmental protection and medicine.
RESUMO
OBJECTIVES: The synthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities was investigated and extracellularly biosynthesized using Penicillium italicum isolated from Iraqi lemon fruits. RESULTS: The formation of synthesized nanoparticles was observed after 72 h of incubation. Color changing, ultraviolet and visible spectrum, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive analysis X- ray confirmed the biosynthesis and characterization of silver nanoparticles. Ultraviolet and visible spectroscopy showed silver surface plasmon resonance band at 415 nm. X- ray diffraction showed that the particles were crystalline with face-centered cubic lattice phase and a size of 39.5 nm. Fourier transform infrared analysis shows the possible interactions between silver and bioactive molecules, which may be responsible for synthesis and stabilization of silver nanoparticles. Scanning electron microscopy imaging revealed different morphologies of the AgNPs, some of nanoparticles were close to spherical in shape, while others had platelet like structure, in size range between 32 and 100 nm. The transmission electron microscopy image demonstrated that AgNPs were spherical with a size < 50 nm. The biosynthesized silver nanoparticles were proved to be potential antioxidants by showing effective radical scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl, hydroxyl radical and resazurin. The nanoparticles also showed potent antimicrobial activity against various pathogens, including bacteria and fungi as well as significant concentration-dependent cytotoxic effects against human breast cancer cells. CONCLUSIONS: The powerful bioactivity of the synthesized silver nanoparticles recommends their biomedical use as antioxidant, antimicrobial as well as cytotoxic agents.