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Gastric diseases are increasing with the infection of Campylobacter jejuni. Late stages of infection lead to peptic ulcer and gastric carcinoma. C. jejuni infects people within different stages of their life, especially childhood, causing severe diarrhea; it infects around two-thirds of the world population. Due to bacterial resistance against standard antibiotic, a new strategy is needed to impede Campylobacter infections. Plants provide highly varied structures with antimicrobial use which are unlikely to be synthesized in laboratories. A special feature of higher plants is their ability to produce a great number of organic chemicals of high structural diversity, the so-called secondary metabolites. Twenty plants were screened to detect their antibacterial activities. Screening results showed that Rheum officinalis was the most efficient against C. jejuni. Fractionation pattern was obtained by column chromatography, while the purity test was done by thin-layer chromatography (TLC). The chemical composition of bioactive compound was characterized using GC-MS, nuclear magnetic resonance, and infrared analysis. Minimal inhibitory concentration (MIC) of the purified compound was 31.25 µg/ml. Cytotoxicity assay on Vero cells was evaluated to be 497 µg/ml. Furthermore, the purified bioactive compound activated human lymphocytes in vitro. The data presented here show that Rheum officinalis could potentially be used in modern applications aimed at the treatment or prevention of foodborne diseases.

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Background: aqueous extracts of six species of marine seaweed were studied as antiviral activity on different viruses. Materials and methods: these collected from two sites Hurghada at the Red Sea and Al-Agami area in Alexandria Mediterranean Sea Egypt and belonging to the classes Chlorophyta, Phaeophyta and Rhodophyta were assayed for the cytotoxicity and antiviral activity by MTT [3-(4,5dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] and by neutralization methods.Results: these extracts have antiviral activity to herpes simplex virus types-1 (HSV-1) and type-2 (HSV-2), hepatitis A virus (HAV-H 10 ), and Coxsackie B 4 virus in Vero cells with very low cytotoxicity to the host cells.

Background Green, eco-friendly, cost effective, safe, and reliable processes for the synthesis of nanoparticles using microorganisms as bio-nanofactories have attracted interest due to its ability in transforming metals into nanosize to their use in various fields. In this study silver nitrate and supernatants of Cladosporium herbarum isolated from water samples of Qarun Lake, Egypt was used for extracellular biosynthesis of silver nanoparticles (AgNPs) and their activity against different pathogenic microorganisms was tested. Methods Silver nanoparticles were biosynthesized using four isolated marine fungi, the reaction parameters were optimised and the biosynthesized nanoparticles were characterized by various analytical techniques such as Transmission Electron Microscopy (TEM), Fourier transform infrared (FT-IR) and X-Ray analysis. Antimicrobial activity and mode of action of the biosynthesized silver nanoparticles were tested against variety of pathogens (Gram-positive and Gram-negative bacteria, yeast, and fungi). Results The results revealed that biosynthesized silver nanoparticles mediated by marine fungus Cladosporium herbarum are proven to have potent antimicrobial effect against different pathogens with optimum substrate concentration of 5 Mm at 37 oC, 6 pH, and 24 h incubation time. TEM analysis revealed the formation of spherical, well-dispersed nanoparticles with size ranging between 4 and 23.1 nm and FTIR shows the bands at 556, 762, 1349, 1451, 1562, 1620, and 3352 cm− 1 corresponding to the binding vibrations of stretch of alkyl halides, C-H group, O-H group of phenol, C-N group of amides, NH2 group, N-H group, and–OH group, respectively. Conclusions Biosynthesis of silver nanoparticles mediated by Cladosporium herbarum could be a promising product used as antimicrobial agents against various pathogenic microbes.