Green Synthesis of Chitosan-Capped Gold Nanoparticles Using Salvia officinalis Extract: Biochemical Characterization and Antimicrobial and Cytotoxic Activities.

Increasing antimicrobial resistance to the action of existing antibiotics has prompted researchers to identify new natural molecules with antimicrobial potential. In this study, a green system was developed for biosynthesizing gold nanoparticles (BAuNPs) using sage (Salvia officinalis L.) leaf extract bioconjugated with non-toxic, eco-friendly, and biodegradable chitosan, forming chitosan/gold bioconjugates (Chi/BAuNPs). Characterization of the BAuNPs and Chi/BAuNPs conjugates takes place using transmission electron microscopy (TEM), X-ray spectra, Fourier transform infrared (FT-IR) spectroscopy, and zeta potential (Z-potential). The chemical composition of S. officinalis extract was evaluated via gas chromatography/mass spectrometry (GC/MS). This study evaluated the antioxidant and antimicrobial activities of human pathogenic multidrug-resistant (MDR) and multisensitive (MS) bacterial isolates using the agar diffusion method. Chi/BAuNPs showed inhibition of the MDR strains more effectively than BAuNPs alone as compared with a positive standard antibiotic. The cytotoxicity assay revealed that the human breast adenocarcinoma cancer cells (MCF7) were more sensitive toward the toxicity of 5-Fu + BAuNPs and 5-Fu + Chi/BAuNPs composites compared to non-malignant human fibroblast cells (HFs). The study shows that BAuNPs and Chi/BAuNPs, combined with 5-FU NPs, can effectively treat cancer at concentrations where the free chemical drug (5-Fu) is ineffective, with a noted reduction in the required dosage for noticeable antitumor action.

Biochemical Characterization, Antifungal Activity, and Relative Gene Expression of Two Mentha Essential Oils Controlling Fusarium oxysporum, the Causal Agent of Lycopersicon esculentum Root Rot.

Tomato (Lycopersicon esculentum Mill.) is important food in daily human diets. Root rot disease by Fusarium oxysporum caused huge losses in tomato quality and yield annually. The extensive use of synthetic and chemical fungicides has environmental risks and health problems. Recent studies have pointed out the use of medicinal plant essential oils (EOs) and extracts for controlling fungal diseases. In the current research, Mentha spicata and Mentha longifolia EOs were used in different concentrations to control F. oxysporum. Many active compounds are present in these two EOs such as: thymol, adapic acid, menthol and menthyl acetate. These compounds possess antifungal effect through malformation and degradation of the fungal cell wall. The relative expression levels of distinctly upregulated defense-related WRKY genes (WRKY1, WRKY4, WRKY33 and WRKY53) in seedling root were evaluated as a plant-specific transcription factor (TF) group in different response pathways of abiotic stress. Results showed significant expression levels of WRKY, WRKY53, WRKY33, WRKY1 and WRKY4 genes. An upregulation was observed in defense-related genes such as chitinase and defensin in roots by application EOs under pathogen condition. In conclusion, M. spicata and M. longifolia EOs can be used effectively to control this plant pathogen as sustainable and eco-friendly botanical fungicides.

Assessment of the antioxidant and anticancer potential of different isolated strains of cyanobacteria and microalgae from soil and agriculture drain water.

The potential usage of cyanobacteria and microalgae as a promising and alternative source for new and safe therapeutic compounds is recently caught the attention, due to its versatile properties as antitumor, antioxidant, antifungal, and antiviral agents. Primarily, the cyanobacteria and microalgae from fresh and marine water are previously studied, however those isolated from soil and agriculture drain water were poorly investigated. Therefore, this study aimed to screen and characterize the antioxidant profile, as well as the potential anticancer assessment of 12 species of cyanobacteria and two species of microalgae strains isolated from soil and agriculture drain water. The data showed that total phenol contents were highest in Anabaena oryzae and Aphanizomenon gracile (27.39 and 26.83 mg GAE/g, respectively), followed by Leptolyngbya fragilis (22.96 mg GAE/g). Out of the 14 species identified, the cyanobacterium Dolichospermum flos-aquae HSSASE2 exhibited the most elevated antioxidant activity in terms of NO scavenging activity and anti-lipid peroxidation potential (IC50 = 28.7 ± 0.1 and 11.9 ± 0.2 µg/ml, respectively) and the lowest DPPH radical scavenging activity (467.7 µg/ml). Screening of the anticancer potential of all studied strains against four different human cancer cell lines (Caco-2, MCF-7, PC3, and HepG-2) demonstrated that Dolichospermum crassum HSSASE20 has the highest anticancer effect among all tested species against colon and prostate cancer cell lines (IC50 = 57.9 ± 0.4 and 44.1 ± 0.2 µg/ml, respectively), while Oscillatoria sancta HSSASE19 recorded the most anticancer effect against MCF-7 (breast cancer) cell line (IC50 = 15.1 ± 0.7 µg/ml). Dolichospermum spiroides HSSASE18 obtained the highest anticancer effect HepG-2 (hepatic cancer) cell line (IC50 = 48.8 ± 0.7 µg/ml). Additionally, cytotoxicity against healthy peripheral blood mononuclear cells was studied and revealed that Oscillatoria sancta was the safest one among all studied strains. Data obtained from the sensitivity index demonstrated that Dolichospermum crassum was the most sensitive strain against the four cancerous cell lines. Cyanobacteria and microalgae from the soil and drain water sources are efficient free radical scavengers, containing apoptogens capable of stimulating apoptotic cascades and overcoming chemo-resistance in cancer therapy. Thus, these novel secondary metabolites are an excellent alternative, safe, and low-cost antioxidant and anticancer therapeutic compounds.