Chemical composition of the fresh and dried mushroom Pleurotus ostreatus and their bioactive secondary metabolic products were studied. The ethanolic extracts of the P. ostreatus cultivated on rice straw supplemented by wheat bran were studied by Gas Chromatography/Mass Spectrometry (GC/MS) analysis. A total of hundred and seven metabolites were detected in tested samples. These include 56 metabolites only detected in fresh sample, 37 metabolites only detected in dry sample, and 14 metabolites were detected in the both samples. The detected metabolites could be classified into nine chemical groups including 2 metabolites related to acids, 5 alcohols, 27 alkane, 3 amides, 27 esters, 8 fatty acids, 4 terpenoids, 29 heterocyclic and 2 phenols. The bioactivity of the metabolic products could be classified: anticholesterol, anticancer and essential fatty acids which support human health. On comparison between fresh and dried P. ostreatus samples, we found that the high number of metabolites was recorded in the fresh extract. Fifty five aroma compounds were recorded and including (27 esters, 9 ketones, 7 thiols, 5 alcholos, 4 terpenoids, 2 phenols and 1 aldehyde). The selenium content in P. ostreatus samples was measured by using ACAL -APR -51-00 test methods and showed that the fresh sample has 58.24 mg/kg but the dry sample has 100.31 mg/kg.

Biological green synthesis of silver nanoparticles (AgNPs) from silver salts is a growing advanced approach to avoid the requirement of costly instruments and involvement of hazardous chemicals as well. However, increasing use of AgNPs raises potential toxicity level in the environment. In this investigation, leaf extract of rosemary (Rosmarinus officinalis) used as a reducing and stabilizing agent for biosynthesis of AgNPs. The biosynthesized AgNPs were authorized by UV-vis spectrophotometer and X-ray diffraction (XRD) analysis. The shape and size of the biosynthesized AgNPs were studied using high resolution transmission electron microscope (TEM). The toxicity of the biosynthesized silver nanoparticles on wheat and tomato plants was studied by soaking wheat grains and tomato seeds in 100 mg/L AgNPs and follow its effect on seedling growth of wheat (at 10 days) and on vegetative growth of tomato and wheat plants (at 35 days). Some physiological parameters as germination percentage of wheat seedling, length of seedling, dry weight, pigment fractions (chl.a, chl.b and caroteinoids), soluble proteins, lipid peroxidation (MDA) and antioxidant enzymes (catalase and peroxidase) of two plants were measured. AgNPs has a non-significant inhibitory effect on germination percentage of wheat, dry weight and pigment fractions. The biosynthesized AgNPs has a noticeable stress effect on tomato plant as reduced chlorophyll a and dry weight. Generally, AgNPs stimulate MDA accumulation in tomato and wheat plants. There was a noticeable different effect of AgNPs on soluble proteins and antioxidant enzymes as catalase and peroxidase among tomato and wheat plants.

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The structure and function of cellular membranes were sustained by redox-enzymes. We studied the interaction between the oxidative stress caused by excessive accumulation of ZnO-nanoparticles (ZnO-NPs) in plants and the role of redox-enzymes that can alleviate this stress. The crude callus extract from pomegranate, which was treated with 0, 10, and 150 µg mL−1 ZnO-NPs or bulk particles (ZnO-BPs), was applied to study the activity and kinetics of redox-enzymes. The elevated ZnO-NPs, enhanced the lipoxygenase and polyphenol oxidase activity, while the ZnO-BPs did not modify them. The activities of superoxide dismutase, catalase, and phenylalanine ammonia-lyase were induced under ZnO-NPs or BPs treatments, whilst the opposite trend of peroxidase was observed. Ascorbate peroxidase activity increased under ZnO-NPs treatments but decreased under ZnO-BPs. The kinetics activity of enzymes showed changes under different levels of NPs and BPs. Additionally, NPs or BPs treatments reduced the uptake of copper, iron, magnesium, but increased zinc accumulation in callus tissues. Meanwhile, these treatments enhanced the accumulation of manganese ions but did not affect the accumulation of potassium and phosphorous in ZnO-NPs or BPs-stressed calli. Collectively, these results gave a quantitative evaluation of the competition of zinc and other minerals on the carriers, and in addition, they provided a basis for how to control ZnO-NPs or BPs toxicity via redox-enzymes.