Effect of azoxystrobin fungicide on the physiological and biochemical indices and ginsenoside contents of ginseng leaves

Preparation of Azoxystrobin-Zinc Metal-Organic Framework/Biomass Charcoal Composite Materials and Application in the Prevention and Control of Gray Mold in Tomato

In order to reduce the use of fungicide and ensure food safety, it is necessary to develop fungicide with low toxicity and high efficiency to reduce residues. Azoxystrobin (AZOX), which is derived from mushrooms, is an excellent choice. However, conventional AZOX release is difficult to regulate. In this paper, a pH-responsive fungicide delivery system for the preparation of AZOX by impregnation method was reported. The Zinc metal-organic framework/Biomass charcoal (ZIF-8/BC) support was first prepared, and subsequently, the AZOX-ZIF-8/BC nano fungicide was prepared by adsorption of AZOX onto ZIF-8/BC by dipping. Gray mold, caused by Botrytis cinerea, is one of the most important crop diseases worldwide. AZOX-ZIF-8/BC could respond to oxalic acid produced by Botrytis cinerea to release loaded AZOX. When pH = 4.8, it was 48.42% faster than when pH = 8.2. The loading of AZOX on ZIF-8/BC was 19.83%. In vitro and pot experiments showed that AZOX-ZIF-8/BC had significant fungicidal activity, and 300 mg/L concentration of AZOX-ZIF-8-BC could be considered as a safe and effective control of Botrytis cinerea. The above results indicated that the prepared AZOX-ZIF-8/BC not only exhibited good drug efficacy but also demonstrated pH-responsive fungicide release.

Analysis of Key Chemical Components in Aqueous Extract Sediments of Panax Ginseng at Different Ages

Panax ginseng beverages have been some of the most popular plant drinks among consumers in recent years, but they become turbid and sediment are easily formed during production and marketing, these are some of the key issues that affect the quality of the beverages. In this study, we analysed the physicochemical properties of sediments in aqueous extracts of 3- to 6-year-old ginseng, and by tracing the sediment formation process from 0-40 days, we observed that the sediment was gradually beginning on day 10. The solid content of ginseng aged 5 and 6 years was significantly higher than that of ginseng aged 3 and 4 years. There was no significant difference in the sediment amount sediment in the extracts of ginseng of different ages. The light transmittance of the extracts after centrifugation was significantly higher than before centrifugation. Colour-difference analysis found that there was a significant positive correlation between ginseng age and colour-difference value (ΔE). Chemical composition analysis showed that total sugar and proteins were the main components of the sediment. In addition, ginsenosides, amino acids and minerals were also involved in sediment formation to different degrees. A stepwise regression model was established through principal component analysis (PCA), and the regression equation for predicting the sediment amount was obtained as follows: sediment amount (mg/mL) = 2.906 - 0.126 × C_{Total saponins} - 0.131 × C_{Free amino acids}.

A Novel Analysis Method for Simultaneous Determination of 31 Pesticides by High-Performance Liquid Chromatography-Tandem Mass Spectrometry in Ginseng

Ginseng is a perennial herb with a long growth cycle and is known to easily accumulate pesticides during its growth process, seriously threatening people's health. Therefore, to ensure safe consumption, it is necessary to detect and monitor pesticide residues in ginseng. In this study, a novel analysis method was established for simultaneous determination of 31 pesticides in ginseng by high-performance liquid chromatography-mass spectrometry. Ginseng samples were extracted using acetonitrile, cleaned up by primary secondary amine (PSA) solid-phase extraction column eluted with acetonitrile-toluene, and then detected in multiple reaction mode (MRM). The calibration curves of target compounds were linear in the range of 0.005-1.0 mg/L, with correlation coefficients greater than 0.9921. The limits of detection of all the pesticides in ginseng were between 4.4×10^-5 and 1.6 × 10^-2 mg/kg. For fresh ginseng, the average recoveries ranged from 72.1 to 111.6%, and the relative standard deviations were 1.3-12.2%. For dry ginseng, the average recoveries were 74.3-108.3%, and the relative standard deviations were 0.9-14.9%. The residual concentrations of some pesticides in real samples were greater than the maximum residue limit (MRL) for European Union (EU). The method established here is rapid and simple with high sensitivity and good reproducibility, which is sensitive in the residue analysis of many pesticides in ginseng.

Tebuconazole and trifloxystrobin regulate the physiology, antioxidant defense and methylglyoxal detoxification systems in conferring salt stress tolerance in Triticum aestivum L

Fungicides are widely used for controlling fungi in crop plants. However, their roles in conferring abiotic stress tolerance are still elusive. In this study, the effect of tebuconazole (TEB) and trifloxystrobin (TRI) on wheat seedlings (Triticum aestivum L. cv. Norin 61) was investigated under salt stress. Seedlings were pre-treated for 48 h with fungicide (1.375 µM TEB + 0.5 µM TRI) and then subjected to salt stress (250 mM NaCl) for 5 days. Salt treatment alone resulted in oxidative damage and increased lipid peroxidation as evident by higher malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content. Salt stress also decreased the chlorophyll and relative water content and increased the proline (Pro) content. Furthermore, salt stress increased the dehydroascorbate (DHA) and glutathione disulfide (GSSG) content while ascorbate (AsA), the AsA/DHA ratio, reduced glutathione (GSH) and the GSH/GSSG ratio decreased. However, a combined application of TEB and TRI significantly alleviated growth inhibition, photosynthetic pigments and leaf water status improved under salt stress. Application of TEB and TRI also decreased MDA, electrolyte leakage, and H₂O₂ content by modulating the contents of AsA and GSH, and enzymatic antioxidant activities. In addition, TEB and TRI regulated K⁺/Na⁺ homeostasis by improving the K⁺/Na⁺ ratio under salt stress. These results suggested that exogenous application of TEB and TRI rendered the wheat seedling more tolerant to salinity stress by controlling ROS and methylglyoxal (MG) production through the regulation of the antioxidant defense and MG detoxification systems.

Toxicity of secondary metabolites

Secondary metabolites, commonly referred to as natural products, are produced by living organisms and usually have pharmacological or biological activities. Secondary metabolites are the primary source for the discovery of new drugs. Furthermore, secondary metabolites are also used as food preservatives, biopesticides or as research tools. Although secondary metabolites are mainly used by their beneficial biological activity, the toxicity of some of them may limit their use. The toxicity assessment of any compound that is prone to be used in direct contact with human beings is of vital importance. There is a vast spectrum of experimental methods for toxicity evaluation, including in vitro and in vivo methodologies. In this work, we present an overview of the different sources, bioactivities, toxicities and chemical classification of secondary metabolites, followed by a sketch of the role of toxicity assessment in drug discovery and agrochemistry.

Exogenous Tebuconazole and Trifloxystrobin Regulates Reactive Oxygen Species Metabolism Toward Mitigating Salt-Induced Damages in Cucumber Seedling

The present study investigated the role of tebuconazole (TEB) and trifloxystrobin (TRI) on cucumber plants (Cucumis sativus L. cv. Tokiwa) under salt stress (60 mM NaCl). The cucumber plants were grown semi-hydroponically in a glasshouse. Plants were exposed to two different doses of fungicides (1.375 µM TEB + 0.5 µM TRI and 2.75 µM TEB + 1.0 µM TRI) solely and in combination with NaCl (60 mM) for six days. The application of salt phenotypically deteriorated the cucumber plant growth that caused yellowing of the whole plant and significantly destructed the contents of chlorophyll and carotenoids. The oxidative damage was created under salinity by increasing the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage (EL) resulting in the disruption of the antioxidant defense system. Furthermore, in the leaves, stems, and roots of cucumber plants increased Na+ content was observed under salt stress, whereas the K+/Na+ ratio and contents of K+, Ca2+, and Mg2+ decreased. In contrast, the exogenous application of TEB and TRI reduced the contents of MDA, H2O2, and EL by improving the activities of enzymatic and non-enzymatic antioxidants. In addition, ion homeostasis was regulated by reducing Na+ uptake and enhanced K+ accumulation and the K+/Na+ ratio after application of TEB and TRI. Therefore, this study indicates that the exogenous application of TEB and TRI enhanced salt tolerance in cucumber plants by regulating reactive oxygen speciesproduction and antioxidant defense systems.