Trends in science on glyphosate toxicity: a scientometric study

Functionalized p-cymene and pyrazine derivatives: Physicochemical, ADMT, drug-likeness, and DFT studies

The p-cymene and pyrazine derivatives functionalized with the hydroxy and methoxy group(s) were under the focus to explore the electronic structural properties, which would play a critical role in the biochemical reactivity features via performing systematic computational analyses. The DFT computations of the data set were performed by B3LYP/6-311 G* * level to predict the structural and electronic properties as well as the physicochemical values. The physicochemical properties such as lipophilicity and water solubility features were determined because these values should be in balance with each other in early-stage-drug-design research. The averaged lipophilicity of the p-cymene and pyrazine derivatives were calculated as CYM3 (2.39)< CYM1 (2.82)< CYM4 (3.11)< CYM2 (3.21)< CYM (3.50) and PYZ3 (1.22)< PYZ (1.28)< PYZ1 (1.40)< PYZ2 (1.79)< PYZ4 (2.00), respectively. According to the ESOL approach, the water solubility (mg/mL)x10-2 values of the p-cymene and pyrazine compounds were changed in the following orders of CYM3 (15.6)> CYM4 (10.2)> CYM1 (7.40)>CYM2 (5.16)> CYM (3.12) and PYZ (512)> PYZ1 (170)> PYZ3 (166)> PYZ2 (118)> PYZ4 (77.3), respectively. The ADMT properties of the data set were dealt with in detail to estimate the structural advantage or disadvantage because the possible side effects on human-health and the environment have to be considered in designing the novel agent in addition to the possible potencies. All compounds would be promising agents in terms of the Caco-2 and MDCK penetration and Pgp-inhibition potencies. According to the IGC50, LC50FM, and LC50DM results, the p-cymene compounds could have lower (or no) risk than the glyphosate and pyrazine derivatives like being for BCF scores. The FMO analyses were performed to estimate the possible reactive region for nucleophilic or electrophilic attacks.

Combining digital imaging and quantum dots for analytical purposes

This review provides a critical assessment of the most recent advances in digital imaging (DI) methods, applied for the development of analytical methodologies combining quantum dots (QDs). The state-of-the-art, treatment of data, instrumental considerations, software, sensing approaches, and optimization of the resulting methods are reported. Applications of the technology for the analysis of food and beverages, biomedically relevant analytes, drugs, environmental samples and forensic samples are also discussed. These examples aim to highlight the advantages of DI over traditional instrumentation, that in combination with QDs represents a powerful option for low-cost and on-site analyses. Moreover, some of these DI methods have been explored in the context of green chemistry principles, demonstrating a sustainable approach to modern analytical challenges.

Disturbance of cellular calcium homeostasis plays a pivotal role in glyphosate-based herbicide-induced oxidative stress

Glyphosate-based herbicides (GBHs) are the most worldwide used pesticides. The wide application of GBHs contaminates the soil and, consequently, water and food resources reaching human consumption. GBHs induce oxidative stress in non-target organisms, leading to a pro-inflammatory and pro-apoptotic cellular status, promoting tissue dysfunction and, thus, metabolic and neurobehavioral changes. This review presents evidence of oxidative damage induced by GBHs and the mechanism of cell damage and health consequences. To summarize, exposure to GBHs may induce disorders in calcium homeostasis related to the activation of ion channels. Also, alterations in pathways related to redox state regulation must have a primordial role in oxidative stress caused by GBHs.

Derivation of water quality criteria for glyphosate and its formulations to protect aquatic life in China

Extensive use of the herbicide glyphosate leads to a high detection rate in the environment and potential risks to nontarget aquatic life. China ranks first globally in the production and consumption of glyphosate, but there are no glyphosate water quality criteria (WQCs) for protecting aquatic life. Here, data on the acute and chronic toxicity of glyphosate and glyphosate-based formulations (GBFs) to freshwater aquatic life were collected and screened. Significant differences in species sensitivity distributions (SSDs) and toxicity values for acute or chronic toxicity were found between glyphosate and GBFs. The hazardous concentrations for 5% of species (HC₅) of glyphosate or GBFs between native and nonnative species were different, and native species were found to be more sensitive to the toxicity of glyphosate. The acute and chronic WQCs derived with the SSD method for glyphosate based on the toxicity data for native species in China were 3.35 and 0.26 mg/L, respectively, and those found for GBFs were 0.21 and 0.005 mg/L, respectively. The WQCs in this study were quite different from those estimated using similar statistical extrapolation methods in other countries, which reflects the differences in species sensitivity to glyphosate toxicity in different regions. The hazard quotients (HQs) were calculated based on the WQCs and concentrations of glyphosate in some surface waters in China and indicated that glyphosate exhibits medium or high hazard risk in some samples of Tai Lake, surface water in Guiyang, fishpond water in Chongqing, rural drinking water, and surface water and reservoir water in Henan Province. The WQCs of glyphosate and GBFs have scientific significance for the exposure and pollution control of herbicide formulations and the protection of aquatic life in China.

Toxicological effects of active and inert ingredients of imazethapyr formulation Verosil® against Scenedesmus vacuolatus (Chlorophyta)

Imazethapyr, a selective systemic herbicide, is widely used in agriculture and it is frequently detected in water bodies close to application areas. Like other agrochemicals, imazethapyr is commercialized in formulations containing a mixture of additives that increase the effectiveness of the active ingredient. These complex mixtures may cause adverse effects on non-target primary producers, such as microalgae, when they reach freshwater bodies. The aim of this study was to assess the effects, separately, of the formulation Verosil^®, the formulation additives, and technical-grade imazethapyr, in the acidic form or as ammonium salt, on the microalga Scenedesmus vacuolatus (Chlorophyta). Verosil^®, formulation additives, and acid imazethapyr significantly inhibited the growth of S. vacuolatus (Verosil^® > formulation additives > acid imazethapyr) and caused morphological alterations from 2 mg L^-1, 4 mg L^-1, and 60 mg L^-1 onwards, respectively. Verosil^® and formulation additives caused the most adverse effect including membrane disorganization, cytoplasm contraction, cell wall thickening, thylakoidal membrane disaggregation, and starch granule accumulation. In addition, Verosil^® and formulation additives increased the chl a/chl b ratio, indicating possible alterations in photosystems as a stress response. The carotene/chl a ratio was also increased in microalgae exposed to both Verosil^® and formulation additives, suggesting an antioxidant response to these toxic compounds. All these results support the hypothesis that the formulation additives contribute significantly to the toxicity and alterations caused by the commercial formulation Verosil^® on S. vacuolatus.

Antioxidant activities and Allelopathic Potential of Chonemorpha splendens Chun et Tsiang Stem Methanol Extract

Finding agriculturally active compounds from nature or finding active lead compounds from natural products, artificial synthesis and structural modification are the main ways to create new agrochemical. In order to explore the agricultural activities of Chonemorpha splendens Chun et Tsiang (C. splendens), an important medicinal plant, the antioxidant activities and allelopathic potential were investigated. C. splendens was extracted with methanol, then, C. splendens methanol extract (CSME) were extracted with petroleum ether, chloroform, ethyl acetate and n-butanol. Reducing activity, lipid peroxidation, and the scavenging abilities for DPPH∙, O2-∙, HO∙, and H2O2 were also measured and allelopathic potentials were evaluated by bioassay method. GC-MS analysis revealed that esters were the main component (66.34%) of CSME, the total CSME flavonoid content was 313 mg g-1 (rutin equivalent). The chloroform phase of CSME was identified as stigmasterol by NMR for the first time. The DPPH• scavenging rate of CSME was 87%, with an IC50 value of 0.12 ± 0.02 mg mL-1, which was significantly difference from the positive control, trolox. Chloroform fraction showed the strongest inhibitory effect against Mimosa pudica (MP) seed germination at 1.0 mg mL-1 (100% inhibition), which was better than that of the chemical herbicide paraquat. In the seed growth experiment, systematic EC50 and the principal component analysis (PCA) were used to assess the allelopathic potential of extracts. The systematic EC50 values of Crotalaria pallida Ait. (CP), Bidens pilosa L. (BP) were significantly greater than MP. MP, Oryza sativa L. (OS) and Lactuca satiua L., (LS) inhibited all parameters. Our results would provide an idea for controlling weeds through allelopathy from C. splendens to reduce dependency on synthetic herbicides.