The latest research progress on the prevention of storage pests by natural products: Species,mechanisms, and sources of inspiration

The quality of grains is influenced by storage pests, which are not only spoilers of stored grain, but also vectors of human and animal diseases. Chemical pesticides play an essential role in the cultivation and storage of cereals, however, due to the low degradability and residual toxicity of synthetic pesticides on the environment and non-target organisms, as well as the increasing resistance of target organisms to them, consideration should be given to the development of alternative pest control agents. Compounds isolated from natural sources have emerged as preferred targets for the development of novel insecticidal agents because of their eco-friendliness, safety, and effectiveness. In this review, we primarily focus on the natural product (NPs) control of storage pests. The effective monomer components of NPs and their anti-insect mechanisms were discussed, and natural sources of inspiration and models for insect repellents are described. This review aimed to provide guidelines for the exploitation and utilization of green and efficient natural insecticides.     

Evaluation of pesticide residue in grape juices and the effect of natural antioxidants on their degradation rate

Various studies have been drawn toward the beneficial properties of fruit juices because they have several components, such as phenols, vitamins, and flavonoids, with antioxidant effects. However, fruit juices can also contain residues of pesticides used as standard pest control methods in crops. Many of these pesticides are degraded through oxidative mechanisms, and their persistence in juices can be enhanced by antioxidants. This study covers the degradation of four pesticides, aldicarb, demeton-S-methyl, fenamiphos, and methiocarb, to their respective sulfoxide and sulfone in grape juices, water (pH 3.5) and water (pH 3.5) with quercetin (one of the most important flavonoids of grape) added in an attempt to establish whether the presence of antioxidants can affect the degradation rate of pesticides. For this purpose, a multiresidue method based on solid-phase extraction (SPE) was developed for the simultaneous determination of these pesticides and their metabolites in commercial juices. The extraction procedure was carried out in C₁₈ columns. The subsequent elution of pesticides was performed with dichloromethane prior to the determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS), using two precursor-product ion transitions. Average recoveries for all the pesticides studied were higher than 80%, with relative standard deviations lower than 15% in the concentration range 0.005–0.05 μg/mL, and the quantification limits achieved ranged from 0.1 to 4.6 μg/L. The results demonstrated that degradation was slower in fruit juices and aqueous solutions with quercetin than in water. Several commercial grape juices were also analyzed to establish the levels of these pesticides. Methiocarb, fenamiphos, and demeton-S-methyl were found at low levels in some samples.     

A Brief Overview of Potential Treatments for Viral Diseases Using Natural Plant Compounds: The Case of SARS-Cov

The COVID-19 pandemic, as well as the more general global increase in viral diseases, has led researchers to look to the plant kingdom as a potential source for antiviral compounds. Since ancient times, herbal medicines have been extensively applied in the treatment and prevention of various infectious diseases in different traditional systems. The purpose of this review is to highlight the potential antiviral activity of plant compounds as effective and reliable agents against viral infections, especially by viruses from the coronavirus group. Various antiviral mechanisms shown by crude plant extracts and plant-derived bioactive compounds are discussed. The understanding of the action mechanisms of complex plant extract and isolated plant-derived compounds will help pave the way towards the combat of this life-threatening disease. Further, molecular docking studies, in silico analyses of extracted compounds, and future prospects are included. The in vitro production of antiviral chemical compounds from plants using molecular pharming is also considered. Notably, hairy root cultures represent a promising and sustainable way to obtain a range of biologically active compounds that may be applied in the development of novel antiviral agents.     

Recent achievements on the agricultural applications of thioether derivatives: A 2010–2020 decade in review

Thioether derivatives, an important synthetic strategy in drug discovery, are acquiring more importance in plant protection field in recent years because of their broad spectrum of agricultural activities, such as antifungal, antibacterial, insecticidal, acaricidal, nematocidal, antiviral, herbicidal, and plant growth-regulating activity. Thioethers and their analogues have been an area of great interest in recent years. This review summarizes the structure and agricultural activities of the thioether derivatives as reported in the literature that mainly covers the past 10 years from 2010 to 2020 as well as may contribute to a better understanding of thioether derivatives as efficient agricultural agents and provide some ideas on the development of novel pesticides.     

Monitoring pesticide residues in Egyptian fruits and vegetables in 1995.

Organophosphorus, dithiocarbamates, and some synthetic pyrethroids pesticides, which are commonly used in Egypt for pest control, were monitored, as well as persistent organochlorines, which had been prohibited from use several years ago. Fruit and vegetable samples (397) were collected from 8 local markets and examined for 52 pesticides. Of all analyzed samples, 42.8% contained detectable residues, of which 1.76% exceeded their maximum residue limits (MRLs). The rates of contamination with the different pesticides were 0-86%. However, violation rates among contaminated products were very low, ranging from 0 to 4.6%. In general, organochlorine pesticide residues were not detected in most samples. Dithiocarbamate residues were found in 70.4% of 98 samples analyzed for dithiocarbamates, but only one grape sample had residues exceeding the MRL established by the Codex Committee on Pesticide Residues.     

金属纳米颗粒制备中的还原剂与修饰剂*

金属纳米颗粒由于其独特的光学、电学、化学性质以及各种潜在的应用价值,受到不少研究人员的广泛关注。实现金属纳米粒子尺寸、形貌可控,改善粒子分散性和稳定性,提高产率及纯度已成为具有挑战性的研究课题,不断发展和完善金属纳米粒子的合成方法则显得尤为重要。本文总结了目前制备金属纳米材料的几种化学方法：化学试剂还原法、电化学还原法、辐射还原法等,分类介绍了化学试剂还原法中常用的无机、有机还原剂,以及含氮、磷、羧基、巯基小分子有机化合物以及高分子聚合物等修饰剂并重点总结了其还原和修饰机理。     

Tyrosinase inhibition organic phase biosensor for triazinic and benzotriazinic pesticide analysis (part two)

Several triazine pesticides, such as atrazine, are much more soluble in several organic solvents, such as chloroform, than in water. Our recent research was aimed at analyzing this class of pesticides using tyrosinase OPEE (organic phase enzyme electrodes), exploiting their inhibiting action on the tyrosinase enzyme when operating in water-saturated chloroform medium. In this work we studied the response of a tyrosinase inhibition enzyme sensor to several triazinic (simazine, propazine, terbuthylazine) and benzotriazinic (azinphos-ethyl and azinphos-methyl) pesticides (LOD=0.5×10⁻⁹ mol l⁻¹). Recovery trials were also performed in vegetal matrixes (corn, barley, lentils). Lastly, the effect of the solvent (chloroform or water) on the inhibition process was investigated via Hill’s equation and the diffusion of analyte from the solvent to the enzyme membrane.     

Diatomaceous Earth for Arthropod Pest Control: Back to the Future

Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food security are pushing agriculture toward a more sustainable approach, and research is moving in this direction, looking for environmentally friendly alternatives to be adopted in Integrated Pest Management (IPM) protocols. In this regard, inert dusts, especially diatomaceous earths (DEs), hold a significant promise to prevent and control a wide range of arthropod pests. DEs are a type of naturally occurring soft siliceous sedimentary rock, consisting of the fossilized exoskeleton of unicellular algae, which are called diatoms. Mainly adopted for the control of stored product pests, DEs have found also their use against some household insects living in a dry environment, such as bed bugs, or insects of agricultural interest. In this article, we reported a comprehensive review of the use of DEs against different arthropod pest taxa, such as Acarina, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Ixodida, Lepidoptera, when applied either alone or in combination with other techniques. The mechanisms of action of DEs, their real-world applications, and challenges related to their adoption in IPM programs are critically reported.     

Characteristics and enantiomeric analysis of chiral pyrethroids

Pyrethroids are synthetic pesticides that originated from the modification of natural pyrethrins to improve their biological activity and stability. They are a family of chiral pesticides with a large number of stereoisomers. Enantiomers of synthetic pyretroids present different insecticidal activity, toxicity against aquatic invertebrates and persistence in the environment so the development of rapid and sensitive chiral methods for the determination of different enantiomers is necessary. Several techniques have been employed for this purpose including gas chromatography, high performance liquid chromatography or more recently capillary electrophoresis and sub or supercritical fluid chromatography. A general view on the different chiral separation methods applied to the analysis of pyrethroids and the most important information about these pesticides is provided in this review.     

Recent advances in biodegradable matrices for active ingredient release in crop protection: Towards attaining sustainability in agriculture

Climate changes, emerging species of plant pests, and deficits of clean water and arable land have made availability of food to the ever-increasing global population a challenge. Excessive use of synthetic pesticides to meet ever-increasing production needs has resulted in development of resistance in pest populations, as well as significant ecotoxicity, which has directly and indirectly impacted all life-forms on earth. To meet the goal of providing safe, sufficient, and high-quality food globally with minimal environmental impact, one strategy is to focus on targeted delivery of pesticides using eco-friendly and biodegradable carriers that are derived from naturally available materials. Herein, we discuss some of the recent approaches to use biodegradable matrices in crop protection, while exploring their design and efficiency. We summarize by discussing associated challenges with the existing approaches and future trends that can lead the world to more sustainable agricultural practices.     

Could Polyphenols Really Be a Good Radioprotective Strategy?

Currently, radiotherapy is one of the most effective strategies to treat cancer. However, deleterious toxicity against normal cells indicate for the need to selectively protect them. Reactive oxygen and nitrogen species reinforce ionizing radiation cytotoxicity, and compounds able to scavenge these species or enhance antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) should be properly investigated. Antioxidant plant-derived compounds, such as phenols and polyphenols, could represent a valuable alternative to synthetic compounds to be used as radio-protective agents. In fact, their dose-dependent antioxidant/pro-oxidant efficacy could provide a high degree of protection to normal tissues, with little or no protection to tumor cells. The present review provides an update of the current scientific knowledge of polyphenols in pure forms or in plant extracts with good evidence concerning their possible radiomodulating action. Indeed, with few exceptions, to date, the fragmentary data available mostly derive from in vitro studies, which do not find comfort in preclinical and/or clinical studies. On the contrary, when preclinical studies are reported, especially regarding the bioactivity of a plant extract, its chemical composition is not taken into account, avoiding any standardization and compromising data reproducibility.     

Recent Advances in the Synthesis and Biomedical Applications of Heterocyclic NO-Donors

Nitric oxide (NO) is a key signaling molecule that acts in various physiological processes such as cellular metabolism, vasodilation and transmission of nerve impulses. A wide number of vascular diseases as well as various immune and neurodegenerative disorders were found to be directly associated with a disruption of NO production in living organisms. These issues justify a constant search of novel NO-donors with improved pharmacokinetic profiles and prolonged action. In a series of known structural classes capable of NO release, heterocyclic NO-donors are of special importance due to their increased hydrolytic stability and low toxicity. It is no wonder that synthetic and biochemical investigations of heterocyclic NO-donors have emerged significantly in recent years. In this review, we summarized recent advances in the synthesis, reactivity and biomedical applications of promising heterocyclic NO-donors (furoxans, sydnone imines, pyridazine dioxides, azasydnones). The synthetic potential of each heterocyclic system along with biochemical mechanisms of action are emphasized.     

Insights into the synthesis and mechanism of green synthesized antimicrobial nanoparticles,answer to the multidrug resistance

Emergence of the multidrug resistant human pathogenic strains is posing a serious health challenge. Resistant strains carry mutations which help them to resist conventional drugs. Therefore, it is required to produce more effective agents that are able to degrade the resistant pathogenic bacterial strains. The antimicrobial properties of nanoparticles (NPs) by eco-friendly green synthetic methods have pulled attention everywhere owing to their exceptional properties and small particle size of 100 nm. NPs are considered to belong to a group of antimicrobial agents which have ability to go inside microbial cells and kill them. In this comprehensive review, we are discussing the green synthetic methods used for the synthesis of NPs targeting the microbes. Additionally, several characterization techniques of antimicrobial NPs are also discussed. Subsequently, various methods used for the analysis of antimicrobial activities and their mechanisms are also examined.     

Chemistry and Biology of the Enediyne Anticancer Antibiotics

Novel, biologically active substances from nature often provide excitement, stimulation, challenges, and opportunities for the scientific and medical communities. Experience and wisdom dictate investigation of their chemistry and pursuit of their chemical synthesis for more often than not, the rewards for both chemistry and medicine are great. The enediyne anticancer antibiotics are a rapidly emerging class of such compounds derived from bacterial sources. Combining unprecedented and highly unusual molecular architecture, phenomenal biological activities and fascinating modes of action, these DNA cleaving compounds burst onto the scene in the latter half of the 1980s when their structures became known, and they rapidly moved to center stage. Today the enediyne family includes the neocarzinostatin chromophore, the calicheamicins, the esperamicins, and the dynemicins, and soon the number of family members is certain to increase. These molecules elicited extensive research activities in chemical, biological, and biomedical circles and inspired the design of a number of novel molecular assemblies to probe and mimic their chemical and biological actions. A new body of synthetic technology and several novel synthetic strategies have already been devised to address the challenges posed by these molecules, and several new DNA cleaving agents have been designed and synthesized. This article summarizes the chemistry and biology of the enediynes and discusses mechanistic, synthetic, molecular design, and DNA cleavage aspects associated with the field.     

Mono‐ and Dinuclear Phosphorescent Rhenium(I) Complexes: Impact of Subcellular Localization on Anticancer Mechanisms

Elucidation of relationship among chemical structure, cellular uptake, localization, and biological activity of anticancer metal complexes is important for the understanding of their mechanisms of action. Organometallic rhenium(I) tricarbonyl compounds have emerged as potential multifunctional anticancer drug candidates that can integrate therapeutic and imaging capabilities in a single molecule. Herein, two mononuclear phosphorescent rhenium(I) complexes ( Re1 and Re2 ), along with their corresponding dinuclear complexes ( Re3 and Re4 ), were designed and synthesized as potent anticancer agents. The subcellular accumulation of Re1–Re4 was conveniently analyzed by confocal microscopy in situ in live cells by utilizing their intrinsic phosphorescence. We found that increased lipophilicity of the bidentate ligands could enhance their cellular uptake, leading to improved anticancer efficacy. The dinuclear complexes were more potent than the mononuclear counterparts. The molecular anticancer mechanisms of action evoked by Re3 and Re4 were explored in detail. Re3 with a lower lipophilicity localizes to lysosomes and induces caspase‐independent apoptosis, whereas Re4 with higher lipophilicity specially accumulates in mitochondria and induces caspase‐independent paraptosis in cancer cells. Our study demonstrates that subcellular localization is crucial for the anticancer mechanisms of these phosphorescent rhenium(I) complexes.     

Monitoring the effects of component structure and source on formulation stability and adjuvant activity of oil-in-water emulsions

Oil-in-water emulsions have shown promise as safe and effective adjuvant formulations for vaccines. In particular, formulations consisting of metabolizable oils such as shark-derived squalene and detergents such as egg phosphatidylcholine have been used to produce stable vaccine emulsion formulations. However, there is an emphasis in pharmaceutical regulatory bodies on using synthetic or plant-derived components from sustainable sources instead of animal-derived components. This study compares the physicochemical properties and biological efficacy of emulsions consisting of oil and detergent components from animal, plant, and synthetic sources. In particular, effects of component structure and source on emulsion stability and biological activity are examined. It is shown that oil-in-water emulsions using animal-derived components can be substituted with synthetic or plant-derived materials while still exhibiting satisfactory physicochemical and biological properties.     

Research progress of triazole derivatives in the discovery of agricultural chemicals

Triazole groups play an important role in the construction of agricultural bioactive molecules, often acting as linking units to organically graft different pharmacophore groups, so as to obtain efficient and broad-spectrum pesticide molecules. After decades of development, triazole derivatives have made remarkable achievements in the discovery of pesticides, especially the discovery of fungicides. In addition, highly effective triazole insecticides, herbicides, and anti-plant virus agents have also been found, and commercial triazole pesticides have occupied a large market share. At present, the study of triazole compounds has become one of the important fields in the development of new pesticides. We systematically reviewed the application of triazole derivatives in the discovery of new pesticides since 2010, summarized the antifungal, antibacterial, insecticidal, herbicidal, and anti-plant virus activities of triazole derivatives, and discussed the structure–activity relationship and mechanism of action in order to provide inspiration and ideas for the discovery of new triazole agrochemicals.     

Selenium Nanomaterials to Combat Antimicrobial Resistance

The rise of antimicrobial resistance to antibiotics (AMR) as a healthcare crisis has led to a tremendous social and economic impact, whose damage poses a significant threat to future generations. Current treatments either are less effective or result in further acquired resistance. At the same time, several new antimicrobial discovery approaches are expensive, slow, and relatively poorly equipped for translation into the clinical world. Therefore, the use of nanomaterials is presented as a suitable solution. In particular, this review discusses selenium nanoparticles (SeNPs) as one of the most promising therapeutic agents based in the nanoscale to treat infections effectively. This work summarizes the latest advances in the synthesis of SeNPs and their progress as antimicrobial agents using traditional and biogenic approaches. While physiochemical methods produce consistent nanostructures, along with shortened processing procedures and potential for functionalization of designs, green or biogenic synthesis represents a quick, inexpensive, efficient, and eco-friendly approach with more promise for tunability and versatility. In the end, the clinical translation of SeNPs faces various obstacles, including uncertain in vivo safety profiles and mechanisms of action and unclear regulatory frameworks. Nonetheless, the promise possessed by these metalloid nanostructures, along with other nanoparticles in treating bacterial infections and slowing down the AMR crisis, are worth exploring.     

Application of artificial neural networks to the determination of pesticides by linear sweep stripping voltammetry

In this work, artificial neural network (ANN), a powerful chemometrics approach for linear and nonlinear calibration models, was applied to detect three pesticides in mixtures by linear sweep stripping voltammetry (LSSV) despite their overlapped voltammograms. Electrochemical parameters for the voltammetry, such as scan rate, deposit time and deposit potential, were evaluated and optimized from the signal response data using ANN model by minimizing the relative prediction error (RPE). The proposed method was successfully applied to the detection of pesticides in synthetic samples and several commercial fruit samples.     

Nanomaterial Based Biosensors for Detection of Biomarkers of Exposure to OP Pesticides and Nerve Agents: A Review

Organophosphorus (OP) pesticides are primarily used as insecticides and chemical warfare agents worldwide. Due to their impact on the environment and health, it is important to develop prompt and accurate pesticide analysis method. This review addresses recent advances and new trends in nanotechnology‐based biosensors for biological monitoring of exposures to OP pesticides and nerve agents. In order to determine them, we have to find the corresponding biomarkers. In 1989, the national academy of sciences (NAS)divided biomarkers into the following three categories: biomarker of exposure, biomarker of effect and biomarker of susceptibility (Figure 1A). The unique chemical and physical properties of nanomaterial have paved the way to new and improved sensing devices, in general, and electrochemical/optical biosensors, in particular. In this paper, background information and a general overview of electrochemical/immunoassay detection techniques are provided. Various nanomaterial labels are discussed. Usually nanomaterials can be roughly divided into nanometer powder, nanometer fiber, nanometer film, nanometer block and so on four classes, such as colloidal gold, semiconductor nanoparticles and carbon nanomaterial (Figure 1B). In addition, we discuss some future considerations and opportunities for advancing the use of biosensors for environmental and health studies.