Residue and dissipation kinetics of toosendanin in cabbage, tobacco and soil using IC-ELISA detection

Rational hapten design, monoclonal antibody preparation, and immunoassays development for rapid detection of fomesafen in agricultural products and soil

Fomesafen is a diphenyl ether herbicide, and the residues in soil or agricultural products caused by its misused not only affect the yield and quality of sensitive crops, but also pose a threat to human health through the food chain. In order to achieve rapid and sensitive detection of fomesafen in situ, this study redesigned and synthesized two new haptens based on previous work, and obtained three monoclonal antibodies (mAbs). Indirect competitive ELISA (ic-ELISA) and lateral flow immunoassay (LFIA) methods were established based on heterologous haptens for fomesafen detection. The IC50 value and linear range for ic-ELISA were 1.56 ± 0.24 ng/mL and 0.08-28.86 ng/mL, respectively. The sensitivity of ic-ELISA developed in this study increased by nearly 25 times compared to our previous work. Meanwhile, the visual limit of detection (vLOD) of LFIA was 2.5 ng/mL with the cutoff value of 16.0 ng/mL. This study is of great significance for achieving rapid on-site detection of fomesafen in agricultural products, soil, and other environmental matrices.

Nanoporous 3D Polyurethane for Toosendanin Adsorption, Encapsulation, and High-Efficient Utilization

Nanoporous 3D-polyurethane (3D-PU) was prepared based on nano-CaCO3 templated controllably confined polymerization assembly and weak acid etching strategies. Nanopores with diameters ranging from 48 to 72 nm were distributed on 3D-PU, facilitating its high BET surface area of 468.0 m2/g. The 3D-PU exhibited enhanced adsorption selectivity to multi-H-bond donors and acceptors, multirings contained compounds based on pore filling, hydrogen-bonding, and π-π interactions; therefore, the novel 3D-PU had promising adsorption ability to toosendanin (TSN) with a maximum theoretical adsorption capacity of 361.6 mg/g. Adsorption isotherm, kinetic, and thermodynamic investigations revealed that the adsorption was heterogeneous and was supported by multiple adsorption sites, controlled by a chemical adsorption mechanism, endothermic, spontaneous, and with increased entropy. Based on the optimized adsorption, the loading capacity (LC) of 3D-PU toward TSN attained 23.4%. After encapsulation, the effective period of TSN was extended to 11 days, the photolysis half-life of TSN was increased 3.2 times, and the LC50 for Aphis citricola was reduced approximately 6.0 times, indicating that 3D-PU effectively improved the performance of TSN. The porous 3D-PU can serve as a promising carrier for more pesticide adsorption, encapsulation, safe, highly efficient, and environmentally friendly utilization.

A flexible 3D ordered SERS sensor for rapid and reliable detection of pesticide residues in fruits

We fabricated flexible, three-dimensional (3D) ordered silicon nanowire (SiNW) arrays decorated with high-density silver nanoparticles (AgNPs) for the sensitive and reproducible detection of pesticide residues. These sensors demonstrated a detection limit of 10-9 M for methyl parathion (MPT) on curved surfaces.

Monospecific, ultrasensitive, and quantitative lateral flow immunoassay for dibutyl phthalate via epitopes rational design strategies

Due to the characteristics of long-term persistence, leading to extensive temporal and spatial distribution of the environmental pollutant dibutyl phthalate (DBP), analyzing of a large number of food and environment samples over a long period and at a high frequency must be necessary. It is of great significance to construct a simple, rapid, sensitive and high-throughput immunoassay method. For the first time, 8 different DBP hapten molecules were designed using computer simulation to provide DBP epitope informations from both conformation and electrostatic aspects for the target molecule. This approach helped to establish a reasonable hapten design strategy while reducing the cost and increasing the success rate of producing the required high-specificity and high-sensitivity DBP antibodies. Hapten DBP-1 was proposed, and the effectiveness of computer-aided hapten DBP-1 design was further verified by mouse antiserum experiments. A highly-specific monoclonal antibody (mAb) against DBP with an IC50 value of 19.8 ng/mL was obtained by mAb screening with enhanced matrix effect. A colloidal gold immunochromatographic test strip (CIS) which can be used to detect DBP in environmental, food and human urine samples was further prepared, and the DBP content in positive samples such as water, soil, and liquor samples could be rapidly analyzed within 15 min, which were basically consistent with the data by Gas Chromatography-Mass Spectrometry (GC-MS). In summary, our study proposed a detection method that can be directly used to detect DBP in environmental water, soil, liquor and human urine samples, which is ready for application in environmental monitoring, food safety control and clinical use.

Harnessing natural inhibitors of protein synthesis for cancer therapy: A comprehensive review

Cancer treatment remains a formidable challenge in modern medicine, necessitating a nuanced understanding of its molecular underpinnings and the identification of novel therapeutic modalities. Among the intricate web of cellular pathways implicated in oncogenesis, protein synthesis has emerged as a fundamental process warranting meticulous investigation. This review elucidates the multifaceted role of protein synthesis pathways in tumor initiation and progression, highlighting the potential of targeting key nodes within these pathways as viable therapeutic strategies. Natural products have long served as a source of bioactive compounds with therapeutic potential owing to their structural diversity and evolutionary honing. Within this framework, we provide a thorough examination of natural inhibitors of protein synthesis as promising candidates for cancer therapy, drawing upon recent advancements and mechanistic insights. By synthesizing current evidence and elucidating key challenges and opportunities, this review aims to galvanize further research into the development of natural product-based anticancer therapeutics, thereby advancing the clinical armamentarium against malignancies.

Rosmarinic acid alleviates toosendanin-induced liver injury through restoration of autophagic flux and lysosomal function by activating JAK2/STAT3/CTSC pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rosmarinic acid (RA), a natural polyphenol abundant in numerous herbal remedies, has been attracting growing interest owing to its exceptional ability to protect the liver. Toosendanin (TSN), a prominent bioactive compound derived from Melia toosendan Siebold & Zucc., boasts diverse pharmacological properties. Nevertheless, TSN possesses remarkable hepatotoxicity. Intriguingly, the potential of RA to counteract TSN-induced liver damage and its probable mechanisms remain unexplored.

AIM OF THE STUDY

This study is aimed at exploring whether RA can alleviate TSN-induced liver injury and the potential mechanisms involved autophagy.

MATERIALS AND METHODS

CCK-8 and LDH leakage rate assay were used to evaluate cytotoxicity. Balb/c mice were intraperitoneally administered TSN (20 mg/kg) for 24 h after pretreatment with RA (0, 40, 80 mg/kg) by gavage for 5 days. The autophagic proteins P62 and LC3B expressions were detected using western blot and immunohistochemistry. RFP-GFP-LC3B and transmission electron microscopy were applied to observe the accumulation levels of autophagosomes and autolysosomes. LysoTracker Red and DQ-BSA staining were used to evaluate the lysosomal acidity and degradation ability respectively. Western blot, immunohistochemistry and immunofluorescence staining were employed to measure the expressions of JAK2/STAT3/CTSC pathway proteins. Dual-luciferase reporter gene was used to measure the transcriptional activity of CTSC and RT-PCR was used to detect its mRNA level. H&E staining and serum biochemical assay were employed to determine the degree of damage to the liver.

RESULTS

TSN-induced damage to hepatocytes and livers was significantly alleviated by RA. RA markedly diminished the autophagic flux blockade and lysosomal dysfunction caused by TSN. Mechanically, RA alleviated TSN-induced down-regulation of CTSC by activating JAK2/STAT3 signaling pathway.

CONCLUSION

RA could protect against TSN-induced liver injury by activating the JAK2/STAT3/CTSC pathway-mediated autophagy and lysosomal function.

Establishment of Indirect Competitive Enzyme-linked Immunosorbent Assay (ic-ELISA) for Copper ion (Cu2+) in Raw Meat Products

Adding an appropriate amount of copper to feed can promote the growth and development of livestock; however, a large amount of heavy metal copper can accumulate in livestock through the enrichment effect, which poses a serious threat to human health. Traditional Cu2+ detection relies heavily on complex and expensive instruments, such as inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS); thus, convenient and simple rapid detection technologies are urgently needed. In this paper, synthesized copper antigens were used to immunize mice and highly specific anticopper monoclonal antibodies were obtained, which were verified to exhibit high affinity and specificity. Based on the above antibodies, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for the rapid detection of copper content in pork. The standard inhibition curve of the method was obtained by antigen-antibody working concentration screening, in which the half inhibitory concentration (IC50) was 11.888 ng/mL, the limit of detection (LOD) was 0.841 ng/mL and the correlation coefficient R2 of the curve was 0.998. In the additive recovery experiment, the recovery rate ranged from 90% to 110%, and the coefficient of variation (CV) was less than 10%, indicating that the method achieved high accuracy and precision. Finally, the results of ic-ELISA combined with Bland-Altman analysis showed a high correlation with ICP-MS, and the correlation coefficient (R2) reached 0.990 when the copper concentration was less than 200 ng/mL. Thus, the ic-ELISA method exhibits high reliability.

Integration of Metallic Nanomaterials and Recognition Elements for the Specifically Monitoring of Pesticides in Electrochemical Sensing

Although all countries have been controlling the excessive use of pesticides, incidents of pesticide residues still existed. Electrochemical biosensors are extensively applied detection techniques to monitor pesticides with the help of different types of biorecognition components mainly including, antibodies, aptamers, enzymes (i.e., acetylcholinesterase, organophosphorus hydrolase, etc.), and synthetic molecularly imprinted polymers. Besides, the electrode materials mainly affected the sensitivity of electrochemical biosensors. Metallic nanomaterials with various structures and excellent electrical conductivity were desirable choice to construct electrochemical platforms to achieve the detection with high sensitivity and good specificity toward the target. This work reviewed the developed metallic materials including monometallic nanoparticles, bimetallic nanomaterials, metal atoms, metal oxides, metal molybdates, metal-organic frameworks, MXene, etc. Integration of recognition elements endowed the electrode materials with higher specificity toward the target pesticide. Besides, future challenges of metallic nanomaterials-based electrochemical biosensors for the detection of pesticides are also discussed and described.

Highly selective monoclonal antibody-based fluorescence immunochromatographic assay for the detection of fenpropathrin in vegetable and fruit samples

Fenpropathrin (FPT) is a typical pyrethroid pesticide that can cause chronic toxicity to humans. Herein, an anti-FPT monoclonal antibody (mAb) was elicited via a novel hapten synthesized by introducing a carboxyl-containing spacer arm in the cyclopropane moiety of FPT. Characterized by enzyme-linked immunosorbent assay (ELISA), the mAb exhibited high affinity and selectivity to FPT with a half-maximal inhibitory concentration of 31.05 μg/L and negligible cross-reactivities with analogs of pyrethroids. Based on the mAb, a fluorescence immunochromatographic assay (FICA) for FPT detection was firstly developed. The detection limit of the FICA is 0.012 mg/kg which is much lower than the maximum residue limit of FPT for food samples. The average recoveries of FPT from spiked food samples by the FICA were 85.0-105.0%, and the obtained results were in good agreement with those of gas chromatography-tandem mass spectrometry. Overall, this work provided a reliable tool suitable for the detection of FPT residue for large-scale samples in a rapid and cost-effective manner.

Comparison of Chemiluminescence Enzyme Immunoassay (Cl-ELISA) with Colorimetric Enzyme Immunoassay (Co-ELISA) for Imidacloprid Detection in Vegetables

Imidacloprid is one of the most commonly used insecticides for managing pests, thus, improving the quality and yield of vegetables. The abuse/misuse of imidacloprid contaminates the environment and threatens human health. To reduce the risk, a colorimetric enzyme-linked immunoassay assay (Co-ELISA) and chemiluminescence enzyme-linked immunoassay assay (Cl-ELISA) were established to detect imidacloprid residues in vegetables. The linear range of Co-ELISA ranged between 1.56 μg/L and 200 μg/L with a limit of detection (LOD) of 1.56 μg/L. The values for Cl-ELISA were 0.19 μg/L to 25 μg/L with an LOD of 0.19 μg/L, which are lower than those of Co-ELISA. Fortifying Chinese cabbage, cucumber, and zucchini with imidacloprid at 10, 50, and 100 μg/L yielded recoveries between 81.7 and 117.6% for Co-ELISA and at 5, 10, and 20 µg/L yielded recoveries range from 69.7 to 120.6% for Cl-ELISA. These results indicate that Cl-ELISA has a high sensitivity and a rapid detection time, saving cost (antigen and antibody concentrations) and serving as a more efficient model for the rapid detection of imidacloprid residue.

Modeling pesticide residues in tobacco leaves for improving life cycle inventory analysis of pesticides in the cigarette industry

To promote pesticide management in tobacco products, we conducted a life cycle inventory (LCI) analysis by simulating pesticide residues in tobacco leaves during tobacco farming, manufacturing, and product use stages in the cigarette industry. For the tobacco farming stage, the bioaccumulation-potential analysis of pesticide residues in fresh tobacco leaves indicated that lipophilicity and degradation half-life in soil were two significant factors determining residue mass in leaves. For the manufacturing stage, the persistence analysis of pesticide residues in processed tobacco leaves revealed that pesticides with high volatility or high degradability in plant tissues had small processing factors. For the product use stage, exposure and toxicity assessment of pesticide residues were conducted for tobacco consumed via smoking, which generated characterization factors linking pesticides to impacting human health. According to the LCI analysis, we quantitatively showed that pesticides with low lipophilicity, high degradability, and high volatility limited consumers' exposure to residues via smoking.

Insecticidal Triterpenes in Meliaceae: Plant Species, Molecules, and Activities: Part II (Cipadessa, Melia)

Plant-originated triterpenes are important insecticidal molecules. Research on the insecticidal activity of molecules from Meliaceae plants has always been a hotspot due to the molecules from this family showing a variety of insecticidal activities with diverse mechanisms of action. In this paper, we discussed 116 triterpenoid molecules with insecticidal activity from 22 plant species of five genera (Cipadessa, Entandrophragma, Guarea, Khaya, and Melia) in Meliaceae. In these genera, the insecticidal activities of plants from Entandrophragma and Melia have attracted substantial research attention in recent years. Specifically, the insecticidal activities of plants from Melia have been systemically studied for several decades. In total, the 116 insecticidal chemicals consisted of 34 ring-intact limonoids, 31 ring-seco limonoids, 48 rearranged limonoids, and 3 tetracyclic triterpenes. Furthermore, the 34 ring-intact limonoids included 29 trichilin-class chemicals, 3 azadirone-class chemicals, and 1 cedrelone-class and 1 havanensin-class limonoid. The 31 ring-seco limonoids consisted of 16 C-seco group chemicals, 8 B,D-seco group chemicals, 4 A,B-seco group chemicals, and 3 D-seco group chemicals. Furthermore, among the 48 rearranged limonoids, 46 were 2,30-linkage group chemicals and 2 were 10,11-linkage group chemicals. Specifically, the 46 chemicals belonging to the 2,30-linkage group could be subdivided into 24 mexicanolide-class chemicals and 22 phragmalin-class chemicals. Additionally, the three tetracyclic triterpenes were three protolimonoids. To sum up, 80 chemicals isolated from 19 plant species exhibited antifeedant activity toward 14 insect species; 18 chemicals isolated from 17 plant species exhibited poisonous activity toward 10 insect species; 16 chemicals isolated from 11 plant species possessed growth-regulatory activity toward 8 insect species. In particular, toosendanin was the most effective antifeedant and insect growth-regulatory agent. The antifeedant activity of toosendanin was significant. Owing to its high effect, toosendanin has been commercially applied. Three other molecules, 1,3-dicinnamoyl-11-hydroxymeliacarpin, 1-cinnamoyl-3-methacryl-11-hydroxymeliacarpin, and 1-cinnamoyl-3-acetyl-11-hydroxymeliacarpin, isolated from Meliaazedarach, exhibited a highly poisonous effect on Spodoptera littoralis; thus, they deserve further attention.

Extraction and determination of flubendiamide insecticide in food samples: A review

Flubendiamide (FBD) is the first commercially available phthalic acid diamide that targets ryanodine receptors (RyRs) in insects, which play a major role in lepidoptera control. However, excessive use of FBD can influence the quality of treated products leading to toxic effects on human health. The availability of rapid and convenient methods for evaluating FBD amount in the environment is necessary. Therefore, analytical methods were developed for the determination of residues of FBD and its metabolite desiodo in different food matrices like tomato, cabbage, pigeon pea, apple, chilli and rice. The current review carries forward methods for FBD residues analysis in foods by using several chromatographic techniques including sample preparation steps. The comparison between the different methods employed for quantitative and qualitative analysis of food quality and safety is also discussed. Liquid chromatography (LC) is the predominant analytical method for assessing the quality of foods treated with FBD. Studies related to LC coupled multichannel detector (Ultraviolet (UV), Mass spectrometry (MS)) are also applied to detect pesticide residues. Extraction and clean up steps are essential to obtain reliable results. Moreover, this review reports the allowed limits of residues for the safety of consuming products treated with FBD.

Toosendanin and isotoosendanin suppress triple-negative breast cancer growth via inducing necrosis, apoptosis and autophagy

Toosendanin (TSN) and isotoosendanin (ITSN) are two natural triterpenoids isolated from Fructus Meliae Toosendan or Cortex Meliae. This study aims to observe the inhibition of TSN and ITSN on the growth of triple-negative breast cancer (TNBC) and the preliminary engaged mechanism. Cell viability assay showed that both TSN and ITSN had obvious cytotoxicity in a variety of tumor cells, and they had the best inhibitory effect on TNBC cells including MDA-MB-231, BT549 and 4T1. Propidium iodide (PI) staining results showed the increased number of necrotic MDA-MB-231 and 4T1 cells induced by TSN (20 nM) and ITSN (2.5 μM). Annexin V-FITC and PI double-staining results showed that TSN (20 nM) and ITSN (2.5 μM) induced cell apoptosis in both MDA-MB-231 and 4T1 cells. Moreover, TSN (20 nM) and ITSN (2.5 μM) induced the cleavage of pro-caspase-3 and pro-caspase-9, and decreased the expression of anti-apoptotic Bcl-xL in both MDA-MB-231 and 4T1 cells. Results from scanning electron microscope observation and detecting the expression of microtubule-associated protein 1 light chain 3B (LC3B) and Beclin 1 evidenced that TSN (20 nM) and ITSN (2.5 μM) induced autophagy in both MDA-MB-231 and 4T1 cells. TSN and ITSN decreased 4T1 xenograft tumor growth without inflicting toxicity on vital organs in mice. Collectively, this study shows that natural compound TSN and ITSN suppress TNBC growth via inducing necrosis, apoptosis and autophagy. TSN and ITSN could be promising drugs for TNBC treatment.

A Sensitive Liquid Chromatography-Mass Spectrometry Method for Determination of Toosendanin in Rat Plasma and its Application to Pharmacokinetic Study

A simple, rapid and sensitive analytical method was developed for the determination of toosendanin in rat plasma using liquid chromatography tandem mass spectrometry (LC-MS/MS). Andrographolide was selected as the internal standard, and the plasma samples were extracted by liquid-liquid extraction with diethyl ether. Chromatographic separation was performed on a Dikma Spursil C18, 3.5 μm (150 × 2.1 mm i.d) analytical column with 85% methanol:water (v/v) containing 0.025% formic acid (pH = 3.9) as mobile phase. The flow rate was 0.25 mL/min, and the total run time was 3 min. Detection was performed with a triple-quadrupole tandem mass spectrometer using negative ion mode electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. The MS/MS ion transitions monitored were m/z 573.1 → 531.1 and 349.0 → 287.0 for toosendanin and andrographolide, respectively. Good linearity was observed over the concentration range of 3.125-500 ng/mL in 100 μL of rat plasma with a correlation coefficient ˃0.9997. Intra- and inter-assay variabilities were ˂8.5% in plasma. The recovery and the matrix effect were in the range 71.8-73.5% and 96.4-103.8%, respectively. The analyte was stable under various conditions (at room temperature, during freeze-thaw settings, in the autosampler, and under deep-freeze conditions). The method was successfully applied to a pharmacokinetic study of toosendanin after its oral administration in rats at a dose of 10 mg/kg.

Gold-based immunochromatographic assay strip for the detection of quinclorac in foods

In this study, a highly specific and sensitive monoclonal antibody (mAb) against quinclorac (Qui) was prepared. Based on the selected mAb, 2G3, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were established for the detection of Qui in actual samples. The 50%-inhibitory concentration of mAb 2G3 against Qui was 48.763 ng mL^-1. No cross-reaction with other quinolines indicated that mAb 2G3 had high specificity. The recovery of the established ic-ELISA method was in the range of 85.6% to 98.9%. The cut-off value of Qui in cucumber and tomato by immunochromatographic strip was 200 ng g^-1. The analysis results of ic-ELISA and immunochromatographic strip assay were consistent with the results of LC-MS/MS, which further proved that the established ic-ELISA and immunochromatographic strip assay could provide valuable tools for the rapid detection of Qui residues in cucumber and tomato samples.

Development of an Immunoassay for the Detection of Copper Residues in Pork Tissues

The presence of high concentrations of copper (Cu) residues in pork is highly concerning and therefore, this study was designed to develop a high-throughput immunoassay for the detection of such residues in edible pork tissues. The Cu content in the pork samples after digestion with HNO₃ and H₂O₂ was measured using a monoclonal antibody (mAb) against a Cu (II)–ethylenediaminetetraacetic acid (EDTA) complex. The resulting solution was neutralized using NaOH at pH 7 and the free metal ions in the solution were chelated with EDTA for the immunoassay detection. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method was developed for Cu ion analysis. The half maximal inhibitory concentration of the mAb against Cu (II)–EDTA was 5.36 ng/mL, the linear detection range varied between 1.30 and 27.0 ng/mL, the limit of detection (LOD) was 0.43 μg/kg, and the limit of quantification (LOQ) was 1.42 μg/kg. The performances of the immunoassay were evaluated using fortified pig serum, liver, and pork samples and had a recovery rate of 94.53–102.24%. Importantly, the proposed immunoassay was compared with inductively coupled plasma mass spectroscopy (ICP-MS) to measure its performance. The detection correlation coefficients of the three types of samples (serum, pork, and liver) were 0.967, 0.976, and 0.983, respectively. Thirty pork samples and six pig liver samples were collected from local markets and Cu was detected with the proposed ic-ELISA. The Cu content was found to be 37.31~85.36 μg/kg in pork samples and 1.04–1.9 mg/kg in liver samples. Furthermore, we detected the Cu content in pigs with feed supplemented with tribasic copper chloride (TBCC) and copper sulfate (CS) (60, 110, and 210 mg/kg in feed). There was no significant difference in Cu accumulation in pork tissues between the TBCC and CS groups, while a remarkable Cu accumulation was found for the CS group in liver at 210 mg/kg, representing more than a two-fold higher level than seen in the TBCC group. Therefore, the proposed immunoassay was found to be robust and sensitive for the detection of Cu, providing a cost effective and practical tool for its detection in food and other complicated samples.