Biopesticides

Science Paper | Engineering | 2024Read Original Full Article at sciencedirect Executive Brief This review explores vanillin — a GRAS food additive widely used in baked goods, confectionery and infant formula — as a low-cost, inherently safe starting material for green pesticide development. With a price of USD 3–4/kg, vanillin’s simple structure featuring a reactive hydroxyl and aldehyde group enables efficient synthesis of antiviral and antibacterial derivatives via ether bond formation, thioacetalisation and reductive amination. Pioneering work by Song et al. has delivered compounds like vanisulfane with superior activity against plant viruses such as PVY, CMV, ToCV and TSWV, often outperforming commercial benchmarks like ribavirin and ningnanmycin. These derivatives primarily act as plant immune activators, boosting defensive enzymes (POD, PAL, SOD, CAT), ROS accumulation and SA/ABA signalling pathways, whilst some directly bind viral coat or nucleocapsid proteins to disrupt replication and assembly. Biosafety studies confirm rapid degradation and low mammalian toxicity, positioning vanillin-derived pesticides as a promising path for sustainable crop protection. Keywords: Vanillin Pesticides, Green Pesticides, Plant Immune Activator, Vanisulfane, Antiviral Derivatives, Thioacetalisation, Biosafety. Technical Intelligence 1. Core Technology / Process Vanillin structural advantages: Hydroxyl group (–OH): Under basic conditions, forms a nucleophilic anion that reacts with electrophiles (alkyl halides) to create ether linkages, enabling splicing of bioactive moieties like thienopyrimidine, coumarin or mesoionic structures. Aldehyde group: Highly versatile for imine formation (reductive amination), thioacetalisation (with mercaptans) or β-cyclodextrin-SO3H catalysed annulation to imidazopyridin-3-amines. Synthesis strategies: Two-step thioacetalisation (vanisulfane): Vanillin → etherified vanillin → thioacetal with ZrCl4 catalyst. Click chemistry for glycoside derivatives: Azide-functionalised glucose + vanillin alkyne → 1,2,3-triazole → thioacetalisation or deacetylation. Multi-step for mesoionic: Quinazoline ring closure → hydroxymethylation → chlorination → etherification → thioacetalisation. Catalytic innovations: ZrCl4 for chemoselective thioacetalisation (protects hydroxyl). NaHSO4·SiO2 as economical ZrCl4 alternative. 2. Key Ingredients / Specifications Lead compound: Vanisulfane (3a / "xiangcaoliusuobingmi"): Broad-spectrum antiviral against PVY, CMV, PMMoV, ToCV and TSWV. EC50 superior to ribavirin, NNM and dufulin. Strobilurin hybrids (7b): β-methoxyacrylate replaces 4-chlorophenyl in vanisulfane; improved activity against PVY, CMV and TMV. Glycoside derivatives (13c): Glucopyranoside via click chemistry; best anti-ToCV activity (EC50 < NNM/COS); Kd 0.12 μmol·L⁻¹ to ToCV-CP (vs NNM 0.26 μmol·L⁻¹). Quinazolinone derivatives (18c): EC50 188 μg·mL⁻¹ vs TSWV; superior to ribavirin (642 μg·mL⁻¹), vanisulfane (420 μg·mL⁻¹), NNM (257 μg·mL⁻¹). Mesoionic pyridopyrimidinone derivatives: 28d: EC50 10.9 μg·mL⁻¹ (Xoo), 17.5 μg·mL⁻¹ (Xac); protective efficacy 43.9% (BLB), 41.7% (BLS). 3. Performance Data Compound Target EC50 / Activity Comparison Vanisulfane PVY/CMV Superior to ribavirin/NNM/dufulin Protective: 59.4% vs PMMoV (COS: 36.9%) 7b PVY/CMV/TMV Improved vs vanisulfane - 13c ToCV Superior to NNM/COS/ribavirin Kd 0.12 μmol·L-1 to ToCV-CP 18c TSWV 188 μg·mL-1 Ribavirin: 642 μg·mL-1 28d Xoo/Xac 10.9/17.5 μg·mL-1 Bismerthiazol: 29.3/39.8 μg·mL-1 Enzyme activation: Vanisulfane boosts POD, PAL, SOD, CAT; upregulates ROS, ABA; downregulates SA repressor ABR1. Gene/protein: Increases UspA, DEAD-box RNA helicase, POD52, APX, PR-1. Binding affinity: 13d Kd 0.12 μmol·L⁻¹ (ToCV-CP); 29 Kd 10.22 μmol·L⁻¹ (TSWV-N). 4. Market / Sustainability Cost/safety: USD 3–4/kg; FDA GRAS status (used in infant formula). Degradation: Rapid hydrolysis accelerated by Cu2+ and fulvic acid; forms thioether cleavage, reverse thioacetalisation, ether cleavage, demethylation, dehydration products. Metabolism (rats): 83.30%–87.51% excreted in 24h (urine/feces); liver/kidney accumulation; gender differences (males prefer biliary excretion); 8 metabolites identified via 14C labelling + LC–QTOF–MS. Perspective: Aldehyde modification (aldol, Perkin, asymmetric catalysis). Insecticide/herbicide pharmacophores (2-chlorothiazole, cyano, pyrimidinedione). Solid chemistry (polymorphs, cocrystals, salts) for bioavailability. Target identification (activity-based protein profiling, co-IP, Y2H). Entity & Keyword Index Category Items Lead Compounds Vanisulfane (3a); 7b; 13c; 18c; 28d Targets PVY, CMV, PMMoV, ToCV, TSWV, Xoo, Xac, BLB, BLS Mechanisms Immune activation (ROS, SA/ABA pathways); CP/N-protein binding Catalysts ZrCl4, NaHSO4·SiO2, CuSO4·5H2O/ascorbate Techniques MST, RT-qPCR, Western blot, proteomics, LC–QTOF–MS Disclaimer This content is an independent analysis and structured summary of publicly available industry news, prepared solely for professional research, information exchange and educational purposes. It does not constitute endorsement, promotion or recommendation of any product, company, brand or technology mentioned herein. All technical data, structures, mechanisms and bioassay results cited herein are extracted from the original article as published and have not been independently verified by us. Readers are advised to consult the original source for authoritative information. Copyright of the original article by iScience. 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