Research Publications (Food Safety)

Thionins are important antibacterial peptides in plants. However, the roles of plant thionins, especially the defensin-dissimilar thionins, in alleviating heavy-metal toxicity and accumulation remain unclear.

To replace biohazardous nematicides, there is an ever-increasing need to identify natural product-based agents to contain root-knot nematodes (RKNs) in agriculture. In this chemical ecology study, an antagonistic fungus Aspergillus fumigatus 1T-2, which could cause the formation of withering of the gut and vacuole-like structures in the nematode body, was isolated based on the gradually increased antagonistic interactions between the soil fungi and RKNs.

Synthetic pesticides are often associated with issues such as pest resistance, persistent residue, nontarget toxicity, and environmental issues. Therefore, the research and development of novel, safe, and effective pesticides has become a focus in pesticide discovery. Monoterpenes are secondary plant metabolites that commonly have multiple action targets and have been used in aromatherapy, alternative medicine, and food industries. Some are highly potent and stereoselective.

As our further research, a series of new 7-chloro-9-methyl-2-phenyl-3,4-dihydro-β-carbolin-2-iums were designed and synthesized. Twelve compounds were found with excellent inhibition activity in vitro on three to five out of six phytopathogenic fungi, superior to standard drugs thiabendazole and/or azoxystrobin. Especially, 18 displayed the highest activity against three out of the fungi and the highest comprehensive activity for all of the fungi.

Over the years, scaffold hopping has proven to be a powerful tool in the agrochemical optimization process. It offers the opportunity to modify known molecular lead structures to improve a range of parameters, including biological efficacy and spectrum, physicochemical properties, toxicity, stability, and to secure new intellectual property.

Pyruvate kinase (PK) has been considered as a promising fungicide target discovered in our previous studies. Natural compounds are important sources for discovery and development of new pesticides. To continue our ongoing studies on the discovery of novel PK-targeted fungicides, a series of novel psoralen derivatives including a 1,3,4-oxadiazole moiety were designed by a computer-aided pesticide molecular design method, synthesized, and evaluated for their fungicidal activity.

Trimethylamine N-oxide (TMAO) is a pro-atherosclerotic product of dietary choline metabolism generated by a microbiome–host axis. The first step in this pathway is the enzymatic metabolism of choline to trimethylamine (TMA) by the gut microbiota. This reaction could be targeted to reduce atherosclerosis risk.

In response to the invasion of plant viruses and pathogenic fungi, higher plants produce defensive allelochemicals. Finding candidate varieties of botanical pesticides based on allelochemicals is one of the important ways to create efficient and green pesticides. Here, a series of camalexin derivatives based on a phytoalexin camalexin scaffold were designed, synthesized, and assessed for their antiviral and fungicidal activities systematically.

Laccase is a novel target for fungicides. We previously developed a new fungicide, 4-chlorocinnamaldehyde thiosemicarbazide (PMDD-5Y), as a laccase inhibitor. The introduction of active groups of natural products into the framework of a pesticide molecular structure is an effective method for discovering active lead compounds, and it has applications in the discovery of new pesticides.

Pyruvate kinase (PK) was discovered as a potent new target for novel fungicide development. A series of novel triazolothiadiazine derivatives were rationally designed and synthesized by a ring expansion strategy and computer-aided pesticide design using the 3D structure of Rhizoctonia solani PK (RsPK) obtained by homology modeling as a receptor and our previously discovered lead YZK-C22 as a ligand.

Up to now, a total of 24 succinate dehydrogenase inhibitors (SDHIs) fungicides have been commercialized, and SDHIs fungicides were also one of the most active fungicides developed in recent years. Carboxamide derivatives represented an important class of SDHIs with broad spectrum of antifungal activities. In this review, the development of carboxamide derivatives as SDHIs with great significances were summarized.

Protoporphyrinogen oxidase (PPO, EC 1.3.3.4) is an important target for discovering novel herbicides, and it causes bleaching symptoms by inhibiting the synthesis of chlorophyll and heme. In this study, the active fragments of several commercial herbicides were joined by substructure splicing and bioisosterism, and a series of novel diphenyl ether derivatives containing five-membered heterocycles were synthesized.

To improve the insecticidal activity of (+)-nootkatone, a series of 42 (+)-nootkatone thioethers containing 1,3,4-oxadiazole/thiadiazole moieties were prepared to evaluate their insecticidal activities against Mythimna separata Walker, Myzus persicae Sulzer, and Plutella xylostella Linnaeus.

A total of 52 novel 1,2,4-triazole thioether and thiazolo[3,2-b]-1,2,4-triazole derivatives bearing the 6-fluoroquinazolinyl moiety were designed, synthesized, and evaluated as antimicrobial agents in agriculture based on the molecular hybridization strategy. Among them, molecular structures of compounds 5g and 6m were further confirmed via the single-crystal X-ray diffraction method.

Catalytic asymmetric synthesis has become an essential tool for the enantioselective synthesis of pharmaceuticals, natural products, and agrochemicals (mainly fungicides, herbicides, insecticides, and pheromones).

A key objective for herbicide research is to develop new compounds with improved bioactivity. Protoporphyrinogen IX oxidase (PPO) is an essential target for herbicide discovery. Here, we report using an in silico structure-guided optimization approach of our previous lead compound 1 and designed and synthesized a new series of compounds 2–6.

A series of unreported novel dithioacetal derivatives containing a 4(3H)-quinazolinone pyrimidine ring were synthesized, and their antiviral activities were evaluated against tomato spotted wilt virus (TSWV). A three-dimensional quantitative structure–activity relationship (3D-QSAR) analysis was established, and compound D32 was designed and synthesized according to the analysis results of the CoMFA and CoMSIA models.

The development of antiviral agents with an original structure and noticeable effect is always in great need. Natural products are important lead compounds in the development of new pesticides. Crocin-1 and crocin-2 were effectively isolated from Gardeniae fructus and found to have higher anti-tobacco mosaic virus (TMV) activity levels than ribavirin.

In this study, limonin derivatives were used to design new anti-inflammatory compounds with high pharmacological activity and low toxicity. A total of 23 new limonin derivatives were discovered, synthesized, and screened for their anti-inflammatory activity against lipopolysaccharide (LPS)-treated RAW 264.7 cells. Of them, compound f4 was found to be the most active, with a higher efficiency compared with limonin and celecoxib.

Rubusoside (Rub) is a highly sweet diterpene glycoside mainly isolated from the leaves of Rubus suavissimus (Rosaceae). It has been used as a low-calorie natural sweetener for decades and was recently found to be a potential drug lead. In this study, we designed a whole-cell biocatalyst to achieve the glycosylation of steviol to Rub in Saccharomyces cerevisiae.

Tomato spotted wilt virus (TSWV) is a plant virus with strong infectivity and destructive power. Given the lack of effective control agents, TSWV causes significant economic damage to several vegetables and ornamental plants worldwide. In this study, we designed and synthesized a series of novel quinazolinone derivatives containing a dithioacetal moiety and evaluated their antiviral activity in vitro and in vivo against TSWV. Some candidate compounds showed good anti-TSWV activity.

Enlightened from our previous work of structural simplification of quinine and innovative application of natural products against phytopathogenic fungi, lead structure 2,8-bis(trifluoromethyl)-4-quinolinol (3) was selected to be a candidate and its diversified design, synthesis, and antifungal evaluation were carried out.

The correlation of in vitro and in vivo assays for determining bioavailable Cd amounts in vegetables is limited. Herein, the correlations between Cd relative bioavailability (Cd-RBA) in rat models and Cd bioaccessibility in four in vitro assays were examined in vegetables. Results showed that the combined liver plus kidney data provided the appropriate endpoint and was used as a biomarker to estimate Cd-RBA.

Dietary flavonoids are known to have anti-inflammatory and anticancer effects, but their influences on human macrophage migration inhibitory factor (MIF), a vital proinflammatory cytokine recognized as a therapeutic target for infectious diseases and cancers, have been rarely reported.

Lead (Pb) is a common toxic heavy metal pollutant in the environment that seriously endangers the health of animals. The liver is a key target organ affected by Pb toxicity. Plant extracts allicin and quercetin have a strong antioxidant capacity that can promote the excretion of heavy metals by improving the body’s antioxidant defense and chelating heavy metal ions.