Synthesis and Photoactivated Toxicity of 2-Thiophenylfuranocoumarin Induce Midgut Damage and Apoptosis in Aedes aegypti Larvae

Photoactivated 9-methylacridine destroys midgut tissues of Aedes aegypti larvae by targeting ROS-mediated apoptosis in the mitochondrial pathway of midgut cells

An aromatic ring-containing compound with a wide range of biological activities, 9-methylacridine (AD-9-Me) is a precursor for the synthesis of various drugs. However, its photoactivation properties and mechanism of damage as a photo activator against Aedes aegypti are unknown. The toxic effects of AD-9-Me on Aedes aegypti mosquitoes were determined under light and non-light conditions. The results showed that the toxicity of AD-9-Me to mosquito larvae was significantly higher than that of the dark treatment after 24 h of light exposure; AD-9-Me was mainly distributed in the midgut of larvae, after 24 h of treatment, it can cause an increase in calcium ion concentration, reactive oxygen species (ROS) eruption and ROS accumulation by blocking the ROS elimination pathway in midgut cells. This in turn caused an increase in protein carbonyl and malondialdehyde (MDA) content, a decrease in mitochondrial membrane potential (MMP), a disruption of the barrier function of midgut tissues, a significant decrease in midgut weight and chitin content, which induced the up-regulation of AeDronc, AeCaspase8 and AeCaspase7 genes, leading to apoptotic cell death. In this study, we confirmed that AD-9-Me has photoactivation activity and mainly acts on the midgut of mosquito larvae, which can generate a large amount of ROS in the cells of the midgut and induce apoptosis to occur, resulting in the disruption of the function of the tissues of mosquito larvae, accelerating the death and delaying the development of the mosquito larvae.

Discovery of Pesticide Candidates from Natural Plant Products: Semisynthesis and Characterization of Andrographolide-Based Esters and Study of Their Pesticidal Properties and Toxicology

To explore the use of nonfood plant-derived secondary metabolites for plant protection, a series of ester derivatives for controlling the major migratory agricultural pests were obtained by structural modification of andrographolide, a labdane diterpenoid isolated from Andrographis paniculata. Compound Id showed good insecticidal activity against the fall armyworm Spodoptera frugiperda Smith. Compounds IIa (LC50: 0.382 mg/mL) and IIIc (LC50: 0.563 mg/mL), the acaricidal activities of which were, respectively, 13.1 and 8.9 times that of andrographolide (LC50: 4.996 mg/mL), exhibited strong acaricidal and control effects against Tetranychus cinnabarinus Boisduval. Against Aphis citricola Van der Goot, compounds IIIc and IVb displayed 3.9- and 3.7-fold pronounced aphicidal activity of andrographolide. Effects of compound Id on three protective enzymes (superoxide dismutase, peroxidase, and catalase) of S. frugiperda were also observed. The obvious differences of epidermal cuticle structures of mites treated with compound IIa were determined by scanning electron microscopy. Structure-activity relationships indicated that 14-ester derivatives of andrographolide showed potential insecticidal/acaricidal activities and can be further utilized as lead compounds.

Identification and potential application of key insecticidal metabolites in Tilia amurensis, a low-preference host of Hyphantria cunea

Developing effective insecticidal strategies is an important means of reducing the spread and host plant damage by Hyphantria cunea. In this study, key metabolites with insecticidal activity against H. cunea were screened by targeted metabolomics in Tilia amurensis, a low-preference host plant. Subsequently, the potential of key metabolites that could be used as botanical pesticides was evaluated. The results showed that coumarin was the key insecticidal metabolite of T. amurensis and had a significant insecticidal effect and weight inhibition effect on H. cunea larvae. Coumarin treatment significantly decreased the larval nutrient content and the gene expression of rate-limiting enzymes in the glycolytic pathway and tricarboxylic acid cycle. A significantly enhanced detoxification enzyme activity (CarE and GST), antioxidant oxidase activity (SOD and CAT), non-enzymatic antioxidant levels (GSH), and total antioxidant capacity were observed in coumarin-treated larvae. Coumarin treatment resulted in a significant increase in the expression levels of detoxification enzyme genes (CarE1, CarE2, CarE3, GST2, and GST3) and antioxidant oxidase genes (SOD1, CAT1, and CAT2) in H. cunea larvae. Coumarin treatment significantly increased the levels of MDA and H2O2 in larvae but did not cause pathological changes in the ultrastructure of the larval midgut. Coumarin solution sprayed directly or as a microcapsule suspension formulation with coumarin as the active ingredient had significant insecticidal activity against the H. cunea larvae. Overall, coumarin, a key anti-insect metabolite identified from T. amurensis, can significantly inhibit the growth and survival of H. cunea larvae and has the potential to be developed as a botanical pesticide.

Screening of low-toxic zinc oxide nanomaterials and study the apoptosis mechanism of NSC-34 cells

With the increasing application of ZnO nanomaterials (ZnO-NMts) in the biomedical field, it is crucial to assess their potential risks to humans and the environment. Therefore, this study aimed to screen for ZnO-NMts with low toxicity and establish safe exposure limits, and investigate their mechanisms of action. The study synthesized 0D ZnO nanoparticles (ZnO NPs) and 3D ZnO nanoflowers (ZnO Nfs) with different morphologies using a hydrothermal approach for comparative research. The ZnO-NMts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Mouse brain neuronal cells (NSC-34) were incubated with ZnO NMts for 6, 12, and 24 h, and the cell morphology was observed using TEM. The toxic effects of ZnO Nfs on NSC-34 cells were studied using CCK-8 cell viability detection, reactive oxygen species (ROS) measurement, caspase-3 activity detection, Annexin V-FITC/PI apoptosis assay, and mitochondrial membrane potential (Δφm) measurement. The results of the research showed that ZnO-NMts caused cytoplasmic vacuolization and nuclear pyknosis. After incubating cells with 12.5 µg mL-1 ZnO-NMts for 12 h, ZnO NRfs exhibited the least toxicity and ROS levels. Additionally, there was a significant increase in caspase-3 activity, depolarization of mitochondrial membrane potential (Δφm), and the highest rate of early apoptosis.This study successfully identified ZnO NRfs with the lowest toxicity and determined the safe exposure limit to be < 12.5 µg mL-1 (12 h). These findings will contribute to the clinical use of ZnO NRfs with low toxicity and provide a foundation for further research on their potential applications in brain disease treatment.

Deuterohemin-Ala-His-Thr-Val-Glu-Lys (DhHP-6) Mimicking Enzyme as Synergistic Antioxidant and Anti-Inflammatory Material for Periodontitis Therapy

Periodontitis is an inflammatory disease induced by plaque microorganisms. In the clinic, antibiotic assistant periodontal mechanical therapy is the most effective therapy for the treatment of periodontitis. However, the drug resistance of the antibiotics and the repeated coming and diminishing of the disorder of oxidation-reduction balance in the inflammatory tissue could not meet the high requirements for periodontic health control in long periods. Deuterohemin-ala-his-thr-val-glu-lys (DhHP-6) is a biomimetic oxidase-mimicking enzyme that simulates the reactive oxygen radical scavenger function of heme by synthesizing the new molecular material following the key structure and amino acid sequence of heme. In this article, we report the antioxidant and anti-inflammatory properties of DhHP-6 by building a inflammatory model for human gingival fibroblasts (HGFs) stimulated by lipolysaccharide (LPS) and its effects on periodontitis in Wistar rats. DhHP-6 reduced the oxidative stress of HGFs by increasing the amount of the reductase species of glutathione (GSH) and catalase (CAT) while decreasing the amount of oxidase species of malonaldehyde (MDA) and reactive oxygen species (ROS). DhHP-6 had a dose-dependent protective effect on alveolar bone absorption in rats with periodontitis, enhanced antioxidant capacity, and reduced inflammation. As determined by Micro-CT scanning, DhHP-6 reduced alveolar bone loss and improved the bone structure of the left maxillary first molar of rats. There were no obvious morphological and histological differences in the rat organs with or without DhHP-6 treatment. These results suggest that DhHP-6 can be used to treat periodontitis by increasing the expression levels of antioxidant enzymes and antioxidants in systemic and local tissues, thereby reducing levels of oxidation products and cyto-inflammatory factors. The synergistic antioxidant and anti-inflammatory effects of DhHP-6 suggest that there are promising applications of this biomimetic enzyme molecular material for the next generation of agents for periodontitis therapy.

Potential Biochemical Pesticide-Synthesis of Neofuranocoumarin and Inhibition the Proliferation of Spodoptera frugiperda Cells through Activating the Mitochondrial Pathway

Furanocoumarins, the secondary metabolites of plants, are considered to be natural insecticides and fungicides because they prevent the invasion of plant pathogenic microorganisms and the predation of herbivorous insects. In this study, novel 2-arylfuranocoumarin derivatives were designed to synthesize by condensation, esterification, bromination, and Wittig reaction. The results showed an excellent photosensitive activity of 2-thiophenylfuranocoumarin (I34). Cell Counting Kit-8 detected that I34 could inhibit the proliferation of Spodoptera frugiperda (Sf9) cells in a time- and concentration-dependent manner under ultraviolet A (UV-A) light for 3 min. The inverted microscope revealed that cells treated with I34 swelled, the membrane was ruptured, and apoptotic bodies appeared. The flow cytometry detected that I34 could induce apoptosis of Sf9 cells, increase the level of intracellular reactive oxygen species (ROS), decrease the mitochondrial membrane potential, and block cell cycle arrest in the G2/M phase. Transmission electron microscopy detected cell mitochondrial cristae damage, matrix degradation, and mitochondrial vacuolation. Further enzyme activity detection revealed that the enzyme activities of apoptosis-related proteins caspase-3 and caspase-9 increased significantly (p < 0.05). Finally, Western blotting analysis detected that the phosphorylation level of Akt and Bad and the expression of the apoptosis inhibitor protein Bcl-XL were inhibited, cleaved-PARP and P53 were increased, and cytochrome C was released from the mitochondria into the cytoplasm. Moreover, under UV-A irradiation, I34 promoted the increase in ROS in Sf9 cells, activated the mitochondrial apoptotic signal transduction pathway, and finally, inhibited cell proliferation. Thus, novel furanocoumarins exhibit a potential application prospect as a biochemical pesticide.

Light-induced activities of novel naphtho[1,8-ef]isoindole-7,8,10(9H)-trione and oxoisoaporphine derivatives towards mosquito larvae

Infected mosquitoes are significant vectors of dengue, yellow fever, chikungunya, zika and other pathogens. In the view of increasing resistance in mosquito larvae control, photoactivated insecticides is a promising approach by utilizing highly toxic singlet oxygen produced by photosensitizer through irradiation. However, the choice of photosensitizer for mosquito control is limited. Here, we report a novel series of naphtho[1,8-ef]isoindole-7,8,10(9H)-trione and oxoisoaporphines derivatives as excellent type II photosensitizers. Meanwhile, the light-dependent activities against permethrin-susceptible and permethrin-resistant strain of Aedes aegypti mosquito larvae of these compounds were evaluated. Among them, compound 7b was proved to be potential photodynamic insecticide due to its excellent phototoxicity, the LC₅₀ value was 0.19 μg mL^-1 under visible light irradiation. The irradiation-generated enhancement in the activity was more than 520-fold. This compound could be the potential candidate in the search for new photoactivated insecticide leads. Importantly, 7b has good fluorescence quantum yield (ϕ_F = 0.70), it can be used as a fluorescence indicator in mosquito larvae to observe uptake and morphology change.

Antidiabetic Function of Lactobacillus fermentum MF423-Fermented Rice Bran and Its Effect on Gut Microbiota Structure in Type 2 Diabetic Mice

Rice bran is an industrial byproduct that exerts several bioactivities despite its limited bioavailability. In this study, rice bran fermented with Lactobacillus fermentum MF423 (FLRB) had enhanced antidiabetic effects both in vitro and in vivo. FLRB could increase glucose consumption and decrease lipid accumulation in insulin resistant HepG2 cells. Eight weeks of FLRB treatment significantly reduced the levels of blood glucose and lipids and elevated antioxidant activity in type 2 diabetic mellitus (T2DM) mice. H&E staining revealed alleviation of overt lesions in the livers of FLRB-treated mice. Moreover, high-throughput sequencing showed notable variation in the composition of gut microbiota in FLRB-treated mice, especially for short-chain fatty acids (SCFAs)-producing bacteria such as Dubosiella and Lactobacillus. In conclusion, our results suggested that rice bran fermentation products can modulate the intestinal microbiota and improve T2DM-related biochemical abnormalities, so they can be applied as potential probiotics or dietary supplements.