BACKGROUND:Natural products and their synthetic derivatives are notable sources for discovering new lead compounds of herbicides. Terpene natural product (3E)-4, 8-dimethyl-1, 3, 7-nontriene (DMNT) has been proven to be able to repel and kill the insects, whereas its other bioactivities have rarely been studied. RESULTS:In this study, we focus on the herbicidal activity of DMNT and its derivatives. A series of oxygen- or nitrogen-containing DMNT allyl derivatives were designed and synthesized as novel herbicide candidates. They were characterized by 1H NMR, 13C NMR and HRMS spectral analysis. Compared to DMNT, the herbicidal activities of its derivatives were generally enhanced against monocotyledonous (Echinochloa crus-galli, Lolium perenne L.) and dicotyledonous weeds (Portulaca oleracea L., Abutilon theophrasti Medicus). Particularly, the DMNT hydroxylation product (DMNT-OH, 2) completely inhibited the germination of E. crus-galli at 300 mg/L in the Petri dish assay, and also showed good herbicidal activity against the growth of weeds in the greenhouse test. Furthermore, it exhibited excellent crop safety for peanuts, wheat, rice and maize even at a dosage up to 2000 g/hm2. Ultimately, to further demonstrate the structural specificity and superior activity of DMNT-OH, its herbicidal activity was comparatively analyzed with geraniol and geranial. CONCLUSION:These findings suggested that the herbicidal activity of DMNT significantly enhanced after structural modification, and DMNT-OH has great potential as environmentally-friendly herbicide candidate for further development. This study lays the basis for the exploration of DMNT as a botanical herbicide. © 2026 Society of Chemical Industry.

A novel solid‐state melt rearrangement reaction from primary amides and PhI(OAc) 2 without any solvents in reactive eutectic medium was established. Compared with traditional solvent‐involved or high‐temperature solid‐state reactions, this reaction features lower temperature, shorter time, and higher efficiency. Especially for the aliphatic diamides and PhI(OAc) 2 , they could easily form a reactive eutectic mixture and undergo double Hofmann‐type rearrangement reactions, giving the diamine diacetylated products in high yields. Notably, the products can be easily isolated through a direct precipitation–filtration method.

ABSTRACT Two new C-glycoside angucycline-related analogs, urdamycin Y (1) and grincamycin W (2), as well as eight known metabolites (3–10), were identified from termite-associated Streptomyces lannensis BYF-106 based on global natural products social molecular networking (GNPS). The putative biosynthetic pathways of urdamycin Y (1) and grincamycin W (2) were proposed using bioinformatic analysis of the full genome of S. lannensis BYF-106. In addition, four new derivative compounds (4A, 5A, 6A, and 6B) were synthesized via acetylation and methylation, respectively. Partial compounds were evaluated in vitro for antibacterial, anti-inflammatory, and cytotoxic activities. Vineomycinone B2 (3), fridamycin D (4), and 6-hydroxytetrangulol (5) displayed broad-spectrum antibacterial activities against S. aureus, methicillin-resistant S. aureus, and P. syringae pv. actinidae. Furthermore, urdamycin Y (1) exhibited potent inhibition on NO production, with an IC50 value of 4.8 µM, which was comparable to that of Bay11-7082 with an IC50 value of 2.1 µM. Subsequently, the possible anti-inflammatory mechanism of urdamycin Y (1) was explored by molecular docking simulation. Finally, most of the tested metabolites showed significant cytotoxic activities against HCT-116, HT-29, and A375. Notably, 6-hydroxytetrangulol (5) and the acetyl derivative 5A showed extremely strong cytotoxic activities against HCT-116, with IC50 values of 9.8 and 2.2 µM, respectively. Moreover, 5A showed extremely strong cytotoxic activity against A375 (IC50 <0.2 µM), and the conceivable cytotoxic activity mechanism was also proposed by molecular docking. These findings indicated metabolites of insect-associated S. lannensis BYF-106 might be a potential source for developing new bioactive drugs in food, agriculture, and biomedical fields.IMPORTANCEFrequent attention to soil microorganisms has led to the rediscovery of known compounds. By contrast, insect-associated Streptomyces have been shown to produce a more diverse array of unique bioactive secondary metabolites compared to soil Streptomyces. In our ongoing effort to explore structurally diverse bioactive natural products from termite-associated Streptomyces, we discovered that the strain S. lannensis BYF-106 exhibited potent bioactivity. Chemical investigation of BYF-106 resulted in the isolation of two new C-glycoside angucycline-related analogs: urdamycin Y (1) and grincamycin W (2). In addition, four new derivative compounds (4A, 5A, 6A, and 6B) were synthesized through acetylation and methylation, respectively. Urdamycin Y (1) exhibited a strong inhibitory effect on NO production, and most of the tested metabolites showed significant cytotoxic activity. These findings indicate that the metabolites of BYF-106 may offer promising avenues for the exploration and development of new bioactive drugs.

Selective hydrogenation of plant oils is an important step in the production of oleochemicals. In this work, a new protocol for photoinduced selective hydrogenation of methyl eleostearates under aqueous conditions has been reported. Using palladium supported on porous graphitic carbon nitride (Pd/pg-C3N4) as a heterogeneous catalyst, formic acid as a hydrogen donor instead of potentially dangerous hydrogen gas, and water as a solvent, methyl eleostearates could be selectively transformed into monounsaturated fatty acid methyl esters (C18:1), which show a high selectivity of >90% under room temperature. The excellent selectivity is attributed to the synergistic effects of the Pd nanoparticles with pg-C3N4. Subsequently, dimethyl 1,19-nonadecanedioate (C19 alpha,omega-diesters) was prepared by isomerizing alkoxycarbonylation of the synthesized C18:1 product. The purity of the C19 alpha,omega-diester monomer is calculated to be higher than 96%, which is critical for the production of polymeric materials.

Objective: The aim of this research is to synthesize and evaluate beta-amyloid (A beta) binding probes for early diagnosis of Alzheimer's disease (AD). Methods: We designed and synthesized two new fluorine tag Indanone derivatives (compounds a and b), and then based on the platform of ultra-high-performance liquid chromatography-mass spectrometry for its affinity with beta-amyloid (A beta) protein determination, and use of compounds a and b solution as dyes for AD brain tissue staining in vitro. To evaluate the lipid solubility and stability of the drug, the lipid-water partition coefficient was determined using n-octanol as the lipid phase, and the stability of compound b was tested in vitro to mimic the in vivo environment. Results: Both compounds a and b exhibit high affinity for binding to A beta. The Kd values of compound a for A beta 1-40 and A beta 1-42 were found to be 467.40 +/- 63.26, and 227.57 +/- 19.08 nmol/L, respectively. Similarly, the Kd values of compound b for A beta 1-40 and A beta 1-42 were 438.13 +/- 26.77 and 167.27 +/- 23.70 nmol/L, respectively. In the staining experiment of human brain slices of AD, both compounds a and b were found to bind to A beta plaques, and their staining effect was stronger than positive control (0.1 % ThS). In the lipid-water partition coefficient experiment, compound a and compound b exhibited logP values of 0.84 and 1.85, respectively, indicating good lipid solubility. In the in vitro stability experiment, compound b exhibited a concentration of 74.79 %, 80.47 %, and 70.00 % after incubation in liver, brain homogenate, and blood, respectively. Conclusion: We have successfully designed and synthesized two probes labeled with fluoride that can be used for diagnosing AD. These probes have a high affinity for A beta protein and good lipid solubility. As A contrast agent based on A beta protein, compound b showed greater potential than compound a.

HOAc-promoted construction of chroman-4-ones with a sulfur atom and an α-carbonyl quaternary carbon center directly from ortho-hydroxyacetophenones and DMSO is described. In these unique reactions, DMSO is activated by HOAc and provides three different units (CH2, CH2OH, and CH2SMe) in the target molecules. This reaction displays good substrate scope and reaction yields with a series of substitutes. The mechanism showed that the three units were formed in sequential order.

BACKGROUND Insect-associated Streptomyces is a valuable resource for development of compounds with antibacterial potential. However, relatively little is known of the secondary metabolites produced by termite-associated Streptomyces. RESULTS Here, seven compounds including o-acetaminophenol (1), phenazine-1,6-dicarboxylic acid (2), phenylacetic acid (3), phenazinolin D (4), izumiphenazine A (5), izumiphenazine B (6) and phenazinolin E (7) were obtained from the fermentation broth of a termite-associated Streptomyces showdoensis BYF17, which was isolated from the body surfaces of Odontotermes formosanus. Two additional novel derivative compounds (6a and 6b) were synthesized via acetylation and methylation, respectively. The structures of these compounds were elucidated by spectroscopic analyses. The antibacterial bioassay showed that compound 6a displayed strong inhibitory effects against Pseudomonas syringae pv. actinidiae (Psa), with the diameter of inhibition zone (ZOI) value of 20.6 mm, which was comparable to that of positive gentamicin sulfate with the ZOI value of 25.6 mm. Furthermore, the 5th-day curative activities of both compounds 6 and 6a against kiwifruit bacterial canker were 71.5%, which were higher than those of referred oxine-copper (55.0%) and ethylicin (46.8%) at the concentration of 200 μg/mL. In addition, the mechanism analysis based on a scanning electron microscope revealed that both compounds 6 and 6a destroyed the integrity of the Psa cells membrane. CONCLUSION The results of biological tests showed that these bioactive compounds exhibit potent antimicrobial activities, which have the potential to be developed into new antibacterial agents. This article is protected by copyright. All rights reserved.

Background: Alzheimer's disease (AD) is one of the most common causes of dementia, affecting many old people. Objectives: By designing and synthesizing intracerebral imaging probes, we try to provide a new solution for early diagnosis of AD. Methods: We designed and synthesized bis-iodine-labeled curcumin, and verified its performance through in vivo and in vitro experiments. Results: In this study, bis-iodine-labeled curcumin (7, BICUR) was synthesized. In the in vitro mass spectrum binding assay, Kd values of BICUR with Aβ1-40 and Aβ1-42 aggregates were 46.29 nM and 64.29 nM, respectively. Aβ plaques in AD brain adjacent sections were positively stained by BICUR, which was similar to some other curcumin derivatives. The LogP value of BICUR was 1.45. In the biodistribution experiment, BICUR showed the highest initial brain uptake (5.87% compared with the blood concentration) two minutes after the tail vein injection and rapid clearance from the mouse brain. In the acute toxicity experiment, BICUR showed low toxicity, and the LD50 was > 100 mg/kg. Moreover, BICUR showed a high stability in vitro (86.68% unchanged BICUR after incubation for 120 min in mouse brain homogenate). Besides, BICUR produced an enhanced CT imaging effect that could be sensitively detected in vitro, but it also showed an obvious differentiation from surrounding tissues after intracerebral injection. Conclusion: All results suggested that BICUR could probably act as a targeted CT imaging agent for Aβ plaques in the brain.

BACKGROUNDPlant secondary metabolites and their modified derivatives play an important role in the discovery and development of novel insecticides. The natural plant product (3E)-4,8-dimethyl-1,3,7-nontriene (DMNT) has been proven to be able to effectively repel and kill the lepidopteran insect pest Plutella xylostella. RESULTSIn this study, four oxygenated derivatives of DMNT were synthesized by allylic hydroxylation and subsequent etherification or esterification. Bioassays on P. xylostella larvae showed that the compounds DMNT-OCH3 (2), DMNT-OCy (3) and DMNT-OAc (4) were more toxic to the larvae than DMNT alone. The most pronounced effect was observed for compound 2, which showed a 22.23% increase in lethality at a concentration of 0.25 mu m. Moreover, the peritrophic matrix (PM) barrier in the insect midgut was more severely damaged by compounds 2, 3 and 4 than by DMNT. The median lethal concentration (LC50, 48 h) of compounds 2, 3 and 4 on P. xylostella was determined to be 0.98, 1.13 and 1.11 mg mL(-1), respectively, which is much lower than the commercial insecticides eucalyptol (2.89 mg mL(-1)) and thymol (2.45 mg mL(-1)). CONCLUSIONThese results suggested that oxygenated DMNT derivatives offer a significantly improved killing effect over DMNT on P. xylostella. This work has provided a basis for further design, structural modification and development of DMNT as botanical insecticides. (c) 2023 Society of Chemical Industry.

The design of functional monomers and their functional polymer materials from renewable biomass is gaining more and more attention. This work describes a simple and efficient method to synthesis multi-functional monomers derived from castor oil (Ricinus communis L). Methyl undecylenate was used as starting materials to synthesize epoxy methyl undecylenate monomer via double-bonded epoxidation, and subsequent ammonia ring opening reaction were conducted subsequently to obtain long-chain multi-functional monomer. The prepared multi-functional monomer was applied to design functional polymers by melt polycondensation. For self-condensation, the hydroxyl and secondary amine group of the multi-functional monomer can react with the ester group to form cross-linked polyamide, which possess elastic recovery of up to 97 % after five cycles of stretching. When the multi-functional monomer was copolymerized with 1, 6-hexamethylenediamine, functional polyamide with tensile strength of 43 MPa and elongation at break of 265 % was obtained.

The lepidopteran crop pest Plutella xylostella causes severe constraints on Brassica cultivation. Here, we report a novel role for RPX1 (resistance to P. xylostella) in resistance to this pest in Arabidopsis thaliana. The rpx1-1 mutant repels P. xylostella larvae, and feeding on the rpx1-1 mutant severely damages the peritrophic matrix structure in the midgut of the larvae, thereby negatively affecting larval growth and pupation. This resistance results from the accumulation of defence compounds, including the homoterpene (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), due to the upregulation of PENTACYCLIC TRITERPENE SYNTHASE 1 (PEN1), which encodes a key DMNT biosynthetic enzyme. P. xylostella infestation and wounding induce RPX1 protein degradation, which may confer a rapid response to insect infestation. RPX1 inactivation and PEN1 overexpression are not associated with negative trade-offs for plant growth but have much higher seed production than the wild-type in the presence of P. xylostella infestation. This study offers a new strategy for plant molecular breeding against P. xylostella.

In order to realize the early diagnosis of Alzheimer's disease (AD), we designed and synthesized a series of multi-fluorine labeled indanone derivatives based on indanone which could target β-amyloid (Aβ). Through the in vitro staining experiment and affinity experiment, we selected 7d out, and then evaluated it through other in vivo and in vitro experiments. The staining of AD human brain adjacent sections revealed that compound 7d could bind to Aβ plaques with high affinity. In the in vitro binding assay, 7d showed a balanced affinity with Aβ1-40 (Kd = 367 ± 13) and Aβ1-42 (Kd = 384 ± 56). Also, 7d exhibited a low toxicity (LD50 > 50 mg/kg) and an excellent ability to pass through the blood-brain barrier (Log p = 3.87). The biodistribution experiment in mice showed that 7d reached the highest brain uptake after 1 h of tail vein injection and cleared after 24 h. A low concentration of 7d (1.875 mg/ml) showed a strong imaging ability (19F-weighted mode), and the imaging capability increased with the increasing of concentration. All the results showed that 7d could provide a feasible solution for the early diagnosis of AD under non-radioactive condition.

Insect-associated Actinobacteria are a potentially rich source of novel natural products with antibacterial activity. Here, the community composition of Actinobacteria associated with Apis mellifera ligustica was investigated by integrated culture-dependent and independent methods. A total of 61 strains of Streptomyces genera were isolated from the honeycomb, larva, and different anatomical parts of the honeybee’s body using the culture-dependent method. Amplicon sequencing analyses revealed that the actinobacterial communities were dominated by the family of Bifidobacteriaceae and Microbacteriaceae in the honeybee gut, and Nocardiaceae and Pseudonocardiaceae in the honeycomb, whereas only Streptomyces genera were isolated by the culture-dependent method. Culture-independent analyses showed more diverse actinobacterial communities than those of culture-dependent methods. The antibacterial bioassay showed that most crude extracts of representative isolates exhibited antibacterial activities. Among them, the crude extract of Streptomyces sp. FCF01 showed the best antibacterial activities against Staphylococcus aureus, Micrococcus tetragenus, and Pseudomonas syringae pv. actinidiae (Psa) with the disc diameter of inhibition zone diameter (IZD) of 23.00, 15.00, and 13.33 mm, respectively. Chemical analysis of Streptomyces sp. FCF01 led to the isolation of three secondary metabolites, including mayamycin (1), mayamycin B (2), and N-(2-Hydroxyphenyl) acetamide (3). Among them, compound 1 displayed strong antibacterial activity against S. aureus, M. tetragenus, and Psa with minimum inhibitory concentrations (MIC) values of 6.25, 12.5, and 6.25 μg/ml, respectively. In addition, two novel derivative compounds 1a and 1b were synthesized by acetylation of compound 1. Both compounds 1a and 1b displayed similar antibacterial activities with those of metabolite 1. These results indicated that Streptomyces species associated with honeybees had great potential in finding antibiotics.

Substrate-induced synthesis of 6H-Chromeno[4,3-b]quinolin-6-ones has been developed directly from anilines, 4-hydroxycoumarins and DMSO under air without any catalysts and additives in one pot. This protocol highlights dual roles of 4-hydroxycoumarins which were not only used as reactants but also activated DMSO to provide one-carbon unit in the desired products.

A metal-free and oxidant-free acid-promoted DMSO activation and subsequent reaction is reported. In this protocol, two molecules of DMSO are activated by HOAc and serve as dual synthons which react with ortho-hydroxyacetophenones, affording 3-(methylthiomethyl)chroman-4-ones in moderate to good yields with high selectivity.

A metal-free direct synthesis of pyrimidines from amidine hydrochlorides, ketones and DMSO through substrate-induced DMSO activation and subsequent reactions has been developed. In this protocol, amidine hydrochlorides were not only used as reactants but also activated DMSO to form a sulfenium ion intermediate which then participated in the reactions.

建立基于质谱的受体结合分析方法 (MSBA),测定小分子探针与淀粉样蛋白-β(Aβ)聚集体的亲和力.针对阳性探针IMPY及其氘代产物IMPY-D6建立液相色谱-质谱(LC-MS)联用方法 和定量方法 ,随后进行基于质谱的饱和结合实验及竞争结合实验,最后将结果 与文献中放射性受体结合实验结果 进行比较.成功建立了IMPY的LC-MS方法 及基于质谱的受体结合测定方法 .其中,饱和结合实验中IM-PY与Aβ1-40及Aβ1-42的Kd分别为(3.80±0.39)nmol/L和(18.38±1.11)nmol/L.竞争结合实验中IMPY与Aβ1-40及Aβ1-42的Ki分别为(18.64±0.76)nmol/L和(25.44±2.38)nmol/L.均与文献中放射性受体结合实验结果 基本一致.MSBA作为一种非放射性结合实验方法 ,测定结果 与放射性受体结合实验基本一致,可用于小分子探针与Aβ的亲和力的测定,该技术平台可拓展至用于常规小分子配体与受体亲和力的测定.

We describe a method to test the preference of insects in response to (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT). We use a device that includes a horizontal glass tube, two grooves (with activated carbon), air flow, rubber stoppers/tubes, transparent glass containers (optional), and a holder for the glass tube (optional). Equal amounts of activated carbon in the groove (removable) are placed at both ends to avoid air contamination. The air flow is generated by an air pump. In the closed device, different samples are placed at each end of the glass tube. The air pump at the top of the glass tube forms an air flow that converges to the middle site of the glass tube. In each test, insect larvae are located in the middle of the glass test tube. If the test samples release DMNT that can be sensed by insects, the insects will selectively move to one specific end of the glass tube. The number of insects that move to each end will be recorded for further studies. This method can also be used to test the preference of insects in response to other volatile compounds.

Insect pests negatively affect crop quality and yield; identifying new methods to protect crops against insects therefore has important agricultural applications. Our analysis of transgenic Arabidopsis thaliana plants showed that overexpression of pentacyclic triterpene synthase 1, encoding the key biosynthetic enzyme for the natural plant product (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), led to a significant resistance against a major insect pest, Plutella xylostella. DMNT treatment severely damaged the peritrophic matrix (PM), a physical barrier isolating food and pathogens from the midgut wall cells. DMNT repressed the expression of PxMucin in midgut cells, and knocking down PxMucin resulted in PM rupture and P. xylostella death. A 16S RNA survey revealed that DMNT significantly disrupted midgut microbiota populations and that midgut microbes were essential for DMNT-induced killing. Therefore, we propose that the midgut microbiota assists DMNT in killing P. xylostella. These findings may provide a novel approach for plant protection against P. xylostella.