Biological activity evaluation and action mechanism of 1,4-Pentadien-3-one derivatives containing thiophene sulfonate

Novel 1,3,4-oxadiazole sulfonate/carboxylate flavonoid derivatives: synthesis and biological activity

BACKGROUND

With the long-term use of traditional bactericides and antiviral agents, drug resistance has become increasingly prominent, resulting in impaired crop growth and yields. Based on this, the introduction of small molecular active groups into natural products has become the direction of research for green pesticides.

RESULTS

In this study, novel 1,3,4-oxadiazole sulfonate/carboxylate flavonoid derivatives were explored. Among them, D4 exhibited good inhibitory effects on plant bacteria. It is worth mentioning that D4 (15 μg ml^-1 ) exhibited an excellent median effective concentration (EC₅₀ ) value against Xanthomonas oryzae pv. oryzae (Xoo), which was better than bismerthiazol (73 μg ml^-1 ) and thiodiazole copper (100 μg ml^-1 ). The EC₅₀ for D4 was much lower than the two positive controls (bismerthiazol, thiodiazole copper), making D4 more potent in this assay of bacterial growth inhibition. In addition, mechanism research using scanning electron microscopy revealed that D4 could cause deformation or rupture of the cell membranes of Xoo and Pseudomonas syringae pv. actinidiae. Moreover, D4 exhibited the best EC₅₀ for in vivo curative (132 μg ml^-1 ) and protective (101 μg ml^-1 ) activities against tobacco mosaic virus, which were more effective than ningnanmycin. Microscale thermophoresis data suggested that D4 [dissociation constant (K_d ) = 0.038 ± 0.011 μmol L^-1 ] exhibited a stronger binding capacity than the control agent ningnanmycin (K_d = 4.707 ± 2.176 μmol L^-1 ).

CONCLUSION

The biological activity data and mode of action demonstrated that D4 had the best antibacterial and antiviral effects. Compound D4 discovered in the current work may be a very promising agricultural drug. © 2022 Society of Chemical Industry.

Synthesis, Antibacterial and Insecticidal Activities of Novel Capsaicin Derivatives Containing a Sulfonic Acid Esters Moiety

In order to develop an efficient and broad-spectrum bactericide, a series of novel capsaicin derivatives containing a sulfonic acid esters moiety was synthesized. The structure of these compounds were confirmed by nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrum (HRMS). The results of the bioactivities revealed that some target compounds exhibited remarkable antibacterial activity. Compound 3b exhibited the highest activities against Pseudomonas syringae pv. actinidiae (Psa), Xanthomonas oryzae pv. oryzae (Xoo), and Xanthomonas axonopodis pv. citri (Xac), and the values were 86, 54, and 92% at 50 μg/ml, respectively, which were higher than were for thiodiazole copper (87, 34, and 77%) and bismerthiazol (87, 37 and 75%). Although some compounds also showed certain activity against Spodoptera frugiperda, it was weaker than the positive controls monosultap and mulfoxaflor. Thus, the bioassay results recommend that these newly designed and synthesized scaffolds should be used as a bactericide lead compound rather than an insecticide lead compound.

Synthesis and Bioactivities of Novel Piperonylic Acid Derivatives Containing a Sulfonic Acid Ester Moiety

The crop loss caused by bacteria has increased year by year due to the lack of effective control agents. In order to develop efficient, broad-spectrum, and structurally simple agricultural bactericide, the structure of piperonylic acid was modified and a series of novel piperonylic acid derivatives containing a sulfonic acid ester moiety was synthesized. Bioassay results indicated the compounds exhibited significantly antibacterial activities. Among them, compound 41 exhibited excellent antibacterial activities against Pseudomonas syringae pv. Actinidiae (Psa), with inhibitory value 99 and 85% at 100 μg/ml and 50 μg/ml, respectively, which was higher than that of thiodiazole-copper (84 and 77%) and bismerthiazol (96 and 78%). In addition, some compounds also showed moderate insecticidal activity against Spodoptera frugiperda. The abovementioned results confirm the broadening of the application of piperonylic acid, with reliable support for the development of novel agrochemical bactericide.

A review of approaches to control bacterial leaf blight in rice

The Gram-negative bacteria Xanthomonas oryzae pv. oryzae, the causative agent of bacterial leaf blight (BLB), received attention for being an economically damaging pathogen of rice worldwide. This damage prompted efforts to better understand the molecular mechanisms governing BLB disease progression. This research revealed numerous virulence factors that are employed by this vascular pathogen to invade the host, outcompete host defence mechanisms, and cause disease. In this review, we emphasize the virulence factors and molecular mechanisms that X. oryzae pv. oryzae uses to impair host defences, recent insights into the cellular and molecular mechanisms underlying host-pathogen interactions and components of pathogenicity, methods for developing X. oryzae pv. oryzae-resistant rice cultivars, strategies to mitigate disease outbreaks, and newly discovered genes and tools for disease management. We conclude that the implementation and application of cutting-edge technologies and tools are crucial to avoid yield losses from BLB and ensure food security.

Synthesis and Antibacterial Evaluation of Novel 1,3,4-Oxadiazole Derivatives Containing Sulfonate/Carboxylate Moiety

Abstract: In order to discover new lead compounds with high antibacterial activity, a series of new derivatives were designed and synthesized by introducing a sulfonate or carboxylate moiety into the 1,3,4-oxadiazole structure. Antibacterial activity against two phytopathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas axonopodis pv. citri (Xac), was assayed in vitro. The preliminary results indicated that ten compounds including 4a-1-4a-4 and 4a-11-4a-16 had good antibacterial activity against Xoo, with EC50 values ranging from 50.1-112.5 µM, which was better than those of Bismerthiazol (253.5 µM) and Thiodiazole copper (467.4 µM). Meanwhile, 4a-1, 4a-2, 4a-3 and 4a-4 demonstrated good inhibitory effect against Xanthomonas axonopodis pv. citri with EC50 values around 95.8-155.2 µM which were better than those of bismerthiazol (274.3 µM) and thiodiazole copper (406.3 µM). In addition, in vivo protection activity of compound 4a-2 and 4a-3 against rice bacterial leaf blight was 68.6% and 62.3%, respectively, which were better than bismerthiazol (49.6%) and thiodiazole copper (42.2%). Curative activity of compound 4a-2 and 4a-3 against rice bacterial leaf blight was 62.3% and 56.0%, which were better than bismerthiazol (42.9%) and thiodiazole copper (36.1%). Through scanning electron microscopy (SEM) analysis, it was observed that compound 4a-2 caused the cell membrane of Xanthomonas oryzae pv. oryzae ruptured or deformed. The present results indicated novel derivatives of 5-phenyl sulfonate methyl 1,3,4-oxadiazole might be potential antibacterial agents.