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

Abstract

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 ∼g ml −1 ) exhibited an excellent median effective concentration (EC 50 ) value against Xanthomonas oryzae pv. oryzae (Xoo), which was better than bismerthiazol (73 ∼g ml −1 ) and thiodiazole copper (100 ∼g ml −1 ). The EC 50 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 EC 50 for in vivo curative (132 ∼g ml −1 ) and protective (101 ∼g 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 ∼mol L −1 ] exhibited a stronger binding capacity than the control agent ningnanmycin (K d = 4.707 ± 2.176 ∼mol 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.

Design, Synthesis, Biological Activity Evaluation and Action Mechanism of Myricetin Derivatives Containing Thiazolebisamide

“…To further investigate the inhibition of TMV by compounds A4 (A,B) and A23 (C,D) with the commercial antiviral ningnanmycin (E,F), we intended to investigate the binding mode of the compounds to TMV‐CP (PDB code: 1EI7) at the molecular level and therefore performed molecular docking in Autodock 1.5.6 using it as the target protein [29] . The results are shown in Figure 4.…”

Design, synthesis, and antiviral activities of myricetin derivatives containing pyridazinone

“…Intermediates 2 and 3 were synthesized using the method reported in the literature, and the specific steps were described in the corresponding literature. 42,43…”

“…Intermediates 2 and 3 were synthesized using the method reported in the literature, and the specific steps were described in the corresponding literature. 42,43 2.2.2 General synthesis of target compounds A1-A26. Taking A1 as an example, 0.38 g (2.00 mmol) of intermediate 1, 20 mL of DMF, and 1.00 g (7.24 mmol) of K 2 CO 3 were added to a 100 mL round-bottomed flask sequentially, and after stirring for 10 min at room temperature, 0.85 g (1.67 mmol) of intermediate 3 was added, the reaction was heated, and the end point was monitored by thin-layer chromatography (TLC).…”

Synthesis, antibacterial and antifungal activity of myricetin derivatives containing piperidine and amide fragments

“…In addition, to demonstrate the interaction of Z30 and Z26 with pathogens at nanoscale and to capture events of cellular damage and pathogenic cells internal modifications, TEM studies were performed. The detailed procedures of SEM and TEM have been reported in the literature 37,38,40–42 …”

“…The detailed procedures of SEM and TEM have been reported in the literature. 37,38,[40][41][42] 2.7 Enzyme activity test Five mycelial blocks (diameter = 4 mm) of Rs were cultured and shaken in 50 mL liquid PDB medium for 48 h on a rotary shaker at 25 °C and 180 rpm. The mycelium was filtered and treated with Z26 at the concentrations of 10, 25 and 50 μg mL −1 .…”