Allicin-Inspired Heterocyclic Disulfides as Novel Antimicrobial Agents

Abstract

In this work, a series of derivatives with disulfide bonds containing pyridine, pyrimidine, thiophene, thiazole, benzothiazole, and quinoline were designed and synthesized based on the various biological activities of allicin disulfide bond functional groups. The antimicrobial activities of the target compounds were determined, and the structure–activity relationships were discussed. Among them, compound S8 demonstrated the most potent antifungal activity in vitro against Monilinia fructicola (M. fructicola), with an EC50 value of 5.92 μg/mL. Furthermore, an in vivo bioassay revealed that compound S8 exhibited equivalent curative and higher protective effects as the positive drug thiophanate methyl at a concentration of 200 μg/mL. The preliminary mechanism experiments showed that compound S8 could inhibit the growth of M. fructicola’ s hyphae in a time- and concentration-dependent manner, and compound S8 could induce the shrinkage of hyphae, disrupt the integrity of the plasma membrane, and cause the damage and leakage of cell contents. More than that, compound S5 also demonstrated an excellent antibacterial effect on Xanthomonas oryzae (X. oryzae), with a MIC90 value of 1.56 μg/mL, which was superior to the positive control, thiodiazole copper.

An Oxidoreductase-like Protein is Required for Verticillium dahliae Infection and Participates in the Metabolism of Host Plant Defensive Compounds

“…37,38 Plant organic heterocyclic compounds are another kind of secondary metabolite that exhibit antimicrobial activity. 39,40 In this study, metabolomic analysis revealed that the levels of 10 organic heterocyclic compounds and 4 phenylpropanoids were significantly increased in ΔVdOrlp-infected plants than in wild-type plants. Gayoso et al showed that the levels of phenylpropanoid metabolic products, including ferulic acid, vanillin, and p-coumaric acid, were significantly increased in tomato resistant to V. dahliae after fungal infection.…”

“…This adaptation increases the host’s resilience to changes in external environments. , The inhibitory effects of phenylpropanoids, such as caffeic acid, ferulic acid, naringin, and quercetin, on V. dahliae have been observed. , Plant organic heterocyclic compounds are another kind of secondary metabolite that exhibit antimicrobial activity. , In this study, metabolomic analysis revealed that the levels of 10 organic heterocyclic compounds and 4 phenylpropanoids were significantly increased in Δ VdOrlp -infected plants than in wild-type plants. Gayoso et al showed that the levels of phenylpropanoid metabolic products, including ferulic acid, vanillin, and p -coumaric acid, were significantly increased in tomato resistant to V.…”

Discovery of Pyrazole-5-yl-amide Derivatives Containing Cinnamamide Structural Fragments as Potential Succinate Dehydrogenase Inhibitors

“…The box containing apples was cultured in an incubator with constant temperature and humidity (28 °C) for 14 days, and then the plaque diameter was measured and repeated three times for each experiment. For the curative activity, 33 inoculated the mycelium plug onto the apple and cultured it in a constanttemperature incubator for 5 days before spraying the test sample solution. The other steps were the same as those above.…”

Melatonin targets MoIcl1 and works synergistically with fungicide isoprothiolane in rice blast control

“…24 Thiophanate methyl inhibits hyphal growth and causes abnormal germ tube formation, suppressing infection. 25 Carbendazim mainly interferes with mitotic spindles formation during cell division, inhibiting mycelial growth. 26 Two million tons of fungicides are applied worldwide annually.…”

“…Tricyclazole inhibits melanin biosynthesis of M. oryzae , which is crucial for the formation and penetration of appressorium 24 . Thiophanate methyl inhibits hyphal growth and causes abnormal germ tube formation, suppressing infection 25 . Carbendazim mainly interferes with mitotic spindles formation during cell division, inhibiting mycelial growth 26 .…”