Enantioselective Antifungal Activity of Pefurazoate against Pathogens of Rice Seed Diseases

Abstract

Pefurazoate is a 14a-demethylation inhibitor of 24-methylenedihydrolanosterol (24-MDL) and has an asymmetric carbon atom in its structure. We previously reported that the antifungal activity of the (S)-(-)-isomer of pefurazoate against Gibberella fujikuroi was about thirty times that of the (R)-(+)isomer. This enantioselective antifungal activity was presumed to be due to an asymmetric molecular shape caused by the binding of a bulky 2-furanylmethyl group to a nitrogen atom adjacent to the asymmetric carbon atom. Therefore, to further elucidate the difference in antifungal activity between the two enantiomers of pefurazoate, we synthesized optically active N-methyl analogues of pefurazoate, and evaluated their antifungal activity. Optical (R)-(+)-and (S)-(-)-isomers of pefurazoate exhibited different activities against Cochliobolus miyabeanus and Pyricularia oryzae as well as Gibberella fujikuroi, but the N-methyl (R)-(+)-and (S)-(-)-isomers of the pefurazoate analogues had almost the same degree of activity against these three fungi and of inhibition of ergosterol biosynthesis in G. fujikuroi. These findings strongly suggest that the enantioselective antifungal activity of pefurazoate is due to its asymmetric molecular shape caused by substitution of the furan ring.

Chiral Fungicide Famoxadone: Stereoselective Bioactivity, Aquatic Toxicity, and Environmental Behavior in Soils

“…For instance, the fungicidal activity of S -imazalil was 3.00–6.59 times that of R -imazalil toward different pathogens . The bioactivity of S -pefurazoate was 30 times higher than that of R -pefurazoate …”

“…18 The bioactivity of S-pefurazoate was 30 times higher than that of R-pefurazoate. 26 Molecular Docking. Previous studies showed that famoxadone was a specific Q o site bc 1 inhibitor for electron transfer in mitochondria of pathogen cells.…”

Long-Chain Molecules with Agro-Bioactivities and Their Applications

“…As a fungitoxic agent, it is effective against seed-borne pathogenic fungi such as Gibbeyella fujikuyoi, Pyricularia oryzae, and Cochliobolus miyabeanus [28]. Similar to other azole fungicides, pefurazoate acts as by inhibiting the 14α-demethylation of 24-methylene dihydro lanosterol [28,29]. In addition to its sterilization and disease-control effects, pefurazoate also has a positive effect on promoting seed germination and seedling growth, thereby promoting healthy rice plant development (Figure 6).…”

“…The World Health Organization (WHO) has classified disulfoton as "extremely hazardous" (Figure 16). AMTSn (29), a small molecule containing methanethiosulfonate, was developed by Pang as an inhibitor of AChE activity. It was found to irreversibly inhibit 99% of the AChE derived from the green insect aphid (Schizaphis graminum) at a concentration of 6.0 mM.…”

Fungicides, Agricultural, 2. Individual Fungicides

“…C, is a pale brownish liquid which is slightly soluble in water, moderately soluble in hexane and cyclohexanone, and soluble in dimethyl sulfoxide, ethanol, acetone, acetonitrile, chloroform, ethyl acetate, and toluene [54,141].…”