2020/07/20 by Marco Masi, Ernesto Santoro, Suzette Clement +5
Agricultural and Biological Sciences · Chemistry · Medicine · #Allelopathy and phytotoxic interactions #Chemical synthesis and alkaloids #Microbial Natural Products and Biosynthesis
paper · doi:10.1002/chir.23270
openalex publication_date 2020/07/20 · openalex created_date 2020/07/29 · openalex updated_date 2026/07/29
Abstract The fungal pathogen Pyricularia grisea has been studied to evaluate its production of phytotoxins for the biocontrol of the buffelgrass ( Cenchrus ciliaris L.) weed. A first investigation allowed to isolate several new and known phytotoxic metabolites. However, the further investigation on the organic extract obtained from the fungus liquid culture showed the presence of other metabolites possibly contributing to its phytotoxicity. Thus, four known metabolites were isolated and identified by spectroscopic (nuclear magnetic resonance [NMR] and high‐resolution electrospray ionization mass spectrometry [HRESIMS]) methods as dihydropyriculol ( 1 ), epi ‐dihydropyriculol ( 2 ), 3‐methoxy‐6,8‐dihydroxy‐3‐methyl‐3,4‐dihydroisocoumarin ( 3 ), and ( R )‐mevalonolactone ( 4 ). The absolute configuration of 1 – 3 was determined for the first time by a computational analysis of their electronic circular dichroism (ECD) spectra. When the isolated compounds were bioassayed at a concentration of 5 × 10 –3 M in a buffelgrass coleoptile and radicle elongation test no toxicity was detected. On the contrary, compounds 1 and 3 showed a significant stimulating effect of radical elongation. Furthermore, the difference in growth stimulation between 1 and its epimer 2 highlights the tight relationship between absolute configuration and biological activity of these fungal metabolites.