jf9b06116_si_001.pdf (2.15 MB)
Herbicidal Polyketides and Diketopiperazine Derivatives from Penicillium viridicatum
journal contribution
posted on 2019-12-11, 16:03 authored by Zhao-Fu Wang, Ze-Chun Sun, Lin Xiao, Yuan-Ming Zhou, Feng-Yu DuHerbicidal activity-guided isolation from the fermentation
extract
of Penicillium viridicatum had obtained two herbicidal
series of polyketides (1–7) and diketopiperazine
derivatives (8–11), especially including
three novel polyketides (1–3). The
structures and absolute configurations of new polyketides 1–3 were elucidated by extensive spectroscopic
analyses, as well as comparisons between measured and calculated ECD
spectra. Novel polyketides 1–3 and
known 4, all bearing the heptaketide skeleton with a trans-fused decalin ring of 8-CH3 substitution,
could significantly inhibit the radicle growth of Echinochloa
crusgalli seedlings with a dose-dependent relationship. Especially
at the concentration of 10 μg/mL, 1–4 exhibited the inhibition rates with 81.5% ± 2.0, 76.4%
± 0.8, 79.6% ± 1.1, and 80.0 ± 1.8%, respectively,
even better than the commonly used synthetic herbicide of acetochlor
with 76.1 ± 1.4%. Further greenhouse bioassay revealed that 4 showed pre-emergence herbicidal activity against E. crusgalli with the fresh-weight inhibition rate of 74.1%
at a dosage of 400 g ai/ha, also better than acetochlor, while the
other isolated metabolites (5–11)
exhibited moderate herbicidal activities. The structure–activity
differences of isolated polyketides indicated that the heptaketide
skeleton, characterized by a trans-fused decalin
ring with 8-CH3 substitution, should be the key factor
of their herbicidal activities, which could give new insights for
the bioherbicide developments.