Abstract:
Seven novel acylphloroglucinol-sesquiterpenoid adducts, designated as dryatraols J–P (
1–
7), were isolated from the rhizomes of
Dryopteris atrata (Wall. ex Kunze) Ching. The structures, including absolute configurations, were elucidated using comprehensive spectroscopic data, calculated
13C Nuclear Magnetic Resonance-Diastereotopic Probability Assignment Plus (
13C NMR-DP4+) probability analysis, and ECD calculations. These structures represent a rare subclass of carbon skeleton of acylphloroglucinol-sesquiterpenoid adducts with a furan ring connecting the acylphloroglucinol and sesquiterpenoid moieties. Notably, compounds
1–
6 are the first reported examples of acylphloroglucinol-sesquiterpenoid adducts with dimeric acylphloroglucinol incorporated into the aristolane- or rulepidanol-type sesquiterpene, while compound
7 features a hydroxylated monomeric acylphloroglucinol motif. A preliminary evaluation of their antiviral activities revealed that compounds
1–
6 exhibited more potent activities against respiratory syncytial virus (RSV) with IC
50 values ranging from 0.75 to 3.12 μmol·L
−1 compared to the positive control (ribavirin).