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 IC₅₀ values ranging from 0.75 to 3.12 μmol·L^-1 compared to the positive control (ribavirin).
Antiviral Agents/isolation & purification* ; Phloroglucinol/isolation & purification* ; Sesquiterpenes/isolation & purification* ; Molecular Structure ; Dryopteris/chemistry* ; Respiratory Syncytial Viruses/drug effects* ; Humans ; Rhizome/chemistry* ; Drugs, Chinese Herbal/pharmacology*