Asponchimides A−E: new enantiomeric N-acetyldopamine trimers from Aspongopus chinensis

Five new racemic N-acetyldopamine (NADA) trimers, asponchimides A−E ( 1 − 5 ), were isolated from Aspongopus chinensis, a prominent traditional Chinese medicinal insect employed for alleviating pain, treating indigestion, and addressing kidney ailments. Compounds 1 − 5 were successfully resolved by chiral high-performance liquid chromatography (HPLC), yielding five pairs of enantiomers: (+)- and (−)-asponchimides A−E ( 1a / 1b − 5a / 5b ). Their structural identities were discerned by extensive spectroscopic analyses, including high-resolution mass spectrometry (HRMS), ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR), and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. Compounds 1 − 5 are pioneering instances of NADA trimers featuring a Δ⁷ double bond. When subjected to a series of bioassays, a majority of the compounds exhibited weak inhibitory activity against nitric oxide (NO) production in LPS-induced RAW 264.7 cells.