A new oxoaporphine alkaloid, (-)-(6aR,7R)-N-acetylnorushinsunine (1) together with eight known compounds (2-9) had been isolated from the aerial part of VietnamesePiper hymenophyllumMiq., Piperaceae. The chemical structures of1-9were established mainly by spectroscopic, spectrometric, and chiroptical spectra. Their anti-inflammatory activity was evaluated against lipopolysaccharides-induced nitric oxide production in RAW264.7 cellsin vitro. Among them, compounds2-4showed significant inhibitory activities against the lipopolysaccharide-induced nitric oxide production in RAW264.7 cells with IC(50)values of 7.2, 9.3, and 4.5 mu M, respectively. In addition, compounds2and4suppressed both lipopolysaccharides-induced cyclooxygenase-2 and inducible nitric oxide synthase expressions. These results proposed thatPiper hymenophyllumand its constituents may exert anti-inflammatory effects..