Sesquiterpenoids from the fruits of Alpinia oxyphylla and inhibition of nitric oxide production in lipopolysaccaride-activated macrophages

► Six sesquiterpenoids including three new compounds were isolated from Alpinia oxyphylla fruits. ► Mandassions A and B are novel C-7 epimers with 1,10-seco-15-norguaiane skeleton. ► The absolute configurations of the epimers were assigned by the ECD spectra calculation. ► All isolated sesquiterpenoids showed inhibition of NO production.