(Z,Z')-Diligustilide (DLG) or levistolide A is a dimeric phthalide isolated from Ligusticum porteri (Osha), the roots of which are used in the traditional treatment of many diseases including gastric aches. However, its action has not been completely elucidated. We analyzed the contributions of hydrogen sulfide and S-nitrosothiols to the action of DLG. Animals were pretreated with freshly formed in vitro nitrosothiol using Na2S and sodium nitroprusside to elucidate participation in the action of DLG. We also evaluated the production of H2S in vivo and in real time on the stomach via a specific electrode introduced into the stomachs of anaesthetized animals pretreated with DLG. Treatment with 10 mg/kg DLG increases gastric H2S production in vivo from 7.8 ± 0.81 ppm to 13.1 ± 3.01 ppm and prevents the decrease in gastric injury caused by absolute ethanol. In addition, it maintains endogenous concentrations of GSH and NO·. Exogenous S-nitrosothiols protect the gastric mucosa from damage, suggesting that the action of DLG might be associated with S-nitrosothiol and H2S formation.
Keywords: Diligustilide; Gastric ulcer; Gastroprotection; Hydrogen sulfide; Nitrosothiols.