RESUMO
The aims of the study were to evaluate the pharmacodynamic interaction between 3α-hydroxymasticadienonic acid and diligustilide (DLG), isolated from the plants Amphiptherygium adstringens and Ligusticum porteri, respectively, using the indomethacin-induced gastric injury model, as well as their individual gastroprotective efficacy in this model. Male Wistar rats were orally administered with 3α-hydroxymasticadienonic acid, DLG or the mixture of 3α-hydroxymasticadienonic acid-DLG (at a fixed-ratio combination of 1:1, 1:3, and 3:1). Thirty minutes later, the gastric damage was induced by a single oral dose of indomethacin (30 mg/kg). Three hours later, the gastric injury (mm2 ) was determined. 3α-hydroxymasticadienonic acid and DLG as individual compounds showed a gastroprotective effect against indomethacin-induced gastric damage (p < .05). The effective dose (ED50 ) values for each compound were 6.96 ± 1.25 mg/kg for 3α-hydroxymasticadienonic acid and 2.63 ± 0.37 mg/kg for DLG. The isobolographic analysis performed showed that the combination exhibited super-additive interaction as the experimental ED50 values (Zexp) were lower than theoretical additive dose values (Zadd; p < .05). Our results identify the super-additive (synergist) interaction between 3α-hydroxymasticadienonic acid and DLG and the gastric safety of both compounds in the indomethacin-induced gastric injury model, suggesting their potential in the future as a strategy to decrease the gastric damage associated to the chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs).