Anticonvulsant Interactions: Borneol and Scoparone

All drugs—borneol, carbamazepine, phenytoin, phenobarbital and valproate—were purchased from Sigma-Aldrich (Poznań, Poland). scoparone was isolated from Artemisia umbelliformis Lam. (Asteraceae), as reported previously [19 (link)]. All the studied drugs, except for valproate (i.e., borneol, scoparone, carbamazepine, phenobarbital and phenytoin), were suspended in a 1% aqueous solution of Tween 80 (Sigma-Aldrich, Poznań, Poland), while valproate was dissolved in distilled water. The ASMs were administered intraperitoneally (ip) as follows: phenytoin—120 min, phenobarbital—60 min and carbamazepine and valproate—30 min, before the experiments, as reported earlier [39 (link),40 (link)]. borneol and scoparone were injected i.p. at increasing time periods of 15, 30, 60 and 120 min. Of note, these pretreatment times for borneol and scoparone when used separately (i.e., 15, 30, 60 and 120 min.) were based on our previously published work in order to make the results for scoparone comparable to those for other coumarins (i.e., osthole, imperatorin and xanthotoxin) tested earlier [10 (link),26 (link)]. For all the combinations with ASMs, both borneol and scoparone were administered i.p. 15 min. before the MES test and brain tissue sampling.