Exploration for the opioidergic, GABAergic and histaminergic potentials of synthesized Schiff’s base derivatives: An in-vivo approach

Herein, five Schiff's base analogs (designated as AK1 to AK5) were synthesized and screened for their analgesic and anti-inflammatory efficacies. All compounds exhibited analgesic activity at selected doses from 45.31 % to 75.75 %, while the standard drug diclofenac sodium produced result as 86.33 %. Compounds AK1, AK3, AK4 and AK5 were found significantly P<0.001 effective at a dose of 25 mg/kg body weight (b.w). Similarly, in tail immersion test the produced percentage activity were in range from 40.19 % to 62.35 %. in which the compounds AK1, AK2, AK4 and AK5 were significantly P<0.01 effective at dose 12.5 mg/kg b.w, while at this dose significance level of efficacy of AK3 was P<0.05. Similarly, at administering doses of 25 mg/kg b.w all compounds were effective with significance level P<0.001, n = 8. Administration of the synthesized Schiff's bases at the tested doses significantly reduced paw edema as compared to control. Results of paw edema at 3rd hour was significant P<0.001. AK4 and AK5 were subjected to mechanistic approaches by GABAergic, opiodergic and histaminergic pathways. In GABAergic pathway bicuculline caused a partial reversal of writhings responses indicating the involvement of GABA receptors and therefore the tested compounds may have act through GABAergic pathway. The naloxone caused a mild reversal in the tail immersion test and indicated that some other mechanisms are additionally involved in mode of action of these compounds. Additionally a mild response was observed while studying its action involving histaminergic pathway.