Biology-Oriented Synthesis (BIOS) of Piperine Derivatives and their Comparative Analgesic and Antiinflammatory Activities

Abstract

Serious side effects such as gastric intestinal ulcer, bleeding etc. are associated with most of the antiinflammatory and analgesic drugs. So, there is a need to search novel, potent, and safer antiinflammatory and analgesic drug. Based on "biology-oriented synthesis approach", piperine alkaloid was isolated from Piper nigrum L. and some derivatives of piperine having azomethine, sulfamoyl, propanoyl, acetamoyl and heterocyclic oxadiazole were synthesized. The structures of synthetic derivatives were confirmed by using different spectroscopic techniques such as 1H-, 13C-NMR, EI-MS, and IR. Melting points were also determined for all compounds. Piperine and its all the synthetic derivatives were subjected to comparative in vivo evaluation of analgesic and antiinflammatory activities at the oral dose of 6 mg/kg/day. Analgesic activity was evaluated by tail immersion, hot plate and acetic acid writhing methods. While, antiinflammatory activity was evaluated by carrageenan-induced paw inflammation. In silico studies of all synthetic compounds was also conducted on COX-2 and adenosine kinase enzymes. A number of derivatives showed enhanced antiinflammatory and analgesic activities as compared to piperine and standard drug diclofenac. The newly identified molecules may serve as lead for the future research in connection of potent and safer antiinflammatory and analgesic drug candidate.