Synthesis of 9-O-3-(1-piperazinyl/morpholinyl/piperidinyl)pentyl-berberines as Potential Antioxidant and Cytotoxic Agents

A new series of 9-O-3-(1-piperazinyl/morpholinyl/piperidinyl)pentyl-berberines has been efficiently formulated via coupling 1,5-dibromopentane with berberrubine which was obtained by treating berberine in a vacuum oven at optimum temperature and pressure. Nucleophilic substitution of a variety of substituted piperazines, morpholine, carbazole and piperidine furnished analogues 5a-i. Final compounds were evaluated for their in vitro antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid) (ABTS) bioassays. Also, cancer cell inhibitory potential of titled compounds was screened for cervical cancer, HeLa and CaSki employing SRB assay in terms of cytotoxicity. A minimum inhibitory concentration of 5a-i towards normal cells was studied using Madin-Darby canine kidney (MDCK) cell line. Final compounds with carbazole and 1-(naphthalen-2-yl)piperazine showed excellent free radical scavenging efficacies in DPPH and ABTS bioassays, respectively. The presence of naphthyl, benzhydryl, benzoyl, furoyl and heterocyclic rings on the piperazine system was essential to exert anticipated cytotoxic effects against cancer cell lines. The structure of the final compounds was adequately confirmed via spectroscopic techniques, elemental analysis analysis and characterization of physical properties.