Abstract
The 9-demethylated derivative of the isoquinoline alkaloid berberine was derivatised in its isoquinoline moiety using enamines derived from formaldehyde and morpholine, piperidine, carbazole and six variously substituted piperazines to form Mannich base products which were evaluated for their in vitro biological effects. Standard tests determined their radical scavenging potential and their ferric reducing antioxidant power (FRAP). Cancerous growth inhibitory efficacies were assessed using cervical cancer cell lines HeLa and CaSki and their cytotoxicities towards normal cell lines were evaluated using Madin–Darby canine kidney (MDCK) cell lines. Piperazine derivatives bearing a heterocyclic nitrogen substituent such as a pyridyl or a pyrimidyl ring were the most active antioxidant and anticancer agents. A carbazole moiety attached to the berberine core also demonstrated excellent inhibitory effects on cancerous cells.