Isolation and evaluation of the biological activity related to the major alkaloids in Tabernaemontana angulata Mart. ex Müll. Arg., Apocynaceae

Abstract

Introducing new chemotherapeutic agents is a great demand in the control of infectious diseases. Brazil is one of the richest countries in biodiversity and the Laboratório de Extração at UNIP has been collecting plants from the Amazon and Atlantic Rain Forests with the aim of screening for new antibacterial and antitumor plant extracts. Previous studies demonstrated that the ethanol fraction obtained from the crude extract of Tabernaemontana angulata stems showed an antibacterial activity against Staphylococcus aureus (ATCC 6538) in the microdilution broth assay. Two alkaloids were the major compounds in the active fraction, verified by thin layer chromatography analysis. In the present study, the total alkaloids were obtained from the crude extract and were fractionated by preparative thin layer chromatography for the isolation of the main components. The isolated compounds were identified by GC/MS and 1H-NMR as coronaridine and voacangine. The alkaloid fractions obtained from the isolation procedure were tested for antibacterial activity, but no activity was detected.