Isolation of anthraquinones from morinda citrifolia and semi-synthesis of its metal complexes / Nur Dzaina Zaidel

Extensive study on the isolation has been carried out on the stem bark of Morinda citrifolia. The synthesis of metal complexes were carried out using one pot reaction method. This study focused on the isolation of two anthraquinones, nordamnacanthal (10) and damnacanthal (11) and four synthesized metal complexes, Cu- nordamnacanthal complex (163), Fe-nordamnacanthal complex (164), Cu- damnacanthal complex (165) and Zn-damnacanthal complex (166).The ligands were characterized using spectroscopic method sucah as NMR, MS, FTIR and UV-Vis. The spectroscopy data of the two ligands obtained were compared with the previous literature. The synthesized metal complexes obtained were characterized using CHNS elemental analysis, FTIR and UV-Vis. From the analysis results, the geometry of the Cu-nordamnacanthal was confirmed as square planar while geometry for Fe- nordamnacanthal, Cu-damnacanthal and Zn-damnacanthal were confirmed as octahedral. The crude extracts of Morinda citrifolia, the isolated anthraquinones and their metal complexes were then tested for their antimicrobial and antioxidant activities. Antimicrobial activity was carried out using five different strains of bacteria namely Escherichia coli, Salmonella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris and Klebsiella pneumoniae. From the antimicrobial and antioxidant activities evaluation results, the synthesized metal complexes showed better antimicrobial activity and more potent antioxidant activity compared to the crude extracts and isolated anthraquinones, nordamnacanthal (10) and damnacanthal (11).