Ultraviolet-Visible Spectroscopic Evaluation of Complexation Equilibria of Some Complexes of Loranthus Micranthus Linn Plant Parasitic on Kola AcumiNAnata

Abstract

Some complexes of crude methanol extract of Loranthus micranthus Linn parasitic on Kola acuminata were evaluated using ultraviolet-visible absorption spectrophotometry. The crude methanol extract was complexed with ferric chloride solution, borate mixture, methanolic aluminum nitrate and aluminum chloride solutions respectively and the absorption spectra of the resulting complexes obtained using UVVis spectrophotometer. The numbers of complexation equilibria of the formed complexes were determined between the pH of 1 and 12. The formed complexes, except the borate complex, showed bathochromic shift in their absorption spectra. While the borate and aluminum chloride complexes had two inflections each, the ferric chloride and methanolic aluminum nitrate complexes had three inflections and one inflection respectively in the pH-absorbance graph. The use of methanolic aluminum nitrate as a complexing agent is recommended for the development of UV-Vis spectrophotometric assay method for the constituents, formulations or extracts of L. micranthus leaves.

Keywords: Loranthus micranthus; complexation; phytomedicine; ultraviolet-visible spectrophotometry; methanolic, aluminum nitrate

Nigerian Journal of Pharmaceutical Research, Vol. 8 No 1 pp. 62 - 66 (September 2010)