Formation of beta s-Cu Complexes Via pH-Metric Titration for Antimicrobial Studies

beta-Sitosterol (beta s) is one of important phytosterols, which is well known for its ability to lower the cholesterol level and is also useful in the treatment of various diseases. Keeping in mind its biological activities, complexation of beta s with Cu(II) was performed and it was found that beta s-Cu complex enhances the biological activities of beta s. The pH-metric titration technique was used to control the formation of metal (M)-ligand (L) complexes beta s-Cu in solutions with variable mole ratio of metal ion to ligand, 1:1, 1:2 and 1:3 (denoted as ML, ML2 and ML3 respectively). The complex formation was indicated by change in the solution color due to change in pH. Results obtained by the mole ratio variation and isomolar series method revealed the formation of ML2 complex. The synthesized beta s-Cu complex was characterized by elemental analysis and various spectroscopic techniques including IR, UV/Vis, and H-1 NMR. The results of analysis indicated that complexes contained Cu(II) ions coordinated via OH and C=C groups of the steroid. The data of antimicrobial activity assay showed higher activity of beta s-Cu in 1:2 (ML2) form as compared to other mole ratios.