title: Interaction and solubilization of some phenolic antioxidants in Pluronic® micelles.
abstract: The solubilization of four phenolic antioxidants, namely p-hydroxybenzoic acid (PHBAA), syringic acid, sinapic acid, and quercetin in micelles of an ethylene oxide (EO)-propylene oxide (PO) triblock copolymer Pluronic® P104 (EO27-PO61-EO27, PPO mol wt=3540, % PEO=40) was examined at different temperatures, pHs, and in the presence of sodium chloride. The nano-size core-shell micelles of P104 characterized by dynamic light scattering had hydrodynamic diameter of about 18-20 nm with low polydispersity. Antioxidants induced micellization and micellar growth were observed. The critical micellar concentration (CMC), critical micellar temperature (CMT), cloud point (CP) of P104 decreased due to solubilization and interactions of antioxidants. The solubilization was favored at higher temperature, pH and in the presence of salt and follows the order PHBA>syringic acid>sinapic acid>quercetin which corresponds to the trend in their aqueous solubility. The location of antioxidant in micelles observed from NOESY spectra. Structure and hydrophobicity of antioxidants were found to be governing factors for their interaction and location in the micelles.
authors.affiliation: Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India. arpan_parmar1985@yahoo.co.in
authors.forename: Arpan
authors.initials: A
authors.lastname: Parmar
authors.forename: Kulbir
authors.initials: K
authors.lastname: Singh
authors.forename: Anita
authors.initials: A
authors.lastname: Bahadur
authors.forename: Gerrard
authors.initials: G
authors.lastname: Marangoni
authors.forename: Pratap
authors.initials: P
authors.lastname: Bahadur
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism; D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D057446:Hydrodynamics; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010226:Parabens / Q000737:chemistry / Q000378:metabolism; D010636:Phenols / Q000737:chemistry* / Q000378:metabolism; D020442:Poloxamer / Q000737:chemistry* / Q000378:metabolism; D011794:Quercetin / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D008823:Micelles; D010226:Parabens; D010636:Phenols; D014867:Water; D020442:Poloxamer; D005707:Gallic Acid; C073734:sinapinic acid; D011794:Quercetin; C001945:syringic acid; C038193:4-hydroxybenzoic acid