title: Autographic assay for the rapid detection of antioxidant capacity of liquid and semi-solid pharmaceutical formulations using ABTS•+ immobilized by gel entrapment.
abstract: An autographic assay suitable for the detection of antioxidant compounds in a complex matrix (liquid and semi-solid pharmaceutical formulations) or in isolated compounds was described. The pre-formed radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(•+)) was generated by oxidation of ABTS with potassium persulfate and reduced in the presence of hydrogen-donating antioxidants. For a further comparative estimation of its applicability and sensitivity, different medicinal plant extracts, hydrogels and antioxidant compounds were dot seeded or chromatographed on silica gel (TLC) and revealed with ABTS(•+) solution (System I) or ABTS(•+) immobilized by gel entrapment (System II). Both systems were effective and able to detect antioxidant activity in a micromolar range in seconds. System II was more sensitive and reproducible than System I. This micromethod is quick, inexpensive, and particularly helpful whether it works with numerous samples or on a small scale.
authors.affiliation: INQUINOA, CONICET, Facultad de Bioquímica, Química y Farmacia. Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, (4000) San Miguel de Tucumán, Tucumán, Argentina.
authors.forename: Iris Catiana
authors.initials: IC
authors.lastname: Zampini
authors.forename: Roxana Mabel
authors.initials: RM
authors.lastname: Ordoñez
authors.forename: María Inés
authors.initials: MI
authors.lastname: Isla
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D052160:Benzothiazoles / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods*; D004339:Drug Compounding / Q000379:methods; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005782:Gels / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis*; D010946:Plants, Medicinal / Q000737:chemistry*; D011208:Powders; D012996:Solutions; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D005782:Gels; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D011208:Powders; D012996:Solutions; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid