1. Electrochemical quantification of the antioxidant capacity of medicinal plants using biosensors.
- Author
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Rodríguez-Sevilla E, Ramírez-Silva MT, Romero-Romo M, Ibarra-Escutia P, and Palomar-Pardavé M
- Subjects
- Catechols chemistry, Electrochemistry methods, Electrodes, Enzymes, Immobilized chemistry, Humans, Mexico, Monophenol Monooxygenase chemistry, Antioxidants chemistry, Biosensing Techniques methods, Plants, Medicinal chemistry
- Abstract
The working area of a screen-printed electrode, SPE, was modified with the enzyme tyrosinase (Tyr) using different immobilization methods, namely entrapment with water-soluble polyvinyl alcohol (PVA), cross-linking using glutaraldehyde (GA), and cross-linking using GA and human serum albumin (HSA); the resulting electrodes were termed SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/HSA/GA, respectively. These biosensors were characterized by means of amperometry and EIS techniques. From amperometric evaluations, the apparent Michaelis-Menten constant, Km', of each biosensor was evaluated while the respective charge transfer resistance, Rct, was assessed from impedance measurements. It was found that the SPE/Tyr/GA had the smallest Km' (57 ± 7) µM and Rct values. This electrode also displayed both the lowest detection and quantification limits for catechol quantification. Using the SPE/Tyr/GA, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined from infusions prepared with "mirto" (Salvia microphylla), "hHierba dulce" (Lippia dulcis) and "salve real" (Lippia alba), medicinal plants commonly used in Mexico.
- Published
- 2014
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