Electrochemical Quantification of the Antioxidant Capacity of Medicinal Plants Using Biosensors

Sensors

Erika Rodríguez-Sevilla¹  Mar໚-Teresa Ramírez-Silva¹  Mario Romero-Romo²  Pedro Ibarra-Escutia³ 

[1] Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Área de Química Analítica, San Rafael Atlixco 186, Col. Vicentina, Del. Iztapalapa, México D.F., C.P. 09340, Mexico; E-Mail:;Departamento de Materiales, Universidad Autónoma Metropolitana-Azcapotzalco, Área Ingeniería de Materiales, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Del. Azcapotzalco, México, D.F., C.P. 02200, Mexico; E-Mail:;SEP-Instituto Tecnológico de Toluca. Departamento de Ingeniería Química y Bioquímica. Av, Tecnológico S/N. Fraccionamiento La Virgen, Metepec, Edo de México, C.P. 52149, Mexico; E-Mail:

关键词: medicinal plants;    antioxidant capacity;    biosensors;    tyrosinase;    immobilization;    screen-printed electrodes;    Michaelis-Menten constant;   

DOI  :  10.3390/s140814423

来源: mdpi

【 摘 要 】

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, K_m′, 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 K_m′ (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.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.