Capacity of a Red Cabbage (Brassica oleracea var. capitata) Cyanidin to Neutralize Sodium Hypochlorite Toxicity in Daphnia magna Straus
Jacive Pérez Jiménez
Maestría en Ciencias en Sistemas del Ambiente. Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Km 10.5 Autopista Tlaxcala–San Martín, San Felipe Ixtacuixtla, Tlaxcala, Mexico.
Margarita Cervantes Rodriguez
Facultad de Ciencias de la Salud, Programa Educativo de Nutrición, San Pablo del Monte Campus, Tlaxcala, Universidad Autónoma de Tlaxcala, Mexico.
Alba Mónica Montiel González
Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Autopista San Martín Texmelucan-Tlaxcala Km 10.5, 90120 San Felipe Ixtacuixtla, Tlaxcala, México.
Hipolito Muñoz Nava
Facultad de Agrobiología, Universidad Autónoma de Tlaxcala, Autopista Tlaxcala-San Martin Texmelucan Km 10.5, CP 90120 Tlaxcala, Mexico.
Brenda Angela Zarate Maldonado
Facultad de Ciencias de la Salud, Programa Educativo de Nutrición, San Pablo del Monte Campus, Tlaxcala, Universidad Autónoma de Tlaxcala, Mexico.
Oscar Antonio Aguilar Paredes
Centro de Investigación de Biotecnología Aplicada, Instituto Politécnico Nacional, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla, Km 1.5, Tepetitla de Lardizábal, 90700, Tlaxcala, México.
Daniel Méndez Iturbide *
Facultad de Ciencias de la Salud, Programa Educativo de Nutrición, San Pablo del Monte Campus, Tlaxcala, Universidad Autónoma de Tlaxcala, Mexico.
*Author to whom correspondence should be addressed.
Abstract
Residual sodium hypochlorite (NaClO) discharged after disinfection may adversely affect aquatic organisms. This study examined whether anthocyanins extracted from red cabbage (Brassica oleracea var. capitata f. rubra) could reduce NaClO concentration and attenuate its toxicity to Daphnia magna. Anthocyanins were extracted using methanol and 2% hydrochloric acid (80:20), concentrated, purified and separated by column chromatography. Thin-layer chromatography was used to characterise the fractions. NaClO concentration was measured by iodometric titration, while acute toxicity was evaluated through 24-hour D. magna viability assays conducted in triplicate. The extraction yield was 4.59% (w/w). Of 15 coloured fractions, fraction 3 exhibited a retention factor of 69.23%, consistent with its tentative identification as cyanidin. The estimated 24-hour median lethal concentration (LC₅₀) of NaClO was 0.11 mg/L. Fraction 3 caused no observed mortality at the concentrations evaluated in the extract-only bioassays. Addition of 0.02 mg/L of the cyanidin-rich fraction reduced the measured NaClO concentration in an initial 0.11 mg/L solution by up to 93%. In combined-exposure bioassays, the tested extract concentrations were associated with complete D. magna survival after 24 hours. These findings suggest that the cyanidin-rich fraction may reduce NaClO-associated acute toxicity under the experimental conditions. More specific chemical characterisation and evaluation in complex water matrices are needed to establish its wider applicability.
Keywords: Sodium hypochlorite, anthocyanins, cyanidin, red cabbage, Brassica oleracea var, capitata f. rubra, Daphnia magna, ecotoxicology, acute toxicity, iodometric titration, thin-layer chromatography, redox neutralisation