title: Stability of catechins in green tea nutraceutical products: application of solid phase extraction-thin layer chromatography densitometry.
abstract: Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC-densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC-MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50-5.00μg/band and 0.20-2.40μg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation.
authors.affiliation: Biotechnology Centre, Faculty of Pharmacy, Cairo University, Egypt.
authors.forename: Heba-Alla H
authors.initials: HA
authors.lastname: Abd-Elsalam
authors.affiliation: Biotechnology Centre, Faculty of Pharmacy, Cairo University, Egypt; Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Egypt. Electronic address: medhat.alghobashy@cu.edu.eg.
authors.forename: Medhat A
authors.initials: MA
authors.lastname: Al-Ghobashy
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Egypt.
authors.forename: Hala E
authors.initials: HE
authors.lastname: Zaazaa
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Ibrahim
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D002855:Chromatography, Thin Layer / Q000379:methods; D019587:Dietary Supplements / Q000032:analysis*; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods; D013662:Tea / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate
keywords: Accelerated stability; Catechins; Epigallocatechin gallate; Gallic acid equivalent; Nutraceuticals; Solid phase extraction; TLC–densitometry