Correlation of In Vivo and In Vitro Assay Results for Assessment of Free Radical Scavenging Activity of Green Tea Nutraceuticals.
Green tea (GT)-derived catechins; epigallocatechin gallate (EGCG) in particular are commonly used nutraceuticals for their free-radical scavenging activity (FRSA). The influence of photodegradation on the protective power of GT nutracenticals against oxidative stress was thoroughly explored. Photodegradation of GT extracts was carried out and monitored using orthogonal stability-indicating testing protocol; in vitro and in vivo assays. Total polyphenol content (TPC) and FRSA were determined spectrophotometrically while EGCG was selectively monitored using SPE-HPLC. In vivo assessment of photodegraded samples was investigated via measuring a number of biomarkers for hepatic oxidative stress and apoptosis (caspase-3, inducible nitric oxide synthase, nitric oxide, mitogen-activated protein kinase, glutathione, thiobarbituric acid reactive substances, nuclear factor kappa beta, and nuclear factor erythroid 2-related factor) as well as liver damage (alanine transaminase and aspartate transaminase) in serum of rats previously subjected to oxidative stress. Results showed complete degradation of EGCG in photodegraded green tea samples with no correlation with either TPC or FRSA. On the other hand, in vivo assay results revealed not only loss of activity but formation of harmful pro-oxidants. Photostability was found crucial for the protective effect of GT extract against lead acetate insult. Results confirmed that careful design of quality control protocols requires correlation of chemical assays to bioassays to verify efficacy, stability, and most importantly safety of nutraceuticals.
Bioanalysis Research Group, Faculty of Pharmacy, Cairo Univ, Egypt.
Heba-Alla H
HA
Abd-ElSalam
Bioanalysis Research Group, Faculty of Pharmacy, Cairo Univ, Egypt.|Analytical Chemistry Dept., Faculty of Pharmacy, Cairo Univ, Egypt.
Medhat A
MA
Al-Ghobashy
Pharmacology and Toxicology Dept., Faculty of Pharmacy, Cairo Univ, Egypt.
Muhammad
M
Al-Shorbagy
Pharmacology and Toxicology Dept., Faculty of Pharmacy, Cairo Univ, Egypt.
Noha
N
Nassar
Analytical Chemistry Dept., Faculty of Pharmacy, Cairo Univ, Egypt.
Hala E
HE
Zaazaa
Analytical Chemistry Dept., Faculty of Pharmacy, Cairo Univ, Egypt.
Mohamed A
MA
Ibrahim
D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D001219:Aspartate Aminotransferases / Q000378:metabolism; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives / Q000032:analysis / Q000494:pharmacology*; D019587:Dietary Supplements; D005978:Glutathione / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D059808:Polyphenols / Q000032:analysis / Q000494:pharmacology; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013662:Tea / Q000737:chemistry*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D000975:Antioxidants; D016328:NF-kappa B; D010936:Plant Extracts; D059808:Polyphenols; D017382:Reactive Oxygen Species; D013662:Tea; D017392:Thiobarbituric Acid Reactive Substances; D002392:Catechin; C045651:epigallocatechin gallate; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D001219:Aspartate Aminotransferases; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione
Folin-Ciocalteu; SPE-HPLC; free radical scavenging activity; green tea nutraceuticals; photostability