Correlation of In Vivo and In Vitro Assay Results for Assessment of Free Radical Scavenging Activity of Green Tea Nutraceuticals

Abstract

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.

Interaction of Whey Proteins with Phenolic Derivatives Under Neutral and Acidic pH Conditions

“…Dietary phenolic compounds as a special group of natural compounds have received enormous attention in recent years for their numerous bioactivities, such as anti‐inflammatory, anticancer, antioxidant, and antiallergenic activities (Beara and others ; Zhu and others ; Abd‐ElSalam and others ). They are broadly distributed in fruits, vegetables, tea leaves, and coffee beans (Kojima and others ; Harnly and others ).Therefore, incorporation of phenolic compounds into food materials is considered as an effective approach to enhancing antioxidant performance and bioactivity of food, including protein‐based food (Bartolomé and others ).…”

Inhibition of hazardous compound formation in muscle foods by antioxidative phytophenols

“…Because these plant‐derived ingredients are rich sources of phytochemical antioxidants, they have great potential to protect the quality and nutritional value of meat products and possibly enhance the chemical safety as well. While the biological role of phytochemicals may be related to the self‐defense of plants—for example, resistance to pathogens and deterrence of predators—when tested in cell cultures and animals, many of them exhibit remarkable health‐promoting bioactivity, such as anti‐inflammation, anticancer, antioxidation, and antiallergenicity . For food and beverages, the antioxidant activity of phenolic compounds, apart from flavor and color, is of primary interest.…”

“…While the biological role of phytochemicals may be related to the self-defense of plants-for example, resistance to pathogens and deterrence of predators-when tested in cell cultures and animals, many of them exhibit remarkable health-promoting bioactivity, such as anti-inflammation, anticancer, antioxidation, and antiallergenicity. [8][9][10][11][12] For food and beverages, the antioxidant activity of phenolic compounds, apart from flavor and color, is of primary interest.…”

Upregulation and stabilization of senescence marker protein-30 by epigallocatechin gallate against <i>tert</i>-butyl hydroperoxide-induced liver injury <i>in vitro</i> and <i>in vivo</i>

“…(14,27) In contrast, EGCg possesses free radical-scavenging activity and inhibits protein aggregation via proteasomal degradation. (31,32) Here, we determined how EGCg upregulates SMP30 expression. In fact, we found that EGCg can upregulate SMP30 expression even when cells are treated with CHX, an inhibitor of protein synthesis.…”