Common tea formulations modulate in vitro digestive recovery of green tea catechins

Abstract

Epidemiological evidence suggests a role for tea catechins in reduction of chronic disease risk. However, stability of catechins under digestive conditions is poorly understood. The objective of this study was to characterize the effect of common food additives on digestive recovery of tea catechins. Green tea water extracts were formulated in beverages providing 4.5, 18, 23, and 3.5 mg per 100 mL epicatechin (EC), epigallocatechin (EGC), epigallocatechin-gallate (EGCG), and epicatechin-gallate (ECG), respectively. Common commercial beverage additives; citric acid (CA), BHT, EDTA, ascorbic acid (AA), milk (bovine, soy, and rice), and citrus juice (orange, grapefruit, lemon, and lime) were formulated into finished tea beverages at incremental dosages. Samples were then subjected to in vitro digestion simulating gastric and small intestinal conditions with pre- and post-digestion catechin profiles assessed by HPLC. Catechin stability in green tea was poor with <20% total catechins remaining post-digestion. EGC and EGCG were most sensitive with less, not double equals 10% recovery. Teas formulated with 50% bovine, soy, and rice milk increased total catechin recovery significantly to 52, 55, and 69% respectively. Including 30 mg AA in 250 mL of tea beverage significantly (p<0.05) increased catechin recovery of EGC, EGCG, EC, and ECG to 74, 54, 82, and 45% respectively. Juice preparation resulted in the highest recovery of any formulation for EGC (81-98%), EGCG (56-76%), EC (86-95%), and ECG (30-55%). These data provide evidence that tea consumption practices and formulation factors likely impact catechin digestive recovery and may result in diverse physiological profiles.

Pharmacokinetics and Tissue Distribution of14C-Labeled Grape Polyphenols in the Periphery and the Central Nervous System Following Oral Administration

“…The low absorption of some fractions may be partly explained by the instability of the compounds during the digestive process. Green et al 32 demonstrated using an in vitro model that 80% of catechins are destroyed during the process of digestion. Studies of anthocyanin pharmacokinetics in humans 33 from either wine or grape juice showed similar T max (0.5-1.5 hours) to fractions IV and V but had a lower serum percentage dose=mL at C max .…”

Organic acid bioavailability from banana and sweet potato using an in vitro digestion and Caco-2 cell model

“…4 HPLC chromatograms of organic acid concentrations in the apical chamber before (t 0 min) and after (t 120 min) the cell monolayer transport bioassay as well as the organic acid concentrations in the basolateral chamber at t 120 min; from banana (a) and sweet potato (b) Eur J Nutr (2011) 50: 31-40 37 studied in vitro. Many other nutrients such as carotenoids [26], iron [27,28], calcium [29,30] or polyphenols [27,31] have been studied for their intestinal bioavailability using a model of in vitro digestion alone or combining in vitro digestion/Caco-2 cell. However, in most of these studies, the digests were directly used for intestinal absorption without focusing on the nutrient release as a function of time per se.…”

Synthesis of Gelatin-γ-Polyglutamic Acid-Based Hydrogel for the In Vitro Controlled Release of Epigallocatechin Gallate (EGCG) from Camellia sinensis

“…[10]. The poor oral bioavailability of catechins, mainly EGC and EGCG, is attributed to their poor stability, as shown in studies of in vitro digestive simulated gastro-intestinal tract (GIT) conditions [11], and to poor intestinal permeability [12,13].…”

“…The addition of bovine, soy, rice milk, ascorbic acid and citrus juice resulted in the increase of post-digestion recovery of EGCG, EGC, ECG and EC [11]. Hence, protecting the catechins from the GIT environment will increase their post-digestion recovery for oral delivery purposes.…”