Stability of Phenolic Compounds Isolated from Cocoa, Green Tea and Strawberries in Hank’s Balanced Salt Solution under Cell Culture Conditions.

Abstract

The study analysed the stability of polyphenols present in extracts isolated from cocoa, green tea and strawberries in Hank's Balanced Salt Solution buffers. The extracts were incubated under conditions commonly used for intestinal absorption experiments with human epithelial cells. The polyphenols were analysed with HPLC-DAD-FLD-MS method. The concentrations of most of the polyphenols monitored changed during 2 h of incubation. The fl avan-3-ols of cocoa exhibited similar stability and all were more stable at pH 6.5 than 7.4. The concentration of procyanidin B2 at pH 7.4 decreased to the highest extent. Green tea predominant catechins: epigallocatechin gallate and epigallocatechin, were very vulnerable in HBSS both at pH 6.5 and 7.4; their specific molecular structure may be responsible for this phenomenon. The anthocyanins of a strawberry extract were more stable at pH 6.5. The considerable increase in ellagic acid concentration at pH 7.4 might be explained by possible degradation of other compounds of the extract. It is highly recommended to perform stability tests before transport experiments in a cell culture model in order to avoid misinterpretation of results.

Stability and stabilization of (–)‐gallocatechin gallate under various experimental conditions and analyses of its epimerization, auto‐oxidation, and degradation by LC‐MS

“…The catechins are the major bioactive components in tea extracts, but unfortunately, they are unstable under various experimental conditions. Therefore, several investigations have been performed to assess the stability of catechins such as EGCG, EC, ECG, and EGC in different buffers . Efforts have also been made to find ways to stabilize EGCG under the assay conditions .…”

Stability of Dietary Polyphenols under the Cell Culture Conditions: Avoiding Erroneous Conclusions

“…46 They found that most of the polyphenols decomposed during 2 h of incubation. EGCG and EGC were very vulnerable in HBSS both at pH 6.5 and 7.4; their specific molecular structure was discussed to be responsible for this phenomenon.…”

“…EGCG and EGC were very vulnerable in HBSS both at pH 6.5 and 7.4; their specific molecular structure was discussed to be responsible for this phenomenon. 46 The flavan-3-ols from cocoa were more stable at pH 6.5 than at pH 7.4. The major oxidative products of EGCG in McCoy's 5A culture media were theasinensin and its dimer.…”

Identification of bioaccessible and uptaken phenolic compounds from strawberry fruits in in vitro digestion/Caco-2 absorption model

“…Our previous study revealed a non-enzymatic release of EA from sanguiin H-6 and other ellagitannins present in the strawberry extract (Kosiń ska et al, 2012). EA was reported to be liberated from ellagitannins of other fruits, e.g.…”