Chemopreventive potential of the tannase-mediated biotransformation of green tea

Abstract

Green tea (Camellia sinensis) is one of the most widely consumed beverages in the world. The cancer chemopreventive qualities of green tea have been well documented. Epigallocatechin gallate (EGCG) is often described as the most potently chemopreventive green tea catechin; however, the low bioavailability of EGCG is a limiting factor for its biological effect. Thus, the aim of this work was to test the chemopreventive potential of green tea extract and EGCG after tannase-mediated hydrolysis. The results showed that the biotransformed compounds retained most of the beneficial properties of the original compounds, and some beneficial properties were improved in the biotransformed compounds. Biotransformation of EGCG decreased its toxicity without affecting its antiproliferative effects. Furthermore, human cells gene expression profiling showed that the biotransformed compounds modulated the expression of several genes related to carcinogenesis. These results demonstrate the benefits of the biotechnological modification of natural food molecules, allowing the improvement of the nutraceutical potential of a beverage as green tea.

Polyphenolic composition and in vitro antioxidant activities of native‐ and tannase‐treated green tea extracts

“…The antioxidant activities of the green tea extract increased by 39% after enzymatic treatment. Gallic acid can be formed by the degalloylation of the EGCG present in the green tea extract (Macedo et al ., ). We demonstrated that biotransformed green tea extract had a higher gallic acid content compared to the native green tea extract (Table ).…”

“…The lyophilised tea extract (1.0 mg) was dissolved in 1.0 mL of citrate buffer (pH 4.7, 50 m m ) and incubated with 1.0 mg of tannase at 30 °C for 30 min. The reaction tubes were placed in an ice bath for 15 min to constrain the progress of enzymatic reaction (Macedo et al ., , ).…”

Simultaneous Optimal Production of Flavonol Aglycones and Degalloylated Catechins from Green Tea Using a Multi-Function Food-Grade Enzyme

“…For example, the antioxidant capacity of soybean flour was enhanced by the enzymatic hydrolysis of phenolic glucoside in solid-state fungi fermentation [19]. In particular, tannase (EC 3.1.1.20; tannin acyl hydrolase) shows good ability in the bioconversion of green tea extract (GTE), resulting in gallic acid (GA) and degalloylated catechins [20,21].…”

“…Increasing the content of GA through the conversion of GTE by tannase has been shown to improve the radical scavenging activities of GTE [22]. Moreover, conversion of (-)-epigallocatechin gallate (EGCG) by tannase attenuated its toxicity without affecting the antiproliferative effects [21]. Another study demonstrated that tannase-treated catechins influenced the expression of genes involved in the sodium-glucose transport proteins [23].…”

Biotransformation of catechin and extraction of active polysaccharide from green tea leaves via simultaneous treatment with tannase and pectinase

“…Among these, catechins and polysaccharides, which have been used in the food industry and in medicine, have received much attention in recent years due to their biological activities . Macedo et al recently reported the chemopreventive potential of tannase‐mediated biotransformation in green tea extract. Interestingly, a recent study showed that fermentation using microbes also could be used to increase antioxidant activities of polyphenol solution …”