The green tea polyphenol (−)‐epigallocatechin gallate precipitates salivary proteins including alpha‐amylase: biochemical implications for oral health

Abstract

Green tea is a popular drink throughout the world, and it contains various components, including the green tea polyphenol (-)-epigallocatechin gallate (EGCG). Tea interacts with saliva upon entering the mouth, so the interaction between saliva and EGCG interested us, especially with respect to EGCG-protein binding. SDS-PAGE revealed that several salivary proteins were precipitated after adding EGCG to saliva. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peptide mass fingerprinting indicated that the major proteins precipitated by EGCG were alpha-amylase, S100, and cystatins. Surface plasmon resonance revealed that EGCG bound to alpha-amylase at dissociation constant (K(d)) = 2.74 × 10(-6) M, suggesting that EGCG interacts with salivary proteins with a relatively strong affinity. In addition, EGCG inhibited the activity of alpha-amylase by non-competitive inhibition, indicating that EGCG is effective at inhibiting the formation of fermentable carbohydrates involved in caries formation. Interestingly, alpha-amylase reduced the antimicrobial activity of EGCG against the periodontal bacterium Aggregatibacter actinomycetemcomitans. Therefore, we considered that EGCG-salivary protein interactions might have both protective and detrimental effects with respect to oral health.

Salivary α-amylase, serum albumin, and myoglobin protect against DNA-damaging activities of ingested dietary agents in vitro

“…Our study extends prior evidence (Manach et al, 1995; Papadopoulou and Frazier, 2004; Nozaki et al, 2009; Hara et al, 2012; Pal et al, 2012;) that animals have evolved physiological protection against dietary polyphenols and, in particular, PLPs such as EGCG, gallic acid, and pyrogallol. We thus discovered a novel function for saliva in mitigating PLP-induced DNA damage; this is in addition to the known functions of enzymatic activity, moistening, diluting/washing, salivary PRPs binding tannins, and maintenance of tooth integrity through antibacterial activity and specialized interactions with bacterial metabolism in dental plaque (Humphrey and Williamson, 2001).…”

“…We also implicated a high-quantity protein as responsible for this novel function. Saliva contains α-amylase at 400-900 units/ml (Granger et al, 2007; Hara et al, 2012). α-amylase from a purified source inhibited dietary DNA strand-breaking genotoxins at 50 units/ml in our studies, and a 1:20 dilution of saliva produced a similar level of inhibition.…”

An Update on the Health Benefits of Green Tea

“…EGCG also inhibits the hydrogen binding and hydrophobic interactions of bacterial collagenases. Consumption of green tea has also been associated with an increase in oral peroxidase activity [107,[111][112][113].…”

A functional chitosan membrane with grafted epigallocatechin-3-gallate and lovastatin enhances periodontal tissue regeneration in dogs

“…(Jigisha, Nishant, Navin & Pankaj, 2012;Steinmann, Buer, Pietschmann & Steinmann, 2013). For periodontal bacterium such as A. actinomycetemcomitans (Hara et al, 2012), P.…”