Chemical composition of Galla chinensis extract and the effect of its main component(s) on the prevention of enamel demineralization in vitro

Abstract

To determine the chemical composition of Galla chinensis extract (GCE) by several analysis techniques and to compare the efficacy of GCE and its main component(s) in inhibition of enamel demineralization, for the development of future anticaries agents, main organic composition of GCE was qualitatively determined by liquid chromatography–time of flight–mass spectrometry (LC–TOF–MS) and quantified by high-performance liquid chromatography–diode array detector (HPLC–DAD). Inorganic ions were tested by inductively coupled plasma–atomic emission spectroscopy and F was especially measured by ion chromatography. Then, bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times. Each cycle included 5-min applications with one of four treatments: 4 g⋅L−1 GCE solution, 4 g⋅L−1 gallic acid (GA) solution, 1 g⋅L−1 NaF solution (positive control), deionized water (DDW, negative control), and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer. Acidic buffers were retained for calcium analysis. The main organic composition of GCE were GA and its isomer, and, to a lesser extent, small molecule gallotannins. The content of GA in GCE was 71.3%±0.2% (w/w). Inorganic ions were present in various amounts, of which Ca was (136±2.82) µg⋅g−1, and Zn was (6.8±0.1) µg⋅g−1. No F was detected in GCE. In pH cycling, GA showed an effect similar to GCE in inhibiting enamel demineralization (P>0.05). GA was found to be the main effective, demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.

Effects of tannin-fluoride and milk-fluoride mixture on human enamel erosion from inappropriately chlorinated pool water

“…It is possible that tannin inhibits de-mineralization through interaction with the organic matrix of enamel. Changes in organic matrix network in the inter-and intra-prismatic spaces could modify the diffusion pathway inside the tooth structures, thereby affecting the process of enamel de-mineralization (36,37). Our findings are consistent with a previous study wherein tannin-fluoride was reported to promote enamel re-mineralization (16).…”

Control of hydroxyapatite crystal growth by gallic acid

“…Lots of metal ions can bind with GA to form coordination compound 4) . Previous studies indicated that crude aqueous extract of Galla chinensis (GCE) had the ability to inhibit enamel demineralization and enhance remineralization in vitro [5][6][7] . GA is the main active ingredient in GCE.…”

<b><i>Galla chinensis </i></b>Compounds Remineralize Enamel Caries Lesions in a Rat Model

“…G. chinensis is harvested in autumn and is processed into medicine through cooking and drying after removing the aphid larvae. Previous studies have revealed that G. chinensis is an effective anticaries agent [Zhang et al, 2015] by inhibiting cariogenic bacteria [Huang et al, 2003;Cheng et al, 2011;Yuen et al, 2011] and demineralization, and enhancing remineralization [Liu et al, 2003;Chu et al, 2006Chu et al, , 2007Huang et al, 2010Huang et al, , 2012. The effective components were determined to be crude G. chinensis extract (GCE, rich in polyphenols), its purified extract GCE-B, and the further purified extracts GCE-B1 and GCE-B2, which were characterized as gallic acid (GA) and methyl gallate, respectively [Xie et al, 2005;Kang et al, 2008;Xie et al, 2008].…”