Inhibitory effects of green tea polyphenol on glucan synthesis and cellular adherence of cariogenic streptococci.

Abstract

Inhibitory effects of green tea polyphenols on glucan synthesis by glucosyltransferases of Streptococcus mutatis MT8148 and Streptococcus sobrinus 6715DP and on sucrose-dependent adherence of the bacterial cells were examined in vitro. The glucan synthesis by the bacterial glucosyltransferase was strongly inhibited by (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), the main components of the tea polyphenols. It was also demonstrated that ECg and EGCg interfered with the sucrose-dependent adherence of those bacterial cells at much smaller concentrations than those which were needed to inhibit the growth of the bacteria.

Influence of polymer co-intercalation on guest release from aminopropyl-functionalized magnesium phyllosilicate mesolamellar nanocomposites

“…XRD and FTIR spectroscopy confirmed the characteristic disordered lamellar structure typical of this class of synthetic materials. 29,30 Exfoliation of the clay was undertaken by dispersing the bulk powder in water (10 mg mL 21 ), followed by ultra-sonication for 5 min.…”

“…An aqueous solution of the sodium salt of ibuprofen (1 mL, 10 mg mL 21 ) was added slowly to the exfoliated organoclay suspension (1 mL, 10 mg mL 21 ). The product, which precipitated immediately, was left to age overnight and then collected by centrifugation, and dried at room temperature in air.…”

“…Co-intercalation of ibuprofen and PSS (M W = 70 000, 200 000, 1 000 000) within the organoclay matrix was achieved by addition of a mixture containing ibuprofen (10 mg) in 1 mL of aqueous PSS in water (10 mg mL 21 ) to a stirred dispersion of the exfoliated organoclay (4 mL). The precipitate, which formed immediately on addition, was left to age overnight and then collected by centrifugation, and dried at room temperature in air.…”

“…Intercalation of EGCG in association with PSS or PAA was undertaken by adding 1 mL of an aqueous solution containing EGCG (3 mg mL 21 ) and PSS (10 mg mL 21 ) or EGCG (3 mg mL 21 ) and PAA (10 mg mL 21 ) to 4 mL of a delaminated organoclay suspension. Similar preparations were undertaken using mixtures of EGCG (3 mg mL 21 ) and PMAPSA (0.6 wt%), which were added to 2 mL of the organoclay dispersion. In each case, the precipitate was left to age overnight, then collected by centrifugation and dried overnight at room temperature in air.…”

“…Herein, we report the synthesis and characterization of a range of host-guest layered nanocomposites based on the intercalation of small molecule or macromolecular guests, or both, within the interlayer spaces of an aminopropyl-functionalized magnesium phyllosilicate (approximate unit cell composition, [H 2 N(CH 2 ) 3 ] 8 Mg 6 Si 8 O 16 (OH) 4 ). The guest molecules include the anti-inflammatory drug, ibuprofen (pK a = 4.5), 20 the green tea medicinal extract, epigallocatechin gallate, 21,22 (EGCG; pK a1 = 7.6-7.75), 23,24 and the anionic polymers, poly(styrene sulfonate) (PSS), poly(acrylic acid) (PAA) or polymethyl-acrylamidopropanesulfonic acid (PMAPSA) (Fig. 1).…”