The Antibacterial Activity of Plant Extracts Containing Polyphenols against <i>Streptococcus mutans</i>

Abstract

The minimum inhibitory concentrations (MIC) of commercially available and 70% aqueous propanone (P70) extracts from plants chosen for polyphenol content on Streptococcus mutans and other bacteria were determined using a standard susceptibility agar dilution technique to investigate their potential use as anticariogenic agents. The effects on adhesion of S. mutans to glass were also studied. The lowest MICs were for the P70 extracts of red grape skin (0.5 mg ml^–1) and green tea and sloe berry skin (2 mg ml^–1). The commercial extracts generally had a lower activity with a minimum MIC of 2 mg ml^–1 for tea extracts, grape seed extracts and Pynogenol® (extract of maritime pine). All other extracts had MICs of ≧4 mg ml^–1. Unfermented cocoa had greater antimicrobial activity than fermented cocoa and the activity of the fractionated extract increased with the extent of epicatechin polymerization. Epicatechin polymer had an MIC of 1 mg ml^–1 and an MBC of 64 mg ml^–1. Selected extracts were tested against other oral bacteria and showed activity against Gram-positive organisms. P70 extracts of unfermented cocoa, epicatechin polymer fraction, green tea and red grape seed were bacteriostatic and prevented acid production when added at the MIC to cultures of S. mutans grown in a chemically defined medium supplemented with either glucose or sucrose. There was a reduction in viability which was greater when added to washed cells, but there were some viable cells after 24 h. The extracts also reduced adherence of S. mutans to glass.

Isolation and extraction of antimicrobial substances against oral bacteria from lemon peel

“…Inhibition of the growth of these bacteria is considered one of the most important factors for the prevention and treatment of these oral diseases (Takahashi and Schachtele 1990). Polyphenols in foods such as red grape skins and green tea reportedly inhibit the growth of the oral bacteria that cause dental caries and periodontitis (Kakuda et al 1994;Smullen et al 2007). Antibacterial substances in functional foods have been investigated from a practical standpoint.…”

Antibacterial effects of 70% ethanol and water extract of cacao beans (Theobroma cacao L.) on Aggregatibacter actinomycetemcomitans

“…Fermentation and drying processes, however, can reduce the active components of natural materials, such as polyphenol. 18 This research also used a serial dilution method with the concentrations of 100%, 50%, 25%, 12.5%, 6.25%, and 3.125%. A. actinomycetemcomitan bacteria grown on the BHIB media were considered as the positive control (+), whlie the bacteria grown on the BHIB media and the control extracts were considered as as the negative control (-).…”

Antimicrobial activity of Citrox® bioflavonoid preparations against oral microorganisms

“…27,28 From the oral perspective, naringin, a flavonoid extract from grapefruit, has shown promise in the growth inhibition of A. actinomycetemcomitans and P. gingivalis in planktonic phase. 29 Polyphenols extracted from hop extracts and cranberry have shown activity against streptococcal species associated with dental caries [30][31][32] and a citrus extract combined with lemon juice and lemon grass has been used successfully to treat oral candidosis. 33 The results of the present study show for the first time the impact of a citrus fruit bioflavonoid based product (Citrox®) on the growth of a range of oral microorganisms.…”