During the last decade epidemiological studies have demonstrated a clear relationship between diet and health and this has resulted in new roles being ascribed to foods. Foods are now not only regarded as being an indispensable source of nutriment but are also considered to be beneficial in many ways. Foods that have some particular beneficial effects on health are generally defined as functional foods [1
]. Their activity is determined by a specific and selective interaction of their minor components with one or more physiological functions of the organism. Both simple foods and food products, meaning technologically treated foods in which their chemical composition and, therefore, their organoleptic, nutritional, or biological characteristics have been changed, are considered functional foods. Foods depleted in, or enriched with, specific components can also be considered to be functional foods.
Caries is one of the most prevalent chronic diseases of humans. It is an endogenous infection of the calcified tissues of the teeth and is a result of their demineralisation by organic acids produced by those plaque bacteria that ferment dietary carbohydrates. The most common aetiological microbiological agents of enamel caries are considered to be Streptococcus mutans
and Streptococcus sobrinus.
Additional associated microorganisms are lactobacilli and actinomyces, the former being considered as secondary invaders, while the latter being responsible for root surface caries [3
]. The pathogenesis of dental caries is dependent upon the presence of fermentable sugars in the diet and the presence of cariogenic bacterial species. The main virulence properties of S
and S. sobrinus
are their ability to adhere to the tooth surface together with their rapid metabolism of sucrose to organic acids and to extracellular polysaccharides.
Several approaches to caries prevention are possible: (i) elimination of dietary carbohydrates from the diet, (ii) elimination of the causative organisms, (iii) prevention of bacterial adhesion and/or plaque formation, (iv) interference with bacterial metabolism, for example, by fluorides, and (v) enhancing acid resistance of the tooth enamel, for example, by fluoride [7
]. Chemicals able to achieve one or more of the above have been shown to be present in a number of foods. In some foods the presence of compounds with antibacterial activity against different pathogens has been detected; in other foods both antiadhesive activity and inhibitory activity against the extracellular polysaccharide have been demonstrated. Recently, the anticariogenic properties of food components have been verified in vivo
using both animals and humans tests. For example, extracts obtained from different teas and their polyphenol components have been investigated thoroughly for their activity. Polyphenols in tea have been shown to reduce caries development in animals because they decrease the cell surface hydrophobicity of S
and the ability of the organism to synthesize adherent water-insoluble glucan from sucrose [13
]. Additionally propolis [18
] has been shown to possess both antimicrobial and GTF-inhibitory activities. The extract from Lentinus edodes
, an edible mushroom, was studied in rats [19
] and found to have an inhibitory effect on water-insoluble glucan formation by GTF. The same inhibitory effects have been shown by apple procyanidins [20
]. High molecular weight components of hop bract inhibit adherence of water-insoluble glucan synthesis by S
]. The cariostatic activity of cacao mass extract has been observed in vitro
and in animal experiments. In this case, high molecular weight polyphenolic compounds and unsaturated fatty acids were shown to be the active constituents. The former, which showed strong anti-GTF activity, were polymeric epicatechins in an acetylated form. The latter showed bactericidal activity against S
]. An interesting antibacterial activity has been detected in coffee that is effective against S
as well as other Gram-positive bacteria and some Gram-negative species [24
]. In particular, it has been shown that roasted coffee interferes with streptococcal sucrose-independent adsorption to hydroxyapatite (HA) beads. Such activity may be due to not only small molecules occurring naturally, such as trigonelline, nicotinic and chlorogenic acids, but also to coffee components containing condensed polyphenols or melanoidins that occur during the roasting process [27
Periodontal diseases are a heterogeneous group of inflammatory conditions that involve the supporting tissues of the teeth. They include gingivitis, in which only the gingiva is involved, and the various forms of periodontitis in which destruction of alveolar bone occurs. Characteristically, in these diseases, the junctional epithelial tissue at the base of the gingival crevice migrates down the root of the tooth with the result of the formation of a periodontal pocket. The initiation and progression of periodontal diseases is attributed to the presence of elevated levels of pathogenic bacteria within the gingival crevice. Any of several hundred bacterial species may inhabit the gingival crevice; however, it has been shown that only a few play a significant role in the aetiology of the various periodontal diseases. Indeed, it is generally accepted that a consortium of bacteria, not a single species, is involved in these diseases.
Gingivitis is the most prevalent form of periodontal disease and a disease which can be prevented and alleviated by the topical application of suitable agents in oral hygiene products such as toothpastes and mouthwashes. Accumulation of dental plaque at gingival margins due to inadequate dental hygiene leads to the inflammation of the gingivae, defined as gingivitis [28
]. It can be defined as a nonspecific inflammatory process of the gingivae (gums) without destruction of the supporting tissues. This is a reversible condition as a return to meticulous dental hygiene practices will restore gingival health [29
]. The plaque biofilm on the surfaces of teeth at the gum margin can cause inflammation. Several bacterial species have been implicated as aetiological agents of this disease. These include Actinomyces israelii
spp., and Fusobacterium nucleatum
. A key trend observed during gingivitis is the ascendancy of Actinomyces
spp. and Gram-negative rods at the expense of Streptococcus
spp. Gingivitis affects 100% of the adult population at some point during their lives, and, in some cases, it can lead to the development of periodontitis (although this can occur in individuals without any gingivitis) which results in loss of attachment of the gingivae to the teeth, a condition causing major discomfort and tooth loss, and necessitates extensive and costly dental treatment.
In comparison with caries, there is considerably less information available regarding the effects of beverages/foods on periodontal diseases. Possible ways in which such materials could prevent or alleviate gingivitis would be by directly killing the causative organisms, interfering with the formation of plaque at the gingival margin, disrupting preformed plaque, attenuating the virulence of the causative organisms, and acting as free radical scavengers thereby reducing the plaque-induced inflammation. Diets rich in vitamin C have long been known to protect against gingivitis [30
]. Folate also appears to protect against the disease [31
]. Green tea polyphenols have in vitro
inhibitory effects on the adhesion of oral bacteria to epithelial cells [32
]. Furthermore, it has been shown that the high molecular weight material of cranberry juice is effective in inhibiting coaggregation between different causative bacteria and Fusobacterium nucleatum
]. Adhesion of streptococci is inhibited by hop bract polyphenols [34
] and by several tea materials [16
] that have also been shown to inhibit water-insoluble glucan synthesis and bacterial amylases. An interesting antibacterial activity has been detected in coffee [24
The aim of this work was to select foods and beverages from the folk literature and using the knowledge of the authors that had anti-caries and anti-gingivitis activities and to characterize and identify the active ingredients.