# A Potential \"Vitaminic Strategy\" against Caries and Halitosis
## 4 Discussion
This inhibitory action of fatty acids is clearly species specific, since it is related to the profile of fatty acids produced by each species itself. It could be thought of as a \"system of cross-balancing\" of the oral microbiota ecology based on a pool of molecules active against competitors of the same environment. For instance, it was demonstrated that caprylic acid at a dose of 25 ug/mL completely inhibited the growth of _F. nucleatum_ and reduced the growth of _S. mutans_ by 50% [66]. Indeed, _F. nucleatum_ produces butyric, isovaleric, and propionic acids but does not produce capric/caprylic acid to which, therefore, it is sensitive. On the contrary, since _S. mutans_ is the major acidogenic and aciduric microorganism in the oral cavity, it showed higher resistance to the effect of many fatty acids comprising capric/caprylic acid [66]. However, no potential antibiofilm action of capric/caprylic acid has been highlighted. Rather, 1-monoglyceride of capric acid, monocaprin, tested against _S. aureus_, _C. albicans_, and _S. mutans_, showed inhibitory action against strains in the planktonic phase but no effect on the same strains in the biofilm growing state [67]. Then, considering our data in the light of these previous findings, we can infer that the effect of Vea(r) Oris against _S. mutans_ and _F. nucleatum_ is effectively the result of the two combined actions of the two components. The planktonic growth of the two bacteria may be held off by the more prevalent antimicrobial effect of caprylic/capric acid, whereas the antibiofilm effect of Vea(r) Oris may be principally ascribed to alpha-tocopherol acetate. The possibility of a potential synergistic interaction seems to also be supported by the following discussed studies. Medium-chain fatty acids such as caprylic and lauric acids have been demonstrated to enhance their bactericidal effect when used in association with essential oils (i.e., carvacrol, eugenol, b-resoricylic acid, trans-cinnamaldehyde, thymol, and vanillin), which, similarly to alpha-tocopherol, are extracted from plants and seeds [68; 69]. Consistently, we are encouraged to speculate a similar relationship of synergism between caprylic/capric acid and alpha-tocopherol acetate in the Vea(r) Oris formulation. The enhanced activity of the mixture may be due to the same mechanism of synergism identified by [PERSON] et al. (2013) for ascorbate and \(\alpha\)-tocopherol in association. These two compounds, recycling each other, produce an increased antioxidant effect with respect to the ascorbate alone [70]. Our results also suggested the potential of using Vea(r) Oris to modulate the H\({}_{2}\)S production of _F. mutans_ in halitosis. Although the tested concentrations of Vea(r) Oris in our experiments induced only weak and nonsignificant decreases in H\({}_{2}\)S of 5-12%, an interesting concentration-dependent trend of reduction was obtained. Although further investigations are needed to investigate this H\({}_{2}\)S-inhibitory putative action, we can confidently speculate that the observed effect is principally attributable to vitamin E. Indeed, [PERSON] et al. (2017) demonstrated that green tea extract and the principal tea catechin,epigallocatechin-3-gallate (EGCG), at a high concentration of 2000 ug/mL markedly reduced the H\({}_{2}\)S production of _F. nucleatum_ (reduction of about 80%) [51]. A weaker but significant reduction was also verified at lower concentrations (\(\leq\)500 ug/mL) for both substances and theaflavins [51]. A similar inhibitory action was verified for thymoquinone, the prevalent aromatic compound of the essential oil obtained from _N. sativa_ seeds [50]. Used at the concentration of 100 ug/mL, it reduced 40% of the H\({}_{2}\)S level in _F. nucleatum_ cultures and, at the even lower concentration of 6.25 ug/mL, 45% of H\({}_{2}\)S production in _Porphyfromonas gingivalis_ cultures. These data lead us to suppose, also for alpha-tocopherol, a possible involvement of its similar aromatic structure in inhibitory action.