## 7 Conclusions and Future Directions  
Turmeric-derived compounds are currently among the most extensively investigated plant compounds. Their numerous activities including antioxidant, anti-inflammatory and antimicrobial ones confirmed in numerous studies are also considered useful in the treatment of inflammatory conditions localized in the oral cavity. For example, most of the comparative studies summarized in this review indicate that topical curcumin can be at least as effective in relieving the symptoms of inflammation as chlorhexidine, commonly accepted as a \"gold standard\" in the therapy. Other advantages of curcumin as an alternative to the conventional treatment comprise its low cost and low toxicity associated with minimized risk of side effects which are observed in chlorhexidine treatment. On the other hand, the studies comparing the efficacy of curcumin and topical steroids indicate that the conventional therapy most probably could not be replaced with the same effects. However, it is noteworthy that the summarized in vivo studies differ significantly in terms of experimental setup, measured responses, applied dosage form, etc. Therefore, direct comparisons of the presented results should be done carefully. Another conclusion that can be drawn from the summarized studies is that harmonized protocols for in vivo  
Figure 7: Effect of curcumin (CUR), 5-fluorouracil(5-FU) and doxorubicin (DOX) alone and in the combination treatments on NT8e cell survival by a colony-forming assay. After the treatment, the colonies were stained and photographed (**A**). The survival fraction NT8e cells after the respective treatments was represented (**B**); the values are presented as mean \(\pm\) SD from three independent experiments (\(p<0.05\) statistically). \({}^{\rm a}\) Control vs. CUR-FU and CUR-DOX, \({}^{\rm b}\) 5-FU vs. CUR-5-FU and \({}^{\rm c}\) DOX vs. CUR-DOX. Reproduced from [184] with permission. Copyright 2016 American Chemical Society. studies would be useful. As it was already mentioned by the other authors [169], some of the in vivo studies available in the literature regarding curcumin and its activities are constructed in a questionable way, without blinding or without reference groups of subjects treated with placebo formulation. It must also be emphasized that some of the studies indicating the potential of curcumin as an active pharmaceutical ingredient report effects observed in vitro. The studies involving cell lines should be considered as a good starting point in the search for new pharmacological activities. However, in order to confirm the potential unambiguously, properly designed and conducted in vivo studies are necessary. It should also be noted that in the case of plant-derived compounds and plant extracts, the exact form must be taken into consideration, and standardized extract should not be treated as equivalent to the corresponding amount of pure active ingredient. As it was already mentioned in this review, turmeric rhizome is a rich source of many potentially active ingredients which can act synergistically. Therefore, the investigated form should be carefully described to avoid confusion and misinterpretation of the results, especially when the comparisons between different studies are made. In the review, several different formulations designed for different purposes were presented, including mouthwashes, gels, different kinds of curcumin-loaded nanoparticles, collagen sponges and in situ gelling systems. As it was already mentioned, most of the summarized studies used different methodologies, which makes the direct comparisons difficult. However, in the selection of the most promising dosage form, a few important formulation aspects should be taken into consideration. As curcumin, the main active component of turmeric, reveals low stability susceptibility to photodegradation, the type of formulation should enable solubilization and also play a protective role towards the active ingredient.