## 3 Active Ingredients of Turmeric
### Curcuminoids
#### 3.1.2 Potential Problems Related to Curcumin Application
[69], in the case of simple curcumin dispersion irradiated with the use of fluorescent lamp (50 Hz, 30 W) for 5 min, the concentration was reduced to 60%. For curcumin incorporated in egg ovalbumin and subjected to the same treatment, however, the initial concentration dropped to 90%. The observed results indicate that the application of a carrier for curcumin incorporation can effectively improve its photostability. Similar conclusions have been made by [PERSON] et al. [70] who compared photostability of free curcumin to curcumin-loaded solid lipid nanoparticles. Promising results were also observed for other carriers, including dendrimers [71], Eudragit\({}^{\text{\textregistered}}\) microparticles [72] and PLGA nanoparticles [73]. All of the issues mentioned above can be potentially regarded as challenging when commercial product design is taken into consideration. Apart from low bioavailability related to poor solubility and rapid metabolism, as well as susceptibility to degradation, the clinical data proving the efficacy of turmeric-derived compounds still seem to be insufficient to include them in treatment guidelines for any particular condition. It is noteworthy that there are several curcumin-based commercial products, available either as dietary supplements or as topical products, including also formulations intended for mouth application (Table 1). According to [PERSON] et al. [74], the most important factors limiting medical application of curcumin are related to its unfavorable pharmacokinetic features described above. Curcumin is classified as safe and non-toxic, even when doses as high as 6 g/day are administered orally [75]. Taking into consideration medical conditions localized in the oral cavity and topical curcumin-based formulations, it may be assumed that the amount of the active ingredient administered to the patient in such cases is low, and so is the risk of any toxic effects. However, some areas related to general curcumin toxicity seem to be unclear and require more extensive investigations. For example, the scientific literature does not provide sufficient data on the potential risk related to prolonged exposure to curcumin [74]. Moreover, curcumin has been successfully applied in the studies focusing on cancer treatment, and its cytotoxic effects were confirmed in some conditions [76]. The observed toxicity towards cancer cells may suggest that curcumin can also be potentially toxic in some other conditions, so the exact mechanisms of these actions should be investigated in detail. Finally, curcumin is frequently incorporated in various types of nanocarriers in order to improve its unfavorable pharmacokinetic profile, and such novel formulations require additional safety studies [77]. \begin{table}
\begin{tabular}{c c c c} \hline
**Name, Dose** & **Active Ingredient** & **Dosage Form** & **Application** \\
**(Manufacturer)** & **(Dose)** & & \\ \hline \begin{tabular}{c} Curenext\({}^{\text{\textregistered}}\) \\ (Abbott India Ltd., \\ Mumbai, India) \\ \end{tabular} & \begin{tabular}{c} _Curcuma longa_ \\ extract (10 mg/g) \\ \end{tabular} & oral gel & gingivitis prevention \\ \begin{tabular}{c} SNEC-G (Arbro Pharmaceuticals \\ Pvt. Ltd., New Delhi, India) \\ \end{tabular} & \begin{tabular}{c} curcumin \\ (5 mg/g) \\ \end{tabular} & self-nanoemulsifying gel & mouth ulcers, gingivitis, \\ \begin{tabular}{c} Colgate\({}^{\text{\textregistered}}\) \\ (Colgate-Palmolive, Taguig, \\ Philippines) \\ \end{tabular} & turmeric extract 1 & toothpaste & gum health improvement, \\ \begin{tabular}{c} Curcuzenica \\ (Herbzenica Lifesciences Pvt. Ltd., \\ Bhubaneswar, India) \\ \end{tabular} & \
\begin{tabular}{c} soluble _Curcuma longa_ \\ extract \\ (1\% \(w/w\)) \\ \end{tabular} & oral gel &
\begin{tabular}{c} aphthous ulcers, gingivitis, \\ submucous fibrosis, mucositis \\ and ulceration related to \\ cancer treatment \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 1: Marketed products with curcumin for the application in the oral cavity—examples.