3. Discussion
inflammation, death, tumor necrosis, ultraviolet exposure-induced apoptosis
TUMOR NECROSIS, INFLAMMATION, AUTOIMMUNE DISEASES, MALIGNANCIES, OXIDATIVE STRESS, DISEASES
Cell apoptosis or programmed cell death serves as an integral part of cellular homeostasis. An increase in the abnormal viability of cells influenced by endogenous or exogenous factors can lead to the development of various diseases, most prominently malignancies and autoimmune diseases. The protein family BCL-2 is responsible for regulating cellular apoptosis balance through pro-apoptotic and pro-survival members and thus serves as a basis for potential therapeutic developments for various diseases [The usefulness of curcumin has long been explored, and the compound is associated with modulation on various pathways. Special interest has been directed to the autophagy or degradation of supernumerary or dysfunctional components within cells, in which curcumin inhibits the formation of reactive oxygen species (ROS) and acts as an antioxidant agent [Minimal differences in apoptotic cell count were observed among the three curcumin concentrations of 0.1, 1, and 10 μM in single application with subsequent UVB radiation. However, a drastic decrease was found when the concentration was increased to 100 μM. In addition, the highest concentration (100 μM) yielded the lowest number of apoptotic cells after daily use for 7 consecutive days, providing the best result in this study. Although an increase in application and concentration seemed to result in an overall low apoptotic cell count, the single application of the low concentrations of 0.1 and 1 μM was superior compared with their daily application. We have yet to establish the reason behind this phenomenon. However, we hypothesized that this phenomenon may be related to the biphasic effect of curcumin on the oxidation of post-prandial chylomicrons and its biphasic hormetic response on proteasome activity and heat-shock protein synthesis in human keratinocytes [The protective effect of curcumin in this research was supported by other experimental studies. Li et al. [In the current study, we observed that the application of topical curcumin gave a protective effect against ultraviolet exposure-induced apoptosis in mice. However, this study has limitations because it did not examine the markers of oxidative stress (reactive oxygen species, hydrogen peroxide, and malondialdehyde) and inflammation (cyclooxygenase-2, interleukin, prostaglandin E2, tumor necrosis factor-alpha, and nitric oxide) that may have an effect on the process of apoptosis.