Inhibitory Activities of Essential Oil Obtained from Turmeric and Its Constituents against β-Secretase

Abstract

The need for a preventive agent against dementia led us to screen natural plant resources. Among the herbs and spices tested, turmeric, from rhizomes of Curcuma longa, showed high potency against β-secretase. The active principles were determined as α-turmerone, β-turmerone and ar-turmerone, with IC 50 values of 39, 62 and 92 µM respectively. In this study, the efficiency of collecting the essential oil using steam distillation of the volatile substance was disclosed. The active principles were explored, and four sesquiterpenoids and five monoterpenoids were revealed as active principles against β-secretase. On the other hand, α-turmerone, β-turmerone and ar-turmerone were also investigated in a pharmacokinetic absorption experiment. After oral administration, these compounds were detected in an intact form in the brain and serum. These results suggest that consumption of turmeric constituents may prevent dementia.

Curcuma longa L. Rhizome Essential Oil from Extraction to Its Agri-Food Applications. A Review

“…For instance, Chandra et al incorporated a continuous water circulation process to the regular steam distillation of the essential oil of turmeric rhizomes and leaves, achieving 13% and 29% more yield, respectively, compared to the conventional process [ 71 ]. Moreover, a subsequent distillation with vacuum allows a more efficient extraction of turmeric monoterpenes and sesquiterpenes [ 72 ]. The addition of a packed bed of turmeric rhizomes above the steam source has been also key to maximize the essential oil yield [ 73 ].…”

“…Concretely, turmerones (α-, β- and ar-) represent the major and the most distinctive individual components [ 108 , 109 ] ( Table 2 and Figure 1 ). They give interesting properties to C. longa essential oil, such as anticancer, anti-inflammatory, antioxidant and the prevention of dementia [ 72 , 110 , 111 , 112 , 113 ]. Even they enhance the bioavailability and activity of other important turmeric components like curcumin [ 114 , 115 , 116 ].…”

Using Turmeric Oil as a Solvent Improves the Distribution of Sesamin‐Sesamolin in the Serum and Brain of Mice

“…c) and β‐turmerone (Fig. d), are major components of TO and have been reported to exert β‐secretase inhibitory activity in previous studies (Matsumura et al, , b). Therefore, TO might be expected to enhance the β‐secretase inhibitory activity of SE.…”

Chemical Diversity of β-Secretase Inhibitors From Natural Resources

“…Using this strategy, we have already reported on its application to various crude extracts from plant resources to reveal their inhibitory activities and investigate their active constituents. [43][44][45] This method is expected to be recognized as an efficient strategy for natural product studies.…”