Compositions for inhibiting beta secretase activity are disclosed. Compositions that enhance bioavailability of curcumin, demethoxycurcumin, bisdemethoxycurcumin, a-turmerone, ar- turmerone, or, sesamolin are disclosed. Some compositions include a curcuminoid mixture and essential oil of turmeric having a-turmerone. Some compositions include a curcuminoid mixture and a combination, wherein the combination includes essential oil of turmeric having a-turmerone, and, an extract of sesame oil having sesamolin. Some compositions are a combination of essential oil of turmeric having a-turmerone, and, an extract of sesame oil having sesamolin. Methods of preparing the compositions are disclosed. Methods of treatment of central nervous system or neurological disorders are provided.
