Fuente: WIPO "essential oil or extracts" A sustained release curcuminoid composition having a bioavailable curcumin composition and a release rate controlling excipient. The bioavailable composition of curcumin includes a curcuminoid mixture and an added essential oil of turmeric. The curcuminoid mixture includes curcumin, demethoxycurcumin and bisdemethoxycurcumin. The added essential oil of turmeric includes about 40% to about 50% of ar-turmerone. Methods of preparing sustained release compositions having a bioavailable curcumin composition and a release rate controlling excipient.