Structure and morphological studies of curcuminoids and curcuminoid mixture

Turmeric and commercial curcumin contains curcumin, desmethoxycurcumin and bisdesmethoxycurcumin as major components and they exhibit potential biological applications. Controlled crystallization of curcuminioids could lead to formation of new polymorphs/with different morphological features. In this report the structure and morphological changes taking place during the crystallization of curcuminoid mixture as well as individual curcuminoid polymorphs at different temperatures have been reported. The samples have been characterized using powder X-ray diffraction, infrared spectroscopy, 1H and 13C NMR and scanning electron microscopy. Our results show that curcumin exhibit polymorphs of which curcumin form 1 (monoclinic crystal system) has rod like morphology while curcumin form 2 (orthorhombic crystal system) shows sheet like morphology. Desmethoxycurcumin and bisdesmethoxycurcumin does not exhibit polymorphism and possess spherical shape and irregular morphology respectively.