Purification and characterization of pure curcumin, desmethoxycurcumin, and bisdemethoxycurcumin from North-East India Lakadong turmeric (Curcuma longa)

Lakadong turmeric has been outlined for its high content of curcuminoids across the globe. Three significant molecular markers are widely present in turmeric viz, curcumin, desmethoxycurcumin, and bisdemethoxycurcumin, and they are present very high amount in Lakadong turmeric. Curcuminoids have been reported for structural and spectrum similarity of 3 to 4 nm (432, 434, and 436 nm, respectively). Current purification methods are based on recrystallisation where it is difficult to get highly pure material and preparative methods associated with tedious separation with high cost. Lakadong turmeric has not been explored commercially since long time. No reports are available in the literature with highly pure reference materials with in-depth characterization data and purity assessment. Curcumin, desmethoxycurcumin, and bisdemethoxycurcumin were characterized using different analytical techniques viz, UV-Visible Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Proton Nuclear Magnetic Resonance (1HNMR), Carbon-13 Nuclear Magnetic Resonance (13CNMR), High-Resolution Mass Spectrometry (HR-MS) and Inductive Coupled Plasma Mass Spectrometry (ICP-MS). Purified 3 markers has shown High-Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) purity more than 99.5%. DSC the melting peaks of curcumin, desmethoxycurcumin and bisdemethoxycurcumin were observed at 168 °C, 165 °C, and 210 °C, respectively. These plant-based markers have high commercial potential as reference material for routine Quality Assurance and Quality Control (QAQC) in herbal industries.