Green Organic Chemistry: Halogen Free Isolation of Crude Curcumin and Ar-Turmerone from Turmeric

Abstract

The spice Turmeric, which comes from the underground stem of the Curcuma longa plant, has many compounds in it, such as curcumin or (1E, 6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione. Curcumin has a vast number of beneficial properties such as, antioxidant properties, anti-inflammatory properties, boosting brain-derived neurotrophic factor, and other great properties. Curcumin is a conjugated molecule, meaning that it has special chemical properties such as absorbing UV light. So far, the known isolation methods used chlorinated solvents like Dichloromethane and Chloroform. These compounds are great solvents, especially for conjugated systems because they interact favorably with the delocalized π electron system of conjugated molecules. However, these solvents are dangerously carcinogenic and are toxic to the environment. So, with that in mind, a new solvent system without any halogenated solvents at all was developed. A system of 60% Hexanes, 39% Ethyl Acetate and 1% Methanol proved to be effective in isolating Curcumin from Turmeric by methods of Thin-Layer chromatography and Column Chromatography. This solvent system uses much safer compounds compared to halogenated solvents and is much less hazardous for the environment. The extraction and isolation yielded 0.2376g of Curcumin from 5.0125g of Turmeric (4.74% yield). Curcumin was characterized by TLC, NMR-Spectroscopy and IR-Spectroscopy.