Since curcumin was first isolated from turmeric in 1815, it is still attracting researchers from all over the world.
Reference: Molecules 2014.DOI:10.3390/molecules191220091
Physico-chemical Properties
- Curcumin is a yellowish crystalline, odourless powder (melting point 184-186°C), poorly soluble in water, petroleum ether and benzene; soluble in ethyl alcohol, glacial acetic acid and in propylene glycol; very soluble in acetone and ethyl ether.
- Absorption spectra of Curcumin and Curcuminoids are very similar, with their maximum absorption (λ) at 429 nm and 424 nm, respectively.
- Below table displays physico-chemical analysis of turmeric powder.
| S.No. | Constituents | Composition w/w |
|---|---|---|
| 1 | Curcuminoids | 1-6% |
| 2 | Volatile (Essential) Oil | 3-7% |
| 3 | Fiber | 2-7% |
| 4 | Mineral matter | 3-7% |
| 5 | Protein | 6-8% |
| 6 | Fat | 5-10% |
| 7 | Moisture | 6-13% |
| 8 | Carbohydrates | 60-70% |
Reference: Majeed M, Nagabhushanam K, Pande A, Paliwal P, Nayak M. Tetrahydrocurcuminoids: C3 Reduct® - The Cascading Anti-oxidant. New Jersey: Nutriscience Publishers, LLC., 2012; pp.09.
Curcumin: Structural Characteristics
- Curcumin, a symmetric molecule, is also known as diferuloyl methane.
- Chemical formula: C21H20O6 and Molecular weight: 368.38.
- Three chemical entities are in the structure: Two aromatic ring systems containing o-methoxy phenolic groups, connected by a seven carbon linker consisting of an α, β-unsaturated β-diketone moiety.
- Exists in multiple tautomeric states in which the diketone is stable in the enol state while being easily deprotonated to the keto state.
Classification of Active Compounds in Turmeric
The active compounds in turmeric are typically classified as non-volatile or volatile compounds:
- Major non-volatile compounds are Curcuminoids, mainly Curcumin, Demethoxycurcumin and Bisdemethoxycurcumin.
- Major volatile compounds identified are ar-turmerone, α-turmerone, β-turmerone (curlone), ar-curcumene, zingiberene, α-phellandrene, 1, 8-cineol and some other sesquiterpenes. Turmerones are sesquiterpenoid cyclic ketones, accounting for 40-50% of the volatile oil.
The Curcuminoids
The rhizomes of turmeric abound in many phenolic compounds known as Curcuminoids —responsible for the yellow colour.
It is comprised of Curcumin (75–81%), Demethoxycurcumin (15–19%) and Bisdemethoxycurcumin (2.5–6.5%).
Most of commercial Curcuminoids sold as "Curcumin", are mixtures of the three Curcuminoids. Curcumin C3 Complex®, the branded composition of natural Curcuminoids, pioneered and patented by Sabinsa Corporation, is a well characterized composition. The Curcumin C3 Complex® is standardized to contain ≥95% Curcuminoids by HPLC analysis and is currently being used by several clinical researchers with Investigational New Drug (IND) approval from the USFDA and other regulatory organizations overseas.