Review Article

Biochemistry, Safety, Pharmacological Activities, and Clinical Applications of Turmeric: A Mechanistic Review

Table 2

The main products of turmeric, their descriptions, and uses.

Product nameDescriptionUses

Whole rhizome (dried form)Appearance: orange-brown, red-yellow, or pale yellowMedicinal purposes
Chemical composition: it may contain 3–15% curcuminoids, and 1.5 to 5% essential oils
Preparation: finger rhizomes and mother rhizomes are generally boiled, separately for about 40–60 min, under slightly alkaline conditions. It should be followed by sun-drying for 10–15 days to diminish the moisture content about 10%

Ground turmericAppearance: either yellow or red-yellow in colorUsed as a spice, dye, medicine, and as a dietary supplement
Chemical composition: the main active ingredients (i.e., curcuminoids and essential oils) may lessen during the process and also by exposure to light. It is necessary to pack the powder in a UV protective container
Preparation: dried finger rhizomes are grounded to produce its powder

Turmeric oilAppearance: yellow to brown oilUsed as spice, medicine, and dietary supplement
Chemical composition: essential oils from the leaves are usually dominated by monoterpenes. Rhizomes oil mainly contains sesquiterpenes
Preparation: extract procured from dried rhizomes or leaves by steam distillation or supercritical CO2 extraction

Turmeric oleoresinsAppearance: dark yellow, reddish-brown viscous fluidUsed as a food coloring, medicine, and dietary supplement
Chemical composition: they consist of up to 25% essential oil and 37–55% curcuminoids
Preparation: extract from dried rhizomes by solvent extraction with organic solvents (acetone, dichloromethane, 1,2-dichloroethane, methanol, ethanol, isopropanol, and light petroleum (hexanes)) or by the application of supercritical CO2 extraction

CurcuminAppearance: crystalline powder of yellow to orange-red colorUsed as medicine and dietary supplement
Chemical composition: a mixture of curcumin and its bisdemethoxy- and demethoxy- derivatives (no fixed proportions). The three major curcuminoids may occupy 90% of the whole proportion. Oils and resins may be the minority of composition
Preparation: it is obtained by solvent extraction from ground turmeric rhizomes followed by the purification of the extract through the crystallization process
Organic solvents used for extraction are acetone, carbon dioxide, ethanol, ethyl acetate, hexane, methanol, and isopropanol