Turmeric root (Curcuma longa L.) is a popular herbal material used and sold worldwide as a spice, herbal medicine and food supplement.
The terms turmeric and curcumin are often used interchangeably in the marketplace, but have different meanings. Turmeric is the common name for the rhizome of Curcuma longa L., a herb grown in tropical and subtropical regions of the world, with India being one of the largest producers of turmeric in the world. The rhizome is the most commonly used part of the plant and contains a variety of compounds, including the bioactive, non-volatile curcuminoids and volatile compounds present in the oil (mono- and sesquiterpenoids).
Curcumin, together with desmethoxycurcumin and bisdesmethoxycurcumin, belongs to the “curcuminoids”, a natural complex of diarylheptanoid derivatives isolated from turmeric.
Curcumin, the major and most active component of turmeric, has multiple therapeutic potentials for both health promotion and disease prevention, with emphasis on its anti-inflammatory and antioxidant properties.
Curcumin is widely used in the pharmaceutical, cosmetic and dietary supplement industries and is available in various forms such as capsules, tablets, ointments, energy drinks, soaps and cosmetics.
Currently, curcumin is approved in the EU as a food colorant under code E 100 for food (20 to 500 mg/kg) and beverages (100 to 200 mg/L). The FDA concluded that curcuminoids used as antioxidants and flavoring agents at maximum levels of > 20 mg per serving in certain foods are safe. However, the agency “has not made its own determination of “Generally Recognized As Safe” status for the use of curcuminoids”. Based on the long-established safety record in both animals and humans, it is considered that curcuminoids are safe for consumption even at doses as high as 8 g/day.
And although the US Pharmacopeia states that curcuminoid ingredients should contain no less than 95.0% w/w (dried basis) of curcuminoids, calculated as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin, many curcuminoid raw materials contain less and are commercially available, usually at a lower price.
Turmeric is often sold in powder form as a root powder or dry extract; however, it is susceptible to contamination and adulteration from ingredients with similar particle size and appearance. Previous studies have shown that turmeric ingredients are mixed with or substituted for the powder of other turmeric species, starch, chalk powder, dyes, and synthetic curcuminoids.
Natural turmeric extracts contain a mixture of curcumin, desmethoxycurcumin and bisdesmethoxycurcumin.
A high percentage of curcumin to curcuminoids can be used as an indicator of the presence of synthetic curcumin.
Another known safety concern with curcumin and/or raw turmeric is lead contamination, either from turmeric grown in lead-contaminated soil or from intentional adulteration with a Pb-based dye used to improve the appearance of turmeric. As a result, raw or ground turmeric could potentially contain high concentrations of lead.
The main challenge in analyzing turmeric supplements is the rather unclear packaging, which often does not contain information about the curcuminoid content of the product. Analysis of the supplements showed that supplements containing raw turmeric contained significantly less curcuminoids than the extracted supplements. Another factor is stability. Curcumin has been shown to be unstable and photosensitive in aqueous solution.
To meet industry requirements, analytical testing for identity and content analysis of the main active ingredients is essential to support quality control and label claim purposes of turmeric products. HPLC has proven to be a reliable and robust tool for the analysis of raw materials, food supplements, foods and beverages, as the method provides rapid and selective results for the tested compounds.
With our selective, sensitive and validated HPLC-UV method, our laboratory can provide you with routine quantitative analysis of curcumin, desmethoxycurcumin and bisdesmethoxycurcumin in various samples tailored to the specifics of your product.
For further questions please do not hesitate to contact us.
