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Botanical Adulterants Prevention Program Publishes Turmeric Laboratory Guidance Document

The ABC-AHP-NCNPR Botanical Adulterants Prevention Program (BAPP) recently published a Laboratory Guidance Document (LGD) on turmeric (Curcuma longa, Zingiberaceae) raw material and products.

Turmeric has a long history of use as a spice and medicinal plant, but its popularity in countries outside Asia has recently started to surge because of its medicinal properties. In 2018, turmeric dietary supplements ranked second in sales in the US natural channel and third in the US mainstream channel, according to HerbalGram’s 2018 Herb Market Report.1

Reports of turmeric adulteration often describe substitution with other Curcuma species or the undeclared admixture of starches or dyes. More recently, the addition of undeclared synthetic curcumin, one of the naturally occurring substances in turmeric, and mixtures of synthetic curcuminoids to turmeric extracts have been reported. Synthetic curcuminoids can be made for about one-third of the cost of natural curcuminoids, giving some suppliers a financial incentive to dilute or replace turmeric extracts with synthetic materials.

The new LGD was written by John H. Cardellina II, PhD, a noted expert in natural products chemistry and analysis. The LGD evaluates published analytical methods to detect the adulteration of turmeric root/rhizome raw material and extracts and finished turmeric products and summarizes the main advantages and disadvantages of each method regarding its suitability for use in a quality control laboratory. In addition, the document details the chemical composition of turmeric root and rhizome, potential confounding species, and known adulterants. The LGD was reviewed by 29 international experts from academia, third-party contract analytical laboratories, and the herbal dietary supplement and herb and spice industries. BAPP published a Botanical Adulterants Prevention Bulletin on turmeric in May 2018.

Stefan Gafner, PhD, chief science officer of ABC and technical director of BAPP, explained: “Because adulteration of turmeric comes in various forms, a number of orthogonal methods (i.e., multiple methods that can measure different analytes in a sample) are needed to ensure that the turmeric ingredient is authentic. Chromatographic methods may be useful for the detection of other Curcuma species or certain pigments, but they may miss the undeclared admixture of starches or the presence of lead chromate, which is sometimes added to impart a stronger yellow color. The possible addition of synthetic curcuminoids presents yet another analytical challenge. As such, we hope that the turmeric LGD will be a useful guide for industry quality control analysts tasked with selecting the most appropriate assays for turmeric authentication.”

Mark Blumenthal, ABC founder and executive director and BAPP founder and director, said: “BAPP has identified turmeric as a common spice with a growing public demand for its medicinal properties, and which unscrupulous sellers in the international herb market have adulterated with lower-cost and fraudulent materials. BAPP’s LGD on turmeric will be a much-needed resource for hundreds of industry, university, third-party, and government analytical laboratories around the world.”

Cardellina said: “The adulteration of turmeric is one of the more complex cases that BAPP has tackled. Synthetic organic and inorganic colorants used to improve the color of poor grade or fraudulent raw material present serious health and safety concerns, while substituting or admixing with other species of Curcuma deprives consumers of the beneficial compounds provided by turmeric. The addition of synthetic curcuminoids can create safety issues due to the possible presence of reagents and side products from the synthetic methods used. Fortunately, this LGD reviews a substantial number of analytical methods to address these many forms of adulteration.”

The turmeric LGD is the 10th publication in the series of LGDs published by BAPP. As with all publications in the program, the LGDs are freely available on ABC’s website.

About the ABC-AHP-NCNPR Botanical Adulterants Prevention Program

The ABC-American Herbal Pharmacopoeia (AHP)-National Center for Natural Products Research at the University of Mississippi (NCNPR) Botanical Adulterants Prevention Program is an international consortium of nonprofit professional organizations, analytical laboratories, research centers, industry trade associations, industry members, and other parties with interest in herbs and medicinal plants. The program advises industry, researchers, health professionals, government agencies, the media, and the public about various challenges related to adulterated botanical ingredients sold in commerce. To date, more than 200 US and international parties have financially supported or otherwise endorsed the program.

The program has produced 57 extensively peer-reviewed publications, including HerbalGram articles, Botanical Adulterants Prevention Bulletins, LGDs, and Botanical Adulterants Monitor e-newsletters.


  1. Smith T, Gillespie M, Eckl V, Knepper J, and Morton Reynolds C. Herbal Supplement Sales in US Increased by 9.4% in 2018. HerbalGram. 2019;123:62-73.