Investigation into the Authenticity of Cinnamon Materials Sold as Medicinal Products in Korea

 

Reviewed: Doh EJ, Kim JH, Oh SE, Lee G. Identification and monitoring of Korean medicines derived from Cinnamomum spp. by using ITS and DNA marker. Genes Genom. 2017;39:101-109.

 

Keywords: DNA barcoding, cinnamon, Cinnamomum burmannii, Cinnamomum cassia, species-specific DNA marker

 

Members of the genus Cinnamomum (Lauraceae), such as cinnamon (C. verum), cassia (C. aromaticum syn C. cassia), Padang cassia (C. burmannii), Saigon cinnamon (C. lourerii), or camphor (C. camphora) are widely used for culinary purposes and/or in herbal medicine. In addition to cinnamon, cassia, camphor, and Saigon cinnamon, the American Herbal Products Association’s Herbs of Commerce lists Indian cassia (C. tamala) as a species in commerce.¹ However, in Korea, China, Taiwan, and Japan, C. cassia is the only species of Cinnamomum officially permitted as the source of traditional medicines. Several parts of cassia are used in traditional Korean medicine, including dried young branches (Cinnamomi ramulus), dried stem bark (Cinnamomi cortex), and dried inner stem bark (Cassiae cortex interior).

 

This study investigated the authenticity of 160 commercial cassia samples used for medicinal purposes from suppliers in China, Japan, and Korea. The identity of the materials was determined by comparing the nuclear internal transcribed spacer 2 (ITS2) sequence of the samples to the sequences obtained from botanically authenticated C. burmannii (n=4), C. camphora (n=3), C. cassia (n=10), C. iners (n=3), C. japonicum (n=3), C. pauciflorum (n=2), and C. verum (n=4). In addition, a primer pair was designed to amplify a 408 base pair-long C. cassia species-specific DNA segment of the ITS gene region to confirm the barcoding results.

 

DNA sequences of sufficient quality were obtained for all voucher and commercial samples. The results showed that 158 commercial products were using C. cassia, while two samples (1.25%) originating from Sri Lanka, and sold on the Japanese market, were identified as C. burmannii. This suggests that the vast majority of cassia raw materials supplied to the Chinese, Japanese, and Korean markets are authentic

 

Comment: Cinnamomum species have a long-standing use in herbal medicine, and evidence in support of its use as an adjuvant therapy in type 2 diabetic patients has been provided in a number of randomized controlled clinical studies that were subject of systematic reviews.^2,3 The clinical studies have been mainly carried out using cassia bark powder; however, a number of Cinnamon species are used medicinally, and some of them are considered interchangeable. On the contrary, the European Pharmacopoeia recognized only C. verum as a medicinal species, while other countries, e.g., China, Japan, and Korea, list only C. cassia. A number of species are acceptable as ingredients in dietary supplements in the US market (see above), but C. burmannii and C. cassia seem to become more widespread as sources for commercial cinnamon spices,⁴ possibly due to plantations in Indonesia and Sri Lanka being depleted and used for other crops, and the lower prices of cassia materials sourced from other Asian countries (John Cardellina, email communication, December 31, 2015).

 

Test methods to distinguish Cinnamomum species based on chemical fingerprints using thin-layer chromatography (TLC),⁵ high-performance liquid chromatography ultraviolet spectrophotometry (HPLC-UV),^4,6 or direct analysis in real time mass spectrometry (DART-MS)⁷ have been published previously. The DNA method above represents an additional tool for authentication of crude Cinnamomum species bark materials.

 

References

1.     McGuffin M, Kartesz JT, Leung AY, Tucker AO. American Herbal Products Association’s Herbs of Commerce. 2^nd ed. Silver Spring, MD: American Herbal Products Association; 2000.

2.     Allen RW, Schwartzman E, Baker WL, Coleman CI, Phung OJ. Cinnamon use in type 2 diabetes: An updated systematic review and meta-analysis. Ann Fam Med. 2013 Sep-Oct;11(5):452-459.

3.     Akilen R, Tsiami A, Devendra D, Robinson N. Cinnamon in glycemic control: Systematic review and meta analysis. Clin Nutr. 2012;31(5):609-615.

4.     Wang YH, Avula B, Nanayakkara NP, Zhao J, Khan IA. Cassia cinnamon as a source of coumarin in cinnamon-flavored food and food supplements in the United States. J Agric Food Chem. 2013;61(18):4470-4476.

5.     He ZD, Qiao CF, Han QB, et al. Comparison and quality assessment of cassia bark (Cortex cinnamomi) by thin layer chromatography. J Chin Pharm Sci. 2006;15(4):195-199.

6.     He ZD, Qiao CF, Han QB, et al. Authentication and quantitative analysis on the chemical profile of cassia bark (Cortex cinnamomi) by high-pressure liquid chromatography. J Agric Food Chem. 2005;53(7):2424-2428.

7.     Avula B, Smillie TJ, Wang YH, Zweigenbaum J, Khan IA. Authentication of true cinnamon (Cinnamon verum) utilising direct analysis in real time (DART)-QToF-MS. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2014;24:1-8.