FWD 2 Botanical Adulterants Monitor


HPLC-UV Fingerprinting Method to Authenticate Guggul

 

Reviewed: Ahmed R, Wang YH, Ali Z, Smillie TJ, Khan IA. HPLC method for chemical fingerprinting of guggul (Commiphora wightii) – quantification of E- and Z-guggulsterones and detection of possible adulterants. Planta Med. 2016;82(4):356-361. doi: 10.1055/s-0035-1558211.

 

Keywords: Commiphora wightii, Commiphora mukul, guggul, adulteration, HPLC-UV

 

The gum resin of guggul (Commiphora wightii syn. C. mukul, Burseraceae) is an important ingredient in Ayurvedic, Unani, and Siddha traditional medicine systems in India. Due to overharvesting, poor seed set, and slow growth, the numbers of guggul trees have diminished and the plant has been put on the list of endangered species by the International Union for Conservation of Nature and Natural Resources (IUCN).1

 

The shortage in the supply of guggul has created an incentive for economically motivated adulteration. Adulterants reportedly include the gums of gum arabic tree (Acacia senegal, Fabaceae), Indian gum Arabic tree (Acacia nilotica), lebbek tree (Albizia lebbeck, Fabaceae), neem (Azadirachta indica, Meliaceae), mango (Mangifera indica, Anacardiaceae), and horseradish tree (Moringa oleifera, Moringaceae), and the resins of Indian frankincense (Boswellia serrata, Burseraceae), and myrrh (Commiphora myrrha).2

 

The sample set included authentic and commercial samples of guggul (n=22), mango (n=4), neem (n=1), Indian gum Arabic tree (n=2), and myrrh (n=2), obtained from India, Pakistan, or the United States. After extraction using methanol, the sample solutions were analyzed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV), with a run time of 46 minutes (excluding the 5-minute washout and 15-minute equilibration time). In addition, the method was validated for quantification of E- and Z-guggulsterones.

 

The HPLC-UV fingerprints of the guggul samples varied considerably, but could be readily distinguished from the fingerprints of the adulterants. In the case of the adulterants, either no peak or only one small peak was observed within the first 30 minutes. The trace between 30 and 46 minutes was more distinct for the various materials, except for Acacia nilotica, where not a single peak eluted during the whole 46 minutes. Guggulsterones were absent in any of the potential adulterants, but were found at concentrations between 0.05% (per weight) and 0.80%, and 0.07% and 3.18%, for E- and Z-guggulsterones, respectively, in the guggul samples.

 

Comment: Most methods for the analysis of guggul have focused on the guggulsterones. However, these triterpenes are present in other plant species as well; therefore, the development of an HPLC-UV fingerprinting technique to authenticate materials labeled to contain guggul makes sense. The optimization and validation of the extraction procedure is especially helpful for a method that may be used in a quality control setting, although an exhaustive extraction may not be necessary for the purpose of the detection of adulteration.

 

As shown in the variability of the HPLC-UV chromatograms, the composition of the guggul resin can differ considerably, making it difficult to establish meaningful specifications to accept raw materials. In addition, the lack of characteristic peaks in the adulterating materials makes this method unsuitable to detect admixtures of Acacia nilotica, for example. The high-performance thin-layer chromatography (HPTLC) methods published by the HPTLC Association,3 or the United States Pharmacopeia,4 are additional methods that may further assist in authenticating this ingredient.

 

References

1.   Ved D, Saha D, Ravikumar K, Haridasan K. 2015. Commiphora wightii. The IUCN Red List of Threatened Species 2015: e.T31231A50131117. Available at: http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T31231A50131117.en. Accessed September 19, 2016.

2.   Mills S, Bone K. The Essential Guide to Herbal Safety. St. Louis, MO: Elsevier, Inc.; 2005:459-462.

3.   International Association for the Advancement of High Performance Thin Layer Chromatography (HPTLC Association). Methods: Commiphora wightii syn. Commiphora mukul (Guggul). Guggul oleo-gum-resin (Commiphora wightii syn. Commiphora mukul). HPTLC Association website. Available at: http://www.hptlc-association.org/methods.cfm. Published October 4, 2013. Accessed September 19, 2016.

4.   United States Pharmacopeial Convention. Guggul. In: United States Pharmacopeia and National Formulary (USP 39–NF 34). Rockville, MD: United States Pharmacopeial Convention; 2016:6699-6700.