Débora Arruda Frommenwiler1, Anthony Booker2, Roser Vila3, Michael Heinrich4, Eike Reich5, Salvador Cañigueral6. 1. Unitat de Farmacologia, Farmacognòsia i Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Av. Joan XXIII, 27-31, ES-08028, Barcelona, Spain; CAMAG AG, Sonnenmattstrasse 11, 4132, Muttenz, Switzerland. 2. Pharmacognosy and Phytotherapy, Biodiversity and Medicines Research Cluster, Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy. 29-39 Brunswick Square, WC1N 1AX, London, UK; Herbal and East Asian Medicine, Department of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK. 3. Unitat de Farmacologia, Farmacognòsia i Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Av. Joan XXIII, 27-31, ES-08028, Barcelona, Spain. 4. Pharmacognosy and Phytotherapy, Biodiversity and Medicines Research Cluster, Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy. 29-39 Brunswick Square, WC1N 1AX, London, UK. 5. CAMAG AG, Sonnenmattstrasse 11, 4132, Muttenz, Switzerland. 6. Unitat de Farmacologia, Farmacognòsia i Terapèutica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Av. Joan XXIII, 27-31, ES-08028, Barcelona, Spain. Electronic address: s.canigueral@ub.edu.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Herbal medicinal products based on ginkgo leaf refined dry extract (GBE) are an European development from the Eastern Asia traditionally used species Ginkgo biloba L. Nowadays, ginkgo products have increased the presence in the market, mainly as dietary supplements. Its adulteration with rutin and quercetin or herbal extracts rich in these compounds is a common practice. Tests featuring assays and detection of adulterants need to be performed on top of other existent methods (e.g. identification test). This may increase the costs of evaluating the quality of ginkgo products. AIM OF THE STUDY: To prove that comprehensive HPTLC fingerprinting can provide information beyond identification of ginkgo products, avoiding additional chromatographic tests for detection of adulterations. MATERIALS AND METHODS: The information contained in the fingerprint obtained by HPTLC analysis of flavonoids was used for identification and for detection of adulterants, as well as to verify the limits of rutin and quercetin, which are normally determined by HPLC and used for detection of adulterants. For this purpose, peak profiles were generated from HPTLC chromatogram images. USP-HPLC methods were used for quantification of total flavonoids and testing the limits of rutin and quercetin. HPLC data were used to support the validity of the HPTLC method. An additional reversed phase HPTLC method was developed as a possible confirmatory method for the quercetin limit test. RESULTS: The proposed HPTLC method uses a particular sequence of detections, resulting in a number of images, which are later interpreted in a certain order. It is able to identify ginkgo products, to detect adulterants (rutin, quercetin, sophora fruit and flower bud, and buckwheat), and, using peak profiles generated from the chromatogram images prior to and after derivatisation, to evaluate the limits of rutin and quercetin. Forty-eight out of fifty-nine ginkgo dietary supplements analysed contained one or more adulterants. Furthermore, results of the HPTLC and HPLC limit tests for rutin and quercetin were in agreement in 98% of the cases. Finally, a decision tree showing the sequence of interpretation of the fingerprints obtained with the different detections after a single HPTLC analysis is included to help the analyst to evaluate whether samples have the correct identity and whether they contain or not adulterants. CONCLUSION: A single HPTLC analysis is able to provide information on identity and purity of the products. This simplifies the analytical workflow and reduces the number of analyses prescribed in the USP powdered ginkgo extract monograph.
ETHNOPHARMACOLOGICAL RELEVANCE: Herbal medicinal products based on ginkgo leaf refined dry extract (GBE) are an European development from the Eastern Asia traditionally used species Ginkgo biloba L. Nowadays, ginkgo products have increased the presence in the market, mainly as dietary supplements. Its adulteration with rutin and quercetin or herbal extracts rich in these compounds is a common practice. Tests featuring assays and detection of adulterants need to be performed on top of other existent methods (e.g. identification test). This may increase the costs of evaluating the quality of ginkgo products. AIM OF THE STUDY: To prove that comprehensive HPTLC fingerprinting can provide information beyond identification of ginkgo products, avoiding additional chromatographic tests for detection of adulterations. MATERIALS AND METHODS: The information contained in the fingerprint obtained by HPTLC analysis of flavonoids was used for identification and for detection of adulterants, as well as to verify the limits of rutin and quercetin, which are normally determined by HPLC and used for detection of adulterants. For this purpose, peak profiles were generated from HPTLC chromatogram images. USP-HPLC methods were used for quantification of total flavonoids and testing the limits of rutin and quercetin. HPLC data were used to support the validity of the HPTLC method. An additional reversed phase HPTLC method was developed as a possible confirmatory method for the quercetin limit test. RESULTS: The proposed HPTLC method uses a particular sequence of detections, resulting in a number of images, which are later interpreted in a certain order. It is able to identify ginkgo products, to detect adulterants (rutin, quercetin, sophora fruit and flower bud, and buckwheat), and, using peak profiles generated from the chromatogram images prior to and after derivatisation, to evaluate the limits of rutin and quercetin. Forty-eight out of fifty-nine ginkgo dietary supplements analysed contained one or more adulterants. Furthermore, results of the HPTLC and HPLC limit tests for rutin and quercetin were in agreement in 98% of the cases. Finally, a decision tree showing the sequence of interpretation of the fingerprints obtained with the different detections after a single HPTLC analysis is included to help the analyst to evaluate whether samples have the correct identity and whether they contain or not adulterants. CONCLUSION: A single HPTLC analysis is able to provide information on identity and purity of the products. This simplifies the analytical workflow and reduces the number of analyses prescribed in the USP powdered ginkgo extract monograph.
Authors: Débora A Frommenwiler; Eike Reich; Maged H M Sharaf; Salvador Cañigueral; Christopher J Etheridge Journal: Front Pharmacol Date: 2022-08-08 Impact factor: 5.988