the sum of each components’ activities in it. Due to various synergistic effects, they form a unity that cannot be separated. In this way, multicomponents in phytopharmaceuticals are considered “an active ingredient”. This active ingredient has been clinically proven used as a standard reference for quality control. This concept is known as “phytoequivalence” developed in Germany to ensure the consistency of phytopharmaceuticals [65].
Multicomponent active ingredients in phytopharmaceuticals can be extracts or fractions of medicinal plants’ raw materials. So, this extract or fraction is treated as a single chemical entity in every possible way. However, some difficulties must be faced when applying Good Manufacturing Practices (cGMP) of medicinal products to phytopharmaceuticals. There are many element in the active ingredients of phytopharmaceuticals, including, active, inactive, unknown compound, and elements that are dietary rather than therapeutic. Another difficulty for this analysis is to provide a standard reference that is always available. The analytical method that meets these conditions is the chromatographic fingerprint. The use of chromatographic fingerprints for phytopharmaceuticals is carried out with a focus on compounds that can be detected by the type of chromatography used with or without knowing the compounds’ structure [66].
Chromatographic fingerprints are chromatographic patterns of multicomponent active ingredients that show some pharmacologically active chemical components and show chemical characteristics. The chemical components in phytopharmaceutical active ingredients are unknown and many are in low quantities. This makes it very difficult to obtain reliable chromatographic fingerprints representing pharmacologically active components and chemical characteristics. Chromatography (TLC, HPLC, and GC), which has a powerful separation ability, is an appropriate method to meet chemical fingerprinting desires. Furthermore, the application of hyphenated chromatography and spectrometry such as HPLC-DAD, GC-MS, CE-DAD, HPLC-MS, and HPLC-NMR, can provide additional spectral information, which is very helpful in determining the chemical structure of detected compounds. Chemical fingerprint combined with a chemometric approach will provide more accurate analysis results [65].
Several factors will influence in establishing good chromatographic fingerprints. These factors include sample preparation, instrument selection, measurement conditions, and analytical methods validation. These factors must bring up all compounds in the fingerprint profile so that they can represent the integrity of phytopharmaceuticals. In sample preparation, the critical point is the method of sample extraction. The selection of instruments must pay attention to the sensitivity, selectivity, ability of the detector, and the measurement conditions. The last thing to do is to validate the method [65].
Fingerprint analysis begins with the matrix construction of peak area data—retention time of the selected peak, known or unknown identity of the compound. The matrix is then analyzed to determine the similarity or difference compared to the standard fingerprint. The most important thing in this process is peak detection (integration) and peak selection, which becomes very difficult because of complex samples containing more than 100 peaks. The disadvantage of peak selection is the amount of peak data that will be rejected. For this reason, the most recent chemometric analysis uses all data points collected in the study. Next, chromatographic fingerprints are analyzed through comparisons to determine the similarity or dissimilarity of the sample with the reference standard, presented as a correlation coefficient or congruence coefficient. The fingerprint reference standard is derived from the standardized extract of phytopharmaceuticals, which has become a product prototype. Currently, chemometric analysis methods using pattern recognition have been highly developed with various methods such as K-nearest neighbors (KNN), soft independent modeling of class analogy (SIMCA), etc. [65].
1.4 Conclusion
The use of chemical fingerprints for quality control purposes only determines the similarities and/or differences. This objective can be applied from raw material authentication, in-process manufacturing control, and end process control of finished products. But it has not yet considered the complex relationship between chromatographic fingerprints and the efficacy of phytopharmaceuticals. The efficacy of phytopharmaceuticals has the characteristics of a complex mixture of chemical compounds found in herbs. For that reason, the evaluation method of their relationship is not a trivial task. It is not easy to find a suitable method for quality control of phytopharmaceutical. The variability of medicinal plants’ chemical content as the raw materials of phytopharmaceuticals is a challenge that must be conquered with the developments of chemical and chemometric analysis methods.
Acknowledgment
Thank you to Dr. Isnaeni for useful suggestions to this chapter and to all of my students for supporting my research.
References
1. Bandaranayake, W.M., Quality Control, Screening, Toxicity, and Regulation of Herbal Drugs. Mod. Phytomedicine Turn. Med. Plants into Drugs, I. Ahmad, F. Aqil, M. Owais, (Eds.), Wiley-VCH Verlag GmbH & Co, Weinheim, 2006.
2. Leung, E.L., Cao, Z.W., Jiang, Z.H., Zhou, H., Liu, L., Network-based drug discovery by integrating systems biology and computational technologies. Brief. Bioinformatics, 14, 491–505, 2013.
3. Mohamed, I., Shuid, A., Borhanuddin, B., Fozi, N., The Application of Phytomedicine in Modern Drug Development. Internet J. Herb. Plant Med., 1, 1–9, 2012.
4. Silva Junior, J.O.C., Ribeiro Costa, R.M., Martins, F., Ramos Barbos, W.L., Chap. 11, in: Quality Control of Herbal Medicines and Related Areas, Y. Shoyama, (Ed.), pp. 195–222, Intechopen, Croatia, Shanghai, 2011.
5. Hussain, K., Majeed, M.T., Ismail, Z., Sadikun, A., Ibrahim, P., Traditional and complementary medicines: Quality assessment strategies and safe usage. South. Med. Rev., 2, 19–23, 2009.
6. Kaur, J., Kaur, S., Mahajan, A., Herbal Medicines: Possible Risks and Benefits. Am. J. Phytomedicine Clin. Ther., 1, 226–239, 2013.
7. Abdel-Aziz, S.M. and Aeron, A.A.K.T., Microbes in Food and Health, N. Garg, S.M. Abdel-Aziz, A. Aeron, (Eds.), pp. 97–116, Springer International Publishing, Switzerland, 2016.
8. WHO, WHO guidelines on good agricultural and collection practices (GACP) for medicinal plants, World Health, Geneva, 2003.
9. Zhang, J., Wider, B., Shang, H., Li, X., Ernst, E., Quality of herbal medicines: Challenges and solutions. Complement. Ther. Med., 20, 100–106, 2012.
10. Tarkang, P.A., Appiah-Opong, R., Ofori, M.F., Ayong, L.S., Nyarko, A.K., Application of multi-target phytotherapeutic concept in malaria drug discovery: A systems biology approach in biomarker identification. Biomark. Res., 4, 1–16, 2016.
11. Pferschy-Wenzig, E.M. and Bauer, R., The relevance of pharmacognosy in pharmacological research on herbal medicinal products. Epilepsy Behav., 52, 344–362, 2015.
12. Mukherjee, P.K., Phyto-Pharmaceuticals, Nutraceuticals and Their Evaluation, in: Qual. Control Eval. Herb. Drugs, Elsevier, Amsterdam, Oxford, Cambridge, 2019.
13. Fadzil, N.F., Wagiran, A., Salleh, F.M., Abdullah, S., Izham, N.H.M., Authenticity testing and detection of Eurycoma longifolia in commercial herbal products using bar-high resolution melting analysis. Genes (Basel), 9, 1–12, 2018.
14. Yu, N., Wei, Y.-l., Zhu, Y., Zhu, N., Wang, Y.-l., Zhang, H.-p., Sun, A.-d., Integrated approach for identifying and evaluating the quality of Marsdenia tenacissima in the medicine market. PLoS One, 13, 1–11, 2018.
15. Folashade, O., Omoregie, H., Ochogu, P., Standardization of herbal medicines—A review. Int. J. Biodivers. Conserv., 4, 101–112, 2012.
