MARKER FINGERPRINTS ORIGINATING FROM TLC AND HPLC FOR SELECTED PLANTS FROM THE LAMIACEAE FAMILY

Abstract

Phytochemical analysis of plant extracts is an increasingly important field of analytical chemistry, and for several reasons. In the case of medicinal plants usually traded in a dried and crumbled form, phytochemical analysis serves the purpose of authentication of herbal material and protects patients against adulteration. In botanical sciences, phytochemical analysis is employed for the development of plant systematics known as chemotaxonomy. Due to an unknown composition of plant extracts and an inherent difficulty in selecting proper phytochemical standards, a phytochemical approach has been developed known as fingerprinting. This approach circumvents tedious identification of individual constituents of plant extracts and instead, focuses on a comparison of the whole chromatograms in order to trace similarities and dissimilarities among the plants. In this study, we present the results of a comparison of six plant species belonging to three genera of the Lamiaceae family (i.e., Salvia, Thymus, and Dracocephalum). This comparison was purposely carried out for the Lamiaceae plants, as many of them have been recognized for their curative properties by traditional medicines in many regions of the world (and in the first instance, in the Mediterranean zone). As phenolic acids and flavonoids play crucial role in many curative processes, in our study we employed TLC and HPLC to fingerprint the selectively extracted six phenolics fractions for the six plants belonging to the three aforementioned genera. The obtained results point out to the flavonoid aglycons (FA) fraction which most distinctly discriminates among the individual plant species, while the remaining five fractions are the carriers of less vital information. Finally, an assumption was made that the chromatograms derived by means of TLC and HPLC for the fraction of flavonoid aglycons can be considered as marker fingerprints, able to distinguish among closely related plants belonging to different genera of the Lamiaceae family.