Autofluorescence of Plant Secretory Cells as Possible Tool for Pharmacy

Abstract

First experiments for identification of intact plant secretory cells filled with products of secondary metabolism known as drugs based on their fluorescence characteristics has been analyzed on some medicinal plants. Autofluorescence of compounds containing in intact and dried cells induced, mainly, by ultra-violet or violet light was well seen in visible region under various types of luminescent microscopes, including laser-scanning confocal microscope. In the fluorescence spectra of the objects one could see characteristic maxima that may be used in practice of pharmacy. The autofluorescence application gives a possibility to study occurrence and location of natural drugs within tissues and cells. Examples of similar analysis have been considered by use alkaloid-, anthraquinone- and terpenoid-containing medicinal plant species. Especially informative were the fluorescence spectra of pharmaceutically-valuable Chelidonium majus and Frangula alnus where the emission of alkaloids and anthraquinones, relatively, as drugs prevailed in the natural samples. In first species secretory cells of laticifers contained alkaloids chelerythine and sanguinarine. In more complex, multicomponent samples such as terpenoid-enriched species Achillea millefolium, Artemisia absinthium and Calendula officinalis the interference terpenoids and phenols (brightly fluoresced in glands and secretory hairs) in blue or blue-green emission were observed. Perspectives and difficulties of pharmaceutical analysis with using of autofluorescence were also considered.