State of knowledge: Histolocalisation in phytochemical study of medicinal plants

The renewed interest in medicinal plants has led us to examine more closely the usefulness of metabolite histolocalisation in screening work before any in-depth phytochemical studies. Indeed, this method is a histochemical technique allowing characterizing plant tissues constituents; and in particular metabolites of therapeutic interest, without destroying or altering as much as possible the studied plant material. This work aims at allowing us carring out a wide screening to highlight bioactive metabolites in plants studied from our rich university heritage collection.

The histochemical characterisation used in our work is a chemical, morphological and topographical (localisation) technique that uses precipitation reactions using dyes, among others. To do this we made thin cross-sections using razor blades on fresh plant material. The sections were then coloured using conventional chemical stains and observations were made using a MOTIC BA210 microscope equipped with a MOTICAM camera.

In view of obtained results, this technique, therefore, proves to be a useful screening and analysis method when applied in phytochemical studies on plants such as Datura stramonium, Peperomia obtusifolia, Cecropia obtusa, Orthosiphon aristatus and Vitex agnus castus. The obtained results confirm presence of sought metabolites, and allow their precise histological localisation. This will make extraction process more profiTable, simpler or even more ecological by avoiding waste.