PHARMACOGNOSY & PHYTOCHEMISTRY

The subject of pharmacognosy (from the Greek words pharmacon = drug and gnosia = knowledge) and phytochemistry (from the Greek words phyton = plant and chemeia = chemistry) deals with the knowledge of natural products from plant origin exhibiting bioactivity. Pharmacognosy itself is generally regarded as the oldest of the pharmaceutical sciences and, since prehistoric times, the pharmacognost has been the person whose role it was in the society to identify crude drug materials, to assure the absence of adulteration and to diagnose and dispense an appropriate regimen. Nowadays, approximately 25% of prescriptions contain a plant-derived natural product, but in China, for example, about 8,000 plants species are utilized as medicinal agents. On the other hand, only about 5% of all plants (ca. 300,000 plant species known today) have been investigated for the presence of pharmacologically actve constituents.

Tradtional pharmacognosy was focused on botanical - morphological aspects, but pharmacognosy today is mainly phytochemistry, specially devoted to the study of pharmacologically active natural products. Modern phytochemistry constitutes an important area for pursuit as physiologically or biologically active factors. It is a highly interdisciplinary science, encompassing a broad range of studies involving biologically active principles obtained from plants. Fundamental to all of the phytochemical work is collaboration. The days of working as an individual scientist in this field have ended, since no single person has all of the necessary skills to be successful. Therefore, the forming of interdisciplinary and international research groups is becoming a very fundamental aspect. Three primary roles for phytochemistry in the future can be presented: i) drug discovery, ii) establishing the rationale for the successful employment of crude plant extracts in disease treatment, iii) development of plants as chemopreventive agents which might prevent disease or toxicity of other agents (nutritional and preventive medicine, functional medicine). An area, where substantial new effort will be made, is the examination of compounds which may have prophylactic activity.

Teaching and research in modern pharmacognosy and phytochemistry, emphasizing the biodiversity of plants, encompasses biosynthesis, extraction, isolation, identification, analysis, bioactivity determination and synthesis of plant components of interest.

State-of-the-art techniques involve:

• extraction via liquid - liquid distribution, supercritical fluids, solid phases and microwaves,
  

• separation and analysis via capillary gas chromatography (CGC), high performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE) and capillary electrochromatography (CEC),
  

• identification via UV and IR spectroscopy, mass spectroscopy (MS) and nuclear magnetic resonance (NMR) spectroscopy (proton and carbon-13),
  

• bioactivity determination via selective and sensitive in vitro and in vivo bioassays,
  

• synthesis of (modified) plant-derived substances with proven or potential therapeutical value.

Frequently, hyphenated separation - identification technques are used, such as HPLC-UV, CGC-MS, HPLC-MS, CEC-MS and even HPLC-NMR. Mastering modern pharmacognosy and phytochemistry requires thorough knowledge of all the abovementioned techniques in their most sophisticated forms, e. g. special MS ionization methods, or MS/MS studies, or multidimensional NMR techniques. Successfull research endeavors in up-to-date pharmacognosy and phytochemistry definitely mandate a multidisciplinary approach.

Pharmacognosy and phytochemistry, the study domain of biologically active natural products, are presently undergoing a renaissance at the forefront of the pharmaceutical sciences. Opportunities abound to contribute in a meaningful way for the benefit of mankind. Thus, pharmacognosy and phytochemistry are key sciences poised to contribute substantially to the discovery of new medicinal and biological agents.