Extraction and HTS of Crude Plant Extracts

Medicinal plants have formed the basis of health care throughout the world since the earliest days of humanity and are still widely used and have considerable importance in international trade. Recognition of their clinical, pharmaceutical, and economic value is still growing, although this varies widely between countries. Plants are important for pharmacological research and drug development, not only when bioactive phytocompounds are used directly as therapeutic agents, but also as starting materials for the synthesis of drugs or as models for pharmacologically active compounds.

High-throughput screening, often abbreviated as HTS, is a method of scientific experimentation especially relevant to the fields of biology and chemistry. Through a combination of modern robotics and other specialized laboratory hardware, it allows a researcher to effectively conduct hundreds of scientific experiments at once. In essence, HTS uses a brute-force approach to collect a large amount of experimental data, usually observations about how some biological entity reacts to exposure to various chemical compounds in a relatively short time. A screen, in this context, is the larger experiment, with a single goal to which all this data may subsequently be applied.

Just like drugs of synthetic origin, bioactive phytocompounds range from simple to complex structures. Either way, the evaluation of a bioactive phytocompound or a natural product leads to benefits from modern HTS for the generation of analogs . Thus, paradoxically, the same combinatorial chemistry that initially caused the decline in natural product screening now promises to be an essential tool in rejuvenating it. Academic groups in particular are used to allocating significant resources of time and staff towards the total synthesis of bioactive phytocompounds. The ability to adapt such routes for the preparation of analogs is an obvious strategy for leveraging the initial expenditure, and is now increasingly evident in the literature. Because of the stricter timelines, large-scale combinatorial programs

Currently, almost every large pharmaceutical company has established HTS infrastructures and possesses large combinatorial compound libraries, which cover awide range of chemical diversity. However, the ability to detect the desired biological activity directly in the HPLC effluent stream and to chemically characterize the bioactive phytocompound on-line, would eliminate much of the time and labor taken in the fraction collection strategy. This way, cycle times, expenses, and the isolation of known or undesirable compounds would be reduced dramatically, allowing natural products to be screened in an efficient and cost effective manner