ABSTRACT
This chapter discusses the role of LC chemical screening of crude extracts used as a complement to the biological screening will be particularly emphasised and mainly examples of analysis of plants from South America. The rapid disappearance of tropical forests and other important areas of vegetation have meant that it is essential to have access to methods which lead to the rapid isolation and identification of bioactive natural products. Indeed both biological and chemical screenings provide important information on the plant constituents but the results will not be sufficient enough for the discovery of new potent drugs if no suitable pharmacological model exists. Thus, an important condition for success in the discovery of new bioactive plant constituents is the establishment of effective collaborations between botanists, phytochemists and pharmacologists in order to realise all the steps involved, starting with plant material in the field and concluding with viable pharmacologically-active compounds.
