The collection strategy
Plants use a battery of chemical and physical defenses to protect themselves from herbivores and pathogens. Most bioprospecting strategies focus on collecting mature leaves, however, ecological research by Drs. Coley and Kursar has shown that young leaves may be a more promising source of useful pharmaceuticals. Young leaves cannot be tough, an effective defense for mature leaves, so chemical defenses are the only option. Young leaves therefore contain higher concentrations of defensive compounds, as well as compounds that are not found in the mature leaves.

The Botanists
The Panama ICBG employs three botanists who are in charge of collections and recollections of plants throughout the country. Since the inception of the project in 1998, the botanists - Rafael Aizprúa, Blanca Arauz and Nayda Flores - have collected young and mature leaves from over 1000 plant species. They have herbarium vouchers of all samples located at the Smithsonian Tropical Research Institute (STRI) and the University of Panama. The taxonomic identity of all species with activity is confirmed by Professor Mireya Correa, Director of the National Herbarium of Panama.

Collection Techniques
The botanists travel to parks and protected areas in Panama to make their collections. Small quantities (<100g) of young leaves are collected from species that have not previously been sampled. For each plant, the location is noted using GPS (Global Positioning System) and the plant is photographed and marked with a tag. Three botanical samples are taken, one for the herbarium at the University of Panama, one for the herbarium at STRI, and one for the Panama ICBG project. If plants are sterile, they are revisited regularly until fruiting or flowering allows a positive taxonomic identification. If plants are active in bioassays, botanists return and make larger collections that allow bioassay guided fractionation and identification of active compounds. Making small initial collections minimizes the impact on plant populations.

Sample processing and extraction techniques
Once the samples are collected it is important to process them rapidly in order to avoid any degradation or decomposition of the chemical compounds. For that reason, as soon as the botanists return from the field, the chemists (Nivia Ríos and Johant Lakey) extract the samples. Samples are extracted in alcohol, filtered, lyophilized and stored at -70oC. For samples collected on Barro Colorado Island (BCI), extractions were done in the laboratory located on BCI. Currently collections are occurring at other sites within Panama and the extraction laboratory is located at the Earl S. Tupper Center of STRI in Panama City. When collections are made at sites more than a few hours from STRI, the botanists begin the extraction process by cutting leaf samples into ethanol and storing them on dry ice until further homogenization and filtration at the STRI lab.

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