Antimalarial natural products drug discovery in Panama.

CONTEXT: Malaria is still a major public health problem. The biodiversity of the tropics is extremely rich and represents an invaluable source of novel bioactive molecules. For screening of this diversity more sensitive and economical in vitro methods are needed, Flora of Panama has been studied based on ethnomedical uses for discovering antimalarial compounds. OBJECTIVE: This review aims to provide an overview of in vitro screening methodologies for antimalarial drug discovery and to present results of this effort in Panama during the last quarter century. METHODS: A literature search in SciFinder and PubMed and original publications of Panamanian scientists was performed to gather all the information on antimalarial drug discovery from the Panamanian flora and in vitro screening methods. RESULTS AND CONCLUSIONS: A variety of colorimetric, staining, fluorometric, and mass spectrometry and radioactivity-based methods have been provided. The advantages and limitations of these methods are also discussed. Plants used in ethnomedicine for symptoms of malaria by three native Panamanian groups of Amerindians, Kuna, Ngöbe Buglé and Teribes are provided. Seven most active plants with IC(50) values < 10 µg/mL were identified Talisia nervosa Radlk. (Sapindaceae), Topobea parasitica Aubl.(Melastomataceae), Monochaetum myrtoideum Naudin (Melastomataceae), Bourreria spathulata (Miers) Hemsl.(Boraginaceae), Polygonum acuminatum Kunth (Polygonaceae), Clematis campestris A. St.-Hil. (Ranunculaceae) and Terminalia triflora (Griseb.) Lillo (Combretaceae). Thirty bioactive compounds belonging to a variety of chemical classes such as spermine and isoquinoline alkaloids, glycosylflavones, phenylethanoid glycosides, ecdysteroids, quercetin arabinofuranosides, clerodane-type diterpenoids, sipandinolid, galloylquercetin derivatives, gallates, oleamide and mangiferin derivatives.

Lycopodiaceae from Panama: a new source of acetylcholinesterase inhibitors.

Acetylcholinesterase (AChE) inhibitors have been used for the symptomatic treatment of Alzheimer's disease. Eleven whole plants from Panama belonging to the Lycopodiaceae family have been screened for their anticholinesterase inhibitory and antioxidant activities by a thin-layer chromatography (TLC) bioautography method. Of these, only Lycopodium clavatum subsp. clavatum showed strong AChE inhibition. Seven plant extracts showed moderate inhibition, two of them, Huperzia cf chamaeleon and Huperzia reflexa, also possessed an antioxidant activity. This is the first report of anticholinesterase and antioxidant activities in these two native plants. Additionally, alkaloid extracts of the Lycopodiaceae plants were also analysed by TLC and LC-MS to identify the well-known AchE inhibitor, huperzine A. Two plants, H. cf chamaeleon and H. reflexa var. minor, showed the presence of huperzine.