Bio-Assay Guided Isolation of Germacranes with Anti-Protozoan Activity from Magnolia sororum

In the course of our search for antiprotozoal agents from terrestrial plants, three new germacranes 1, 2 and 3, together with the well known sesquiterpene lactones parthenolide (4) and costunolide (5), were isolated from Magnolia sororum using bioassay-guided fractionation methods. The structures of these new compounds were elucidated by 1D and 2D NMR spectroscopic analysis. Compound 5 exhibited activity (IC50 = 9.4 μM) in vitro against the Leishmania mexicana parasite. Additionally, all compounds were also evaluated against Trypanosoma cruzi and Monkey Vero cells without showing much activity.

Simple, specific molecular typing of dengue virus isolates using one-step RT-PCR and restriction fragment length polymorphism

A one-step RT-PCR and one-enzyme RFLP was used to detect and distinguish among flaviviruses, including the four serotypes of dengue and the St. Louis Encephalitis, West Nile and Yellow Fever viruses in cultured virus samples or acute-phase human serum. Using a previously described RT-PCR, but novel RFLP procedure, results are obtained in 24 h with basic PCR and electrophoresis equipment. There is 95% agreement between RT-PCR/RFLP results and those achieved by indirect immunofluorescence assays, and 100% agreement between RT-PCR/RFLP results and gene sequencing. This method is more rapid than tests of cytopathic effect based on virus isolation in tissue culture, and simpler than real-time PCR. It does not require specialized equipment, radioisotopes or computer analysis and is a method that can be applied widely in the developing world. It allows for prompt determination of whether a flavivirus is the cause of illness in a febrile patient, rapid identification of dengue serotypes in circulation, and improved patient management in cases where prior dengue exposure make dengue hemorrhagic fever or dengue shock syndrome a risk.