RESUMEN
New Guinea is the world's largest tropical island and has fascinated naturalists for centuries1,2. Home to some of the best-preserved ecosystems on the planet3 and to intact ecological gradients-from mangroves to tropical alpine grasslands-that are unmatched in the Asia-Pacific region4,5, it is a globally recognized centre of biological and cultural diversity6,7. So far, however, there has been no attempt to critically catalogue the entire vascular plant diversity of New Guinea. Here we present the first, to our knowledge, expert-verified checklist of the vascular plants of mainland New Guinea and surrounding islands. Our publicly available checklist includes 13,634 species (68% endemic), 1,742 genera and 264 families-suggesting that New Guinea is the most floristically diverse island in the world. Expert knowledge is essential for building checklists in the digital era: reliance on online taxonomic resources alone would have inflated species counts by 22%. Species discovery shows no sign of levelling off, and we discuss steps to accelerate botanical research in the 'Last Unknown'8.
Asunto(s)
Biodiversidad , Clasificación/métodos , Islas , Plantas/clasificación , Mapeo Geográfico , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Internet , Nueva Guinea , Especificidad de la Especie , Factores de TiempoRESUMEN
The methanol extract of Melochia odorata yielded three 4-quinolone alkaloids including waltherione A (1) and two new alkaloids, waltherione C (2) and waltherione D (3). Waltheriones A and C showed significant activities in an in vitro anti-HIV cytoprotection assay at concentrations of 56.2 and 0.84 µM and inhibition of HIV P24 formation of more than 50% at 1.7 and 0.95 µM, respectively. The structures of the alkaloids were established by spectroscopic data interpretation.
Asunto(s)
4-Quinolonas/aislamiento & purificación , Alcaloides/aislamiento & purificación , Fármacos Anti-VIH/aislamiento & purificación , Malvaceae/química , 4-Quinolonas/química , 4-Quinolonas/farmacología , Alcaloides/química , Alcaloides/farmacología , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Relación Dosis-Respuesta a Droga , Proteína p24 del Núcleo del VIH/antagonistas & inhibidores , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Papúa Nueva Guinea , Tallos de la Planta/química , QuinolinasRESUMEN
Two new triterpenoids were isolated from the leaves and twigs of Rhus taitensis. Their structures were elucidated by 1D and 2D NMR spectroscopic studies as 1,10,24,25,30-pentahydroxysqualene and dammar-20(22),24-diene-3 ß,26,27-triol. Both compounds exhibited moderate antimycobacterial activities with an MIC of 45 µg/mL.
Asunto(s)
Antibacterianos/farmacología , Extractos Vegetales/química , Rhus/química , Triterpenos/farmacología , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Supervivencia Celular , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/crecimiento & desarrollo , Hojas de la Planta/química , Plantas Medicinales , Triterpenos/química , Triterpenos/aislamiento & purificaciónRESUMEN
Tuberculosis has become a major health problem, in particular with the emergence of extremely drug resistant tuberculosis (XDRTB). In our search for new therapeutic leads against TB, we isolated a new triterpene (1) from the plant Rhus taitensis collected in Papua New Guinea. Tetrahydroxysqualene (1) was isolated using bioassay-guided fractionation of the methanolic extract of R. taitensis leaves and twigs. The structure of tetrahydroxysqualene (1) was elucidated on the basis of HRESIMS and 1D and 2D NMR spectra. Tetrahydroxysqualene (1) exhibited antituberculosis activity with an MIC of 10.0 microg/mL, while showing only modest cytotoxicity.