RESUMEN
International trade in Brazilian rosewood, Dalbergia nigra (Vell.) Allemão ex Benth., is regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). One problem in enforcing these regulations is the difficulty in distinguishing the wood of D. nigra from that of a closely-related but unregulated species, Dalbergia spruceana Benth. Using LC-MS to analyse methanol extracts of xylaria specimens, we identified a chemical marker for D. nigra heartwood, and determined its structure as the neoflavonoid 6-hydroxy-7-methoxy-4-(4-methoxyphenyl)-2H-1-benzopyran-2-one (4'-O-methylmelanettin; dalnigrin), using spectroscopic techniques. Dalnigrin was present in all nine available heartwood specimens of D. nigra, but it was not detected in extracts of 59 other heartwood samples representing 15 species of Dalbergia, including D. spruceana. Five other phenolic compounds were also isolated from D. nigra heartwood and similarly identified as the neoflavonoids 3'-hydroxymelanettin, melanettin, melannein and dalbergin, and the isoflavone caviunin. In extracts of D. spruceana heartwood, pseudobaptigenin was identified by LC-MS to be a major phenolic component that was not detected in wood extracts of D. nigra. We conclude that chemical analysis, in combination with anatomical investigation, can provide persuasive evidence to support the positive identification of untreated heartwood of D. nigra.
Asunto(s)
Biomarcadores/análisis , Cumarinas/análisis , Dalbergia/clasificación , Cromatografía Líquida de Alta Presión , Comercio , Dalbergia/química , Especies en Peligro de Extinción , Especificidad de la Especie , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría UltravioletaRESUMEN
The indole alkaloid geissoschizoline (1) and two new derivatives, geissoschizoline N(4)-oxide (2) and 1,2-dehydrogeissoschizoline (3), were obtained from the bark of Geissospermum sericeum together with the beta-carboline alkaloid flavopereirine (4). The in vitro antiplasmodial activity of these compounds was evaluated in chloroquine-resistant (K1) and chloroquine-sensitive (T9-96) Plasmodium falciparum. Their cytotoxicity was determined in a human (KB) cell line.