RESUMEN
The EtOAc extract from the leaves of Piper carniconnectivum C. DC. was subjected to chromatographic separation to afford two non-aromatic B-ring flavanone compounds: 5-hydroxy-2-(1'-hydroxy-4'-oxo-cyclohex-2'-en-1'-yl)-6,7-dimethoxy-2,3-dihydro-4H-chromen-4-one (1) and 5-hydroxy-2-(1',2'-dihydroxy-4'-oxo-cyclohexyl)-6,7-dimethoxy-2,3-dihydro-4H-chromen-4-one (2). The absolute configuration of (+)-1 was unambiguously determined as 2S,1'R by electronic circular dichroism (ECD) spectroscopy and comparison to simulated spectra that were calculated using time-dependent density functional theory (TDDFT). This methodology allowed the assignment of the absolute configuration of (+)-2 also as 2S,1'R, except for the stereogenic center at C-2', which was assigned as R because of the evidence drawn from high resolution NMR experiments. The cytotoxic activity of both compounds and 3 (hydrogenated B-ring derivative of 1) was evaluated on twelve human leukemia cell lines, and the IC50 values (<10 µM) indicated the activity of 1 against seven cell lines.
Asunto(s)
Flavanonas/aislamiento & purificación , Flavanonas/farmacología , Piper/química , Dicroismo Circular , Ensayos de Selección de Medicamentos Antitumorales , Flavanonas/química , Humanos , Concentración 50 Inhibidora , Resonancia Magnética Nuclear Biomolecular , EstereoisomerismoRESUMEN
The Piper species chemistry has been widely investigated and the phytochemical analyses have led to the isolation of a number of active compounds like alkaloids, terpenes and flavones among others. The aim of this study was to evaluate the leishmanicidal activity of 2-[1-hydroxy-3-phenyl-(Z,2E)-2-propenylidene]-4-methyl-4-cyclopentene-1,3-dione (DCPC), a cyclopentenedione derivative isolated from the roots of Piper carniconnectivum C. DC., Piperaceae. Leishmanicidal activity against Leishmania amazonensis promastigotes was assessed, and the risk to host cell was assessed by measuring the cytotoxicity to peritoneal macrophages from BALB/c mice in vitro. L. amazonensis promastigotes and host macrophages were cultured in the presence of 100, 50, 25, 12.5 and 6 µg/mL of the cyclopentenedione derivative for up to 96 h. At the end of this period, the inhibitory concentrations (IC50) were compared with those from untreated cultures. The IC50 for promastigotes was 4.4 µg/mL after 96 h of treatment with the derivative. The 50% cytotoxic concentration (CC50) against murine peritoneal macrophages was 129 µg/mL. These results indicate that DCPC is a promising molecule for the development of leishmanicidal drugs.
RESUMEN
Os flavonóides 5,3,4-triidroxi-7-metoxiflavona, 5,3-diidroxi-7-4-dimetoxiflavona, 5,4-diidroxi-7-metoxiflavona e uma mistura de esteróides (β-sitosterol e estigmasterol) foram isoladas das partes aιreas de Piper carniconnectivumC.DC, Piperaceae. As estruturas desses compostos foram estabelecidas por análises espectroscópicas de UV, IV e RMN de ¹H e 13C, incluindo técnicas uni e bidimensionais.
The flavonoids 5,3,4-trihydroxy-7-methoxyflavone, 5,3-dihydroxy-7-4-dimethoxyflavone, 5,4-dihydroxy-7-methoxyflavone and steroids mixture (β-sitosterol and stigmasterol) were isolated from the dried aerials parts of Piper carniconnectivumC.DC. Their structures were established by spectroscopic analyses (UV, IV and ¹H, 13C NMR, including 1D and 2D NMR).