ABSTRACT
Abstract Echinodorus scaber Rataj and Echinodorus grandiflorus (Cham. & Schltdl.) Micheli, Alismataceae, are popularly used to relieve inflammatory complaints and as diuretic. A study on the antinociceptive effect and selected marker compounds in eleven extracts from different locations was undertaken and their antinociceptive effect was assessed. The fingerprints were compared by HPLC-DAD and the content of vitexin, isovitexin, isoorientin and vitexin-2-O-rhamnoside were determined. All samples presented antinociceptive activity reducing the writhes by 36.4-62.5% and 47.4-79.8% at 10 and 50 mg/kg, respectively; indomethacin (5 mg/kg) reduced writhes by 82.6-90.1%. The content of the flavonoids C-glycosides, however, presented a strong variation. Isovitexin and isoorientin were found in all the samples, with content ranging from traces to 14.70 µg/mg and 2.12-84.27 µg/mg extract, respectively, while vitexin-2-O-rhamnoside occurred in quantifiable amounts only in 3 out of 11 samples ranging from 5.43 to 33.13 µg/mg extract; vitexin was not detected at all or detected in trace amounts. According to the fingerprints, the samples could be arranged in four main groups. All eleven extracts showed antinociceptive activity. Isovitexin was the only flavonoid present in all samples and can be regarded, acting in synergy with the other compounds or not, as the responsible for the antinociceptive activity. Therefore, isovitexin is a good choice as chemical marker when the antinociceptive activity of E. scaber and E. grandiflorus is investigated.
ABSTRACT
The reaction of the flavonol 3,7,3', 4'-tetra-O-methylquercetin (1) and of the isoflavone 7,4'-di-O-methylgenistein (2) with alkaline iodine in methanol afforded four new iodine derivatives: 8-iodo-5-hydroxy-3,7,3', 4'-tetramethoxy- flavone (1a) and 6-iodo-5-hydroxy-3,7,3', 4'-tetramethoxyflavone (1b) from 1; 2 afforded a mixture of two compounds, identified as a racemic mixture of (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-8-iodo-isoflavanone (2a) and (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-6,8-diiodo-isoflavanone (2b). The formation of these different products reveals a significant difference involving the chemical interaction between the reactive site of α, β-unsaturated ketones of flavonol and isoflavone under the tested reaction conditions (using I2/KOH/MeOH). Furthermore, the trans stereo selectivity is noteworthy in the nucleophylic addition of methanol at the isoflavone α, β-unsaturated system. The structures were identified on the basis of spectral data, mainly 1D and 2D NMR and mass spectra.
A reação do flavonol 3,7,3',4'-tetra-O-metilquercetina (1) e da isoflavona 7,4'-di-O-metilgenisteina (2) com iodo/KOH em metanol forneceu como produto quatro derivados iodados: 8-iodo-5-hidroxi-3,7,3',4'-tetrametoxiflavona (1a) e 6-iodo-5-hidroxi-3,7,3',4'-tetrametoxiflavona (1b) a partir da iodação de 1; a partir de 2 foi obtida uma mistura racêmica composta de (±)-trans-5-hidroxi-2,3,7,4'-tetrametoxi-8-iodo-isoflavanona (2a) e (±)-trans-5-hidroxi-2,3,7,4'-tetrametoxi-6,8-diiodo-isoflavanona (2b). A formação destes diferentes produtos revela a significante diferença envolvendo a interação química entre o sitio reativo de cetonas α, β-insaturadas de flavonol e de isoflavonas nas condições experimentais testadas (usando I2/KOH/MeOH). Além disso, ressalta-se a estereosseletividade trans na adição de metanol ao sistema α, β-insaturado da isoflavona. As estruturas foram identificadas com análise nos dados espectrométricos de RMN 1D e 2D e massas.
Subject(s)
Flavonoids/chemistry , Iodine/chemistry , Isoflavones/chemistry , Spectrum AnalysisABSTRACT
As cascas e as raízes de A. anthelmia têm sido utilizadas tradicionalmente como vermífugas. Um estudo biomonitorado do extrato metanólico das raízes de A. anthelmia conduziu ao isolamento das isoflavonas biochanina A e genisteína da fração acetato de etila; biochanina A 7-O-β-D-glicopiranosídeo, biochanina A 7-O-α-L-rhamnopiranosil-(1→6)-β-D-glicopiranosídeo e biochanina A 7-O-β-D-apiofuranosil-(1→5)-β-D-apiofuranosil-(1→6)-β-D-glicopiranosídeo da fração n-butanólica e catequina da fração metanólica. Suas estruturas foram elucidadas com base em dados espectrométricos. A atividade anti-helmíntica foi investigada em camundongos naturalmente infectados por Aspiculuris tetraptera. Os compostos isolados aplicados nos animais por via intragástrica na dose de 2,0 mg.kg-1 durante três dias consecutivos revelaram percentuais significativos na eliminação de A. tetraptera, quando comparados com o lote controle.
Bioactivity-guided fractions of the methanol extract from the roots of Andira anthelmia led the isolation of the isoflavones biochanin A and genistein from the ethyl acetate fraction; biochanin A 7-O-β-D-glucopyranoside, biochanin A 7-O-α-L-rhamnopyranosyl-(1→6)β-D-glucopyranoside and biochanin A 7-O-β-D-apiofuranosyl-(1→5)-β-D-apiofuranosyl-(1→6)β-D-glucopyranoside from the n-butanol fraction and catechin from the methanol one. Their structures were elucidated on the basis of spectroscopy data. The anthelmintic activity was investigated in mice naturally infected by Aspiculuris tetraptera. The compounds administered in the animals by intragastric route in doses of 2.0 mg.kg-1, were effective in the removal of the total number of the A. tetraptera when compared with the control group.