ABSTRACT
OBJECTIVE: To develop on-line high performance liquid chromatography-biochemical detection (HPLC-BCD) METHODS: to screen effective components in Ginkgo biloba extract for treatment of Alzheimer's disease.METHODS: Radical scavengers and AchE inhibitors in G.biloba leave extract were screened by HPLC-UV-DPPH/ABTS and HPLC-UV-AchE METHODS:, respectively. The stability and repeatability of the on-line HPLC-UV-AchE method were investigated using galanthamine as a positive reference. The main active ingredients in the extract were identified by ultra high performance liquid chromatography linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/orbitrap MS) method. RESULTS: Fourteen antioxidants in G.biloba extract were detected by the HPLC-UV-DPPH/ABTS method, while three AchE inhibitors were found by the HPLC-UV-AchE method. The three AchE inhibitors were tentatively identified by UPLC-LTQ/orbitrap MS as 4-O-beta-glucopyranosyl-cis-coumaric acid ginkgolide A and 3-O-[2-O-(β-D-Glucosyl)-α-L-rhamnosyl]quercetin, respectively. CONCLUSION: The proposed on-line HPLC-BCD method shows high sensitivity, good repeatability and stability. It can be used to screen antioxidants and AchE inhibitors in G. biloba extract. This will provide an effective, quick and convenient analysis tool to quickly find bioactive ingredients of traditional Chinese medicines for treating related diseases.
ABSTRACT
Abstract An antioxidant flavonoid has been isolated from methanolic leaf extract of Alchornea coelophylla Pax & K. Hoffm. by means of different column chromatography steps with DIAION HP-20 resin and silica gel in combination with analytical highperformance liquid chromatography (HPLC). It was identified as Apigenin-8-C- (α-L-rhamnopyranosyl-(1-›2)-β-D-glucopyranoside) on the basis of spectroscopic analysis and by comparison with related values reported in the literature. This compound exhibited high in vitro antioxidant activity through DPPH. and ABTS • + colorimetric assays with IC50 values of 7.528 and 379.7 µg. mL-1, respectively.
Resumen Se aisló un flavonoide antioxidante del extracto metanólico de hojas de Alchornea coelophylla Pax & K. Hoffm. El compuesto se obtuvo por medio de sucesivas cromatografías en columna (con la resina DIAION HP-20 y sílica gel), seguidas de cromatografía líquida de alta eficiencia (HPLC). Con base en el análisis espectroscópico y por comparación con valores relacionados reportados en la literatura, el flavonoide se identificó como Apigenin-8-C-(α-L-rhamnopiranosil-(1-›2)-β-D-glucopiranósido). Este compuesto presentó una alta actividad antioxidante in vitro: ensayos colorimétricos utilizando DPPH. y ABTS • + mostraron valores de IC50 de 7.528 y 379.7 µg mL-1, respectivamente.
Resumen Um flavonoide antioxidante foi isolado do extrato metanólico das folhas de Alchornea coelophylla Pax & K. Hoffm. por meio de diferentes etapas de cromatografia em coluna usando resina DIAION HP-20 e gel de sílica em combinação com Cromatografia Líquida de Alta Eficiencia (HPLC) analítica. O composto foi identificado como apigenina-8-C-(α-L-ramnopiranosil-(1-›2)-β-D-glicopiranosido) com base em análises espectroscópicas e por comparação com valores descritos na literatura. Este composto exibiu elevada atividade antioxidante in vitro por meio de ensaios colorimétricos por DPPH e ABTS • + com valores de IC50 de 7,528 e 379,7 µg. mL-1, respectivamente.