Adsorption separation of terpene lactones from Ginkgo biloba L. extract using glass fiber membranes modified with octadecyltrichlorosilane

In this study porous glass fiber membranes were modified by reaction with octadecyl-trichlorosilane to form C18 hydrophobic membranes. The contact angle and the CH2 vibration bands at 2855 and 2920 cm(-1) found by FTIR measurements verified the successful immobilization of C18 groups on the glass fiber membranes. The resulting C18 hydrophobic membranes were used to adsorb terpene lactones from crude Ginkgo biloba L. extracts. In batch adsorption processes, the modified C18 membranes exhibited a better adsorption performance than commercial C18 solid phase extraction adsorbents. Different desorption solvents were tested and ethyl acetate was found to preferentially desorb terpene lactones from the modified C18 membranes. In flow adsorption experiments at 1 mL/min, terpene lactone contents higher than 6 wt% (the standardized content) could be achieved in the elution step using ethyl acetate.     

Mass spectrometry analysis of terpene lactones in Ginkgo biloba

Terpene lactones are a family of compounds with unique chemical structures, first recognised in an extract of Ginkgo biloba. The discovery of terpene lactone derivatives has recently been reported in more and more plant extracts and even food products. In this study, mass spectrometric characteristics of the standard terpene lactones in Ginkgo biloba were comprehensively studied using both an ion trap and a quadrupole time-of-flight (QTOF) mass spectrometer. The mass spectral fragmentation data from both techniques was compared to obtain the mass spectrometric fragmentation pathways of the terpene lactones with high confidence. The data obtained will facilitate the analysis and identification of terpene lactones in future plant research via the fragmentation knowledge reported here.     

微流蒸发光散射检测器与毛细管液相色谱的联用及其在银杏叶提取物分析中的应用

将微流蒸发光散射检测器( μELSD)与毛细管液相色谱(cLC)联用,应用于中药银杏叶提取物及其分散片制剂的分离检测领域。首先对 μELSD仪器参数进行优化。通过调节漂移管温度与载气流量,提高了分析物的响应,并减小了噪声。然后,搭建了cLC-μELSD分离检测平台,其相对常规LC可大大减小实验试剂消耗。流动相A为0.05%(体积分数,下同)三氟乙酸(TFA)水溶液,流动相B为含0.05% TFA的甲醇溶液。最优的洗脱梯度条件为:0~10 min,5%B~25%B;10~25 min,25%B~38%B;25~35 min,38%B;35~40 min,38%B~42%B;40~55 min,42%B~50%B。银杏叶提取物和复杂中药制剂银杏叶提取物分散片都得到了较好的分离,并在其中鉴定到紫外波段几乎无吸收的重要内酯类活性成分白果内酯以及银杏内酯A、B和C。测定了不同厂家银杏叶提取物中萜类内酯洗脱时间的相对标准偏差,结果均不大于2.42%,表明该体系在目标物的分析上具有良好的重现性。实验证明所建立的cLC-ELSD体系在复杂中药体系的分离检测中有良好的应用性。     

高效液相色谱法快速测定银杏叶提取物中的萜类内酯

 394-397 -------------------------------------------------------------------------------- 建立了液-液萃取后高效液相色谱法（HPLC）测定银杏叶提取物（EGb）中萜类内酯含量的快速方法。EGb样品溶于体积分数为30%的乙醇溶液后用乙醚萃取,有机相浓缩后的残留物以HPLC分析,组分的分离采用C18柱,以甲醇-水-磷酸(体积比为25∶75∶0.1)为流动相,示差检测器检测。结果表明,样品净化程序较已报道的方法更简便,选择性强、快速（少于20 min）。该方法回收率大于99.0%、相对标准偏差小于2.0%、重现性好,可有效地用于银杏叶提取物的产品质量评价。     

Quantitative determination of major active components in Ginkgo biloba dietary supplements by liquid chromatography/mass spectrometry

A reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS) method was developed and validated for the simultaneous determination of ten major active components in Ginkgo biloba extract (bilobalide, ginkgolides A, B, C, quercetin, kaempferol, isorhamnetin, rutin hydrate, quercetin-3-beta-D-glucoside and quercitrin hydrate) which have not been previously reported to be quantified in a single analysis. The ten components exhibit baseline separation in 50 min by C18 chromatography using a water/1:1 (v/v) methanol/acetonitrile gradient. Quantitation was performed using negative ESI-MS in selected ion monitoring (SIM) mode. Good reproducibility and recovery were obtained by this method. The sensitivity of both UV and different mass spectrometry modes (full scan, selected ion monitoring (SIM), and selected reaction monitoring (SRM)) were compared and both quantitation with and without internal standard were evaluated. The analysis of Ginkgo biloba commercial products showed remarkable variations in the rutin and quercetin content as well as the terpene lactone contents although all the products satisfy the conventional quality control method.     

基于离子交换树脂制备多孔氧化铝球及在非水体系中分离银杏内酯

以磺酸型大孔离子交换树脂D072为模板, 设计合成了球形的多孔氧化铝, 利用XRD、SEM和氮气吸附仪对其结构进行了表征. 以这种球形多孔氧化铝作为分离材料, 考察了其在非水体系中对银杏黄酮和银杏内酯的吸附选择性, 在最佳分离条件下, 制备了纯度为58.5%, 且不含任何黄酮的银杏内酯. 利用红外光谱法证明了吸附机理为配位吸附.     

Preparative isolation of terpene trilactones from Ginkgo biloba leaves

This study investigated and compared some techniques for the preparative isolation of terpene trilactones, including ginkgolides (GA and GB, etc.) and bilobalide (BB), from Ginkgo biloba leaves. The crude Ginkgo biloba L. extracts (GBE) were prepared using an extractor with solvent refluxing operated under an optimal extraction condition. The extraction yield was 20-23% and the purity of terpene trilactones was about 1.0-1.4 wt%. Before the isolation operations, the extracts were dissolved in de-ionized water. The isolation procedures included the method of liquid-liquid extraction and the method of column chromatography. For the method of liquid-liquid extraction using ethyl acetate as the organic solvent operated under the optimal extraction conditions, the purity, concentration ratio, and yield of terpene trilactones were 13.5-18.0%, 15-16, and >99%. For the method of column chromatography, XAD-7HP, XAD-4, and C-18 adsorbents with different polarities were used as the packing materials. Only for the XAD-7HP column, a part of more polar impurities was efficiently separated with the majority of terpene trilactones by a proper step-gradient elution, which resulted in an efficient isolation: the purity, concentration ratio, and yield of terpene trilactones were approximately 20, approximately 15, and approximately 80%. In comparison, the XAD-7HP column achieved the highest purity, but at the expense of the yield of terpene trilactones; on the contrary, the liquid-liquid extraction method, achieving the highest yield but with a slightly lower purity, was proved to be superior to the method of column chromatography in the current isolation stage.     

Single-laboratory validation for the determination of terpene lactones in Ginkgo biloba dietary supplement crude materials and finished products by high-performance liquid chromatography with evaporative light-scattering detection

A single-laboratory validation was completed for a method to determine total terpene lactones in Ginkgo biloba products. The method determines terpene lactones on the basis of the main terpene lactones (Bilobalide, Ginkgolide A, Ginkgolide B, Ginkgolide C, and Ginkgolide J) by high-performance liquid chromatography with evaporative light-scattering detection after extraction. Nine matrixes were chosen for study, including crude leaf material, standardized dry powder extract, single- and multiple-entity finished products, and alcohol and glycerin tinctures. The sample purification with prepacked columns allows selective extraction of the terpene lactones with no interferences from any matrix under study. A Youden ruggedness trial testing 7 instrumental and preparation factors with the potential to affect quantitative results showed that 2 factors (volume of the column elution solvent and pH of the diluent) were the most important parameters to control during sample preparation. The method performed well in terms of precision; 4 matrixes tested in triplicate over a 3-day period showed an overall repeatability relative standard deviation (RSD) of about 3%. HorRat values were within the limits for performance acceptability, ranging from 0.5 to 1.0. Analysis of variance testing at a = 0.05 showed no significant differences among the within-or between-group sources of variation, although comparison of within-day, between-day, and total precision showed that most of the RSD came from within-day determinations except those for the Ginkgo dry extract (Gb-SLV-2). Accuracy testing at 4 concentration levels of terpene lactones obtained by spiking a negative control matrix at approximately 300, 750, 1500, and 2250 microg/mL gave recoveries of about 91% for the 300 microg/mL level, about 98% for the 750 microg/mL level, about 99% for the 1500 microg/mL level, and 97% for the 2250 microg/mL level with an overall recovery of 96% and an RSD of 3.2%.     

Liquid chromatography/electrospray mass spectrometry of bioactive terpenoids in Ginkgo biloba L

Standardized extracts of Ginkgo biloba leaves are mainly used in the treatment of peripheral and celebral circulation disorders, and also as a remedy against asthma, coughs, bladder inflammation, blenorrhagia and alcohol abuse. The leaf extracts contain biflavones, flavonol glycosides and terpene lactones. This paper reports a method based on liquid chromatography coupled with electrospray mass spectrometry for the analysis of terpenoids in G. biloba extracts. This method allows the rapid isocratic separation of underivatized ginkgolides (GA, GB, GC and GJ) and bilobalide at very low levels (10 pg on the column) and their quantitative detection by external standardization with relative standard deviations of 3 and 5% for intra- and inter-day analyses, respectively.     

Sample preparation and determination of ginkgo terpene trilactones in selected beverage, snack, and dietary supplement products by liquid chromatography with evaporative light-scattering detection

Ginkgo biloba leaf extract has been widely used in dietary supplements and more recently in some foods and beverages. Sample preparation procedures for determination of ginkgo terpene trilactones (including bilobalide and ginkgolides A, B, C, and J) in various sample matrixes were developed in this study. Ginkgo leaves and capsules were extracted with 5% KH2PO4 aqueous solution under sonication. Tea bags were extracted with boiling water, whereas drink samples were taken directly from the bottles. After filtration and the addition of NaCl to approximately 30% (w/v), the terpene trilactones in aqueous solutions were quantitatively extracted with ethyl acetate-tetrahydrofuran (4 + 1, v/v). Puff samples (a cereal-based fried snack item) were first defatted by using hexane or by using supercritical fluid extraction and then extracting under sonication with methanol-acetic acid (99 + 1, v/v). After evaporation of the organic phase, the terpene trilactones were redissolved in methanol and determined on a C18 reversed-phase column by liquid chromatography (LC) with evaporative light-scattering detection. The method of standard additions and gas chromatography with flame ionization detection were used for method validation. For most samples, the relative standard deviation was <10%. The identities of target compounds in ginkgo leaves and drink samples were confirmed by LC/electrospray ionization-tandem mass spectrometry.     

Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry of terpene lactones in plasma of volunteers dosed with Ginkgo biloba L. extracts

Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-ITMS) was applied to evaluate the levels of ginkgolides A and B and bilobalide in plasma of volunteers after administration of Ginkgo biloba extracts in free (Ginkgoselect) or phospholipid complex (Ginkgoselect Phytosome) forms, providing 9.6 mg of total terpene lactones. The maximum plasma concentrations, C(max), of total ginkgolides A, B and bilobalide were 85.0 and 181.8 microg/mL for Ginkgoselect and Ginkgoselect Phytosome, respectively. The C(max) values were reached at 120 min for the free form and at 180--240 min for the phospholipid complex form. In both cases, the mean elimination half-life of each terpene lactone was in the range 120--180 min. Due to its sensitivity (about 1 ng/mL) and specificity, LC/APCI-ITMS proved to be a very powerful tool for pharmacokinetic studies of these phytochemicals.     

Chromatographic fingerprint analysis for evaluation of <Emphasis Type="Italic">Ginkgo biloba</Emphasis> products

The flavonoids and the terpene lactones are regarded as the two main active components of Ginkgo biloba that affect human health. In the work discussed in this paper, two analytical methods for the characterization of G. biloba authentic materials and commercial products, an LC–UV chromatographic fingerprinting method and a traditional flavonol quantification method, were compared. The traditional method was used to determine the total flavonol content (as glycosides) after acid hydrolysis. The fingerprinting method examined the chromatographic profiles of methanol–water extracts using chemometric methods. The traditional method showed that all the commercial products met the current voluntary standard of 24% flavonols by weight. The chromatographic fingerprinting method revealed significant variations in the commercial products with regard to the relative concentration of individual flavonols.     

Chemistry and biology of terpene trilactones from Ginkgo biloba

Ginkgo biloba, the ginkgo tree, is the oldest living tree, with a long history of use in traditional Chinese medicine. In recent years, the leaf extracts have been widely sold as phytomedicine in Europe and as a dietary supplement worldwide. Effects of Ginkgo biloba extracts have been postulated to include improvement of memory, increased blood circulation, as well as beneficial effects to sufferers of Alzheimer's disease. The most unique components of the extracts are the terpene trilactones, that is, ginkgolides and bilobalide. These structurally complex molecules have been attractive targets for total synthesis. Terpene trilactones are believed to be partly responsible for the neuromodulatory properties of Ginkgo biloba extracts, and several biological effects of the terpene trilactones have been discovered in recent years, making them attractive pharmacological tools that could provide insight into the effects of Ginkgo biloba extracts.     

Development, optimization and validation of a fingerprint of Ginkgo biloba extracts by high-performance liquid chromatography

A four-step development, optimization and validation strategy for high-performance liquid chromatography (HPLC) fingerprints of Ginkgo biloba extract is described. A suitable chromatographic system was selected first. The following step was performing a screening design to select important parameters. After selecting some controllable parameters and their range to further optimize, gradient optimization with uniform design was done. At last, method validation including determination of injection precision, repeatability, and a sample stability test, was performed. Through this effective and integrated four-step method, a feasible and reliable HPLC fingerprint to identify and assess the Ginkgo biloba quality can easily be established using a linear gradient elution with acetonitrile/0.1% phosphoric acid (from 14/86 to 30/70, v/v, in 40 min) as mobile phase, a column temperature of 30 degrees C and a detection wavelength of 350 nm. The strategy can also be applied for the development of fingerprints in the quality control of other herbal medicines.     

全二维液相色谱串联质谱用于银杏叶提取物成分分析的研究

建立了全二维液相色谱串联质谱分离分析模式,将质脂体色谱柱和ODS反相色谱柱作为二维分析色谱柱,二者通过一个连有两个0.5 mL定量环的八通阀耦联。质脂体色谱柱上的馏分在反相色谱柱上分离后,直接进入紫外-检测器,然后经分流器分流后进入大气压电离质谱。将该体系用于银杏叶提取物的组成研究,共检测到至少41个组分,结合紫外-可见光谱和质谱信息,其中13个组分初步鉴定为银杏内酯B、银杏内酯C、白果内酯、槲皮素芸香糖苷、槲皮素、槲皮素-3-O-β-D-葡萄糖基(1-2)-α-L-鼠李糖苷、槲皮素-3-O-β-D-葡萄糖苷、异鼠李素、山柰酚-3-O-β-D-芸香糖基(1-2)-α-L-鼠李糖苷、异鼠李素-3-O-β-D-芸香糖苷、山柰酚-3-O-β-D-葡萄糖苷、山柰酚和山柰酚-3-O-β-D-芸香糖苷。     

Application of reverse-flow micellar electrokinetic chromatography for the simultaneous determination of flavonols and terpene trilactones in Ginkgo biloba dosage forms

A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and -cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 microm I.D. x 360 microm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of -17.5 kV. Samples were injected electrokinetically at -5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 microg/ml and 1.88 microg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products.     

Analysis of terpenelactones in Ginkgo biloba by high performance liquid chromatography and evaporative light scattering detection

A reversed phase HPLC method permitting the determination of 5 terpenelactones in Ginkgo biloba, without the need of any sample preparation is presented in this paper. The compounds were successfully separated within 25 min by using a C-12 column, an evaporative light scattering (ELS) detector and a mobile phase comprising of ammonium acetate buffer, methanol and isobutanol. All terpenelactones were detectable at concentrations as low as 20.3 microg/ml. The analysis of G. biloba market products showed remarkable variations in the lactone content, and more than 2 fold differences in the suggested daily doses of the total lactones, from 8.84 mg to 18.28 mg, respectively.     

Fluorophotometric thin-layer chromatography of ginkgo terpenes by postchromatographic thermochemical derivatization and quality survey of commercial ginkgo products

Terpenoid lactones in Ginkgo biloba leaves are the main active constituents and the content of these terpenes is therefore the key factor for evaluating the quality of the leaves, the extract, and its preparations distributed on the market. The precleanup sample solutions were applied onto the silica gel plate modified with sodium acetate solution and developed with a solvent system of toluene-ethyl acetate-acetone-methanol, and a fluorescence chromatogram was generated by means of postchromatographic thermal chemical reaction. Fluorescence scanning was conducted quantitatively. The methodology validation confirmed that it is a practical alternative for routine quality control for ginkgo terpenes and the results are comparable with those obtained by high-performance liquid chromatography (HPLC). On the basis of the method established, a quality survey of the various commercial ginkgo products from different sources was undertaken. The obtained data demonstrated that the fluctuation of the content of individual terpene and/or the total terpenes among replicate samples is so significant as to cast doubts on the consistency of their pharmacological and clinical efficacy.     

A rapid RP-HPTLC densitometry method for simultaneous determination of major flavonoids in important medicinal plants

A simple, sensitive, selective, precise, and robust high-performance TLC (HPTLC) method was developed and validated for determination of flavonoids in herbal extracts Bauhinia variegata, Bacopa monnieri, Centella asiatica, Ginkgo biloba, Lonicera japonica, Rosa bourboniana, Rosa brunonii, and Rosa damascena. The HPTLC of flavonoids was performed on RP-18 F(254) TLC plates with dual run, water (5% formic acid)/methanol (70:30) and water (5% formic acid)/methanol (50:50) as mobile phases. Densitometric determination of flavonoids was performed at lambda = 280 nm in reflectance/absorbance mode. The linear regression analysis data for the calibration plots showed a good linear relationship with r(2 )= 0.998 +/- 0.0003 in the concentration range of 150-800 ng/spot for apigenin and rutin and 200-1000 ng/spot for quercetin, luteolin, and quercitrin with respect to peak area. The average recovery for apigenin, quercetin, rutin, luteolin, and quercitrin was 97-99.8% indicating the excellent reproducibility. Statistical analysis of the data showed that the method is reproducible and selective for determination of flavonoids.     

Chemical profiling and anticoagulant activity of Ginkgo Biloba leaves under the influence of harvesting time

Gingko biloba, family Gink, is used as a source of food and in traditional medicine for treatment of cough and promoting blood circulation, etc. The aim of the present work is to determine the chemical variation of G. biloba leaves collected from different harvesting time and in vitro anti-platelet aggregation effects, respectively. Methanol extract of G. biloba leaves was subjected to ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry analysis and triple quadrupole mass spectrometry. The anti-platelet aggregation effects induced by platelet-activating factor (PAF) and adenosine diphosphate (ADP) was measured by Born’s method. UHPLC-QTOF-MS analysis confirmed the presence of flavonoids, phenolic acid and terpene lactones in different sample. Partial least square discriminant analysis based on chemical profiling conducted to differentiate the samples according to their harvest time. All samples found highly effective against PAF-induced platelet aggregation with IC₅₀ of 98.87?μg/mL (summer sample) and 51.55?μg/mL (autumn sample). However, on ADP-induced platelet aggregation, IC50 of these samples were greater than 200?μg/mL. Both total contents of flavonoids and terpene lactones in autumn sample were greater than that in summer sample. Qualitative and quantitative analysis showed that the distribution of chemicals was variation in different harvesting time.