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.     

Deep eutectic solvents as green media for efficient extraction of terpene trilactones from Ginkgo biloba leaves

Deep eutectic solvents (DESs)-based ultrasonic extraction of terpene trilactones (TTLs) from Ginkgo biloba leaves was efficiently developed. Sixteen DESs were prepared, and DESs composed of choline chloride-urea (ChCl-U) and betaine-ethylene glycol (BE-EG) gave higher TTL extraction yields than the present, most efficient solvent 70% ethanol. The extraction conditions were further optimized, and the optimum conditions were as follows: taking BE-EG containing 40% (w/w) water as the extraction solvent, 1:10 of G. biloba leaves powder-to-solvent ratio, and ultrasonic treatment at 45°C and 100?W for 20?min. A total extraction yield of 1.94?±?0.03?mg/g was obtained under the optimum conditions, which indicated that 99.37% of TTLs could be extracted from the G. biloba leaves powder by a single extraction. Moreover, the polyamide resin was used to recover the TTLs in DES extracting solution, and recovery yield of 95.1% was attained. Therefore, BE-EG containing 40% (w/w) water was a potential alternative solvent for TTLs extraction from G. biloba leaves.     

Isolation and enrichment of Ginkgo biloba extract by a continuous chromatography system

In this study, an effective method was developed for the isolation and enrichment of Ginkgo biloba extract by continuous chromatography system. The adsorption and desorption ratio of flavonoids as main index, the best macroporous resin was screened out from six resins by static adsorption and desorption tests. At the same time the adsorption and desorption parameters were optimized by dynamic adsorption and desorption tests. Under optimal parameters, five operations consisting of loading, washing, desorbing, regenerating, and balancing were integrated across the continuous chromatography system for the purpose of refining 66 L of crude extract solution. The results were as follows, 198.22 g of Ginkgo biloba extracts was produced, which contained 65.83 g of flavonoids and 15.44 g of lactones. The content of flavonoids and lactones increased from 2.76 and 0.72% in the crude extract to 33.21 and 7.79%, with a recovery yield of 91.26 and 81.21%. Methodology validation showed that the proposed method had high stability and reproducibility. Compared with the traditional macroporous resin method, the proposed method had a short processing time and low solvent consumption. Our studies indicated that the newly developed method is an effective procedure for the isolation and enrichment of Ginkgo biloba extract.     

Occurrence of methylated arsenic species in parts of plants growing in polluted soils

Arsenic compounds were determined in extracts of branches, leaves and roots from plants growing in a mining contaminated area. The selected species were Dryopteris filix-max, Quercus pubescens, Dipsacus fullonum, Alnus glutinosa, Buxus sempervirens and Brachythecium cf. reflexum. Total arsenic content in the subsamples was analysed by ICPMS after acidic digestion. In general, concentrations in the plant parts followed the gradient roots?>?branches?>?leaves indicating that they are arsenic-resistant plants. Arsenic species were determined in water/methanol (9?+?1, v/v) extracts by HPLC-ICPMS. Different levels of organoarsenicals were found depending on plant part and plant species. Higher percentages of organoarsenic compounds were recorded in branches and leaves (up to 35% in the boxtree sample), than in roots (0.7–5.2% in the same plant species). The absence of organic arsenic species in the soil where the plants were collected and the low levels of organoarsenicals found in the roots, indicate that the studied plants have the ability to accumulate or synthesise organoarsenic compounds in relatively high percentages, and this information contributes to enlarge the knowledge of arsenic uptake and speciation in plants.     

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.     

A new sesquiterpene trilactone from the roots of Ginkgo biloba

A new sesquiterpene trilactone, named bilobanol (1), along with four known terpene trilactones (ginkgolide A, B, C and bilobalide) were isolated from the roots of Ginkgo biloba collected in Jiangsu Province, China. The structure elucidation was accomplished by 1D and 2D NMR methods, HR-ESI-MS, and CD spectrum.     

Microphysiometric Measurement of PAF Receptor Responses to Ginkgolides

Microphysiometry was used to evaluate the effects of terpene trilactone and flavonoid constituents of Ginkgo biloba on human platelet‐activating‐factor receptor (PAFR). Inhibition of the platelet‐activating factor response by terpene trilactones was confirmed using this functional assay. Ginkgolide B (GB) and 10‐O‐benzyl‐GB showed the strongest inhibition (81 and 93%, resp.) of the PAFR response, while the flavonoids rutin, quercetin, and kaempferol showed negligible response inhibition. G. biloba extract mixtures were also tested, and results indicate possible synergistic effects among various components.     

Novel <Emphasis Type="Italic">S</Emphasis>-containing lactones from monoterpene oxides

A new type of S-containing terpene lactones was produced by the reactions of limonene-1,2-oxide and β-pinene-α-oxide with mercaptoacetic acid. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 220–223, May–June, 2007.     

Regioselective thionocarbonation of ginkgolides: facile preparation of ginkgolide J

Ginkgolide J, a minor constituent of terpene trilactone mixture of Ginkgo biloba leaves extract, can be readily prepared from an abundant ginkgolide C in two steps: thionocarbonation and subsequent deoxygenation. Regioselectivity of the first thionocarbonation step can be controlled by a proper choice of the base and solvent combination.     

Simultaneous chemical fingerprint and quantitative analysis of Ginkgo biloba extract by HPLC–DAD

A reverse-phase liquid chromatography method with diode array detection was developed to evaluate the quality of Ginkgo biloba extract through establishing chromatographic fingerprint and simultaneous determination of eight flavonoid compounds, namely rutin, myricetin, quercitrin, quercetin, luteolin, kaempferol, apigenin, and isorhamnetin. The chromatographic separation was performed on an Agilent SB-C18 column (250 × 4.6 mm, 5.0 μm) with a gradient elution program using a mixture of methanol and 0.1% formic acid (v/v) as mobile phase within 55 min at 360-nm wavelength. The correlation coefficients of similarity for different batches of G. biloba extract from the same manufacturer and G. biloba extract from different manufacturers were determined from the LC fingerprints, and they shared a close similarity. The eight flavonoid compounds showed good regression (R ² > 0.9995) within test ranges, and the recovery of the method was in the range of 94.1–101.4%. In addition, the content of those eight flavonoid compounds in G. biloba extract prepared by different manufacturers of China was determined to establish the effectiveness of the method. The results indicated that the developed method by having a combination of chromatographic fingerprint and quantification analysis could be readily utilized as a quality control method for G. biloba extract and its related traditional Chinese medicinal preparations.     

Target profiling of flavonol glycosides in the extract of Ginkgo biloba leaf and their pharmacokinetics in rat plasma by ultra-high-performance liquid chromatography with tandem mass spectrometry

The extract of Ginkgo biloba leaf is a popular herbal product or dietary supplement in the world to treat various diseases, and flavonol glycosides are considered as the main bioactive constituents. In this study, 37 flavonol glycosides were rapidly screened out by precursor ion scanning in positive ion mode with production ions at m/z 287.05, 303.05, and 317.06. Subsequently, a reliable and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry approach was established and validated to quantify the 20 prototype flavonol glycosides in rat plasma. Calibration curves showed good linearity (R² ≥ 0.9894) over the corresponding concentration range. The precision, accuracy, extraction recovery, matrix effect, and stability were also satisfactory. The validated method was successfully applied to a pharmacokinetic study of prototype flavonol glycosides in rat after oral administration of the extract of G. biloba leaf. As a result, the T_max of flavonol glycosides was short at 0.11–0.60 h. Quercetin-3-O-(2“,6″-di-O-rhamnosyl)-glucoside, kaempferol-3-O-(2′',6′'-di-O-rhamnosyl)-glucoside, quercetin-3-O-rutinoside, quercetin- 3-O-glucosyl-(1-2)-O-rhamnoside, and kaempferol-3-O-glucoside presented relatively high systemic exposure levels with AUC_0-∞ > 500 μg h/L and C_max > 100 μg/L. This study would provide the valuable information for further scientific research and clinical application of the extract of G. biloba leaf.     

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.     

Investigation of dynamic accumulation and regularity of nine glycosides and saccharides in Rehmannia glutinosa by rapid quantitative analysis technology

In the process of planting and harvesting of Rehmannia glutinosa, only the underground part is used, and a large number of stems and leaves that are considered non‐medicinal parts are usually discarded. Recent studies have shown that the chemical components in the leaves are similar to those identified in the roots. In this study, we selected leaves and roots from Rehmannia glutinosa at different growth stages and leaves from different cultivation regions to investigate the dynamic accumulation of three kinds of glycosides (catalpol, acteoside, and ajugol), six kinds of carbohydrates (rhamnose, fructose, sucrose, melibiose, stachyose, and verbascose), and acidic and neutral polysaccharides via rapid quantitative analysis technology, including ultra high performance liquid chromatography triple quadrupole tandem mass spectrometry, high‐performance liquid chromatography, and UV spectroscopy. The results showed that the Rehmannia glutinosa leaves also contained higher content of catalpol (3.81～24.51 mg/g), ajugol (0.55～10.23 mg/g), acteoside (1.34～21.16 mg/g), monosaccharide/ oligosaccharides (7.71～120.73 mg/g), and polysaccharides (5.63～15.57%). In this study, we developed a new rapid and simple method for determination to clarify the distribution and dynamic accumulation of nine glycosides and saccharides in Rehmannia glutinosa leaves to provide a scientific basis for the discovery, development, and utilization of the resource value of Rehmannia glutinosa leaves.     

Capillary zone electrophorsis for the analysis of naturally occurring 2‐hydroxycitric acids and their lactones

A simple capillary zone electrophoresis method with direct ultraviolet detection has been developed for the analysis of naturally occurring diastereomeric 2‐hydroxycitric acid lactones. Using 50 mM sodium phosphate buffer of pH 7, a baseline resolution R _s > 3.0 was observed for all organic acids selected for the present study. This method was employed for the quantitative determination of title acids present in the plant sources namely Garcinia cambogia fruit rinds and Hibiscus sabdariffa calyx. Conversion of 2‐hydroxycitric acids to their lactones on heating the above plant sources is deliberated. The Hydrolysis of hydroxycitric acid lactones in aqueous solution is reported for the first time.     

Effect of Methyl Jasmonate on the Terpene Trilactones,Flavonoids, and Phenolic Acids in Ginkgo biloba L. Leaves: Relevance to Leaf Senescence

The present study compared the effects of natural senescence and methyl jasmonate (JA-Me) treatment on the levels of terpene trilactones (TTLs; ginkgolides and bilobalide), phenolic acids, and flavonoids in the primary organs of Ginkgo biloba leaves, leaf blades, and petioles. Levels of the major TTLs, ginkgolides B and C, were significantly higher in the leaf blades of naturally senesced yellow leaves harvested on 20 October compared with green leaves harvested on 9 September. In petioles, a similar effect was found, although the levels of these compounds were almost half as high. These facts indicate the importance of the senescence process on TTL accumulation. Some flavonoids and phenolic acids also showed changes in content related to maturation or senescence. Generally, the application of JA-Me slightly but substantially increased the levels of TTLs in leaf blades irrespective of the difference in its application side on the leaves. Of the flavonoids analyzed, levels of quercetin, rutin, quercetin-4-glucoside, apigenin, and luteolin were dependent on the JA-Me application site, whereas levels of (+) catechin and (−) epicatechin were not. Application of JA-Me increased ferulic acid and p-coumaric acid esters in the petiole but decreased the levels of these compounds in the leaf blade. The content of p-coumaric acid glycosides and caffeic acid esters was only slightly modified by JA-Me. In general, JA-Me application affected leaf senescence by modifying the accumulation of ginkogolides, flavonoids, and phenolic acids. These effects were also found to be different in leaf blades and petioles. Based on JA-Me- and aging-related metabolic changes in endogenous levels of the secondary metabolites in G. biloba leaves, we discussed the results of study in the context of basic research and possible practical application.     

Enantioseparation of N‐acetyl‐glutamine enantiomers by LC–MS/MS and its application to a plasma protein binding study

A novel chiral method was developed and validated to determine N‐acetyl‐glutamine (NAG) enantiomers by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Enantioseparation was achieved on a Chiralpak QD‐AX column (150 × 4.6 mm i.d., 5 μm) using methanol–water (50 mm ammonium formate, pH 4.3; 70:30, v/v) at a flow rate of 500 μL/min. The detection was operated with an electrospray ionization source interface in positive mode. The ion transition for NAG enantiomers was m/z 189.0 → 130.0. The retention time of N‐acetyl‐l ‐glutamine and N‐acetyl‐d ‐glutamine were 15.2 and 17.0 min, respectively. Calibration curves were linear over the range of 0.02–20 μg/mL with r > 0.99. The deviation of accuracy and the coefficient of variation of within‐run and between‐run precision were within 10% for both enantiomers, except for the lower limit of quantification (20 ng/mL), where they deviated <15%. The recovery was >88% and no obvious matrix effect was observed. This method was successfully applied to investigate the plasma protein binding of NAG enantiomers in rats. The results showed that the plasma protein binding of NAG enantiomers was stereoselective. The assay method also exhibited good application prospects for the clinical monitoring of free drugs in plasma.     

A capillary electrophoresis method for the determination of soluble monosaccharides in Ginkgo biloba leaves

A method for the simultaneous determination of six monosaccharides by pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone and capillary electrophoresis was developed in this work. The derivatization (i.e., reaction temperature, capillary electrophoresis duration, and extraction number) and separation (i.e., pH and buffer concentration) conditions for capillary electrophoresis were optimized. Results showed that the limits of detection under optimal conditions were in the range of 0.036–0.35 mg/L with a mean correlation coefficient >0.99. The recoveries were in the range of 87.3–108.49%, and the relative standard deviations of intra- and inter-day variations were in the ranges of 2.2–3.8 and 3.2–5.0%, respectively. The method was successfully applied to the analysis of six free monosaccharides in three types of Ginkgo biloba leaves.     

Heavy metal accumulation by selected plant species along the national highway: a case study of Udaipur,Rajasthan, India

ABSTRACT

A detailed research was conducted to find out the heavy metal accumulation by plant species at the roadside. Bioconcentration, bioaccumulation and translocation factors were estimated in 10 individuals of each investigating plant species. The plant and soil samples used in the research were collected along the National Highway-76 from Chittorgarh to Udaipur, Rajasthan, India. The concentration of cadmium and lead in roadside soil, plant roots, stems and leaves shows a correlation. The highest bioconcentration factor of Cd and Pb was 0.22 ± 0.04 and 0.13 ± 0.02 estimated in Bougainvillea spectabilis Willd. The highest translocation factor of Cd was 1.30 ± 0.50 in Pongamia pinnata L., and the highest translocation factor of Pb was 1.63 ± 0.45 estimated for Nerium oleander L. The average concentrations of Cd and Pb were 11.35 ± 1.60 and 223.70 ± 68 mg kg^?1 in investigated roadside soil. The average concentrations of accumulated Cd and Pb in B. spectabilisWilld. were 2.38 ± 0.49, 1.97 ± 0.51, 3.07 ± 0.78 and 29.34 ± 7.82,18.96 ± 5.62, 37.75 ± 12.93 mg kg^?1 in roots, stems and leaves, respectively. The decreasing order of bioaccumulation factor of cadmium in plants was B. spectabilis Willd.>Butea monosperma (Lam.) Taub>Calotropis procera (Ailton) Dryand>N. oleander L.>P. pinnata L. The decreasing order of bioaccumulation factor of lead in plants was B. spectabilis Willd.>P. pinnataL.>B. monosperma (Lam.) Taub>C. procera (Ailton) Dryand>N. oleander L. The B. spectabilis Willd. was identified as a rhizofiltration tool of heavy metals such as Cd and Pb with higher bioconcentration factor. P. pinnata L. for Cd and N. oleander L. for Pb were revealed for phytoextraction technology with high translocator factor to accumulate and eliminate these toxic elements from soil.     

Tetraethylene Glycol Tethered Heteronuclear Bis‐isatin Derivatives: Design,Synthesis, and In Vitro Anti‐mycobacterial Activities

A series of novel tetraethylene glycol tethered heteronuclear bis‐isatin derivatives 7a – l were designed, synthesized, and evaluated for their in vitro anti‐mycobacterial activities against Mycobacterium tuberculosis (MTB) H37Rv and multidrug‐resistant TB (MDR‐TB) as well as cytotoxicity in VERO cell line. All hybrids exhibited potential anti‐mycobacterial activities against MTB H37Rv and MDR‐TB, and acceptable cytotoxicity. Among them, the heteronuclear bis‐isatin 7l [minimum inhibitory concentration (MIC): 16 and 16 μg/mL] was found to be most active against MTB H37Rv and MDR‐TB strains, which was 2‐fold and >8‐fold, respectively, more potent than were the first‐line anti‐tubercular agents rifampicin (MIC: 32 μg/mL) and isoniazid (MIC: >128 μg/mL) against MDR‐TB, also demonstrated acceptable cytotoxicity profile (CC₅₀: 62.5 μg/mL), could act as a starting point for further optimization.     

Low-temperature polymerization of lactams by using as catalyst the salt derived from NaAlEt4 and monomer and with several compounds as initiator

Low-temperature polymerization of α-pyrrolidone, α-piperidone, and ?-caprolactam was examined by using the salts derived from NaAlEt₄ and monomer, sodium lactamates, or the salt derived from AlEt₃ and monomer as catalyst and with N-acetyl lactams, ethyl acetate, or lactones as initiator. Sodium lactamate catalyst gave unsatisfactory results in the cases of ethyl acetate or lactones initiators, and gave the following order for the relative efficiency of initiators: N-acetyl lactam > ?-caprolactone ≥ ethyl acetate > β-propiolactone. The polymerization results obtained by the salt from NaAlEt₄ catalyst–ethyl acetate initiator system were nearly the same as those with N-acetyl lactam. The increases in the degree of polymerization and in the yield of polymer were observed in case of the salt from NaAlEt₄ catalyst-lactone initiator system, particularly in the cases of α-piperidone and ?-caprolactam. Also an incorporation of initiator into polymer chain was observed.