Aurones: A Golden Resource for Active Compounds.

Deemed as poorly represented in nature, aurones have been often overlooked by researchers compared to other members of the flavonoid superfamily. However, over the past two decades, they have been reassessed by the scientific community, who are increasingly appreciating their ability to modulate several biological pathways. This review summarizes the recent literature on this class of compounds, which has been analyzed from both a chemical and a functional point of view. Original articles, reviews and editorials featured in Pubmed and Scifinder over the last twenty years have been taken into account to provide the readers with a view of the chemical strategies to obtain them, their functional properties, and their potential of technological use. The resulting comprehensive picture aims at raising the awareness of these natural derivatives as effective drug candidates, fostering the development of novel synthetic analogues.

Neuroprotective Effects of a Standardized Flavonoid Extract from Safflower against a Rotenone-Induced Rat Model of Parkinson's Disease.

Parkinson's disease (PD) is a major age-related neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra par compacta (SNpc). Rotenone is a neurotoxin that is routinely used to model PD to aid in understanding the mechanisms of neuronal death. Safflower (Carthamus tinctorius. L.) has long been used to treat cerebrovascular diseases in China. This plant contains flavonoids, which have been reported to be effective in models of neurodegenerative disease. We previously reported that kaempferol derivatives from safflower could bind DJ-1, a protein associated with PD, and that a flavonoid extract from safflower exhibited neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of PD. In this study, a standardized safflower flavonoid extract (SAFE) was isolated from safflower and found to primarily contain flavonoids. The aim of the current study was to confirm the neuroprotective effects of SAFE in rotenone-induced Parkinson rats. The results showed that SAFE treatment increased body weight and improved rearing behavior and grip strength. SAFE (35 or 70 mg/kg/day) treatment reversed the decreased protein expression of tyrosine hydroxylase, dopamine transporter and DJ-1 and increased the levels of dopamine and its metabolite. In contrast, acetylcholine levels were decreased. SAFE treatment also led to partial inhibition of PD-associated changes in extracellular space diffusion parameters. These changes were detected using a magnetic resonance imaging (MRI) tracer-based method, which provides novel information regarding neuronal loss and astrocyte activation. Thus, our results indicate that SAFE represents a potential therapeutic herbal treatment for PD.

[Separation and authentication of tilianin and quality standards of semen of Dracocephalum moldavia].

Tilianin was separated and authenticated from the seeds of Dracocephalum moldavia, a Uygur medicine, by chromatographic technique and spectroscopic method. The purity of tilianin is more than 98% determined by HPLC area normalization method. Thin layer chromatography (TLC) method was used to separate tilianin from D. moldavia by mixture of chloroform-methanol (5: 1) as a developing solvent on high performance silicagel precoated plate (SGF254) and using aluminium trichloride as a chromogenic agent for qualitative identification of D. moldavia. To establish a HPLC method for quantitative analysis of D. moldavia, tilianin was used as a Quantitative marker and separated on a C18 (4.6 mm x 250 mm, 5 µm) column with acetonitrile-01% formic acid (25: 75) as the mobile phase and detected at 330 nm. The calibration curve of tilianin displayed ideal linearity over the range of 0.617 2-123.44 µg x mL(-1) with a regression equation of Y = 33.773X - 0.824 8 (r = 1). The average recovery of tilianin was 101.0% with RSD of 3.7%. The RSD values of intra-day and inter-day precision were less than 2%. The content of tilianin in 4 batches of the authenticated semen of D. Moldavia was between 0.016 and 0.187 mg x g(-1). The qualitative and quantitative method established is suitable for the quality evaluation and assessment of semen of D. Moldavia.

Advancement in the chemical analysis and quality control of flavonoid in Ginkgo biloba.

Flavonoids are the main active constituents in Ginkgo biloba L., which have been suggested to have broad-spectrum free-radical scavenging activities. This review summarizes the recent advances in the chemical analysis of the flavonoids in G. biloba and its finished products (from 2009 to 2014), including chemical composition, sample preparation, separation, detection and different quality criteria. More than 70 kinds of flavonoids have been identified in this plant. In this review, various analytical approaches as well as their chromatographic conditions have been described, and their advantages/disadvantages are also compared. Quantitative analyses of Ginkgo flavonoids applied by most pharmacopeias start with an acidic hydrolysis followed by determination of the resulting aglycones using HPLC. But increasing direct assay of individual flavonol glycosides found that many adulterated products were still qualified by the present tests. To obtain an authentic and applicable analytical approach for quality evaluation of Ginkgo and its finished products, related suggestions and opinions in the recent publications are mainly discussed in this review. This discussion on chemical analyses of Ginkgo flavonoids will also be found as a significant guide for widely varied natural flavonoids.

Different extraction pretreatments significantly change the flavonoid contents of Scutellaria baicalensis.

CONTEXT: Scutellaria baicalensis Georgi (Labiatae) is one of the most commonly used medicinal herbs, especially in traditional Chinese medicine. However, compared to many pharmacological studies of this botanical, much less attention has been paid to the quality control of the herb's pretreatment prior to extract preparation, an issue that may affect therapeutic outcomes. OBJECTIVE: The current study was designed to evaluate whether different pretreatment conditions change the contents of the four major flavonoids in the herb, i.e., two glycosides (baicalin and wogonoside) and two aglycones (baicalein and wogonin). MATERIALS AND METHODS: A high-performance liquid chromatography assay was used to quantify the contents of these four flavonoids. The composition changes of four flavonoids by different pretreatment conditions, including solvent, treatment time, temperature, pH value and herb/solvent ratio were evaluated. RESULTS: After selection of the first order time-curve kinetics, our data showed that at 50 °C, 1:5 herb/water (in w/v) ratio and pH 6.67 yielded an optimal conversion rate from flavonoid glycosides to their aglycones. In this optimized condition, the contents of baicalin and wogonoside were decreased to 1/70 and 1/13, while baicalein and wogonin were increased 3.5- and 3.1-fold, respectively, compared to untreated herb. DISCUSSION AND CONCLUSION: The markedly variable conversion rates by different pretreatment conditions complicated the quality control of this herb, mainly due to the high amount of endogenous enzymes of S. baicalensis. Optimal pretreatment conditions observed in this study could be used obtain the highest level of desired constituents to achieve better pharmacological effects.

[Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules].

OBJECTIVE: To study in situ intestinal absorption kinetics of baicalin contained in Tiangou Jiangya capsules, and the effect of different intestinal segments, pH value, drug concentration and P-gp inhibitor on the absorption. METHOD: The in situ intestinal perfusion test was adopted, and HPLC method was used to determine the content of baicalin in samples at different time points. Ultra-violet (UV) spectrophotometry was used to determine the content of phenol red in samples at different time points. RESULT: When pH value was at 5. 0, 6. 5, 7. 4, the absorption of baicalin was not impacted. P-gp inhibitor verapamil could enhance the absorption of baicalin. When the quality concentration of the test solution ranged between 5-20 g L -1 , the linearity of the absorption amount of baicalin increased. The absorption kinetic equation of baicalin was Y = -0. 073 7X +0. 118 7 (r = 0. 994 8) , K. 0. 073 7 h -1 , t1/2 9. 40 h. CONCLUSION: Baicalin is mainly absorbed in colon. The absorption of baicalin shows the first-order kinetics process, with the absorption mechanism of passive diffusion. Baicalin is a substrate for P-gp.

Identification of antioxidants in Fructus aurantii and its quality evaluation using a new on-line combination of analytical techniques.

A new on-line method for simultaneous identification and monitoring of antioxidants in Fructus aurantii was established by coupling high performance liquid chromatography-diode array detector-electrospray ionisation-ion trap-time of flight-mass spectrometry with post-column derivatisation and luminol-potassium ferricyanide chemiluminescence (HPLC-DAD-ESI-IT-TOF-MS-PCD-LPFCL). While the HPLC fingerprint, structural identification and radical scavenging profile were rapidly obtained by an on-line assay using ultraviolet (UV) absorption, MS and LPFCL, details of the precise substitution patterns of various structures were achieved through UV absorption using PCD addition of shift reagents. Twenty-five flavonoids were identified by either their PCD and MS data or comparison with reference substances. Data collected both from chromatograms and activity profiles of 12 samples revealed significant differences among samples from different habitats. The results showed that this method was rapid and precise, and therefore would be an effective and sensitive method for biocompounds analysis and quality evaluation for complex food and medicinal samples.

Orthogonal test design for optimization of the extraction of flavonid from the Fructus Gardeniae.

OBJECTIVE: It is imperative to provide some consistent experimental results for the extraction of flavonid from Fructus Gardeniae. METHODS: The key extraction parameters that influenced the yield of flavonid from Fructus Gardeniae were optimized by employing an orthogonal experiment [L(9)(3)(4)], including the ratio of buffer solution (Na(2)B(4)O(7)·10H(2)O) to raw material, concentration of Fructus Gardeniae in extracting solution, extraction time and pH of buffer solution. An UV/Vis detector was used to perform the qualitative and quantitative analyses of the extracted flavonid with the using of the standard sample. RESULTS: The maximum extraction yield of the crude extract was 5.0533 (mg/g) after 20 min when the mass ratio of Na(2)B(4)O(7)·10H(2)O to raw material was 0.4%, the concentration of Fructus Gardeniae in the extraction solution was 1/12 (g/mL), and pH of buffer solution was 4.5. The positive reactions to the Molish and HCl-Mg tests suggested that the extracted compound was flavonoid, and FTIR measurements also identified the presence of flavonoid in the extracts. CONCLUSION: This work is expected to provide a basis for further research, development, and utilization of Fructus gardenia in flavonid extraction.

[Manufacturing process and quality control of total flavonoid from Chrysanthemum morifolium and Sophora japonica and its quality control].

OBJECTIVE: To optimize the manufacturing process of the total flavonoid from Chrysanthemum morifolium and Sophora japonica, and establish the quality control methods for total flavonoid and its indicative constituents. METHOD: The solvent for extraction was investigated and L9 (3(4)) orthogonal experiment was used to optimize the extraction process of the total flavonoid. Colorimetric method was used to determine the content of total flavonoid, and HPLC was used to determine the content of the indicative constituents. RESULT: The optimized manufacturing process of the total flavonoid was that the prescribed crude drugs were extracted by using 70% ethanol for 3 times, 1 h each time. The extract was concentrated to the final concentration of 0.5 g x mL(-1), and was subjected to HPD-600 macroporous resin column chromatography at the weight ratio 1 : 0. 5 of crude drugs to macroporous resin. The sample was eluted with water in the volume of 10 times of the resin's, and then was desorpted with 85% ethanol in the volume of 5 times of the resin's. The content of total flavonoid was determined as 64.98%-66.79%, and the content of indicative constituents was determined as 5.87% - 6.93% for luteolin-7-O-glucoside and 14.09%-16.62% for rutin. CONCLUSION: Extracting with aqueous alcohol in combination with purifying with macroporous resin column chromatography is an efficient way to prepare the total flavonoid from Ch. morifolium and S. japonica, and the colorimetric and the HPLC methods are useful for its quality control.

Chromatographic fingerprint analysis of Pycnogenol dietary supplements.

The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing.

[Contribution to the phytochemical study of polyphenols in ten hydroalcoholic extracts of Chamomile floss]. / Contributii la analiza fitochimica a polifenolilor existenti in extracte hidroalcoolice preparate din mostre comerciale de Chamomillae flos.

UNLABELLED: Continuing a series of studies that intend to evaluate the pharmaceutical quality of 10 commercial samples of chamomile, we tried to investigate the chemical composition of the hydroalcoholic extracts obtained in our laboratory, starting from this raw material. MATERIAL AND METHOD: The qualitative and semiquantitative analysis of the extracts was done by HPLC means. RESULTS: All extractive solutions have a high content in ferulic acid, whereas the caffeic acid level is the lowest. Regarding the flavonoids, there are many quantitative differences between the samples: one extract lacking the rutoside and two of them having low apigenin-7-glucoside contents.

Stability of active ingredients of traditional Chinese medicine (TCM).

Studies on stability of active ingredients are fundamental and critical for the rational development of Traditional Chinese Medicine (TCM) in view of its modernization and worldwide use. The stability of both active and marker constituents of plants used in TCM is reviewed for the first time. More than 100 papers, mostly written in Chinese, have been reviewed. Studies concerning plant constituents were analyzed according to their chemical classification of active ingredients. In addition, several crude drugs of animal origin are also reported. Stability of active ingredients is summarized during extraction and/or storage of the herbal drug preparations, and under stress conditions (pH, temperature, solvents, light, and humidity) and in the presence of preservatives, antioxidants, and metals.

Selective extraction of Cyclopia for enhanced in vitro phytoestrogenicity and benchmarking against commercial phytoestrogen extracts.

Previous work established the phytoestrogenicity of "unfermented"Cyclopia (honeybush) extracts. The current study investigated the phytoestrogenicity of four Cyclopia harvestings (M6-9) for preparation of extracts with enhanced phytoestrogenicity for benchmarking against commercial preparations. Two extracts, from M6 (C. subternata) and M7 (C. genistoides), were identified as most phytoestrogenic using estrogen receptor binding, an estrogen receptor response element containing promoter reporter assay, alkaline phosphatase activity, and E-screen. M6 and M7 were sequentially and non-sequentially extracted with five solvents of differing polarities. Additionally, two extracts were prepared in the traditional way of preparing a cup of honeybush tea. The resultant 22 extracts were evaluated for estrogenicity. Select extracts were analysed by high-pressure liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS). The sequentially extracted M6 methanol extract (SM6Met) had the highest potency and the sequentially extracted M6 ethyl acetate extract (SM6EAc) had the highest efficacy of all the extracts. The HPLC results suggested enrichment of luteolin in SM6EAc and enrichment of an unidentified polyphenol in SM6Met. Benchmarking against four commercial phytoestrogenic preparations suggest that in terms of the assays used, Cyclopia extracts have comparable potency and efficacy to the commercial extracts and thus have potential as marketable phytoestrogenic nutraceuticals.

Validation of a HPLC method for flavonoid biomarkers in skullcap (Scutellaria) and its use to illustrate wide variability in the quality of commercial tinctures.

PURPOSE: To compare the flavonoid biomarker content (baicalin, baicalein and wogonin) of eleven commercial tinctures derived from Scutellaria lateriflora aerial parts (n=7) and Scutellaria baicalensis root (n=4). S. lateriflora tinctures are used in by western herbal practitioners to treat anxiety whereas S. baicalensis tinctures are used to treat inflammatory disease. METHODS: Baicalin and baicalein were purchased from Aldrich Chemical Co. and Wogonin was purchased from ChromaDex. The internal standard (4-hydroxybenzoic acid) was obtained from Acros Organics. The column used was a Luna C18, 5 m (150 x 4.6 mm, Phenomenex) maintained at ambient room temperature. A HP1050 HPLC system was used, comprising a gradient pump with degasser, a variable wavelength UV detector set to 270 nm, and an autosampler. Gradient elution was performed using 0.1% formic acid (eluent A) and methanol (eluent B). The gradient elution initial conditions were 45% B with linear gradient to 60% from 2 to 10 min, followed by linear gradient to 70% B at 30 min, and then linear gradient to 99% B at 31 min, this proportion being maintained for 1 min. The mobile phase was then returned to initial conditions at 33 min and maintained until the end of the run at 35 min. The flow rate was 1 mL/min. The assay was validated for sensitivity, accuracy and reproducibility. RESULTS: The concentration range of biomarkers (baicalin, baicalein and wogonin) in commercial tinctures is reported for S. lateriflora (baicalin: 0-12.66 mg/mL; baicalein: 0-0.63 mg/mL; wogonin: 0-0.16 mg/mL) and for S. baicalensis (baicalin: 0.12-10.61 mg/mL; baicalein: 0.52-5.88 mg/mL; wogonin: 0.08-1.61 mg/mL). CONCLUSION: The wide variability in biomarker concentrations between commercial tinctures has important implications for the manufacturers of commercial tinctures, for herbal practitioners in the choice of tinctures and not least for pharmacology and clinical researchers.

Variability of total flavonoids in Crataegus--factor evaluation for the monitored production of industrial starting material.

European Hawthorn species (Crataegus spp.) are traditionally used for their demonstrated cardioprotective benefits. Most products are based on the compendial leaf and flower drug (LFD), which is standardised on the total flavonoid content (TF). In order to reduce variability associated with the wild plant origin and to ease product standardisation, we set out to develop a sustainable source of high quality raw material. Firstly, the LFD of wild trees in Germany was screened in terms of TF content (spectrophotometric analysis, calculated as hyperoside) according to the current pharmacopoeia requirements. Secondly, eleven high value provenances were selected, propagated, cultivated and the grafted clones were reanalysed. Thirdly, major environmental and sourcing influences were assessed: the year of harvest, the growing location, exposure to sunlight, the harvest time and the portion of leaf, flower and wood within the LFD. We found the TF in LFD of 150 wild grown Crataegus ranged between 0.28% and 1.92% (average 1.15%). Pure single styled Crataegus monogyna and hybrid trees represented the major portion (57%) of all screened trees. The hybrids with mainly two-styled flowers (pure Crataegus laevigata and hybrids) showed slightly higher TF values. The selected clones proved to maintain a high TF profile in cultivation, although superiority was attenuated when not only O-glycosides, but also C-glycosides were covered by the assay. Environmental influence surpassed in part the genetic variation of the selection in this study. In conclusion, cultivated high performance trees under central European conditions produced LFD exceeding the Pharmacopoeia standards. Careful monitoring of production--particularly in terms of the harvest time and actual LFD location and composition--has decisive impact to guarantee consistent high TF values.

[Research on quality of Epimedium extract in market].

OBJECTIVE: To review the quality of Epimedium extract in the market. METHOD: The contents of icariin, epimedin C, sagittatoside B and total flavonoids in Epimedium extracts sold in the market were assayed by the methods of HPLC and UV respectively. HPLC fingerprintings were obtained at the same time. RESULT: The contents of icariin in most of the extracts are closely similar with the ones labeled by the companies. 3 type chromatograms were classified in all the HPLC fingerprintings, and were corresponded with their raw materials. The contents of epimedin C, sagittatoside B and total flavonoids were different in the samples with the same content of icariin. CONCLUSION: We can primarily confirm the origin of raw materials by comparing the HPLC fingerprinting of extracts with the ones of materials. The difference of extracts quality mainly comes from the difference of materials. So we suggest that Epimedium extract product should be labeled the origin of materials, and assayed with more compound contents, to ensure the quality stabilization.

[Comparison of flavonoids in medicinal plants Melastoma].

The flavonoids in Melastoma dodecandrum Lour., M. sanguineum Sims, M. normale D. Don, M. affine D. Don and M. candidum D. Don were compared by Thin Layer Chromatography (TLC). Rutin was detected in all samples, but flavonoids were similar in M. affine and M. candidum. It suggests that both M. affine and M. candidum can be used for the Herba Melastoma.

[Studies on the HPLC fingerprint spectrum of flavonoids in Gynostemma pentaphyllum].

OBJECTIVE: To establish the HPLC fingerprint spectrum of flavonoids from Gynostemma pentaphyllum. METHODS: The HPLC conditions with TURNER Kromasil C18 column (250 x 4. 6 mm, 5 microm) was used, the mobile phase consisted of 0.4% phosphoric acid-methanol-acetonitrile with gradient elution at flow rate of 0.5 ml/min and the detection wavelength was set at 360nm. RESULTS: Ten common characteristic peaks were taken as fingerprint peaks the presision and the retest are in accordance with the requirement. CONCLUSION: The method is stable, reliable, precision and provides a scientific basis for the quality standard of Gynostemma pentaphyllum.

[Study on pharmacognosy of Ginkgo leaf].

The primary study of Ginkgo leaf such as crude drug macroscopic and powder characteristics were carried out, and the flavonoids content in the leaf of Ginkgo in different areas of Gansu province was determined by HPLC, in order to provide scientific references for the exploitation of Ginkgo in Gansu province.