Quality control evaluation of nutraceutical products from Ginkgo biloba using liquid chromatography coupled to high resolution mass spectrometry

Recent advances in methods of extraction, pre-concentration, purification, identification, and quantification of kaempferol

As a naturally widely-occurring dietary, cosmetic, and therapeutic flavonoid, kaempferol has gained much consideration for its nutritional and pharmaceutical properties in recent years. Although there have been performed a high number of studies associated with different aspects of kaempferol's analytical investigations, the lack of a comprehensive summary of the various methods and other plant sources that have been reported for this compound is being felt, especially for many biological applications. This study, aimed to provide a detailed compilation consisting of sources (plant species) and analytical information that was precisely related to the natural flavonoid (kaempferol). There is a trend in analytical research that supports the application of modern eco-friendly instruments and methods. In conclusion, ultrasound-assisted extraction (UAE) is the most general advanced method used widely today for the extraction of kaempferol. During recent years, there is an increasing tendency towards the identification of kaempferol by different methods.

The Different Phytochemical Profiles of Salvia officinalis Dietary Supplements Labelled for Menopause Symptoms

Phytochemical screening of four commercial products containing Salvia officinalis was carried out. Total phenolic content was estimated spectrophotometrically through the use of the Folin-Ciocalteau method, flavonoid content was measured through the use of aluminum chloride and 2,4-dinitrophenylhydrazine colorimetric assays, and isoflavones and α/β-thujones were analyzed through the use of high-performance liquid chromatograph (HPLC) and the gas chromatographic method. The analyses revealed the absence of thujones and isoflavones (i.e., genistin, genistein, and daidzein) in all four different extracts. The content of polyphenolic compounds varied among the samples, with the extract T being richer in both polyphenols and flavonoids than the other products by 1.8-3.2 and 1.4-4.0 times, respectively (p-value < 0.05). These results highlight the importance of quality control in salvia-based products since a thujone-free extract rich in polyphenols and flavonoids could be a good candidate for further preclinical and clinical studies to identify an effective herbal approach suitable for the long-term therapy of menopausal symptoms.

Quality evaluation of commercial herbal products using chemical methods

Herbal products comprise a wide spectrum of locally, nationally or internationally commercialized commodities. As these products have an increasingly important position in healthcare systems worldwide, a detailed product quality assessment is of crucial importance. For the quality evaluation of commercial herbal products, a wide range of methods were used, from simpler, quicker, and cost-effective HPTLC, to hyphenated methods with MS or NMR, where more precise quantification or specific structural information is required. Additionally, most of the methods have been coupled with chemometric tools, such as PCA, or PDA, for the multivariate analysis of the high amount of data generated by chromatograms, electropherograms or spectra. The chemical methods have revealed the widespread presence of low or variable quality herbal products in the marketplace. The majority of analytical investigations present major, qualitative and quantitative, inter-product variations of their chemical composition, ranging from missing ingredients, to strikingly and unnaturally high concentrations of some compounds. Moreover, the inter-batch quality variations were frequently reported, as well as the presence of some undesirable substances. The chemical analysis of herbal products is a vital component to raise the overall awareness of quality in the herbal market and generate a quality driven approach.

Blending Technology Based on HPLC Fingerprint and Nonlinear Programming to Control the Quality of Ginkgo Leaves

The breadth and depth of traditional Chinese medicine (TCM) applications have been expanding in recent years, yet the problem of quality control has arisen in the application process. It is essential to design an algorithm to provide blending ratios that ensure a high overall product similarity to the target with controlled deviations in individual ingredient content. We developed a new blending algorithm and scheme by comparing different samples of ginkgo leaves. High-consistency samples were used to establish the blending target, and qualified samples were used for blending. Principal component analysis (PCA) was used as the sample screening method. A nonlinear programming algorithm was applied to calculate the blending ratio under different blending constraints. In one set of calculation experiments, the result was blended by the same samples under different conditions. Its relative deviation coefficients (RDCs) were controlled within ±10%. In another set of calculations, the RDCs of more component blending by different samples were controlled within ±20%. Finally, the near-critical calculation ratio was used for the actual experiments. The experimental results met the initial setting requirements. The results show that our algorithm can flexibly control the content of TCMs. The quality control of the production process of TCMs was achieved by improving the content stability of raw materials using blending. The algorithm provides a groundbreaking idea for quality control of TCMs.

Effect of Ginkgo Biloba Powder on the Physicochemical Properties and Quality Characteristics of Wheat Dough and Fresh Wet Noodles

Effects of ginkgo biloba powder (GBP) on the chemical, physicochemical properties and quality of dough and fresh wet noodles were investigated. Lower contents of gluten and starch, and higher contents of fibre, amylose and flavonoids in GBP than wheat flour, were detected. Water absorption of dough increased and the development time and stability time of dough were decreased with GBP addition. Meanwhile, the pasting properties results showed that the addition of GBP reduced the aging degree of starch and improved the thermal stability of dough. Scanning electron microscopy results showed that addition of GBP smoothed the surface of raw noodles while increasing the hole size of the cooked noodles. With increased GBP addition (0~40%), the chewiness and extensibility of the fresh wet noodles increased significantly (p < 0.05), and the sensory scores changed, ascending from 0~20% substitution, and then descending from 20~40% substitution. The digestibility and estimated glycemic index (eGI) values of the GBP fresh wet noodles decreased significantly (p < 0.05). In general, 20% GBP addition could improve the chewiness, extensibility, taste and nutrition of fresh wet noodles, and decrease the digestibility and eGI values of noodles. Thus, GBP has potential for application in the noodle industry.

Identification of Pueraria spp. through DNA barcoding and comparative transcriptomics

BACKGROUND

Kudzu is a term used generically to describe members of the genus Pueraria. Kudzu roots have been used for centuries in traditional Chinese medicine in view of their high levels of beneficial isoflavones including the unique 8-C-glycoside of daidzein, puerarin. In the US, kudzu is seen as a noxious weed causing ecological and economic damage. However, not all kudzu species make puerarin or are equally invasive. Kudzu remains difficult to identify due to its diverse morphology and inconsistent nomenclature.

RESULTS

We have generated sequences for the internal transcribed spacer 2 (ITS2) and maturase K (matK) regions of Pueraria montana lobata, P. montana montana, and P. phaseoloides, and identified two accessions previously used for differential analysis of puerarin biosynthesis as P. lobata and P. phaseoloides. Additionally, we have generated root transcriptomes for the puerarin-producing P. m. lobata and the non-puerarin producing P. phaseoloides. Within the transcriptomes, microsatellites were identified to aid in species identification as well as population diversity.

CONCLUSIONS

The barcode sequences generated will aid in fast and efficient identification of the three kudzu species. Additionally, the microsatellites identified from the transcriptomes will aid in genetic analysis. The root transcriptomes also provide a molecular toolkit for comparative gene expression analysis towards elucidation of the biosynthesis of kudzu phytochemicals.

HPLC-UV/HRMS methods for the unambiguous detection of adulterations of Ginkgo biloba leaves with Sophora japonica fruits on an extract level

CONTEXT

Ginkgo biloba L. (Ginkgoaceae) leaf extract is one of the most frequently sold herbal extracts. There have been reports on poor quality and adulteration of ginkgo leaf extracts or the powdered plant material with extracts or powder of Styphnolobium japonicum (L.) Schott (Fabaceae) (syn. Sophora japonica L.) fruits, which is rich in flavone glycosides.

OBJECTIVE

The study investigates whether ginkgo leaves genuinely contain genistein and sophoricoside and whether these two substances could be used as markers to detect adulterations with sophora fruits.

MATERIALS AND METHODS

A total of 33 samples of dried ginkgo leaves were sourced from controlled plantations in China, the USA, and France. After extraction, the samples were analyzed using two high-performance liquid chromatography (HPLC) coupled with UV/HRMS methods for the detection of genistein and sophoricoside, respectively. Chromatograms were compared to standard reference materials.

RESULTS

In none of the tested ginkgo samples, neither genistein nor sophoricoside could be detected. The applied method was designed to separate genistein from apigenin. The latter is a genuine compound of ginkgo leaves, and its peak may have been previously misidentified as genistein because of the same molecular mass. The method for the detection of sophoricoside allows identification of the adulteration with sophora fruit without prior hydrolysis. By both HPLC methods, it was possible to detect adulterations of ≥2% sophora fruits in the investigated ginkgo extract.

CONCLUSION

The methods allow unambiguous detection of adulterations of ginkgo leaves with sophora fruits, using genistein and sophoricoside as marker compounds.

Ginkgolic Acid Inhibits Coronavirus Strain 229E Infection of Human Epithelial Lung Cells

Since December 2019, the COVID-19 pandemic has affected more than 200 million individuals around the globe and caused millions of deaths. Although there are now multiple vaccines for SARS-CoV-2, their efficacy may be limited by current and future viral mutations. Therefore, effective antiviral compounds are an essential component to win the battle against the family of coronaviruses. Ginkgolic Acid (GA) is a pan-antiviral molecule with proven effective in vitro and in vivo activity. We previously demonstrated that GA inhibits Herpes Simplex Virus 1 (HSV-1) by disrupting viral structure, blocking fusion, and inhibiting viral protein synthesis. Additionally, we reported that GA displays broad-spectrum fusion inhibition encompassing all three classes of fusion proteins, including those of HIV, Ebola, influenza A, and Epstein Barr virus. Here, we report that GA exhibited potent antiviral activity against Human Coronavirus strain 229E (HCoV-229E) infection of human epithelial lung cells (MRC-5). GA significantly reduced progeny virus production, expression of viral proteins, and cytopathic effects (CPE). Furthermore, GA significantly inhibited HCoV-229E even when added post-infection. In light of our findings and the similarities of this family of viruses, GA holds promising potential as an effective antiviral treatment for SARS-CoV-2.

Applicability of high-resolution NMR in combination with chemometrics for the compositional analysis and quality control of spices and plant-derived condiments

Over the last years, the consumption of spices and plant-derived condiments has increased considerably, owing to new culinary trends. Unfortunately, the current marketing channels make them highly vulnerable to adulteration and food fraud. High-resolution nuclear magnetic resonance (NMR) is a powerful tool for the compositional study of spices and plant-derived condiments. It allows the chemical characterization of a wide range of polar and non-polar metabolites, and provides unique structural information not available by other techniques. The chemometric-based analysis of NMR 'fingerprints' has been used to discriminate samples according to species and geographical origin and to detect adulterations, among other applications. The comprehensive identification and quantification of marker compounds can be achieved even in complex mixtures, demonstrating a great potential for high-throughtput quality control applications. © 2020 Society of Chemical Industry.

Development of an HPLC-MS method for the determination of four terpene trilactones in Ginkgo biloba leaf extract via quality by design

Previously reported HPLC-evaporative light scattering detection methods for terpene trilactone determination in Ginkgo biloba leaf extract (EGBL) have complicated sample preparation steps and are time-consuming. Thus, in this work, an HPLC-MS method for the determination of terpene trilactones in EGBL was developed with a novel analytical quality by design approach to provide robust and simple measurements. For this purpose, analytical target profiles and systematic risk analyses were performed to identify potential critical method attributes and critical method parameters. After screening experiments, a Box-Behnken design approach was utilized to investigate the relationships between critical method attributes and critical method parameters. A hypercube design space obtained by a Monte Carlo method was used for choosing the analytical control strategy. Then, verification experiments were performed within the design space, and the models were found to be accurate. After that, the optimized method was verified and successfully used for quality control analysis of EGBL from different manufacturers, and the results were almost the same as those determined by HPLC-evaporative light scattering detection. To our knowledge, this is the first study to establish a robust HPLC-MS method for determination of terpene trilactones in EGBL based on a novel analytical quality by design concept, which can improve the quality control of commercial EGBL.

A nontargeted approach to determine the authenticity of Ginkgo biloba L. plant materials and dried leaf extracts by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and chemometrics

The lack of stringent regulations regarding raw materials for herbal supplements used for medicinal purposes has been a constant challenge in the industry. Ginkgo biloba L. leaf extracts attract consumers because of the supposed positive effect on mental performance and memory. Supplements are produced using dried leaf materials and standardized leaf extracts such as EGb 761. Adulteration of Ginkgo biloba L. plants and extracts are becoming more and more common practice due to economically driven motivation from increasing demand in the market and the high cost of raw materials and production. Reinforcement in quality control (QC) to avoid adulterations is necessary to ensure the efficacy of the supplements. In this study, liquid chromatography-high-resolution mass spectrometry (LC-HRMS) was used with principal component analysis (PCA) as an unsupervised exploratory method to analyze, identify, and evaluate the adulterated Ginkgo biloba L. plant materials and dried leaf extracts using the PCA scores and loadings obtained and compound identification.

Comprehensive HPTLC fingerprinting as a tool for a simplified analysis of purity of ginkgo products

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicinal products based on ginkgo leaf refined dry extract (GBE) are an European development from the Eastern Asia traditionally used species Ginkgo biloba L. Nowadays, ginkgo products have increased the presence in the market, mainly as dietary supplements. Its adulteration with rutin and quercetin or herbal extracts rich in these compounds is a common practice. Tests featuring assays and detection of adulterants need to be performed on top of other existent methods (e.g. identification test). This may increase the costs of evaluating the quality of ginkgo products.

AIM OF THE STUDY

To prove that comprehensive HPTLC fingerprinting can provide information beyond identification of ginkgo products, avoiding additional chromatographic tests for detection of adulterations.

MATERIALS AND METHODS

The information contained in the fingerprint obtained by HPTLC analysis of flavonoids was used for identification and for detection of adulterants, as well as to verify the limits of rutin and quercetin, which are normally determined by HPLC and used for detection of adulterants. For this purpose, peak profiles were generated from HPTLC chromatogram images. USP-HPLC methods were used for quantification of total flavonoids and testing the limits of rutin and quercetin. HPLC data were used to support the validity of the HPTLC method. An additional reversed phase HPTLC method was developed as a possible confirmatory method for the quercetin limit test.

RESULTS

The proposed HPTLC method uses a particular sequence of detections, resulting in a number of images, which are later interpreted in a certain order. It is able to identify ginkgo products, to detect adulterants (rutin, quercetin, sophora fruit and flower bud, and buckwheat), and, using peak profiles generated from the chromatogram images prior to and after derivatisation, to evaluate the limits of rutin and quercetin. Forty-eight out of fifty-nine ginkgo dietary supplements analysed contained one or more adulterants. Furthermore, results of the HPTLC and HPLC limit tests for rutin and quercetin were in agreement in 98% of the cases. Finally, a decision tree showing the sequence of interpretation of the fingerprints obtained with the different detections after a single HPTLC analysis is included to help the analyst to evaluate whether samples have the correct identity and whether they contain or not adulterants.

CONCLUSION

A single HPTLC analysis is able to provide information on identity and purity of the products. This simplifies the analytical workflow and reduces the number of analyses prescribed in the USP powdered ginkgo extract monograph.

A sensitive and selective multiple reaction monitoring mass spectrometry method for simultaneous quantification of flavonol glycoside, terpene lactones, and biflavonoids in Ginkgo biloba leaves

In this study, an efficient and sensitive UHPLC-QQQ-MS/MS (MRM) analytical strategy was established firstly for simultaneous determination of 11 components, including 3 original flavonol glycoside, 4 terpene lactones and 4 biflavonoids in Ginkgo biloba leaves. The validated strategy exhibited proper linearity (R² ≥0.99) in the range of 0.5-125 μg/mL, and intra and inter-day precision were lower than 4.09% and 4.80%, respectively. Limit of detection (LOD) and quantification (LOQ) were calculated, ranging from 0.2-4.6 ng/mL, with repeatability values between 1.98% and 4.48%. The average recoveries were all in the range of 98.45-106.67% with RSD (n = 3) for the related compounds. Subsequently, the proposed method was used for the analysis of Ginkgo biloba leaves during leaf senescence. Results showed the dominant flavonol glycosides were kaempferol-3-O-rutinoside and isorhamnetin-3-O-rutinoside, the level of terpene lactones and biflavonoids reached the highest in the latest harvest samples. Compared with conventional detection method, the present method could directly analyze original flavonol glycoside without acid hydrolysis process and terpene lactones without the ELSD in a high sensitivity. Moreover, the biflavonoids in Ginkgo biloba leaves were also simultaneously quantified. The results demonstrated that the developed method was accurate, sensitive and reliable for simultaneous quantification of multi-components in Ginkgo biloba leaves, and this study should be significant for the comprehensive utilization and development of Ginkgo biloba resources.

An Innovative Metabolomic Approach for Golden Rum Classification Combining Ultrahigh-Performance Liquid Chromatography-Orbitrap Mass Spectrometry and Chemometric Strategies

A comprehensive fingerprinting strategy for golden rum classification considering different categories such as fermentation barrel, raw material, and aging is provided, using a metabolomic fingerprinting approach. A nontarget fingerprinting of 30 different rums using liquid chromatography coupled to high-resolution mass spectrometry (Exactive Orbitrap mass analyzer, LC-HRMS) was applied. Principal component analysis (PCA) was used to assess the overall structure of the data and to identify potential outliers. Different chemometric analyses such as partial least-squares discriminant analysis (PLS-DA) were used. A variable importance in projection (VIP) selection method was applied to identify the most significant markers that allow group separation. Compounds related to aging and fermentation processes such as furfural derivates (e.g., hydroxymethylfurfural) and sugars (e.g., glucose, mannitol) were found as the most discriminant compounds (VIP threshold value >1.5). Suitable separation according to selected categories was achieved, and a classification ability of the models of close to 100% was achieved.

Discovery of a natural PI3Kδ inhibitor through virtual screening and biological assay study

Phosphoinositide-3-kinase-δ (PI3Kδ) is a key regulator in the process of IgE mediated mast cell degranulation, which directly induces allergic diseases, such as asthma. This study is aimed at discovery of natural PI3Kδ inhibitors from Chinese medicine and evaluating their anti-mast cell degranulation activity. A combined virtual screening based on 3D pharmacophore model and molecular docking was used to screen for bioactive ingredients directly targeting PI3Kδ. Then, an in vitro kinase inhibition assay was conducted to evaluate the PI3Kδ inhibitory activity of the virtual screening hits. Subsequently, a β-hexosaminidase release assay was performed to verify the anti-mast cell degranulation activity of the active compounds. Finally, ginkgoneolic acid was identified as a PI3Kδ inhibitor (IC₅₀ = 2.49 μM) and exhibited anti-mast cell degranulation activity in vitro (IC₅₀ = 2.40 μM). Docking studies showed that Glu826, Val827 and Val828 were key amino acid residues for PI3Kδ inhibitory activity. Ginkgoneolic acid may be a potential lead compound for developing effective and safe PI3Kδ-inhibiting drugs.

Quantification of terpene trilactones in Ginkgo biloba with a 1H NMR method

Ginkgo biloba L. has been used as a herbal medicine in the traditional treatment of insufficient blood flow, memory deficits, and cerebral insufficiency. The terpene trilactone components, the bioactive agents of Ginkgo biloba L., have also been reported to exhibit useful functionality such as anti-inflammatory and neuroprotective effects. Therefore, in the present research, we attempted to analyze quantitatively the terpene trilactone components in Ginkgo biloba leaf extract, with quantitative ¹H NMR (qNMR) and obtained almost identical results to data reported using HPLC. Application of the qNMR method for the analysis of the terpene trilactone contents in commercial Ginkgo extract products, such as soft gel capsules and tablets, produced the same levels noted in package labels. Thus, qNMR is an alternative method for quantification of the terpene trilactone components in commercial Ginkgo extract products.