A classification and identification model of extra virgin olive oil adulterated with other edible oils based on pigment compositions and support vector machine.

Adulteration identification of extra virgin olive oil (EVOO) is a vital issue in the olive oil industry. In this study, chromatographic fingerprint data of pigments combined with machine learning methodologies were successfully identified and classified EVOO, refined-pomace olive oil (R-POO), rapeseed oil (RO), soybean oil (SO), peanut oil (PO), sunflower oil (SFO), flaxseed oil (FO), corn oil (CO), extra virgin olive oil adulterated with rapeseed oil (EVOO-RO) and extra virgin olive oil adulterated with corn oil (EVOO-CO). Support vector machine (SVM) classification of EVOO, other edible oils, and EVOO adulteration identification achieved 100% accuracy for the training set sample and 94.44% accuracy for the test set sample. As a result, this SVM model could identify effectively the adulteration EVOO with the limit of 1% RO and 1% CO. Therefore, the excellent classification and predictive power of this model indicated pigments could be used as potential markers for identifying EVOO adulteration.

A comparative study of three chemometrics methods combined with excitation-emission matrix fluorescence for quantification of the bioactive compounds aesculin and aesculetin in Cortex Fraxini.

Cortex Fraxini is an important traditional Chinese herbal medicine with various medical functions. Aesculin and aesculetin are the main effective components of Cortex Fraxini. The fluorescence signals of the two compounds have a high degree of overlap with each other, making quantitative analysis difficult with conventional analytical methods. In the present study, different chemometrics methods, including lasso regression (LAR), interval partial least squares (iPLS), and multidimensional partial least squares (N-PLS) methods, were employed and combined with excitation-emission matrix (EEM) fluorescence for the purpose of accurate quantification of aesculin and aesculetin in Cortex Fraxini samples. The most satisfactory results were obtained by using the N-PLS method based on the EEM spectra without scatterings, with correlation coefficient of calibration and prediction values higher than 0.9972 and 0.9962, respectively, root mean squared errors for calibration and prediction values lower than 0.0304 and 0.1165, respectively, and recovery values in the range of 83.32%-104.62%. The obtained credible models indicated that the N-PLS method combined with EEM spectra has the advantages of being green, low cost, and accurate and it is a good strategy for the determination of active compounds in complex samples. To further confirm the accuracy of the obtained results, the same samples were analyzed by the recognized ultra-performance liquid chromatography method.

Synthesis of Melatonin Derivatives and the Neuroprotective Effects on Parkinson's Disease Models of Caenorhabditis elegans.

Melatonin (MT) is a hormone with antioxidant activity secreted by the pineal gland in the human brain, which is highly efficient in scavenging free radicals and plays an important role in the neuro-immuno-endocrine system. Emerging evidence showed that MT supplementation was a potential therapeutic strategy for Parkinson's disease (PD), which inhibits pathways associated with oxidative stress in PD. In this study, we reported a C7-selective olefination of melatonin under rhodium catalysis with the aid of PIII-directing groups and synthesized 10 new melatonin-C7-cinnamic acid derivatives (6a-6j). The antioxidant potential of the compounds was evaluated both by ABTS and ORAC methods. Among these newly synthesized melatonin derivatives, 6a showed significantly higher activity than MT at 10-5 M. In the transgenic Caenorhabditis elegans model of PD, 6a significantly reduces alpha-synuclein aggregation and dopaminergic neuronal damage in nematodes while reducing intracellular ROS levels and recovers behavioral dysfunction induced by dopaminergic neurodegeneration. Further study of the mechanism of action of this compound can provide new therapeutic ideas and treatment strategies for PD.

Development and validation of ultra-high performance supercritical fluid chromatography method for quantitative determination of six compounds in Guizhi Fuling capsule and tablet samples.

A fast and simple ultra-high performance supercritical fluid chromatography method has been developed for the determination of six analytes, namely (paeonol, coumarin, cinnamic alcohol, cinnamic acid, paeoniflorin, and amygdalin) in Guizhi Fuling capsule and tablet samples. The influence of the key chromatographic parameters for the separation purposes was evaluated. The optimal column was Trefoil CEL1 column. The optimal mobile phase was a gradient mixture of carbon dioxide and methanol at flow rate of 1.0 mL/min. The back pressure of the system was set to 1.38 × 107  Pa and the temperature to 45°C. The six compounds were separated within 11 min by the proposed ultra-high performance supercritical fluid chromatography method with satisfactory resolution. Method validation confirmed that the procedure is accurate with the recovery rates from 87.04 to 104.30%, intraday precision values less than 4.81% and interday precision less than 5.22%, and linear with R2 higher than 0.9967. Therefore, this work provides a simple and novel method for the simultaneous analysis of six compounds in Guizhi Fuling capsule and tablet samples.

Identification of bioactive compounds that contribute to the α-glucosidase inhibitory activity of rosemary.

To investigate the bioactive compounds that contribute to the α-glucosidase inhibitory activity of rosemary, phenolics and triterpene acids were characterized and quantified using quadrupole-Orbitrap mass spectrometry and enzyme assay. Two phenolic diterpenes (carnosol and hydroxy p-quinone carnosic acid) and two triterpene acids (betulinic acid and ursolic acid) were identified as potent α-glucosidase inhibitors. Carnosol, a major diterpene in rosemary, showed significant α-glucosidase inhibitory activity with IC50 value of 12 µg mL-1, and its inhibition mode was competitive. The inhibition mechanism of carnosol on α-glucosidase was further investigated by a combination of surface plasmon resonance (SPR) spectroscopy, fluorescence quenching studies and molecular-modeling techniques. The SPR assay suggested that carnosol had a high affinity to α-glucosidase with equilibrium dissociation constant (KD) value of 72.6 M. Fluorescence quenching studies indicated that the binding between carnosol and α-glucosidase was spontaneous and mainly driven by hydrophobic forces. Molecular docking studies revealed that carnosol bound to the active site of α-glucosidase. Furthermore, the oral administration of carnosol at 30 mg kg-1 significantly reduced the postprandial blood glucose levels of normal mice. This is the first report on the α-glucosidase inhibition and hypoglycemic activity of phenolic diterpenes, and these results could facilitate the utilization of rosemary as a dietary supplement for the treatment of diabetes.

Quality assessment of Traditional Chinese Medicine using HPLC-PAD combined with Tchebichef image moments.

Traditional Chinese medicines have gotten growing attention and the product quality also became uneven. In this paper, Tchebichef image moments coupled with high performance liquid chromatography with photodiode array detector were proposed to the similarity analysis of the fourteen batches of Pudilan Xiaoyan tablets (Chinese medicine complex), which were based on the grayscale images of three dimensional (3D) fingerprint spectra. Hierarchical cluster analysis was used for displaying the classification results. As a comparison, traditional principal component analysis (PCA) method based on the chromatograms under single-fixed wavelength was carried out on the same samples. The analytical results indicated that the proposed approach could provide more accurate and reasonable results owing to its powerful invariant and multi-resolution capability of image moments.

High-performance liquid chromatography with photodiode array detection and chemometrics method for the analysis of multiple components in the traditional Chinese medicine Shuanghuanglian oral liquid.

Shuanghuanlian oral liquid, a traditional Chinese medicine preparation, is a mixture of three herbs (Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae). In this study, the quantitative analysis of three main active compounds, chlorogenic acid, forsythin and baicalin in samples from different manufacturers was performed rapidly by high-performance liquid chromatography coupled with photodiode array detection followed by Contour Projection coupled to stepwise regression treatment of the obtained three-dimensional spectra in which the partial overlap between adjacent target components existed. The method was validated for linearity (R>0.9940), precision (RSD<1.25%), recovery (92.20-102.50%), limit of detection (0.01-0.02 µg/mL) and limit of quantification (0.03-0.07 µg/mL). The results indicated that the combination of the three-dimensional spectra of traditional Chinese medicine and Contour Projection-stepwise regression offered an accurate, simple, low-cost and eco-friendly way for the rapid quantitative analysis of Shuanghuanlian oral liquid samples.

Fast determination of four active compounds in Sanqi Panax Notoginseng Injection samples by high-performance liquid chromatography with a chemometric method.

The application of chemometric methods could decrease the requirements of separation and simplify time-consuming pretreatment and experimental optimization. In this report, the accumulated projection method was developed and utilized for the rapid simultaneous quantification of four active components (notoginsenoside R1, ginsenosides Rg1, ginsenosides Re, and ginsenosides Rb1) in Sanqi Panax Notoginseng Injection samples. The proposed method is based on the three-dimensional fingerprint spectra obtained from high-performance liquid chromatography coupled with photodiode array detection. Although the chromatograms consisted of overlapping peaks, retention time shifts, and unknown interference, all established models showed good linearity (R > 0.9869) within test ranges. The relative standard deviation for intra- and interday precision of the four compounds did not exceed 2.4 and 4.7%, respectively, and the overall recovery was 91.2-106.8%. Compared with N-way principal component analysis, our method provides more satisfactory results, which indicate that the proposed approach is simple, fast, and reliable for the determination of the four analytes in Sanqi Panax Notoginseng Injection samples.

The application of a Tchebichef moment method to the quantitative analysis of multiple compounds based on three-dimensional HPLC fingerprint spectra.

Three-dimensional (3D) fingerprint spectra provide a wealth of information for the quantitative analysis of multiple target compounds in mixtures. In this paper, a Tchebichef moment method based on the 3D fingerprint spectra obtained from high performance liquid chromatography coupled with a photodiode array detector was proposed and used to determine notoginsenoside R1, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 in samples of a traditional Chinese Medicine (Sanqi Panax Notoginseng). The correlation coefficients of the established models were more than 0.9955 within the test ranges, the recovery ranged from 98.41% to 108.00%, and the intra- and inter-day precisions were less than 3.83% and 5.04%, respectively. The obtained results indicated that the Tchebichef moment method had effective feature representation capability and provided satisfactory quantification accuracy. Furthermore, several moment methods applied in analytical chemistry were compared, which provided a valuable insight into the application of moment methods in the analytical field.

A practical application of wavelet moment method on the quantitative analysis of Shuanghuanglian oral liquid based on three-dimensional fingerprint spectra.

The overlapping and shifts of peaks and noise signals appear mostly in high performance liquid chromatography (HPLC) experiments. A practical application of wavelet moment method on the quantitative analysis of the main active components in Shuanghuanglian oral liquid samples was presented based on the determination of HPLC coupled with photodiode array detector (PAD). The wavelet moments were calculated from the divided regions in the grayscale images of three-dimensional (3D) HPLC-PAD fingerprint spectra according to the target peak(s), and then used to establish linear models, respectively. The correlation coefficients (R) were more than 0.9980 within the test ranges. The intra- and inter-day variations were less than 1.13% and 1.10%, respectively. The recovery ranged from 96.2% to 102.7%. The overall LODs and LOQs were less than 0.2 µg/mL and 0.7 µg/mL, respectively. Our study indicated that wavelet moment approach could defuse the overlapping and shifts of peaks and noise signals in the chromatographic determination owing to its multi-resolution and inherently invariance properties. Thus the analytical time was shortened, and the obtained results were reliable and accurate.

An application of wavelet moments to the similarity analysis of three-dimensional fingerprint spectra obtained by high-performance liquid chromatography coupled with diode array detector.

More and more the three-dimensional (3D) fingerprint spectra, which can be obtained by high performance liquid chromatography coupled with diode array detector (HPLC-DAD), are applied to the analysis of drugs and foods. A novel approach to the similarity analysis of traditional Chinese medicines (TCMs) was proposed based on the digital image processing using 3D HPLC-DAD fingerprint spectra. As the one of shape features of digital grayscale image, wavelet moments were employed to extract the shape features from the grayscale images of 3D fingerprint spectra of different Coptis chinensis samples, and used to the similarity analysis of these samples. Compared with the results obtained by traditional features including principal components and spectrum data under single-wavelength, our results represented the more reliable assessment. This work indicates that the better features of fingerprint spectra are more important than similarity evaluation methods. Wavelet moments, which possess multi-resolution specialty and the invariance property in image processing, are more effective than traditional spectral features for the description of the systemic characterisation of mixture sample.