Zhi-Tian Zuo

Phytochemicals and bioactivities of Paris species

The plants of genus Paris, as important Chinese traditional herbs, have been studied from phytochemicals and pharmacological viewpoints for decades, which resulted in the discovery of scores of secondary metabolites with various kinds of bioactivities. This article summarizes the research progress of the genus Paris in the phytochemical and pharmacological respects.

Investigation of chemical diversity in different parts and origins of ethnomedicine Gentiana rigescens Franch using targeted metabolite profiling and multivariate statistical analysis.

Gentiana rigescens, an ethnomedicine, is widely cultivated in Yunnan province of China. Although a wide range of metabolites including iridoid glycosides, flavonoids and triterpenoids have been reported in this ethnomedicine, the data on accumulation and distribution of metabolites in certain parts are limited. In this study, targeted metabolic fingerprinting of iridoid glycosides based on liquid chromatography-ultraviolet detection-tandem mass spectrometry (LC-UV-MS/MS) was developed to investigate the metabolic similarities and differences in different parts and origins. Thirty-one compounds, including iridoid glycosides and flavonoids, were detected from targeted metabolite profiling and plausibly assigned to the different parts of G. rigescens. Multivariate statistical analysis was designed to reveal close chemical similarities between all the selected samples and to identify key metabolites characteristic of the standard. The results suggested that accumulation and distribution of metabolites in aerial and underground parts were different. Moreover, root samples tended to be grouped on the basis of the geographical closeness of region. Five metabolites can be considered as potential markers for the classification of underground parts from different regions. These results provided chemical information on the potential pharmaceutical value for further research, making G. rigescens ideal for the rational usage of different parts and exploitation of the source.

Liquid Chromatography Tandem Mass Spectrometry Combined with Fourier Transform Mid-Infrared Spectroscopy and Chemometrics for Comparative Analysis of Raw and Processed Gentiana rigescens

Herbal medicines have been shown to change chemical constituents upon different processing approaches, which might lead to different pharmacological activities and therapeutic effects. In this study, raw and processed Gentiana rigescens (wine-, vinegar-, and salt water-processed) were extracted and profiled by ultra-fast liquid chromatography tandem mass spectrometry (UFLC–MS/MS) and Fourier transform mid-infrared spectroscopy (FT-MIR). Hierarchical cluster analysis (HCA) based on FT-MIR revealed potential relationships between raw and processed samples, while the processed sample displayed chemical variation. Partial least-squares discriminate analysis (PLS-DA) was used for screening the marker metabolites. The results indicated that UFLC–UV-MS/MS and FT-MIR fingerprints with chemometrics could effectively evaluate the quality of G. rigescens under different processed approaches. Eight compounds were selected as potential marker metabolites for contributing to the most effective classification of raw and processed samples. In addition, these potential marker metabolites were tentatively identified by matching mass information with the fragmentation patterns of the published literature or standard compounds. These results revealed that UFLC–UV-MS/MS and FT-MIR methods coupled with chemometrics could provide an effective platform for monitoring quality variations of G. rigescens under different processed approaches.

Determination of Iridoids in Gentiana rigescens by Infrared Spectroscopy and Multivariate Analysis

ABSTRACT Gentiana rigescens is a famous herbal medicine in China for treatment of convulsion, rheumatism, and jaundice. Here, the infrared determination of gentiopicroside, swertiamarin, sweroside, and loganic acid in G. rigescens from different areas and varieties was presented for the first time. Reference information for the iridoids were obtained by high-performance liquid chromatography. Partial least squares was used to characterize the relationship between spectra matrix and concentration vector for the determination of the analytes. For determination of gentiopicroside, the appropriate performance of partial least squares model was acquired with coefficient of determination of calibration and coefficient of determination of prediction values of 0.965 and 0.868. The root mean square error of estimation (RMSEE), root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP), and residual predictive deviation (RPD) values were 2.612, 5.292, 5.239 mg g−1, and 2.701, respectively, based on the first derivative and multiplicative scatter correction. For determination of the total iridoids, the best results were obtained using the coefficient of determination of calibration and coefficient of determination of prediction of 0.943 and 0.834, RMSEE, RMSECV, RMSEP and RPD of 3.896, 7.536, 6.543 mg g−1 and 2.438, respectively, based on the first derivative. Both models were reliable and robust. The results demonstrated that infrared spectroscopy provided a rapid, low-cost tool to monitor the quality of G. rigescens by the determination of the iridoids.

Characterization of Gentiana rigescens by Ultraviolet–Visible and Infrared Spectroscopies with Chemometrics

ABSTRACT Gentiana rigescens is a medicinal plant for treatment of rheumatism, convulsions, and jaundice. The present paper reports the potential for chemometric characterization of G. rigescens using ultraviolet–visible and infrared spectroscopies, individually and together. Low- and mid-level data fusions were considered in this study. Partial least square discriminant analysis and support vector machine were used to analyze single and fused spectral data, respectively. The data fusion strategy improved the classification capacity. In particular, the mid-level data fusion provided the best results by selecting important variance from the data matrixes, with 100% correct classification of test samples by partial least square discriminant analysis and support vector machine characterization. The results demonstrated that the combined use of ultraviolet–visible and infrared spectroscopies is more suitable for the discrimination of G. rigescens than the individual methods.

Comparison of Mineral Element Content in a Functional Food Maca (Lepidium meyenii Walp.) from Asia and South America

Contents of eight mineral elements in maca (Lepidium meyenii Walp.) from China and Peru were determined by inductively coupled plasma optical emission spectroscopy. Cu contents in maca samples from China (2.5–31 mg kg−1 dry weight, dw) were higher than the samples from Peru (<2.1 mg kg−1 dw). Na in two samples from China was found to be significantly of high content (2400 and 2600 mg kg−1 dw). The contents (mg kg−1 dw) of B, Co, Cr, Li, Ni, and Zn were, respectively, 8.1–21, <0.023, <1.1~3.5, 0.020–0.17, 0.085–4.5, and 10–39 for the samples from China, while being 6.6–12, <0.023, <1.1~2.3, 0.035–0.063, 0.68–1.7, and 27–39 for the samples from Peru.

Quantitative and Qualitative Characterization of Gentiana rigescens Franch (Gentianaceae) on Different Parts and Cultivations Years by HPLC and FTIR Spectroscopy

Gentiana rigescens Franch (Gentianaceae) is a famous medicinal plant for treatments of rheumatism, convulsion, and jaundice. Comprehensive investigation of different parts and cultivation years of this plant has not yet been conducted. This study presents the quantitative and qualitative characterization of iridoid glycosides from G. rigescens performed by HPLC and FTIR spectroscopy techniques. The accumulations of loganic acid, swertiamarin, gentiopicroside, and sweroside were determined. Results indicated that their content and distribution in different parts and cultivation years exhibit great variations. Gentiopicroside was identified as the most abundant compound among iridoid glycosides and its highest level was observed in the root of 2-year-old plant. With respect to qualitative variation of metabolic profile, the 1800–800 cm−1 band of FTIR spectra successfully discriminated different parts and cultivation years with the aid of PLS-DA. In addition, combined with PLSR, the feasibility of FTIR spectroscopy for determination of gentiopicroside was investigated by selecting characteristic wavelengths (1800–800 cm−1), which presented a good performance with a residual predictive deviation (RPD) of 3.646. Our results suggested that HPLC and FTIR techniques can complement each other and could be simultaneously applied for comparing and analyzing different parts and cultivation years of G. rigescens.

Multivariate analyses of major and trace elements in 19 species of herbs consumed in Yunnan, China

ABSTRACT This study aimed to analyze the concentrations of 10 elements in 19 species of herbs related to medical and edible purpose in Yunnan, China. Microwave-assisted acid digestion was used for all of the dried herbs and element contents were determined by inductively coupled plasma atomic emission spectrometry. The accuracy of this method was validated by analyzing GBW07605 certified reference material. The results indicated that the distributions of element contents were varied over a wide range in the specimens tested. The decreasing sequence of average element content expressed as dry weight was presented as follows: calcium (1740–22,246 µg/g dry weight), magnesium (634–6367 µg/g dry weight), iron (52.8–5707 µg/g dry weight), barium (9.19–465 µg/g dry weight), zinc (10.7–82.1 µg/g dry weight), strontium (8.25–69.8 µg/g dry weight), copper (4.10–36.6 µg/g dry weight), chromium (0.26–13.3 µg/g dry weight), nickel (0.57–14.7 µg/g dry weight), and cadmium (0.11–2.66 µg/g dry weight). The element contents of samples were different depending on several species. However, the accumulations of toxic elements (cadmium, chromium, and nickel) were above the international safety standards limit in most samples. Principal component analysis generated three principal components that explained 77% of the total variance in the data. Similar samples may get together by cluster analysis and could correspond to the result of principal component analysis.

Determination of Total Flavonoids for Paris Polyphylla Var. Yunnanensis in Different Geographical Origins Using UV and FT-IR Spectroscopy

Background: Paris polyphylla var. Yunnanensis (PPY) is used in the clinical treatment of tumors, hemorrhages, and anthelmintic. Objective: The aim of this study is to determine total flavonoids of PPY in the Yunnan and Guizhou Provinces, China. Methods: In this study, total flavonoids were determined by UV spectrophotometry at first. Then, Fourier transform mid-infrared (FT-IR) based on various pretreatments include standard normal variate (SNV), first derivative (FD), second derivative (SD), Savitzky-Golay (SG), and orthogonal signal correction (OSC) were investigated. In addition, several relevant variables were screened by competitive adaptive reweighted sampling (CARS). The content of total flavonoids and selected variables of FT-IR were used to establish a partial least squares regression for PPY in different regions. Results: The results indicated that CARS was an effective method for decreasing the variable of the database and improving the prediction of the model. FT-IR with pretreatment SNV + OSC + FD + SG had the best performance, with R2 > 0.9 and residual predictive deviation = 3.3515, which could be used for the predictive model of total flavonoids. Conclusions: Those results would provide a fast and robust strategy for the determination of total flavonoids of PPY in different geographical origin. Highlights: Various pretreatments, including SNV, FD, SD, SG, and OSC, were compared; several relevant variables were selected by CARS; and the content of total flavonoids and selected variable were used to establish a partial least squares regression for PPY in different regions.

Authentication of Dendrobium Species Using Near-Infrared and Ultraviolet–Visible Spectroscopy with Chemometrics and Data Fusion

ABSTRACT Herbal products produced from multiple plants have special characteristics in the clinical practice of traditional Chinese medicine. These traits provide the opportunity for fraudulent merchants to mix other herbal products similar in appearance into authentic herbal medicine. Shihu is a tonic herbal medicine from the Dendrobium plants with complex botanical origins. In this context, 11 Dendrobium plants including 109 individuals from China were collected for authentication work. Nine species have been described as herbal medicines in the literature while D. hookerianum and D. xichouense are not reported to have medicinal benefits. A key feature of this study was that multiple recognition approaches, based on near-infrared and ultraviolet–visible spectra as well as their combination, were compared to investigate their classification performance. Intuitively, score plots using principal component analysis and hierarchical cluster diagrams were used to evaluate the genetic relationships among these species. Compared with support vector machine discrimination analysis and k-nearest neighbor models, the partial least square discrimination analysis model combined with low-level data fusion provided excellent performance for authentication and was the most robust model with 100% accuracy rates for the training and prediction sets. The results indicated that near-infrared and ultraviolet–visible spectra and their fusion dataset combined with supervised recognition analysis are effective and therefore recommended for the authentication of genuine and sham of herbal Shihu species.