Experimental design approach for the quantitative analysis of multicomponents by single marker and HPLC fingerprinting of Thunbergia laurifolia aqueous extract.

INTRODUCTION: Thunbergia laurifolia is used in traditional Thai medicine to reduce fever and treat mouth ulcers. However, the quantitative analysis of chemical markers has not yet been officially defined. OBJECTIVE: The objective of this study is to develop a high-performance liquid chromatography (HPLC) method using a design of experiment (DoE) for the quantitative analysis of multicomponents by single marker (QAMS) and fingerprinting of the T. laurifolia aqueous extract. MATERIALS AND METHODS: Critical variables were screened using a two-level fractional factorial design, followed by the optimization of the selected variables using a central composite design. The validated method was applied for quality assessment based on QAMS and fingerprinting of the extract. RESULTS: Optimum conditions of DoE for the analysis of caffeic acid, vicenin-2, and rosmarinic acid were determined. The relative correction factors for caffeic acid and vicenin-2 were calculated using rosmarinic acid as an internal reference standard, and their contents in 30 samples were determined. The differences between the external standard method (ESM) and QAMS were compared. No significant difference was observed in the quantitative determination, proving the consistency QAMS and ESM. HPLC fingerprints of T. laurifolia were established with 8 of 12 characteristic peaks that were structurally characterized using HPLC-diode array detection-electrospray ionization/tandem mass spectrometry. The similarity of the fingerprints in all samples was ≥0.74, and the pattern recognition of the characteristic peaks was satisfied. CONCLUSION: The proposed method efficiently detected multiple components of the T. laurifolia extract. Thus, the method is beneficial in providing references for enhancing the quality control of other herbal medicines.

[Determination of 13 kinds of free and bound phenolic acids in fruits by high-performance liquid chromatography-mass spectrometry].

OBJECTIVE: To establish a high-performance liquid chromatography-mass spectrometry(HPLC-MS/MS) method for detecting 13 kind of free and bound phenolic acids(chlorogenic acid, protocatechuic acid, ferulic acid, p-coumaric acid, gallic acid, gentisic acid, vanillic acid, caffeic acid, syringic acid, sinapic acid, rosmarinic acid, salicylic acid, p-hydroxybenzoic acid) in fruits, and optimize the pre-treatment conditions to meet the detection requirements for phenolic acid content in various types of fruits. METHODS: Free phenolic acids in fruits were extracted using methanol through ultrasonic extraction. Conjugated phenolic acids in the centrifuged residue were released by alkaline hydrolysis and extracted with ethyl acetate. The two extracts were combined, concentrated, and analyzed using HPLC-MS/MS. Separation was achieved using an Agilent ZORBAX SB-C_(18) chromatography column(3.0 mm×100 mm, 3.5 µm), and detection was performed in multiple reaction monitoring(MRM) mode. RESULTS: All 13 standard phenolic acids achieved complete separation within 10 minutes, with linear correlation coefficients greater than 0.998 and detection limits ranging from 0.172 to 3.471 ng/mL. After optimization of the pre-treatment method, the recovery rates of the method for four types of fruits-apples, strawberries, oranges, and peaches-ranged from 80.0% to 119.4%, and the precision were lower than 7.00%(n=6). The result of testing on four categories of twelve types of fruits demonstrated significant variations in the content of phenolic acids among different fruits, and within the same category, the composition of phenolic acids did not exhibit consistency. CONCLUSION: The HPLC-MS/MS method exhibits high sensitivity, precision, and accuracy. It is suitable for the detection of both free and bound phenolic acids in various types of fruits.

Effect of employing different extraction techniques and solvents on the total phenolic content and antioxidant properties of an Iranian endemic species Zeravschania khorasanica (Apiaceae).

Zeravschania khorasanica, a species endemic to the eastern part of Iran, possesses distinct characteristics that distinguish it from its two closely related species. This research employed five different extraction techniques to identify the active components, total phenolic content and in vitro antioxidant activity of the extract. Furthermore, hydro-distillation was utilized for GC/MS analysis to determine the composition of the essential oil. The total phenolic content was estimated using the Folin-Ciocalteu assay and the antioxidant capacity was evaluated using the DPPH radical scavenging test. The findings revealed that ethanolic Soxhlet extraction yielded the highest efficiency in extracting total phenolic content (88.19 ±1.99 gallic acid mg/100g). In contrast, water maceration extraction demonstrated the highest antioxidant activity (68.1 ±5.4%). Interestingly, the study uncovered that there is no significant positive correlation between the phenolic content and the antioxidant activity of the plant. Additionally, HPLC analysis identified three phenolic constituents in the extract. The Soxhlet extraction method yielded the highest levels of chlorogenic acid (5.8 ppm), caffeic acid (4.1 ppm) and salicylic acid (10.3 ppm). As per the GC/MS analysis, a total of eleven compounds were identified. The predominant compounds were elemicin at 58.19% and trans--bergamotene at 25.78%.

Fast Analysis of Caffeic Acid-Related Molecules in Instant Coffee by Reusable Sonogel-Carbon Electrodes.

Reusable Sonogel-Carbon electrodes containing carbon black (SNGC-CB) have been used for the electrochemical analysis of caffeic acid (CA) in real matrices. Measurements were firstly performed in standard solutions, in which SNGC-CB electrodes allowed the electrochemical determination of CA with high sensitivity and low limit of detection, equal to 0.76 µM. The presence of CB nanostructures in the formulation led to improved performances with respect to pristine SNGC electrodes. Then, measurements were performed in four instant coffees of different brands. A comparison between the results obtained by electrochemical, chromatographic and spectroscopic methods showed that SBGC-CB electrodes represent a simple and economic tool for the rapid assessment of caffeic acid-related molecules in instant coffees.

Influence of Caffeic and Caftaric Acid, Fructose, and Storage Temperature on Furan Derivatives in Base Wine.

The aim of this study was to determine the influence of caffeic and caftaric acid, fructose, and storage temperature on the formation of furan-derived compounds during storage of base wines. Base wines produced from Chardonnay grapes were stored at 15 and 30 °C for 90 days with additions of fructose, caffeic acid, and caftaric acid independently or in combinations. Wines were analyzed following 90 days of storage for: total hydroxycinnamic acids, degree of browning, caffeic acid and caftaric acid concentrations, and nine furan-derived compounds. Caffeic and caftaric acid additions increased homofuraneol concentration by 31% and 39%, respectively, at 15 °C (p < 0.05). Only the addition of caffeic acid increased furfural by 15% at 15 °C (p < 0.05). Results demonstrate that some furan derivatives over 90 days at 15 °C increased slightly with 5 mg/L additions of caffeic and caftaric acid. This is the first time the influence of hydroxycinnamic acids on furan-derived compounds has been reported during short-term aging of base wine at cellar temperature.

Ferocactus herrerae Fruits: Nutritional Significance, Phytochemical Profiling, and Biological Potentials.

The current study reports for the first time the nutritional, fruit volatiles, phytochemical, and biological characteristics of Ferocactus herrerae J. G. Ortega fruits. The nutritional analysis revealed that carbohydrate (20.6%) was the most abundant nutrient followed by dietary fibers (11.8%), lipids (0.9%), and proteins (0.8%). It was rich in vitamins, minerals, essential, and non-essential amino acids. Gas chromatography-mass spectrometry (GC-MS) analysis of the headspace-extracted volatiles showed that 3-methyl octadecane (35.72 ± 2.38%) was the major constituent detected. Spectrophotometric determination of total phenolic and flavonoid contents of the fruit methanolic extract (ME) showed high total phenolic [9.17 ± 0.87 mg/g gallic acid equivalent (GAE)] and flavonoid [4.99 ± 0.23 mg/g quercetin equivalent (QE)] contents. The ME was analyzed using high-performance liquid chromatography with ultraviolet (HPLC-UV), which allowed for both qualitative and quantitative estimation of 16 phenolic compounds. Caffeic acid was the major phenolic acid identified [45.03 ± 0.45 mg/100 g dried powdered fruits (DW)] while quercitrin (52.65 ± 0.31 mg/100 g DW), was the major flavonoid detected. In-vitro assessment of the antioxidant capacities of the ME revealed pronounced activity using three comparative methods; 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (132.06 ± 2.1 µM Trolox equivalent (TE) /g), 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), (241.1 ± 5.03 uM TE/g), and ferric reducing antioxidant power (FRAP) (258.9 ± 1.75 uM TE/g). Besides, remarkable anti-inflammatory [COX-1 (IC50 = 20.2 ± 1.1 µg/mL) and COX-2 (IC50 = 9.8 ± 0.64 µg/mL)] and acetylcholinesterase inhibitory (IC50 = 1.01 ± 0.39 mg/mL) activities were observed. Finally, our results revealed that these fruits could be used effectively as functional foods and nutraceuticals suggesting an increase in their propagation.

Preclinical safety assessment of the crude extract from Sida rhombifolia L. aerial parts in experimental models of acute and repeated-dose 28 days toxicity in rats.

Sida rhombifolia (Malvaceae) is popularly used as a treatment for several pathological conditions; however, there is a lack of studies that identify its compounds and that evaluate comprehensively the safety of its consumption. Therefore, the aim of this study was to determinate the phytochemical constitution of the crude extract of Sida rhombifolia (CESR), and its safety in models of acute and repeated doses (28 days) toxicity. The tested dose for the model of acute toxicity was 2000 mg/kg doses for the repeated dose model were 150, 300 e 600 mg/kg. Hematological, biochemical, histopathological and oxidative markers were investigated. HPLC-DAD-MS analysis evidenced the presence of caffeic acid, coumarin, and rutin. In the acute toxicity model the only altered parameters were tissue ROS, and AST and BUN in serum. As for the repeated dose experiment both hematological and biochemical markers remained within the values of reference for the species. Obtained results demonstrate that the CESR did not present significant toxic effects when administrated orally to male and female rats in acute and repeated doses.

Distributions of eight bioactive components in rat tissues administered Marsdenia tenacissima extract orally detected through UPLC-MS/MS.

Marsdenia tenacissima (Roxb.) Wight et Arn. (M. tenacissima) is considered an anticancer medicine in traditional Chinese medicine, which is extensively used in clinical application since it has great therapeutic effects. Currently, although a number of articles have examined M. tenacissima in terms of its pharmacology and quality control, few have investigated the in vivo mechanism of M. tenacissima active ingredients. Previously, we have studied the pharmacokinetics of eight active ingredients after oral administration of M. tenacissima extracts in rat plasma. This study constructed a new scientific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach to simultaneously quantify the contents of tenacissosides B, G, H and I, cryptochlorogenic acid, chlorogenic acid, neochlorogenic acid and caffeic acid in rats orally administered M. tenacissima extract. The proposed approach was successfully used for investigating the distributions of those eight analytes in rat tissues, with digoxin being used as an internal control. The Eclipse Plus C18 RRHD column was used for determination at a column temperature of 30°C. The mobile phase system consisted of acetonitrile and water (supplemented with 0.1% formic acid) under optimal gradient elution conditions. Afterwards, this approach was validated according to the requirements for the analysis of biological samples developed by the US Food and Drug Administration, including precision, accuracy, stability and matrix effects. Based on tissue distribution analysis, those eight analytes showed rapid distribution within all the tested tissues. With regard to organic acid distribution, it followed the order stomach > liver > kidney > small intestine > lung > spleen > heart, whereas the four steroids followed the order stomach > lung > spleen > small intestine > liver > kidney > heart. The present study lays the theoretical foundation for the use and development of M. tenacissima in clinical practice.

Effect of Elicitation with (+)-Usnic Acid on Accumulation of Phenolic Acids and Flavonoids in Agitated Microshoots of Eryngium alpinum L.

The present work was aimed at studying the potential of elicitation on the accumulation of phenolic compounds in in vitro shoot cultures of Eryngium alpinum L., a protected plant from the Apiaceae family. The study examined the influence of (+)-usnic acid on the biomass growth as well as on the biosynthesis of the desired flavonoids and phenolic acids in the cultured microshoots. The phenolic compound content was determined by HPLC-DAD. The flavonoid of the highest concentration was isoquercetin, and the phenolic acids of the highest amount were rosmarinic acid, caffeic acid and 3,4-dihydroxyphenylacetic acid, both in the non-elicited and elicited biomass. Isoquercetin accumulation was efficiently increased by a longer elicitation with a lower concentration of lichenic compound (107.17 ± 4.67 mg/100 g DW) or a shorter elicitation with a higher concentration of acid (127.54 ± 11.34 and 108.37 ± 12.1 mg/100 g DW). Rosmarinic acid production generally remained high in all elicited and non-elicited microshoots. The highest content of this acid was recorded at 24 h of elicitation with 3.125 µM usnic acid (512.69 ± 4.89 mg/100 g DW). The process of elicitation with (+)-usnic acid, a well-known lichenic compound with allelopathic nature, may therefore be an effective technique of enhancing phenolic compound accumulation in alpine eryngo microshoot biomass.

Screening of secondary metabolites in cladodes to further decode the domestication process in the genus Opuntia (Cactaceae).

MAIN CONCLUSION: During their domestication process, the species of the genus Opuntia lose their ability to survive in the wild. Presence and concentration of secondary metabolites which play a role in the interaction with their surroundings are modified but without an identifiable pattern. A domestication gradient based on morphological characteristics has been previously described for the species in the Opuntia genus. Secondary metabolites are a diverse group of bioactive compounds that relate to a species evolution, both in their natural and artificial (domestication process) selection environments. In addition, these compounds are associated with plant resistance to stress when growing in the wild. A comprehensive characterization of secondary metabolite profiles in the Opuntia genus that accounts for the genotypic differences related to the degree of domestication has not previously been conducted. This study evaluated the phytochemical composition of young cladodes from fifteen variants, of O. ficus-indica, O. albicarpa Sheinvar, and O. megacantha Salm-Dyck, identified as species with a highly advanced, advanced and intermediate degree of domestication, respectively, and O. hyptiacantha A. Web, and O. streptacantha Lem. identified as wild-intermediate and wild species. Analyses were carried out using a HPLC-diode array detection technique. Out of the 13 identified and quantified phenolic molecules and terpenoids, only the caffeic, ferulic and syringic acids, and the terpenoid ß-amyrin were present in all variants. The flavonoid luteolin was absent in all five species. Gallic, vallinic, p-hydroxybenzoic, chlorogenic and p-coumaric acids were only present in 53-87% of variants; flavonoids quercetin, isorhamnetin, rutin and apigenin in 47-87% of the variants. Both, oleanolic acid and peniocerol, were present only in 60% of variants. Isorhamnetin was absent in O. hyptiacantha and quercetin in O. streptacntha. Differences and similarities in the secondary metabolites content showed no recognizable trend relating to the degree of domestication across the species in this genus.

Targeted characterization of acylated compounds from Scrophulariae Radix using liquid chromatography coupled with Orbitrap mass spectrometry and diagnostic product ion-based data analysis.

Acylated compounds are often present in herbal medicines. In this study, a diagnostic product ion-based strategy was established to comprehensively characterize acylated compounds in Scrophulariae Radix. After untargeted data acquisition using ultra-high performance liquid chromatography coupled with Orbitrap mass spectrometry, the data were processed by three-stage diagnostic product ions. First, diagnostic product ions corresponding to the acyl groups (cinnamoyl, p-coumaroyl, feruloyl, and caffeoyl) were used to search 90 compounds. Second, these compounds were divided into three categories using diagnostic product ions for phenylethanoid glycosides, iridoid glycosides, and phenylpropanoids, respectively. Last, the linkage position of the acyl group to iridoid glycosides was discriminated via the third-stage diagnostic product ions. As a result, 90 acylated compounds were characterized, and 37 of them were reported from Scrophulariae Radix for the first time.

Identification of caffeic acid and rutin by UHPLC MS/MS and antioxidant activity of Commelina erecta Lineu. in cell culture.

The Commelina erecta L. (C. erecta) also known as erva-de-santa-luzia is reported by local population to have medical properties against some pathological conditions. In this study, two extracts of C. erecta leaves (aqueous and ethanolic) were phytochemically analysed and evaluated for their in-vitro antioxidant activities by DPPH, TBARS, NO assays and cell viability assays. The ultra-high performance liquid chromatography followed by tandem mass spectrometry analysis showed the presence of rutin and caffeic acid in aqueous and ethanolic extract. The total polyphenols in aqueous and ethanolic extracts found were 142.7 ± 3.0 and 123.1 ± 5.8 µg/mL of GAE, respectively. The ethanolic extract (5 mg/mL) inhibits TBARS by 33.8%, and the aqueous extract (5 mg/mL) exhibited scavenger property against nitric oxide derivatives to an extent of 77.8%. In cell culture, both extracts improved cell survivability under H2O2 induced oxidative stress. Thus, C. erecta extract is a good candidate to become a phytotherapic medicine.

Voltamperometric Sensors and Biosensors Based on Carbon Nanomaterials Used for Detecting Caffeic Acid-A Review.

Caffeic acid is one of the most important hydroxycinnamic acids found in various foods and plant products. It has multiple beneficial effects in the human body such as antioxidant, antibacterial, anti-inflammatory, and antineoplastic. Since overdoses of caffeic acid may have negative effects, the quality and quantity of this acid in foods, pharmaceuticals, food supplements, etc., needs to be accurately determined. The present paper analyzes the most representative scientific papers published mostly in the last 10 years which describe the development and characterization of voltamperometric sensors or biosensors based on carbon nanomaterials and/or enzyme commonly used for detecting caffeic acid and a series of methods which may improve the performance characteristics of such sensors.

Evaluation of the chemical consistency of Yin-Chen-Hao-Tang prepared by combined and separated decoction methods using high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry coupled with multivariate statistical analysis.

In this study, Yin-Chen-Hao-Tang prepared by two decoction methods, namely, combined decoction (modern decoction method) and separated decoction (traditional decoction method), was analyzed by high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry. The acquired datasets containing sample codes, tR -m/z pairs and ion intensities were processed with multivariate statistical analyses, such as principal component analysis and an orthogonal partial least squared discriminant analysis model, to globally compare the chemical differences between the different decoction samples. Then, the chemical differences between the combined and separated decoctions were screened out by S-plots generated from the orthogonal partial least squared discriminant analysis model and compared with chemical information from an established in-house library. The six components that contributed the most to the chemical differences were identified as chlorogenic acid, caffeic acid, geniposide, genipin, scopoletin, and 3,5-dicaffeoylquinic acid. The concentrations of genipin and caffeic acid from the separated decoction were higher than those from the combined decoction, indicating that the separated decoction may present a stronger hepatoprotective effect. However, the results still require further investigation through pharmacological and clinical studies. Our findings not only establish a strategy to evaluate chemical consistency of Yin-Chen-Hao-Tang but also provide the scientific basis for using traditional separated decoction method.

Increased phenolic content and antioxidant capacity of the heated leaves of yacon (Smallanthus sonchifolius).

We investigated the content of phenolic compounds and antioxidant capacity of two batches of non-heated and heated leaves of the yacon cultivar "Andes no yuki", grown in Japan. Lyophilized yacon leaves heated at 160°C for 20 min and 100°C for 60 min had a 1.96 to 9.69-times higher total phenolic content than that of the non-heated leaves. Heated leaves exhibited a 1.98 to 4.07-times higher antioxidant capacity than that of the non-heated leaves in three different free radical scavenging assays. Heated leaves were more efficient at attenuating the superoxide anion radical production in human granulocytic cells than the non-heated leaves. High-performance liquid chromatography analysis revealed that, in the heated leaves, the caffeic acid content was 2.13 to 3.64-times higher and the chlorogenic acid content was slightly lower than those in the non-heated leaves. Hence, heat processing may affect the active constituent contents in yacon leaves, potentiating its antioxidant capacity.Abbreviations: ABTS+: 2,2'-azinobis(2-ethylbenzothiazoline-6-sulfonic acid) cation; DPPH: 1,1-diphenyl-2-picrylhydrazyl, HPLC: high-performance liquid chromatography; NBT: nitroblue tetrazolium; O2-: superoxide anion; PMA: phorbol 12-myristate 13-acetate; PMS: phenazine methosulfate; TEAC: Trolox equivalent antioxidant capacity.

Spectrophotometric and Smartphone-Assisted Determination of Phenolic Compounds Using Crude Eggplant Extract.

In order to develop a simple, reliable and low cost enzymatic method for the determination of phenolic compounds we studied polyphenol oxidase activity of crude eggplant (S. melongena) extract using 13 phenolic compounds. Catechol, caffeic and chlorogenic acids, and L-DOPA have been rapidly oxidized with the formation of colored products. Monophenolic compounds have been oxidized at a much slower speed. Ferulic acid, quercetin, rutin, and dihydroquercetin have been found to inhibit polyphenol oxidase activity of crude eggplant extract. The influence of pH, temperature, crude eggplant extract amount, and 3-methyl-2-benzothiazolinone hydrazone (MBTH) concentration on the oxidation of catechol, caffeic acid, chlorogenic acid, and L-DOPA has been investigated spectrophotometrically. Michaelis constants values decrease by a factor of 2 to 3 in the presence of MBTH. Spectrophotometric (cuvette and microplate variants) and smartphone-assisted procedures for phenolic compounds determination have been proposed. Average saturation values (HSV color model) of the images of the microplate wells have been chosen as the analytical signal for smartphone-assisted procedure. LOD values for catechol, caffeic acid, chlorogenic acid, and L-DOPA equaled 5.1, 6.3, 5.8 and 30.0 µM (cuvette procedure), 12.2, 13.2, 13.2 and 80.4 µM (microplate procedure), and 23.5, 26.4, 20.8 and 120.6 µM (smartphone procedure). All the variants have been successfully applied for fast (4-5 min) and simple TPC determination in plant derived products and L-DOPA determination in model biological fluids. The values found with smartphone procedure are in good agreement with both spectrophotometric procedures values and reference values. Using crude eggplant extract- mediated reactions combined with smartphone camera detection has allowed creating low-cost, reliable and environmentally friendly analytical method for the determination of phenolic compounds.

Unique antioxidant effects of herbal leaf tea and stem tea from Moringa oleifera L. especially on superoxide anion radical generation systems.

This study aimed to investigate the unique antioxidative effects of Japanese moringa products, herbal leaf tea and stem tea, using established free radical assays, focusing on superoxide anion (O2-) radical generation systems. Hot-water extracts from moringa teas resulted in different but lower scavenging activities than Trolox in four synthetic free radical models. Interestingly, these extracts further showed higher O2- radical scavenging effects than Trolox in the phenazine methosulfate-NADH-nitroblue tetrazolium and xanthine oxidase assay systems. Incubating human neutrophils in the presence of these tea extracts rather than Trolox effectively suppressed cellular O2- radical generation. Among the eight known phenolic constituents of moringa leaves, caffeic acid and chlorogenic acid may be responsible for the O2-specific radical scavenging capacity stronger than that of Trolox. These results suggest that moringa herbal teas are a good source of natural antioxidants for preventing O2- radical-mediated disorders. Abbreviations: O2-: superoxide anion; ROS: reactive oxygen species; H2O2: hydrogen peroxide; XOD: xanthine oxidase; DPPH: 1,1-diphenyl-2-picrylhydrazyl; ABTS+: 2,2'-azinobis(2-ethylbenzothiazoline-6-sulfonic acid) cation; CPZ+: chlorpromazine cation; PMS: phenazine methosulfate; NBT: nitroblue tetrazolium; PMA: phorbol 12-myristate 13-acetate.

Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

OBJECTIVES: To achieve biosynthesis of caffeoylmalic acid from glucose in engineered Escherichia coli. RESULTS: We constructed the biosynthetic pathway of caffeoylmalic acid in E. coli by co-expression of heterologous genes RgTAL, HpaBC, At4CL2 and HCT2. To enhance the production of caffeoylmalic acid, we optimized the tyrosine metabolic pathway of E. coli to increase the supply of the substrate caffeic acid. Consequently, an E. coli-E. coli co-culture system was used for the efficient production of caffeoylmalic acid. The final titer of caffeoylmalic acid reached 570.1 mg/L. CONCLUSIONS: Microbial production of caffeoylmalic acid using glucose has application potential. In addition, microbial co-culture is an efficient tool for producing caffeic acid esters.

Comparison of partial least squares and random forests for evaluating relationship between phenolics and bioactivities of Neptunia oleracea.

BACKGROUND: Neptunia oleracea is a plant consumed as a vegetable and which has been used as a folk remedy for several diseases. Herein, two regression models (partial least squares, PLS; and random forest, RF) in a metabolomics approach were compared and applied to the evaluation of the relationship between phenolics and bioactivities of N. oleracea. In addition, the effects of different extraction conditions on the phenolic constituents were assessed by pattern recognition analysis. RESULTS: Comparison of the PLS and RF showed that RF exhibited poorer generalization and hence poorer predictive performance. Both the regression coefficient of PLS and the variable importance of RF revealed that quercetin and kaempferol derivatives, caffeic acid and vitexin-2-O-rhamnoside were significant towards the tested bioactivities. Furthermore, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) results showed that sonication and absolute ethanol are the preferable extraction method and ethanol ratio, respectively, to produce N. oleracea extracts with high phenolic levels and therefore high DPPH scavenging and α-glucosidase inhibitory activities. CONCLUSION: Both PLS and RF are useful regression models in metabolomics studies. This work provides insight into the performance of different multivariate data analysis tools and the effects of different extraction conditions on the extraction of desired phenolics from plants. © 2017 Society of Chemical Industry.

NIR Spectroscopy of Actaea racemosa L. rhizome - En Route to Fast and Low-Cost Quality Assessment.

Rhizomes of Actaea racemosa L. (formerly Cimicifuga racemosa) gained increasing interest as a plant-derived drug due to its hormone-like activity and the absence of estrogenic activity. According to the Current Good Manufacturing Practices guidelines and pharmacopeial standards, quality assessment of herbal starting materials includes tests on identity and substitution, as well as quantification of secondary metabolites, usually by HPTLC and LC methods. To reduce the laboratory effort, we investigated near-infrared spectroscopy for rapid species authentication and quantification of metabolites of interest.Near-infrared spectroscopy analysis is carried out directly on the milled raw plant material. Spectra were correlated with reference data of polyphenols and triterpene glycosides determined by LC/diode array detection and LC/evaporative light scattering detection, respectively. Quantification models were built and validated by cross-validation procedures. Clone plants, derived by vegetative propagation, and plants of a collection from different geographical origins cultivated in Berlin were analysed together with mixed batches from wild harvests purchased at wholesalers.Generally, good to excellent correlations were found for the overall content of polyphenols with coefficients of determination of R2 > 0.93. For individual polyphenols such as fukinolic acid, only models containing clone plants succeeded (R2 > 0.92). For the total content of triterpene glycosides, results were generally worse in comparison to polyphenols and were observed only for the mixed batches (R2 = 0.93).Next to quantitative analysis, near-infrared spectroscopy was proven as a rapid alternative to other, more laborious methods for species authentication. Near-infrared spectroscopy was able to distinguish different Actaea spp. such as the North American Actaea cordifolia and the Asian Actaea cimicifuga, Actaea dahurica, Actaea heracleifolia, and Actaea simplex.