Effects of Different Steeping Temperatures on the Leaching of Aroma Components in Black Tea by SPME-GC-MS Coupled with Chemometric Method.

Background: Black tea is famous for its unique aroma. The analysis of aroma components has attracted considerable attention worldwide because of its complex chemical composition and low concentration. Objective: Steeping temperature is one of the most important factors affecting the aroma of black tea. This study aims to evaluate the effects of four steeping temperatures [60, 70, 80, and 95°C (boiling water)]. Methods: Two major factors affecting extraction performance, including the type of extraction method [direct headspace injection (HS) and solid-phase microextraction (SPME)] and extraction time (50, 60, and 70 min), were optimized to enrich and analyze the aroma components of Congou black tea by GC-MS. In addition, heuristic evolving latent projection (HELP), an effective chemometric resolution method, was employed to resolve the overlapped peaks. Results: A total of 83 aroma components were tentatively identified by GC-MS, such as alcohol (42.06-50.52%), aldehyde (12.09-15.97%), and hydrocarbon (4.79-15.32%). Linalool and its oxides (25.49-36.24%) were the most abundant aroma components, followed by geraniol (2.55-8.54%), methyl salicylate (1.84-9.50%), and nerol (1.93-4.41%). Conclusions: The black tea steeped at 95°C smelled more pleasant with mild green, roast, and fruity aroma. Moreover, at 80°C, the tea had sweeter fragrance with floral aroma, while steeping at 60 and 70°C resulted in more reinforced woody and fatty aroma. Highlights: A total of 83 aroma components of black tea were tentatively identified by SPME-GC-MS. The overlapped peaks were resolved by the HELP method. Aroma characteristics of different steeping temperatures were revealed.

An UPLC Method for Determination of Geraniin in Rat Plasma and its Application to Pharmacokinetic Studies.

INTRODUCTION: Geraniin has many biological activities including anti-osteoporotic and anti-hyperglycemic efficacies. MATERIALS AND METHODS: A rapid and simple method for the determination of geraniin in rat plasma using ultra performance liquid chromatography coupled to ultraviolet detector was developed. The plasma sample, spiked with epicatechin as an internal standard, was subjected to ethyl acetate extraction prior to analysis. Chromatographic separation was performed on the HSS T3 column and monitored at a wavelength of 280 nm. The limit of detection and lower limit of quantification was 0.07 µg/mL and 0.2 µg/mL in rat plasma, respectively. CONCLUSION: Good linearity was obtained in the range of 0.2 - 200 µg/mL, and the correlation coefficient was better than 0.997. The intra-day and inter-day precisions decreased 9.8%. The accuracy of QC samples ranged from 84.4% to 87.1%. The extraction recovery ranged from 88.4% to 90.3% and the matrix effect ranged from 84.4% to 87.2%. The analyte was stable in rat plasma when stored at room temperature for 12 hours, 4°C for 24 hours and -20°C for 15 days. t1/2 and t1/2 for i.v. was 0.21 ± 0.10 and 7.20 ± 2.20 h, respectively. Plasma clearance (CL) was 0.03 ± 0.02 L/h/kg and apparent volume of distribution (Vz) was 0.05 + 0.01 L/kg. The developed method was successfully applied to the pharmacokinetic study of geraniin in rats.

Chromatographic Fingerprints Combined with Chemometric Methods Reveal the Chemical Features of Authentic Radix Polygalae.

GC-MS fingerprints of Radix Polygalae (RP) were measured for deliberately collected samples. A total of 88 volatile components were identified and quantified by subwindow factor analysis, heuristic evolving latent projection, and retention index. Next, an efficient discrimination model based on partial least-squares (PLS) discriminant analysis (DA) was developed to distinguish the superior RP samples from the inferior ones, and the reliability and predictive ability of the model was evaluated by cross-validation and permutation tests. Furthermore, four components (1-octanol, shyobunone, isobornyl acetate, and α-asarone) were screened by coefficient ß of PLS-DA. They represented the important chemical features of authentic RP and could be applied to the accurate discrimination and QC of RP in the future. Our results suggest that chromatographic fingerprints coupled with chemometric methods provide an effective and convenient strategy for QC of RP and are helpful for revealing the chemical features of a complex analytical sample.

Chemical features of Pericarpium Citri Reticulatae and Pericarpium Citri Reticulatae Viride revealed by GC-MS metabolomics analysis.

This paper introduces a detailed method to apply metabolic profiles conducting on tangerine peels (Citrus reticulata 'Dahongpao') at three maturity stages from July to December. Principal component analysis not only demonstrated the metabolic footprints of tangerine peels during ripening but also revealed the compounds (D-limonene and linalool) that mostly contributed to it. Furthermore, some other characteristic compounds were screened to further reveal the chemical features of Pericarpium Citri Reticulatae (PCR) and Pericarpium Citri Reticulatae Viride (PCRV). In particular, compounds such as 4-carene (r = -0.94), 3-carene (r = -0.91), ß-pinene (r = -0.85) and γ-terpinene (r = -0.87) were screened as major components for the pungent smell of PCRV. Geranyl acetate (r = 0.81), farnesyl acetate (r = 0.87) and three alcohols (6-hepten-1-ol, 3-methyl-1-hexanol, 1-octanol) may lead to the pleasant odour of PCR. We therefore propose that the metabolomics analysis focusing on ripening process will be an effective strategy for quality control of closely related herbal medicines.

Main antimicrobial components of Tinospora capillipes, and their mode of action against Staphylococcus aureus.

In this investigation, the antibacterial modes of action of Radix Tinosporae, its major single components, and nine antibiotics with different targets or modes-of-action on Staphylococcus aureus were studied. Metabolic profiles of cultures treated with different medicines were acquired by HPLC/ESI-MS. After HPLC-MS data pretreatment, those profiles acquired were reduced into several MS vectors. Then statistical processing by principal components analysis was carried out upon those vectors, two conclusions could be drawn: (1) the antibacterial mode of action of Radix Tinosporae is similar to that of rifampicin and norfloxacin, which act on nucleic acid; (2) its active components playing main antimicrobial roles on Staphylococcus aureus might be alkaloids, such as palmatine and jatrorrhizine.

Evaluation of the antimicrobial mode of berberine by LC/ESI-MS combined with principal component analysis.

In this investigation, metabolic profiles of Staphylococcus aureus treated by berberine and nine antibacterial substances with known modes of action were acquired by HPLC/ESI-MS. After data pretreatment, those profiles acquired were reduced into several MS vectors. Then, principal component analysis was carried out upon those vectors to classify those drugs according to their mechanisms. From the result obtained by principal component analysis, the possible antibacterial mode of berberine was evaluated.

Validate antibacterial mode and find main bioactive components of traditional Chinese medicine Aquilegia oxysepala.

Traditional Chinese medicines have been used for thousands of years and are still being used as one of the regular treatments for many diseases. However, their mechanisms were still unknown. In this investigation, a possible procedure combining metabonomics and principal component analysis to investigate antibacterial modes of action and find main antimicrobial component in traditional Chinese medicine, Aquilegia oxysepala, is developed. Metabolic profiles of Staphylococcus aureus treated with nine antibiotics of known modes of action and with A. oxysepala were acquired by HPLC/DAD/ESI-MS. After statistical processing by principal components analysis on metabolic profiles, two conclusions could be drawn: (1) the target of A. oxysepala may be similar to that of lincolmensin, erythromycin, chloromycetin, streptomycin, and acheomycin, whose targets are protein; (2) its bioactive component playing main antimicrobial roles on S. aureus may be maguoflorine.

Screening and analysis of the multiple absorbed bioactive components and metabolites of Dangguibuxue decoction by the metabolic fingerprinting technique and liquid chromatography/diode-array detection mass spectrometry.

Based on the metabolic fingerprinting technique and liquid chromatography/diode array detection mass spectrometry (LC/DAD-MS), a method for rapid screening and analysis of the multiple absorbed bioactive components and metabolites of an oral solution of Dangguibuxue decoction (ODD) in rabbit plasma after oral administration of ODD was developed. The results obtained from a comprehensive comparative analysis of the fingerprints of the ODD and its metabolic fingerprints in rabbit plasma indicated that 46 components in the ODD were absorbed into the rabbit's body. Of them, ten components were tentatively identified from their MS and UV spectra and retention behaviors by comparing the results with the reported literature. They were calycosin-7-O-beta-D-glycoside, (6aR,-11aR)-hydroxy-9,10-dimethoxypterocarpan-3-O-beta-D-glycoside, ononin, L-3-hydroxy-9,10-dimethoxypterocarpan, formononetin, (3R)-7,2'-dihydroxy-3',4'-dimethoxyisoflavan, sedanenolide, E-ligustilide, Z-ligustilide, and Z-butylidenephthalide. In addition, 21 components were only found in the metabolic fingerprints, which suggested that they might be metabolites of some components in the ODD. The findings demonstrated that the proposed method could be used to rapidly and simultaneously analyze and screen the multiple absorbed bioactive constituents and metabolites in a formula of traditional Chinese medicines (TCMs) by comparing and contrasting the chromatographic fingerprints with its metabolic fingerprints. This is very important not only for the pharmaceutical discovery process and the quality control of crude drugs, but also to explain the curative mechanism of TCMs.

Quantitative determination of amantadine in human plasma by liquid chromatography-mass spectrometry and the application in a bioequivalence study.

A sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method is developed and validated for rapid determination of amantadine in human plasma. Desloratadine was used as the internal standard (I.S.). Human plasma (0.2 mL) was first alkalified with 100 microL of sodium hydroxide (3M) and then extracted with 1 mL of n-hexane containing 1% isopropanol (v/v) and 10% dichloromethane (v/v) by vortex-mixer for 3 min. The mixture was centrifuged at 14,000 rpm for 5 min. The supernatant was evaporated to dryness and the residue was dissolved in mobile phase. Samples were separated using a Thermo Hypersil-HyPURITYC18 reversed-phase column (150 mm x 2.1 mm i.d., 5 microm). Mobile phase consisted of methanol-acetonitrile-20 mM ammonium acetate (45:10:45, v/v/v) containing 1% acetic acid with pH 4.0. Amantadine and I.S. were measured by electrospray ion source in positive selective ion monitoring mode. The good linearity ranged from 3.9 to 1000 ng/mL and the lowest limit of quantification was 3.9 ng/mL. The extraction efficiencies were approximately 70% and recoveries of method ranged from 98.53 to 103.24%. The intra-day relative standard deviations (R.S.D.) were less than 8.43% and inter-day R.S.D. below 10.59%. The quality control samples were stable when kept at room temperature for 12h, at -20 degrees C for 30 days and after four freeze/thaw cycles. The method has been successfully used to evaluation of the pharmacokinetics and bioequivalence of amantadine in 20 healthy volunteers after an oral dose of 100 mg amantadine.

[Metabonomics and the modernization of traditional Chinese medicine].

The rapid development of systems biology and especially the advances in the high-throughput and comprehensive research technologies and research idea in metabonomics provide new strategies in the analysis of active components in the formula of traditional Chinese medicine (TCM) and pharmacokinetic analysis of their metabolites in vivo. Furthermore, the initiatives of metabonomics may pave a new way to explain the action mode of TCM in the light of modern sciences, while the metabonomic research achievements may contribute to the establishment of a new technique platform for evaluating the efficacy of the formula of TCM.