PresRecST: a novel herbal prescription recommendation algorithm for real-world patients with integration of syndrome differentiation and treatment planning.

OBJECTIVES: Herbal prescription recommendation (HPR) is a hot topic and challenging issue in field of clinical decision support of traditional Chinese medicine (TCM). However, almost all previous HPR methods have not adhered to the clinical principles of syndrome differentiation and treatment planning of TCM, which has resulted in suboptimal performance and difficulties in application to real-world clinical scenarios. MATERIALS AND METHODS: We emphasize the synergy among diagnosis and treatment procedure in real-world TCM clinical settings to propose the PresRecST model, which effectively combines the key components of symptom collection, syndrome differentiation, treatment method determination, and herb recommendation. This model integrates a self-curated TCM knowledge graph to learn the high-quality representations of TCM biomedical entities and performs 3 stages of clinical predictions to meet the principle of systematic sequential procedure of TCM decision making. RESULTS: To address the limitations of previous datasets, we constructed the TCM-Lung dataset, which is suitable for the simultaneous training of the syndrome differentiation, treatment method determination, and herb recommendation. Overall experimental results on 2 datasets demonstrate that the proposed PresRecST outperforms the state-of-the-art algorithm by significant improvements (eg, improvements of P@5 by 4.70%, P@10 by 5.37%, P@20 by 3.08% compared with the best baseline). DISCUSSION: The workflow of PresRecST effectively integrates the embedding vectors of the knowledge graph for progressive recommendation tasks, and it closely aligns with the actual diagnostic and treatment procedures followed by TCM doctors. A series of ablation experiments and case study show the availability and interpretability of PresRecST, indicating the proposed PresRecST can be beneficial for assisting the diagnosis and treatment in real-world TCM clinical settings. CONCLUSION: Our technology can be applied in a progressive recommendation scenario, providing recommendations for related items in a progressive manner, which can assist in providing more reliable diagnoses and herbal therapies for TCM clinical task.

Effects of Dietary Selenium Yeast Supplementation in Pregnant Cashmere Goats on the Development of Offspring Hair Follicles.

The objective of this study was to investigate the effects of maternal dietary selenium yeast (SY) supplementation during pregnancy on the hair follicle development of kids. Sixty pregnant Hanshan white cashmere goats were randomly divided into the con group (fed with a basal diet) and the SY group (fed with a basal diet with 0.4 mg/kg SY). SY was supplemented during the pregnancy until the birth of the kids. The growth performance, cashmere performance, hair follicle characteristics, and serum antioxidant capacity of the kids were periodically determined. The results showed that the birth weight of the kids in the SY group was significantly higher than that in the con group (p < 0.05), and the average weight at 15 days, 1 month, 3 months, and 5 months of age increased by 13.60%, 8.77%, 8.86%, and 3.90%, respectively (p > 0.05). The cashmere fineness at early birth was dramatically reduced with SY supplementation (p < 0.001), whereas cashmere length and production were significantly increased at 5 months of age (p < 0.05). Histology assays indicated that the primary hair follicles were fully developed at birth, and there was no significant difference in the number of primary hair follicles between the two groups (p > 0.05). The number of secondary hair follicles and the number and density of active secondary hair follicles in the SY group at 15 days were significantly higher than those in the con group (p < 0.05) and were increased by 11.18%, 6.18%, and 22.55% at 5 months of age, respectively (p > 0.05). The serum antioxidant capacity analysis revealed that the SY group had higher levels of T-AOC, SOD, CAT, and GSH-Px activities and lower levels of MDA (p > 0.05). These results reveal that the maternal dietary supplementation of SY in gestation can promote the morphogenesis and maturation of secondary hair follicles and increase the number and density of secondary hair follicles by enhancing the body's antioxidant capacity, contributing to the improvement of cashmere quality and yield.

Cerebral blood flow regulates iron overload in the cerebral nuclei of hemodialysis patients with anemia.

Hemodialysis patients exhibit anemia-related cerebral hyperperfusion and iron deposition (ID). However, the mechanisms underlying the pathology of cerebral ID are not clear. We investigated the role of cerebral blood flow (CBF) in the pathophysiology of cerebral ID in hemodialysis patients with anemia. This study recruited 33 hemodialysis patients with anemia and thirty-three healthy controls (HCs). All the subjects underwent quantitative susceptibility mapping (QSM) and arterial spin labeling (ASL) to measure ID and CBF in the cerebral nuclei. Furthermore, we evaluated lacunar infarction (LI), cerebral microbleeds, and total white matter hyperintensity volume (TWMHV). Hemodialysis patients with anemia showed significantly higher ID and CBF in some nuclei compared to the HCs after adjusting for age, sex, and total intracranial volume (TIV) [P < 0.05, false discovery rate (FDR) corrected]. CBF showed a positive correlation with ID in both patients and HCs after adjustments for age, gender, and TIV (P < 0.05, FDR corrected). Serum phosphorus, calcium, TWMHV, hypertension, and dialysis duration were independently associated with ID (P < 0.05). Hemoglobin, serum phosphorus, and LI were independently associated with CBF (P < 0.05). Mediation analysis demonstrated that CBF mediated the effects between hemoglobin and ID. Our study demonstrated that CBF mediated aberrant cerebral ID in hemodialysis patients with anemia.

Construction of dual Z-scheme Bi2WO6/g-C3N4/black phosphorus quantum dots composites for effective bisphenol A degradation.

In this work, a novel dual Z-scheme Bi2WO6/g-C3N4/black phosphorus quantum dots (Bi2WO6/g-C3N4/BPQDs) composites were fabricated and utilized towards photocatalytic degradation of bisphenol A (BPA) under visible-light irradiation. Optimizing the content of g-C3N4 and BPQDs in Bi2WO6/g-C3N4/BPQDs composites to a suitable mass ratio can enhance the visible-light harvesting capacity and increase the charge separation efficiency and the transfer rate of excited-state electrons and holes, resulting in much higher photocatalytic activity for BPA degradation (95.6%, at 20 mg/L in 120 min) than that of Bi2WO6 (63.7%), g-C3N4 (25.0%), BPQDs (8.5%), and Bi2WO6/g-C3N4 (79.6%), respectively. Radical trapping experiments indicated that photogenerated holes (h+) and superoxide radicals (•O2-) played crucial roles in photocatalytic BPA degradation. Further, the possible degradation pathway and photocatalytic mechanism was proposed by analyzing the BPA intermediates. This work also demonstrated that the Bi2WO6/g-C3N4/BPQDs as effective photocatalysts was stable and have promising potential to remove environmental contaminants from real water samples.

[UPLC fingerprint and determination of five components of substance benchmark of classical prescription Shentong Zhuyu Decoction].

Fingerprints of 18 batches of substance benchmark of Shentong Zhuyu Decoction(SZD) were established by UPLC under the following conditions: Waters Sun Fire C_(18) column(3.0 mm×150 mm, 3.5 µm), column temperature of 35 ℃, gradient elution with mobile phase of acetonitrile(A)-0.1% phosphoric acid aqueous solution(B) at the flow rate of 0.4 mL·min~(-1), and detection by wavelength switching. A total of 16 common peaks were identified. The similarities among the fingerprints were calculated by Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 Edition) and the result showed they were in the range of 0.911-0.988. Based on the 16 common peaks, cluster analysis(CA), principal component analysis(PCA), and partial least square discriminant analysis(PLS-DA) all categorized the 18 batches of samples into two groups(S1, S2, S5-S8, S14, and S17 in one group, and S1, S2, S5-S8, S14, and S17 in another), and 11 most influential components were screened. Five known components with great difference among samples(hydroxysafflor yellow A, ferulic acid, benzoic acid, ecdysone, and ammonium glycyrrhizinate) were determined. The combination of multi-component content determination and fingerprints can reflect the overall cha-racteristics of the primary standards of SZD, which is simple, feasible, reproducible, and stable. This study can serve as a reference for the quality control of the primary standards of SZD.

Linking Cortical Morphology to Interindividual Variability in Auditory Feedback Control of Vocal Production.

Speakers regulate vocal motor behaviors in a compensatory manner when perceiving errors in auditory feedback. Little is known, however, about the source of interindividual variability that exists in the degree to which speakers compensate for perceived errors. The present study included 40 young adults to investigate whether individual differences in auditory integration for vocal pitch regulation, as indexed by vocal compensations for pitch perturbations in auditory feedback, can be predicted by cortical morphology as assessed by gray-matter volume, cortical thickness, and surface area in a whole-brain manner. The results showed that greater gray-matter volume in the left inferior parietal lobule and greater cortical thickness and surface area in the left superior/middle temporal gyrus, temporal pole, inferior/superior parietal lobule, and precuneus predicted larger vocal responses. Greater cortical thickness in the right inferior frontal gyrus and superior parietal lobule and surface area in the left precuneus and cuneus were significantly correlated with smaller magnitudes of vocal responses. These findings provide the first evidence that vocal compensations for feedback errors are predicted by the structural morphology of the frontal and tempo-parietal regions, and further our understanding of the neural basis that underlies interindividual variability in auditory-motor control of vocal production.

Rapid identification of Lilium species and polysaccharide contents based on near infrared spectroscopy and weighted partial least square method.

Polysaccharide is the main active compound of Lilium, and showed many activities, such as hypoglycemic, antioxidant, immune-modulatory. There are three types' Lilium in China market, i.e. Lilium lancifolium Thunb (JD), Lilium davidiivar. Unicolor Salisb (L. davidii var)(LZBH), and Lilium brownii F.E. Brown var. viridulum Baker (BH). Near infrared spectroscopy (NIR) technique has become popular in the fields of quality control, due to its advantages, such as fast, non-destructive, and can detect several ingredients, simultaneously. In this study, a classification model was established based on NIR technique and random forest method to accurately distinguish three types' Lilium species, and the classification accuracy reached 94.37%. Furthermore, taking the effects of neighbor wavelength into account, a new weighted partial least square algorithm was proposed to establish an accurate and quantitative model for predicting the polysaccharide contents of these samples. In the model establishing process, some signal pre-treatment methods were optimized, and the validation results with highest determination coefficient (R2) and low root mean square errors of prediction (RMSEP) were, 0.9455 and 0.9098, respectively. The obtained results showed that combined NIR technique with chemometrics was an effective and green method for quality control.

Development and validation of a photobioreactor for uniform distribution of light intensity along the optical path based on numerical simulation.

A theoretical approach was followed to optimize the design of a cylindrical photobioreactor for wastewater treatment based on algal culture. In particular, the problem of uneven light distribution that impairs algal growth was minimized by optimizing the area of uniform illumination distribution for a bioreactor design that can be enlarged without affecting its performance. The theoretical analysis was based on modeled simulations to determine the best configuration and illumination mode. The Monte Carlo method was used to simulate the illumination distribution inside the bioreactor, and the relationships between the width of the area with uniform illumination and related parameters were explored. Based on these theoretical considerations and predictions, an actual experimental photobioreactor was built containing a working area (where culture of Chlorella pyrenoidosa was enabled) and a catchment area for effluent. The performance of this bioreactor was tested with synthetic wastewater as a substrate. The light distribution was found to be relatively uniform inside the bioreactor, supporting excellent algal growth and resulting in maximum removal rates of 84.41% for total nitrogen, 99.73% for total phosphorus, 85.03% for NH4+-N, and 75.94% for chemical oxygen demand (COD) over a period of 32 days of operation. The presented approach provides new insights for improving the efficiency and scalability of photobioreactors and promotes their development for wastewater treatment and resource utilization.

An algorithm to calibrate ionic isotopes using data mining strategy in hyphenated chromatographic datasets from herbal samples.

The bottleneck of analytical instrument itself and non-ideal instrumental performance will produce a certain degree of drifts between the measured isotopes and the true values. An AAID-IC algorithm was thereby proposed to keep the isotopic distributions more accurate in hyphenated instruments, e.g. Gas Chromatography (GC)/ Liquid Chromatography (LC) - Mass Spectrometry (MS). During this data mining process, chemical information will be fully used from dozens of data points in retention time (rt) dimension: the target isotopes were firstly re-constructed in mass charge ratio (m/z) dimension; their re-calculation values were then averaged from an interesting rt zone; the calibration functions were followed established based on a well-defined series of calibration ions. It is worth mentioning that natural metabolites in complex samples can be identified as reference materials to amend the target isotopes. Next, the corrected mass axes (m/z values)/isotope abundances were transformed into an ionic isotopic curve using Gaussian box. Taking herbal sample as an example, AAID-IC can better reduce the systematic and random errors of the m/z ions in one run environment, whether it's profile or bar graph from any type of MS and any ionization method employed. Finally, the calibrated values can be utilized to deduce the elemental compositions of molecular (fragment) ions in GC/LC-MS determination.

[Reverse effect of Yinchenhao decoction in dimethyl nitrosamine-induced hepatic fibrosis in rats].

OBJECTIVE: To discuss the reverse effect of Yinchenhao decoction(YCHD) in dimethyl nitrosamine (DMN)-induced hepatic fibrosis in rats. METHOD: The rat hepatic fibrosis model was established through the intraperitoneal injection with 1% dimethyl nitrosamine (DMN) with a dose of 1.0 mL x kg(-1) x d(-1) for consecutively three weeks, once for the first three days of each. The rats were randomly divided into six groups: the silymarin positive control group (50.0 mg x kg(-1) x d(-1), YCHD high (20.0 g x kg(-1) d(-1)), middle (8.0 g x kg(-1) x d(-1)) and low (3.2 g x kg(-1) x d(-1)) dose groups, the model group and the normal control group. The model group and the normal control group were orally administered with normal saline for consecutively five weeks. The pathologic changes in liver tissues were observed by HE staining. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), g-glutamyltransferase (g-GGT), hyaluronic acid (HA), laminin (LN), collagen type IV (CIV) and type III procollagen amino terminal peptide (PIIINP) in serum were determined. The metabolite profiling of amino acid and the content of hydroxyproline in liver tissues were also measured. RESULT: Compared with the model group, YCHD high and middle dose groups could significantly reverse the pathologic changes in liver tissues of rats. YCHD could reduce the levels of ALT, AST, gamma-GGT, HA, LN, CIV, PIIINP in serum and the content of hydroxyproline in liver tissues in a dose-dependent manner, and altered the metabolite profiling of amino acid in rat liver tissues. CONCLUSION: YCHD has the effect in reversing dimethyl nitrosamine induced hepatic fibrosis in rats.

Sugar beet M14 glyoxalase I gene can enhance plant tolerance to abiotic stresses.

Glyoxalase I is the first enzyme of the glyoxalase system that can detoxify methylglyoxal, a cytotoxic compound increased rapidly under stress conditions. Here we report cloning and characterization of a glyoxalase I from sugar beet M14 line (an interspecific hybrid between a wild species Beta corolliflora Zoss and a cultivated species B. vulgaris L). The full-length gene BvM14-glyoxalase I has 1,449 bp in length with an open reading frame of 1,065 bp encoding 354 amino acids. Sequence analysis shows the conserved glyoxalase I domains, metal and glutathione binding sites and secondary structure (α-helixes and ß-sheets). The BvM14-glyoxalase I gene was ubiquitously expressed in different tissues of sugar beet M14 line and up-regulated in response to salt, mannitol and oxidative stresses. Heterologous expression of BvM14-glyoxalase I could increase E. coli tolerance to methylglyoxal. Transgenic tobacco plants constitutively expressing BvM14-glyoxalase I were generated. Both leaf discs and seedlings showed significant tolerance to methylglyoxal, salt, mannitol and H2O2. These results suggest an important role of BvM14-glyoxalase I in cellular detoxification and tolerance to abiotic stresses.

Rapid simultaneous determination of major isoflavones of Pueraria lobata and discriminative analysis of its geographical origins by principal component analysis.

INTRODUCTION: Isoflavones are main bioactive components of Pueraria lobata (Willd.) Ohwi. Puerarin has been used as the marker compound in herb quality evaluation in the Chinese Pharmacopoiea. However, it is also important to include the other isoflavones present in the herb, such as daidzin, daidzein, genistin and genistein, in the evaluation as they also contribute to the overall bioactivity of the herb. OBJECTIVE: To develop a rapid and reliable method for simultaneous quantitation of isoflavones for P. lobata herb quality evluation. METHODOLOGY: The chromatographic separation was performed on an Agilent rapid resolution liquid chromatographic system through gradient elution. The developed method for the quantification of puerarin, daidzin, daidzein, genistin and genistein was fully validated. When it was applied to analyse the extracts of P. lobata, baseline separation was obtained within 10 min. RESULTS: The amounts of puerarin, daidzin, daidzein and genistin varied greatly among the samples although their chromatographic fingerprints were similar to each other. The 19 samples studied were classified into three clusters (I-III) by principal component analysis based on the amounts of puerarin, daidzin, daidzein and genistin. CONCLUSION: The classification result can be related to herbal origins, but the classification outcome from the chromatographic fingerprinting similarity approach did not provide any geographical origin information. This shows that bioactive constituents can reflect the intrinsic quality of P. lobata more accurately.

Chromatographic fingerprint investigation for quality evaluation and control of Shengui hair-growth tincture.

The quality assessment and control of traditional Chinese medicines (TCM) has received a great deal of attention worldwide with its tremendous increasing use. Chromatographic fingerprinting is thought to be a good approach for this task and has been used for the quality assessment and control of many herbal medicines. However, there are only a few reports on the quality control of TCM preparation by chromatographic fingerprinting. In the present work, gas chromatography-mass spectrometry (GC-MS) combined with chemometric methods were used for the chromatographic fingerprint analysis and characterization of Shengui hair-growth tincture (SGHGT), which is a complex TCM prescription made from 9 herbs. Thirteen "common peaks" were identified by MS and a comparison of retention indices. The software "The Traditional Chinese Medicine Quality Control System 1.0" (TCMQCS, developed by Research Center of Modernization of Chinese Herbal Medicine, Central South University) was used to evaluate the similarities. Principal component analysis (PCA) was used for the classification of 23 batches of SGHGT samples provided by Hunan Fusheng Hairgrowth Pharmaceutical Factory. The 23 batches of samples made in different years had similar GC-MS fingerprints. Four clusters were obtained from PCA treatment according to their production year. The proposed method was validated in precision and repeatability through the calculation of relative retention times and relative peak areas of the 13 common compounds to the reference compound eugenol. The result indicated that the method is feasible and applicable for the quality control of SGHGT. SUPPORTING INFORMATION available online at http://www.thieme-connect.de/ejournals/toc/plantamedica.

The magnesium-chelatase H subunit binds abscisic acid and functions in abscisic acid signaling: new evidence in Arabidopsis.

Using a newly developed abscisic acid (ABA)-affinity chromatography technique, we showed that the magnesium-chelatase H subunit ABAR/CHLH (for putative abscisic acid receptor/chelatase H subunit) specifically binds ABA through the C-terminal half but not the N-terminal half. A set of potential agonists/antagonists to ABA, including 2-trans,4-trans-ABA, gibberellin, cytokinin-like regulator 6-benzylaminopurine, auxin indole-3-acetic acid, auxin-like substance naphthalene acetic acid, and jasmonic acid methyl ester, did not bind ABAR/CHLH. A C-terminal C370 truncated ABAR with 369 amino acid residues (631-999) was shown to bind ABA, which may be a core of the ABA-binding domain in the C-terminal half. Consistently, expression of the ABAR/CHLH C-terminal half truncated proteins fused with green fluorescent protein (GFP) in wild-type plants conferred ABA hypersensitivity in all major ABA responses, including seed germination, postgermination growth, and stomatal movement, and the expression of the same truncated proteins fused with GFP in an ABA-insensitive cch mutant of the ABAR/CHLH gene restored the ABA sensitivity of the mutant in all of the ABA responses. However, the effect of expression of the ABAR N-terminal half fused with GFP in the wild-type plants was limited to seedling growth, and the restoring effect of the ABA sensitivity of the cch mutant was limited to seed germination. In addition, we identified two new mutant alleles of ABAR/CHLH from the mutant pool in the Arabidopsis Biological Resource Center via Arabidopsis (Arabidopsis thaliana) Targeting-Induced Local Lesions in Genomes. The abar-2 mutant has a point mutation resulting in the N-terminal Leu-348-->Phe, and the abar-3 mutant has a point mutation resulting in the N-terminal Ser-183-->Phe. The two mutants show altered ABA-related phenotypes in seed germination and postgermination growth but not in stomatal movement. These findings support the idea that ABAR/CHLH is an ABA receptor and reveal that the C-terminal half of ABAR/CHLH plays a central role in ABA signaling, which is consistent with its ABA-binding ability, but the N-terminal half is also functionally required, likely through a regulatory action on the C-terminal half.

Comparative analysis of essential oils from eight herbal medicines with pungent flavor and cool nature by GC-MS and chemometric resolution methods.

Systematic comparative research was conducted on essential oils from eight traditional Chinese medicines (TCM) of pungent flavor and cool nature because the essential oils are the main active ingredients of herbs of this kind. The work was based on their component analysis by gas chromatography-mass spectrometry (GC-MS), on their retention indices, as well as on chemometric resolution methods. A total of 144 compounds were tentatively identified, accounting for 69.0% to 91.8% of the total essential oils. It is worth noting that there are 67 compounds in at least three of these eight essential oils. Moreover, many biologically active compounds, such as hexanal, alpha-pinene, camphene, beta-pinene, p-cymene, limonene, eucalyptol, (Z)-ocimene, gamma-terpinene, camphor, p-menthone, 4-terpineol, alpha-terpineol, carvone, eugenol, caryophyllene, beta-farnesene, alpha-curcumene, beta-selinene, delta-cadinene, caryophyllene oxide, cedrol, n-hexadecanoic acid, benzaldehyde, benzeneacetaldehyde, phthalic acid diisobutyl ester, linoleic acid, tetradecanoic acid, (Z,Z,Z)-9,12,15-octadecatrienoic acid, eucalyptol, pentadecanoic acid, hexadecanoic acid methyl ester, linoleic acid methyl ester, exist in at least four of the eight essential oils. These results might help us to understand why the eight herbs are all of pungent flavor and cool nature according to the theory of TCM, and may provide a useful chemical basis for future research on herbs of this kind.

Comparative analysis of volatile components from Clematis species growing in China.

The volatile components between stems and roots and also among five Clematis species from China were studied and analyzed by gas chromatography-mass spectrometry (GC-MS) combined with alternative moving window factor analysis (AMWFA), a new chemometric resolution method. Identification of the compounds was also assisted by comparison of temperature-programmed retention indices (PTRIs) on HP-5MS with authentic samples included in our own laboratory database under construction. A total of 153 different compounds accounting for 86.6-96.5% were identified and significant qualitative and quantitative differences were observed among the samples. The major volatile components in different essential oils from Clematis species were n-hexadecanoic acid and (Z,Z)-9,12-octadecadienoic acid. Our work further demonstrated chemometric resolution techniques upon the two-dimensional data and PTRIs can provide a complementary and convenient method for fast and accurate analysis of complex essential oils.

Alternative moving window factor analysis for comparison analysis between complex chromatographic data.

In this investigation, a novel chemometric method is developed for the analysis of five possible relationships of components or spectral features between two correlative but different hyphenated chromatographic systems. It is very helpful for comparison study of components present in different complex systems in both chemistry and systems biology. The proposed method, named alternative moving window factor analysis (AMWFA), could be utilized to determine the number of common components between different samples and then to identify their corresponding spectra half-automatically. AMWFA can alternatively be employed to mind for the selective information hiding in anyone of the two compared data X and Y, and to self-verify the resolution results by changing the extracted target matrices in analysis. From the results of comparison of simulated hyphenated chromatographic data, volatile chemical components in drug pair rhizoma ligustici chuanxiong-radix paeoniae rubra (RLC-RPR) and its single herbal medicines, and analysis of Angelica oral solution and its plasma sample after oral intake to rabbit, powerful ability of the proposed method is shown.

[Chemical components in essential oils from tender branches and leaves of Rhododendron].

AIM: To analyze and compare the compositions in essential oils from branches and leaves of Rhododendron simsii Planch. and Rhododendron naamkwanense Merr. METHODS: Essential oils were extracted by water distillation according to Chinese Pharmacopoeia and analyzed by capillary gas chromatography-mass spectrometry as well as chemometrics resolution method and authentic compounds. The relative contents of each component in the essential oils were obtained by normalization of peak areas. RESULTS: A total of 124 components were identified, of which 48 compounds were existed in both of the samples. Ninety four compounds accounted for 84.47% of the essential oil from Rhododendron simsii Planch. and seventy eight components accounted for 90.25% of the total essential oil from Rhododendron naamkwanense Merr. were identified. 72.76% and 88.07% of the components in Rhododendron simsii Planch and Rhododendron naamkwanense Merr., respectively, included oxygen element. They are mainly terpenol, acids and esters. 1-octen-3-ol (4.00%, 7.90%), 1,6-octadien-3-ol, 3,7-dimethyl-(12.60%, 3.48%), 9,12,15-octadecatrienoic acid, [Z, Z, Z]- (1.15%, 45.34%), phytol (15.21%, 8.56%), p-menth-1-en-8-ol (2.15%, 3.29%), and 9,12,15-octadecatrienoic acid, ethyl ester, [Z,Z,Z]- (9.16%, 8.01%) were their common main compounds, which accounted for 44. 27% and 76.58% of the total amount of the two essential oil samples, respectively. In addition, n-hexadecanoic acid (7.73%), 9,12-octadecadienoic acid (1.85%) and tetracosanoic acid, methyl ester (1.38%) were also the main compounds in essential oil from Rhododendron simsii Planch. CONCLUSION: Much higher reliability and accuracy were obtained with the help of chemometrics resolution method and authentic n-alkane standard solutions than those of using GC-MS alone.

Temperature-programmed retention indices for gas chromatography-mass spectroscopy analysis of plant essential oils.

A total of 95 volatile compounds from the essential oil in buds of Syringa oblata Lindl (lilac) were identified by gas chromatography-mass spectrometry (GC-MS) combined with heuristic evolving latent projections (HELP) and moving subwindow searching (MSS). The identified compounds are mainly aliphatic, terpenes and aromatic compounds. Their temperature-programmed retention indices (PTRIs) on HP-5MS and DB-35MS at three heating rates of 2, 4 and 6 degrees C/min from 80 to 290 degrees C were obtained, which showed that aliphatic compounds give nearly constant PTRIs and PTRIs of terpenoids do not vary much at different heating rates. But PTRIs of aromatic compounds exhibit relatively large temperature dependence. PTRIs vary much more on DB-35MS than those on HP-5MS according to the compound types. In general, differences of PTRIs between the two columns increase from aliphatic compounds to terpenoids to polycyclic aromatic compounds. The PTRIs in different heating rates were used as cross-references in the identification of components in the essential oil. When they were used in analysis of essential oil from flowers of lilac, good results were obtained. These PTRIs would be a part of our PTRI database being constructed on components from plant essential oils. The results also showed that efficiency and reliability were improved greatly when chemometric method and PTRIs were used as assistants of GC-MS in identification of chemical components in plant essential oils.

Identification of structures of nitrogen-containing compounds in crude oils in conjunction with chemometric resolution.

A universal method was established for the systematically structural identification of nitrogen-containing compounds in crude oils. Pre-fractionation of the non-hydrocarbons in a crude oil sample into 7 fractions was performed by di-adsorption column chromatography using neutral aluminum oxide and silica gel; subsequent high-resolution separation of individual components was achieved by using capillary column gas chromatography, and compound types were detected by mass spectrometer. The two-dimensional data from the compounds in the fractions were further resolved by a chemometric method to obtained the deconvoluted chromatogram and mass spectrum of every compound, and then, the nitrogen-containing compounds were identified in combination with the retention indices. This method could relieve the difficulty of classical analysis in identifying those species with very low contents or incompletely separation, particularly in the cases where the authentic standards were not available for addition into the unknown samples in order to reveal what indeed existed in them. The structures of 168 nitrogen-containing compounds in a crude oil sample were determined by this method with satisfactory results.