In-depth theoretical analysis of the influence of an external electric field on charge transport parameters.

It is important to develop materials with environmental stability and long device shelf life for use in organic field-effect transistors (OFETs). The microscopic, molecular-level nature of the organic layer in OFETs is not yet well understood. The stability of geometric and electronic structures and the regulation of the external electric field (EEF) on the charge transport properties of four typical homogeneous organic semiconductors (OSCs) were investigated by density functional theory (DFT). The results showed that under the EEF, the structural changes in single-bond linked oligomers were more sensitive and complex than those of condensed molecules, and there were non-monotonic changes in their reorganization energy (λ) during charge transport under an EEF consisting of decreases and then increases (Series D). The change in λ under an EEF can be preliminarily and qualitatively determined by the change in the frontier molecular orbitals (FMOs) - the number of C-atoms with nonbonding characteristics. For single-bonded molecules, the transfer integral is basically unchanged under a low EEF, but it will greatly change at a high EEF. Because the structure and properties of the molecule will greatly change under different EEFs, the effect of an EEF should be fully considered when determining the intrinsic mobility of OSCs, which could cause a deviation 0.3-20 times in mobility. According to detailed calculations, one heterogeneous oligomer, TH-BTz, was designed. Its λ can be greatly reduced under an EEF, and the change in the energy level of FMOs can be adjusted to different degrees. This study provides a reasonable idea for verification of the experimental mobility value and also provides guidance for the directional design of stable high-mobility OSCs.

A Simulation of Air Lasing Seeded by an External Wave in a Femtosecond Laser Filament.

Air lasers induced by femtosecond laser filaments play an important role in remote sensing applications. Few studies have been dedicated to the spatial distribution of external-seeded air laser radiation in the laser filament based on the numerical simulation method, which can pave the way to understanding the mechanism of the external-seeded air lasing process during filamentation. In this study, numerical simulations of the propagation of an air laser seeded by an external plane wave with a wavelength of 391 nm during femtosecond laser filamentation were performed. The results indicated that the air laser's beam intensity distribution varies from a ring pattern to a donut pattern when the filament length and nitrogen ion density are raised as a result of the defocusing and lasing effects of the filament plasma. Here, the ring pattern is formed by several thin rings, while the donut pattern refers to a notably thicker, ring-like structure. In addition, it has been demonstrated that the air laser's beam power would increase exponentially versus the filament length and the nitrogen ion density. The knowledge about the angular distribution of air lasing could be important for optimizing the detection geometry of the LIDAR setup, including the view angle and the size of the collecting optical component.

Suppressing turbulence-induced laser beam wandering by using an axicon.

Laser beam wandering induced by air turbulence could be crucial for applications such as free-space optical communications, LIDAR, and remote air lasing. In this study, the influence of air turbulence on the transverse wandering of a Gauss laser beam with and without an axicon as the focusing optical component has been investigated. It has been demonstrated that the turbulence-induced beam wandering could be dramatically suppressed by using an axicon. Further, the corresponding mechanism has been discussed. This work would bring great benefits to many practical applications relying on a stable laser beam in a turbulent atmosphere.

Theoretical insight on the charge transport properties: The formation of "head-to-tail" and "head-to-head" stacking of asymmetric aryl anthracene derivatives.

Organic semiconductors (OSCs) are widely used in flexible display, renewable energy, and biosensors, owing to their unique solid-state physical and optoelectronic properties. Among the abundant crystal library of OSCs, asymmetric aryl anthracene derivatives have irreplaceable advantages due to the interplay between their distinct π-conjugated geometry and molecular stacking as well as efficient light emission and charge transport properties that can be simultaneously utilized. However, the poor crystal stacking patterns of most asymmetric molecules limit their utility as excellent OSCs. Thus, it is crucial to clarify the structural features that enable the extremely ordered stacking and favorable electronic structure of asymmetric anthracene derivatives to become high-performance OSCs. This contribution investigates the charge transport properties of a series of asymmetric aryl anthracene derivatives to reveal the modulation factors of the molecular stacking modes and to explore the structural factors, which are beneficial to charge transport. The analysis demonstrated that the vinyl-linker facilitated the injection of hole carriers, and the alkynyl-linker effectively reduces the reorganization energy. Importantly, the linear polarizability and permanent dipole moment of a single molecule play a vital regulation to molecular stacking modes and the transfer integral of the dimer. The "head-to-head stacking" motif shows a compact stacking pattern and the maximum 2D anisotropic mobility more than 10 cm2 V-1 s-1. These findings sharpen our understanding of the charge transport properties in asymmetric organic semiconductors and are essential for developing a diverse range of high-performance OSC materials.

Theoretical Investigation of Ru(II) Complexes with Long Lifetime and a Large Two-Photon Absorption Cross-Section in Photodynamic Therapy.

Two-photon photodynamic therapy (TP-PDT), as a new method for cancer, has shown unique advantages in tumors. A low two-photon absorption cross-section (δ) in the biologic spectral window and a short triplet state lifetime are the important issues faced by the current photosensitizers (PSs) in TP-PDT. In this paper, the photophysical properties of a series of Ru(II) complexes were studied by density functional theory and time-dependent density functional theory methods. The electronic structure, one- and two-photon absorption properties, type I/II mechanisms, triplet state lifetime, and solvation free energy were calculated. The results showed that the substitution of methoxyls by pyrene groups greatly improved the lifetime of the complex. Furthermore, the addition of acetylenyl groups subtly enhanced δ. Overall, complex 3b possess a large δ(1376 GM), a long lifetime (136 µs), and better solvation free energy. It is hoped that it can provide valuable theoretical guidance for the design and synthesis of efficient two-photon PSs in the experiment.

Theoretical study of the tuning role of ß-methylthio or ß-methylselenyl on the charge-transport properties of acenedithiophenes derivatives.

To date, the manipulation of intermolecular nonconjugation interactions in organic crystals is still a great challenge due to the complexity of weak intermolecular interactions. Here we designed molecules substituted by ß-methylselenyl on naphtho[1,2-b:5,6-b']dithiophene and anthra[2,3-b:6,7-b']dithiophene, respectively (anti-ß-MS-NDT, anti-ß-MS-ADT), which together with anti-ß-MS-BDT synthesized experimentally all exhibited 2D brickwork π-stacking. Moreover, their maximum molecular carrier mobilities reached 3.30 and 16.46 cm2 V-1 s-1. These results indicated that the substitution of ß-methylselenyl could be a strategy to directionally adjust the parent herringbone stacking into 2D brickwork π-stacking. Hirshfeld surface analysis and symmetry-adapted perturbation theory (SAPT) were used to investigate the nonconjugated interactions in the pitched π-stacking formed by the ß-methylthio-substituted acenedithiophene derivatives and the 2D brickwork π-stacking of the ß-methylselenyl-substituted ones; wherein, the steric hindrance caused by the introduction of the substituents promoted Csp2-Csp2⋯π interactions to replace Csp2-H⋯π to stabilize the face-to-face stacking. Moreover, by calculating the decomposition energy of the intermediate state model of the molecular stacking mode that may exist in the replacement conversion process, it was found that the energy of this intermediate state was larger than that of the actual ones, finally confirming the inevitability of the actual existence in this stacking. In addition, because of the reduction in intensity of the special vibration modes, it could be found that the ß-methylselenyl substitution showed better phonon assistance than ß-methylthio substitution in terms of dynamic disorder. This study is a further step toward fully understanding the relationship between intermolecular interactions and regulation of the molecular stacking.

Photophysical Exploration of Zn(II) Polypyridine Photosensitizers in Two-Photon Photodynamic Therapy: Insights from Theory.

The high incidence and difficulties of treatment of cancer have always been a challenge for mankind. Two-photon photodynamic therapy (TP-PDT) as a less invasive technique provides a new perspective for tumor treatment due to its low-energy near-infrared excitation, high targeting, and minor damage. At present, the emerging metal complexes used as the photosensitizers (PSs) in TP-PDT have aroused great interest. However, most metal complexes as PSs in TP-PDT still face some problems, such as slow clearance, unsatisfactory two-photon absorption (TPA) characteristics, high price, low reactivity, and poor solubility. In this work, density functional theory and time-dependent density functional theory were used to characterize the one/two-photon response, solvation free energy, and lipophilicity of a series of novel PSs applied in TP-PDT. The results suggest that based on complex 1, replacing Ru(II) center with Zn(II) (complex 2) can effectively prolong the triplet excited state lifetime while reducing the cost and environmental pollution, and the azetidine heterospirocycles were introduced into the ligand scaffold (complex 3), which effectively reduced the vibration relaxation of the ligand group and improved the water solubility; further, the addition of acetylenyl groups subtly enhanced the light absorption and significantly improved the two-photon response (complex 4). In addition, all complexes met the requirement of a PS and could be used as potential candidates for TP-PDT. In particular, complex 4 has the advantages of high solvation free energy, a large TPA cross-section (1413 GM), a long triplet state lifetime (671 µs), good chemical reactivity, and low cost, and it is easy to be scavenged by organisms. Overall, this contribution may provide an important clue to formulate clear design principles for type I/II PSs and rational design of PSs with high intersystem crossing rates, a long lifetime, and therapeutic excitation wavelengths.

Influence of nitrogen sources on the tolerance of Lacticaseibacillus rhamnosus to heat stress and oxidative stress.

It has been found that 32 genes related to nitrogen source metabolism in Lacticaseibacillus rhamnosus are downregulated under both heat stress and oxidative stress. In this study, the influence of different nitrogen sources within the growth medium on the tolerance of L. rhamnosus to heat stress and oxidative stress was investigated. Tryptone-free MRS was found to enhance the tolerance of L. rhamnosus hsryfm 1301 to heat stress and oxidative stress during the whole growth period, and this result was universal for all L. rhamnosus species analyzed. The strongest strengthening effect occurred when the OD600 value reached 2.0, at which the survival rates under heat stress and oxidative stress increased 130-fold and 40-fold, respectively. After supplementing phenylalanine, isoleucine, glutamate, valine, histidine, or tryptophan into the tryptone-free MRS, the tolerance of L. rhamnosus to heat stress and oxidative stress exhibited a sharp drop. The spray drying survival rate of L. rhamnosus hsryfm 1301 cultured in the tryptone-free MRS rose to 75% (from 30%), and the spray dried powder also performed better in the experimentally simulated gastrointestinal digestion. These results showed that decreasing the intake of amino acids is an important mechanism for L. rhamnosus to tolerate heat stress and oxidative stress. When L. rhamnosus is cultured for spray drying, the concentration of the nitrogen source's components should be an important consideration.

Chemical comparison and discrimination of two plant sources of Angelicae dahuricae Radix, Angelica dahurica and Angelica dahurica var. formosana, by HPLC-Q/TOF-MS and quantitative analysis of multiple components by a single marker.

INTRODUCTION: Angelica dahurica(BZ) and Angelica dahurica var. formosana(HBZ) are two plant sources of Angelicae dahuricae Radix. Although BZ and HBZ are commonly used herbal medicines with great medicinal and dietary values, study on their phytochemicals and bioactive compositions is limited. OBJECTIVE: To compare the chemical compositions of BZ and HBZ and find the chemical makers for discrimination and quality evaluation of the two botanical origins of Angelicae dahuricae Radix. METHODOLOGY: A high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established for chemical profiling of BZ and HBZ. Then, a quantitative analysis of multiple components by a single marker method was developed for simultaneous determination of nine bioactive coumarins (xanthotoxol, oxypeucedanin hydrate, byakangelicin, xanthotoxin, bergapten, oxypeucedanin, phellopterin, imperatorin and isoimperatorin). Moreover, chemometrics were performed to compare and discriminate BZ and HBZ samples. RESULTS: A total of 30 coumarins compounds were identified, and the chemical compositions in BZ and HBZ were quite similar. The quantitative analysis showed that there were significant differences in the contents of bioactive coumarins, and the chemometric analysis indicated five coumarins (xanthotoxol, xanthotoxin, bergapten, phellopterin and isoimperatorin) were responsible for the significant differences between BZ and HBZ, which could be used as chemical markers to distinguish the two original plant sources of Angelicae dahuricae Radix. CONCLUSION: The present work provided useful information for understanding the chemical differences between BZ and HBZ and also provided feasible methods for quality evaluation and discrimination of herbal medicines originating from multiple botanical sources.

[Dynamic changes of volatile components in Forsythia suspensa at different harvest periods based on GC-MS and chemometrics analysis].

Forsythiae Fructus is the dried fruit of Forsythia suspensa and the volatile compounds are its main bioactive components. According to the different harvest periods, F. suspensa can be divided into Qingqiao(mature F. suspensa) and Laoqiao(ripe F. suspensa). To investigate dynamic changes of volatile components in Qingqiao and Laoqiao samples collected at different periods, the present study extracted and analyzed the total volatile oils in Qingqiao and Laoqiao samples(four harvest periods for Qingqiao and two for Laoqiao) by steam distillation method. The results indicated that the content of volatile oils in F. suspensa samples at different harvest periods was significantly different. The content of volatile oils in Qingqiao samples(except those harvested in the first period) was higher than that of Laoqiao, and the content of volatile oils in both Qingqiao and Laoqiao increased with the harvest period. Furthermore, volatile compounds in F. suspensa were qualitatively analyzed by the gas chromatography-mass spectrometry(GC-MS), and 28 volatile compounds were identified. Chemometrics analyses including principal component analysis(PCA) and partial least squares discriminant analysis(PLS-DA) were further applied to explore differential markers and dynamic changes of volatile components in Qingqiao and Laoqiao samples at different harvest periods. Finally, four volatile compounds, including α-pinene, sabinene, ß-pinene, and 4-terpenol were selected as potential differential markers. The relative content of α-pinene and 4-terpenol was consistent with that of total volatile oils in the changing trend.

Theoretical investigations on the charge transport properties of anthracene derivatives with aryl substituents at the 2,6-position-thermally stable "herringbone" stacking motifs.

High-performance organic semiconductor materials based on the small aromatic anthracene-core and its derivatives develop comparatively slowly due to the lack of a profound understanding of the influence of chemical modifications on their charge-transfer properties. Herein, the electronic properties and the charge transport characteristics of several typical anthracene-based derivatives with aryl groups substituted at the 2,6-site are systematically investigated by multi-scale simulation methods including Molecular Dynamics (MD) simulation and the full quantum nuclear tunneling model in the framework of density functional theory (DFT). To elucidate the origin of different charge transport properties of these anthracene-based materials, analysis of the molecular stacking and noncovalent intermolecular interaction caused by different substituents was carried out. The results indicate that the electron and hole injection capabilities and the air oxidation stability of the anthracene derivatives are greatly improved when the size of the aryl substituent increases. In addition, the incorporation of 2,6-site aryl substituents can inhibit the stretching vibration of the anthracene-core during charge transport, and allow molecular packing along the long axis (a-axis of DPA and BDBFAnt, and c-axis of dNaAnt) with almost no slippage, and the main transport channels remain unchanged, exhibiting more isotropic 2D transport properties. It should be emphasized that the edge-to-face dimers with smallest dihedral angles are closest to the thermally stable dimer model, with relatively larger π-orbital distributions in transmission channels (dimer 1, 2) and the largest spatial overlap, resulting in the largest hole transfer integral in DPA (Vh1/h2 = 57 meV). Although the analysis of the thermal disorder effect shows a phonon scattering effect, the maximum hole mobility of the DPA molecule is still as high as 1.5 cm2 V-1 s-1.

Natural Deep Eutectic Solvents for the Extraction of Bioactive Steroidal Saponins from Dioscoreae Nipponicae Rhizoma.

In the present study, a simple and environmentally friendly extraction method based on natural deep eutectic solvents (NADESs) was established to extract four bioactive steroidal saponins from Dioscoreae Nipponicae Rhizoma (DNR). A total of twenty-one types of choline chloride, betaine, and L-proline based NADESs were tailored, and the NADES composed of 1:1 molar ratio of choline chloride and malonic acid showed the best extraction efficiency for the four steroidal saponins compared with other NADESs. Then, the extraction parameters for extraction of steroidal saponins by selected tailor-made NADES were optimized using response surface methodology and the optimal extraction conditions are extraction time, 23.5 min; liquid-solid ratio, 57.5 mL/g; and water content, 54%. The microstructure of the DNR powder before and after ultrasonic extraction by conventional solvents (water and methanol) and the selected NADES were observed using field emission scanning electron microscope. In addition, the four steroidal saponins were recovered from NADESs by D101 macroporous resin with a satisfactory recovery yield between 67.27% and 79.90%. The present research demonstrates that NADESs are a suitable green media for the extraction of the bioactive steroidal saponins from DNR, and have a great potential as possible alternatives to organic solvents for efficiently extracting bioactive compounds from natural products.

[Quality control of Dioscoreae Nipponicae Rhizoma based on fingerprint and quantitative analysis].

Dioscoreae Nipponicae Rhizoma, the dried rhizoma of Dioscorea nipponica, has been widely used in traditional Chinese medicines. According to the different of the growth and cultivation patterns, Dioscoreae Nipponicae Rhizoma can be divided into two species, the wild Dioscoreae Nipponicae Rhizoma and the cultivated Dioscoreae Nipponicae Rhizoma. In this paper, an accurate and reliable fingerprint of Dioscoreae Nipponicae Rhizoma was established based on HPLC coupled with evaporative light scattering detector(ELSD). A total of 6 common peaks were marked, and the similarity of the Dioscoreae Nipponicae Rhizoma samples was above 0.950. The results indicated that the established fingerprint could be used for quality evaluation of Dioscoreae Nipponicae Rhizoma. Moreover, an HPLC coupled with ELSD method was developed for simultaneous quantitative analysis of six steroidal saponins, including protodioscin, protogracillin, methyl protodioscin, pseudoprotodioscin, dioscin and gracillin in wild Dioscoreae Nipponicae Rhizoma and cultivated Dioscoreae Nipponicae Rhizoma samples. Furthermore, chemometrics analysis such as principal component analysis and partial least squares discriminant analysis were performed to compare and discriminate wild Dioscoreae Nipponicae Rhizoma and cultivated Dioscoreae Nipponicae Rhizoma samples based on the quantitative data. The results indicated that the contents of steroidal saponins were notably different between the wild and cultivated Dioscoreae Nipponicae Rhizoma, and protodioscin and protogracillin were significant to effectively discriminate the wild and cultivated Dioscoreae Nipponicae Rhizoma samples, and these two compounds could be recognized as chemical markers. In conclusion, this present study might provide useful data and acceptable analysis method for identification and quality evaluation of Dioscoreae Nipponicae Rhizoma.

[Dynamic changes of volatile components of Qiai from different harvest time based on GC-MS and chemometrics analysis].

Artemisiae Argyi Folium, the dried leaves of Artemisia argyi, has been widely used in traditional Chinese and folk medicines for a long time. Qiai is one of the top-geoherb of Artemisiae Argyi Folium. Qiai contains various bioactive constituents, such as volatile oils, phenolic acids, flavonoids and terpenoids. Phytochemical studies demonstrated that volatile compounds are the main bioactive constituents in Qiai. Try to investigate dynamic changes of volatile components of Qiai from different harvest time and explore the optimum harvest time of Qiai, in this study, the contents of total volatile oils in Qiai collected from five different harvest time were analyzed by steam distillation method. The results showed that the contents of volatile oils of Qiai were higher in the third harvest time(around the Dragon Boat Festival), which is basically consistent with the traditional harvest time. Furthermore, a sensitive method based on gas chromatography-mass spectrometry(GC-MS) was established for qualitative analysis of volatile compounds in Qiai, and a total of thirty volatile compounds were identified. Chemometrics methods including principal component analysis(PCA) and orthogonal partial least-squares discriminate analysis(OPLS-DA) were applied to explore chemical markers and dynamic changes of volatile components in Qiai from different harvest time, and the results indicated that there were obvious differences in the relative contents of volatile compounds of Qiai samples from different harvest time. Eight volatile compounds, including α-terpinene, γ-terpinene, D-camphor, trans-carveol, α-copaene, isobornylisobutyrate, humulene, and caryophyllene oxide were selected as potential chemical markers. Among the eight chemical markers, the relative contents of α-terpinene, γ-terpinene, α-copaene and caryophyllene oxide were higher in the third harvest period(around the Dragon Boat Festival), which is consistent with the contents of total volatile oils. The present study could provide the basis for investigating the optimum harvest time of Qiai, and might be useful for the quality control of this herbal medicine.

Transcriptional homogenization of Lactobacillus rhamnosus hsryfm 1301 under heat stress and oxidative stress.

Cross-adaptation, which can improve the stress tolerance of strains, temporarily supplies more matching bases in transcriptome-phenotype matching approaches to reveal novel gene functions in stress responses. Transcriptome-phenotype matching based on RNA sequencing was implemented to reveal the cross-adaptation mechanism of Lactobacillus rhamnosus hsryfm 1301 in response to heat stress and oxidative stress. A total of 242 genes were upregulated and 320 genes were downregulated under heat stress, while 135 genes were upregulated and 206 genes were downregulated under oxidative stress. There were 154 overlapping genes that responded to both stresses, and 97.4% of the overlapping DEGs (differentially expressed genes) were codirectionally regulated. The overlapping DEGs were mainly classified into amino acid or oligopeptide ABC transporters, amino acid metabolism, and quorum sensing pathways. Correspondingly, the heat and oxidative tolerance of L. rhamnosus hsryfm 1301 was stronger in low nitrogen source environment. Thus, the high proportion of transcriptional homogenization, especially the decrease in abundance of nitrogen source transporter and metabolism enzyme genes, was a reason for the cross-adaptation of L. rhamnosus hsryfm 1301 to heat stress and oxidative stress. The survival rate of L. rhamnosus during processes with heat stress and oxidative stress can be improved by reducing the concentration of nitrogen source in the culture medium.

Comparison of remnant cholesterol levels estimated by calculated and measured LDL-C levels in Chinese patients with coronary heart disease.

BACKGROUND: Evidence about whether remnant cholesterol (RC), especially non-fasting RC, is a causal risk factor for coronary heart disease (CHD) in Chinese subjects is rare. Recently, estimated RC level (RCe) was applied in many studies with large population. We aimed to compare fasting and non-fasting RCe calculated by LDL-C level determined by different methods in Chinese subjects, and investigate their contributions to CHD. METHODS: Levels of TC, TG and HDL-C were measured directly in 273 CHD patients (CHD group) and 136 controls (CON group) before and at 4 h after a daily breakfast. LDL-C level was measured directly or calculated by Friedewald equation at TG < 4.5 mmol/L. RC level estimated by calculated or measured LDL-C was termed as RCe1 or RCe2. Contributions of different RC levels to CHD were evaluated by multivariable logistic regression analysis. RESULTS: Both RCe1 and RCe2 increased significantly at 4 h after breakfast (both p < 0.05). RCe1 was significantly higher than RCe2 in fasting or non-fasting state (p < 0.05). RCe1 was closely related to RCe2, especially in the highest quartile of RCe1 (p < 0.05). Non-fasting RCe1 or RCe2 and fasting RCe2 independently predicted CHD after adjustment for traditional risk factors (all p < 0.05). CONCLUSIONS: Although RCe1 was significantly higher than RCe2, non-fasting RCe, no matter RCe1 or RCe2, after a daily breakfast was an independent predictor for CHD risk in Chinese subjects, indicating that the non-fasting state is critical in the development of atherosclerosis.

Theoretical Investigations into the Electron and Ambipolar Transport Properties of Anthracene-Based Derivatives.

To obtain anthracene-based derivatives with electron transport behavior, two series of anthracene-based derivatives modified by trifluoromethyl groups (-CF3) and cyano groups (-CN) at the 9,10-positions of the anthracene core were studied. Their electronic structures and crystal packings were also analyzed and compared. The charge-carrier mobilities were evaluated by quantum nuclear tunneling theory based on the incoherent charge-hopping model. Our results suggest that introducing -CN groups at 9,10-positions of the anthracene core is more favorable than introducing -CF3 to maintain great planar rigidity of the anthracene skeleton, decreasing more lowest unoccupied molecular orbital energy levels (0.45-0.55 eV), reducing reorganization energies, and especially forming a tight packing motif. Eventually, the excellent electron transport materials could be obtained. The molecule 1-B in Series 1 containing -CF3 groups is an ambipolar organic semiconductor (OSC) material with a 2D transport network, and its value of µh-max/µe-max is 1.75/0.47 cm2 V-1 s-1 along different directions; 2-A and 2-C in Series 2 with -CN groups are excellent n-type OSC candidates with the maximum intrinsic mobilities of 3.74 and 2.69 cm2 V-1 s-1 along the π-π stacking direction, respectively. Besides, the Hirshfeld surface and quantum theory of atoms in molecules analyses were applied to reveal the relationship between noncovalent interactions and crystal stacking.

[Study on difference of chemical constituents of Qiai in different harvest periods].

Artemisiae Argyi Folium,the dried leaves of Artemisia argyi,has been widely used in traditional Chinese and folk medicines for a long time. Qiai is one of the top-geoherb of Artemisiae Argyi Folium. Trying to investigate dynamic changes of chemical components of Qiai in different harvest periods and explore the optimum harvest time of Qiai,in this study,the contents of total flavonoids and total phenolic acids of 36 batches of Qiai collected in 6 different harvest periods were analyzed by ultraviolet-visible spectrophotometry. Furthermore,an HPLC method was applied for simultaneous determination of eight bioactive compounds including six phenolic acids( 5-caffeoylquinic acid,3-caffeoylquinic acid,4-caffeoylquinic acid,3,4-di-O-caffeoylquinic acid,3,5-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid) and two flavonoids( jaceosidin and eupatilin) in Qiai samples. The quantitative results indicated that there were some differences in the contents of total flavonoids,total phenolic acids and bioactive compounds of Qiai samples in different harvest periods. The dynamic changes of total flavonoids and total phenolic acids of Qiai in different harvest periods were consistent. The contents of total flavonoids and total phenolic acids of Qiai samples were higher in the third harvest period( around the Dragon Boat Festival),which is basically consistent with the traditional harvest periods. This present study can provide the basis for determining the suitable harvest time of Qiai,and might be useful for the quality evaluation of this herbal medicine.

[Research on XOD captured components in Lagotis brevituba based on UPLC-Q-TOF-MS and molecular docking technology].

Potential xanthine oxidase (XOD) inhibitors in Lagotis brevituba were captured by using affinity and ultrafiltration. The structures of the captured components were identified by ultra-performance liquid chromatography coupled with Q-TOF mass spectrometry (UPLC-Q-TOF-MS). The binding intensity and binding mechanism between the captured components and XOD were analyzed by using molecular docking software Autodock 4.2. A total of 17 compounds were identified, including 9 flavonoids, 5 phenolic acids and 3 triterpenes. Molecular docking results showed that all the captured components could be spontaneously bound with XOD mainly via hydrogen bond, Van der Waals' force and hydrophobic interaction. From the perspective of binding energy and scoring function, the collected fractions all had potential prospects for XOD inhibitors, and the flavonoid luteolin-3',7 glucuronide had the best effect. The results also showed that affinity and ultrafiltration, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and molecular docking technology can provide a powerful tool for the analysis of XOD inhibitor components in natural products.