[Mechanism of Cordyceps militaris against non-small cell lung cancer: based on serum metabolomics].

This study investigated the potential mechanism of Cordyceps militaris(CM) against non-small cell lung cancer(NSCLC) based on serum untargeted metabolomics. Specifically, Balb/c nude mice were used to generate the human lung cancer A549 xenograft mouse model. The tumor volume, tumor weight, and tumor inhibition rate in mice in the model, cisplatin, Cordyceps(low-, medium-, and high-dose), and CM(low-, medium-, and high-dose) groups were compared to evaluate the influence of CM on lung cancer. Gas chromatography-mass spectrometry(GC-MS) was used for the analysis of mouse serum, SIMCA 13.0 for the compa-rison of metabolic profiles, and MetaboAnalyst 5.0 for the analysis of metabolic pathways. According to the pharmacodynamic data, the tumor volume and tumor weight of mice in high-dose CM group and cisplatin group decreased as compared with those in the model group(P<0.05 or P<0.01). The results of serum metabolomics showed that the metabolic profiles of the model group were significantly different from those of the high-dose CM group, and the content of endogenous metabolites was adjusted to different degrees. A total of 42 differential metabolites and 7 differential metabolic pathways were identified. In conclusion, CM could significantly inhibit the tumor growth of lung cancer xenograft mice. The mechanism is the likelihood that it influences the aminoacyl-tRNA biosynthesis, the metabolism of D-glutamine and D-glutamate, metabolism of alanine, aspartate, and glutamate, metabolism of glyoxylate and dicarboxylic acid, biosynthesis of phenylalanine, tyrosine, and tryptophan, arginine biosynthesis as well as nitrogen metabolism. This study elucidated the underlying mechanism of CM against NSCLC from the point of metabolites. The results would lay a foundation for the anticancer research and clinical application of CM.

[Structural Chinese medicine: new research field on pharmacodynamic substance basis of traditional Chinese medicine].

The research on the pharmacodynamic substance basis of traditional Chinese medicine(TCM) is a key scientific issue for the inheritance and development of TCM. At present, a large number of remarkable achievements have been made in the field of chemical components in Chinese medicine, however, another important aspect, namely the physical structure and mode of action of the multi-component assembly of TCM, has not been clearly understood and deeply studied. From the bottleneck of restricting material ba-sic research, we objectively analyzed the common cause of the existing problems. Based on the new discoveries and advances of active substances from TCM emerging in recent years, we extracted and summarized the concept of structural Chinese medicine, elaborated the basic ideas, main features and research modes, hoping to provide theoretical and practical references for the study on the pharmacodynamic substance basis and other research fields of TCM.

[Quality evaluation of fried Glycyrrhizae Radix et Rhizoma pieces by HPLC fingerprint and multicomponent quantitative analysis].

To establish the HPLC fingerprint and multi-component determination method of fried Glycyrrhizae Radix et Rhizoma pieces. HPLC analysis was performed on Thermo Acclaim ~(TM)120 C_(18) column(4.6 mm×250 mm, 5 µm). Acetonitrile-0.1% phosphoric acid aqueous solution was taken as the mobile phase for gradient elution. The flow rate was 1 mL·min~(-1),the column temperature was maintained at 30 ℃, and the detection wavelength was 237 nm and 360 nm. The similarity of 15 batches of fried Glycyrrhizae Radix et Rhizoma pieces was higher than 0.849, and 17 common peaks were identified. Liquiritin, isoliquiritin apioside, isoliquiritin, liquiritigenin, isoliquiritigenin and glycyrrhizic acid were identified; among them, the mass fractions of Liquiritin, isoliquiritin apioside, isoliquiritin, liquiritigenin, glycyrrhizic acid were were 0.519%-3.058%, 0.227%-0.389%, 0.070%-0.439%, 0.038%-0.173%, 1.381%-4.252%, respectively. According to the cluster analysis, the 15 batches of decoction pieces were classified into three categories; principal component analysis screened out four principal components, with the cumulative variance contribution rate of 86.630%, indicating that the principal components contained most information of original data. Partial least squares discriminant ana-lysis marked 6 differential components in the decoction pieces. The established fingerprint and multicomponent determination are stable and reliable, and can provide a reference for the quality control of Radix Glycyrrhizae Radix et Rhizomae and fried Glycyrrhizae Radix et Rhizoma pieces.

[Establishment of quality control model for high performance liquid chromatography fingerprint based on ultraviolet full-wavelength scanning spectrum: case study on different grades of Scrophulariae Radix].

High performance liquid chromatography-ultraviolet(HPLC-UV) fingerprint is one of the most important methods for the quality control of Chinese medicines in Chinese Pharmacopoeia. However, certain subjectivity is present in selection of specific band of UV, and the inherent quality differences of Chinese medicine can't be well characterized by this method. Therefore, with different grades of Scrophulariae Radix were taken as the research object in this study, a new quality control model of HPLC-UV was established in this study based on the ultraviolet full-wavelength scanning spectrum. Firstly, different grades of Scrophulariae Radix samples were collected, and the full-wavelength ultraviolet absorption spectra of all the samples were established at the bands of 200-400 nm. In order to analyze the differences among samples, the analysis model was built following multivariate statistical analysis methods such as principal component analysis(PCA) and partial least squares discrimination analysis(PLS-DA) after the pretreatment of spectral data. The result showed that the ultraviolet band at 251 nm may contribute most to distinguish the quality differences among different grades of samples. Then, the HPLC fingerprints of samples were established with the band at 251 nm. The multivariate statistical analysis showed that there was a more significant classification trend in HPLC fingerprints than that in the original UV fingerprints, which could be used to distinguish different grades of samples, and could better reflect the differences among different grades. The method reported in this study can be of a great guidance and reference for the establishment of specific fingerprints of Chinese medicines as well as for the quality control of Chinese medicine.

Elaboration in type, primary structure, and bioactivity of polysaccharides derived from mollusks.

Over the past decades, numerous Mollusca species have received more attention in development and utilization as valuable bio-resources. Many efforts have been focused on investigating mollusk polysaccharides because of their rich content, ease of extraction, diversified sorts, specific structure, various biofunctions and potent activities. To date, many mollusks, especially species of gastropods, bivalves, or cephalopods, have been reported containing polysaccharide compounds in tissues with abundant amount, and most of polysaccharides are obtainable through combining techniques of extraction, separation and purification. The polysaccharides isolated from mollusks appeared with various structural and physicochemical characteristics, ranged from neutral polysaccharides and sulfated polysaccharides, to GAGs series (including Hep/HS, CS/DS, HA and similarities), even to heterogeneous glycan with high molecular weight. This review article provides comprehensive knowledge of recent researches on type classification, tissue origins and possible biofunctions of various polysaccharides from mollusks. The highlights were placed in structure variation including molecular weight, sulfation pattern, linkages and monomer compositions for repeating unit, and primary molecular construction of the mollusks polysaccharides. In addition, this article covers general information on exhibition of mollusks polysaccharide extracts or preparations in the various bioactivities, such as anticoagulant, antiatherogenic, antioxidant, immunomodulatory, antivirus and antitumor activities, which would reveal their possible potentials in medical application. Furthermore, the article presents a brief overview on several challenges and future scope in this field.

Genome characterization of Sugarcane Yellow Leaf Virus with special reference to RNAi based molecular breeding.

Sugarcane is an essential crop for sugar and biofuel. Globally, its production is severely affected by sugarcane yellow leaf disease (SCYLD) caused by Sugarcane Yellow Leaf Virus (SCYLV). Many aphid vectors are involved in the spread of the disease which reduced the effectiveness of cultural and chemical management. Empirical methods of plant breeding such as introgression from wild and cultivated germplasm were not possible or at least challenging due to the absence of resistance in cultivated and wild germplasm of sugarcane. RNA interference (RNAi) transformation is an effective method to create virus-resistant varieties. Nevertheless, limited progress has been made due to lack of comprehensive research program on SCYLV based on RNAi technique. In order to show improvement and to propose future strategies for the feasibility of the RNAi technique to cope SCYLV, genome-wide consensus sequences of SCYLV were analyzed through GenBank. The coverage rates of every consensus sequence in SCYLV isolates were calculated to evaluate their practicability. Our analysis showed that single consensus sequence from SCYLV could not work well for RNAi based sugarcane breeding programs. This may be due to high mutation rate and continuous recombination within and between various viral strains. Alternative multi-target RNAi strategy is suggested to combat several strains of the viruses and to reduce the silencing escape. The multi-target small interfering RNA (siRNA) can be used together to construct RNAi plant expression plasmid, and to transform sugarcane tissues to develop new sugarcane varieties resistant to SCYLV.

[Tissue Distribution of Alkaloids from Coptidis Rhizoma in Rats Determined by UPLC-MS].

Objective: To develop an UPLC-MS method for simultaneous determination of alkaloids from Coptidis Rhizoma in rat tissues, and to study the tissue distribution of alkaloids from Coptidis Rhizoma in rats. Methods: The samples were extracted with ethyl acetate, and analyzed by UPLC-MS with acetonitrile-0. 2% formic acid solution in a gradient elution mobile phase, the flow rate was 0. 2m L/min. Tetrahydropalmatine was used as an internal standard. The mass spectrometer was operated in selected reaction monitoring( SIM) mode with positive electrospray ionization, the transition were m/z 191. 904 /118. 973( noroxyhydrastinine), m/z 335. 877 /308. 072( 8-ocoptisine),m/z 351. 94 /294. 554( palmatine chloride),m/z 335. 94 /262. 112( epiberberine), m/z 337. 94 /322. 422( columbamine), m/z 319. 904 /292. 037( coptisine), m/z 355. 977 /192. 036( tetrahydropalmatine),m/z 335. 94 /320. 036( berberine hydrochloride),m/z 351. 94 /321. 995( oxyberberin), m/z 337. 94 /322. 949( jatrorrhizine respectively). Results: Excellent linearity was observed in all alkaloids in their linear range( r & 0. 9901). The RSD of precision of the developed method was less than 15%,and the accuracy and stability were less than ± 15%,the extraction recovery was 72. 1% ~ 82. 9% with RSD less than 15%. Coptisine,epiberberine,berberine,jatrorrhizine,columbamine,palmatine were widely distributed in rat tissues. Noroxyhydrastinine,8-ocoptisine,oxyberberin could only be determined in liver and heart or kidney. Conclusion: The established method is simple and accurate. Satisfactory results are obtained with applying this method to the tissue distribution study of alkaloids from Coptidis Rhizoma.

[Comparison of total phenol of magnolia solid dispersion prepared by different methods].

To compare the difference of total phenol of magnolia solid dispersion prepared by different methods. Hot melt extrusion, solvent evaporation method, and fusion-cooling method were used to prepare total phenol of Magnolia accessory solid dispersion, Plastone S-630 and HPC. The drug dispersion state in the prepared solid dispersion was evaluated with DSC and X-ray diffraction; FT-IR method was used to analyze the possible connections between drug and accessories. Finally, accelerated stability-in vivo dissolution test was use to compare the stability differences between these three processes. The results of DSC and X-ray diffraction showed that all of the drug in solid dispersion processed by three processes can exist in amorphous form; FT-IR results also could not distinguish the difference between the three processes; accelerated stability-in vivo dissolution test showed the stability of solid dispersion prepared by HPC was better than Plastone S-630, and the same kinds of materials solid dispersion prepared by hot melt extrusion showed a better stability than the other two processes.

[Active ingredients and its pharmacokinetic behavior and anti-inflammatory effects of ginseng with different steamed times].

HPLC analysis was performed to study the changes in chemical composition of ginseng extracts prepared from high quality ginseng with 0, 2, 4, 8 h of steamed times. An UFLC-MS/MS multiple-reaction monitoring (MRM) quantitative analysis was made to investigate the pharmacokinetic behavior differences of ginsenosides in mice ig administered of ginseng extracts with different steamed times in the negative ion mode, with Digoxin as the internal standard substance. The mice were injected with LPS to establish inflammation model after ig administration of ginseng for a week and the contents of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in mice plasma were detected by ELISA, in order to study on anti-inflammatory effects of ginseng with different steamed times. It was determined that levels of TNF-α and IL-1ß were significantly decreased in inflammation model group ig administered of ginseng extracts with 8h of steamed time. The results showed that the chemical components in ginseng changed after steaming and the components into the blood changed, correspondingly. Ginseng with steamed 8 h contributes to anti-inflammatory effects. These results provided an experimental basis for revealing the active substance basis and dose-effect relationship of ginseng on anti-inflammatory effect.

[HPLC specific chromatogram spectrum-effect relationship for Shuanghuanglian on MDCK cell injury induced by influenza A virus (H1N1)].

To establish HPLC specific chromatogram and its correlation with the protection effect of Shuanghuanglian on MDCK (Madin-Darby canine kidney) cell injury induced by influenza A virus( H1N1). Nine recipes of Shuanghuanglian based on the official prescription were prepared according to orthogonal test for HPLC analysis and MDCK cells protection experiment separately (cytopathic effect (CPE) method was used for observing the virus infectivity and MTT staining results were used as the determining indexes for drug concentration selection and analyzing cell viability). The results suggested that all the other Shuang-Huang-Lian recipes except recipe1 demonstrate protecting effect on MDCK cell injury induced by influenza A virus (P < 0.01, P < 0.001). Stepwise regression analysis was used for analyzing the relationships between HPLC fingerprint and the protecting effect of Shuanghuanglian on influenza A virus induced MDCK cell injury. Peak 2, 3, 6, 8 and 12 were found to be strongly related with anti-influenza A virus efficacy. Stepwise regression analysis of recipes data and efficacy data showed that Lonicerae Japonicae Flos and Forsythiae Fructus were positively associated with the protecting effect of cells injury. From HPLC fingerprints, we found that peak 2, 3, 12 were from Lonicerae Japonicae Flos and peak 6, 8 were from Forsythiae Fructus. Four peaks were identified through comparing the retention time between the standard and Shuanghuanglian recipes, and they were chlorogenicacid, cryptochlorogenic acid, forsythoside B and 3,4-dicaffeoylquinic acid respectively. Caffeic acid derivatives in Lonicerae Japonicae Flos and Forsythiae Fructus were found to be greatly correlated with anti-influenza A virus efficacy and maybe the substance basis of Shuanghuanglian.

[Absorption and transportation of calycosin in Astragali Radix by using Caco-2 monolayer model].

Flavonoids are a class of important active ingredients in traditional Chinese medicine, pharmacological activity and in vivo process is the focus of research in recent years. Calycosin is the main active ingredients of flavonoids in Astragali Radix, recent studies indicate that it has many kinds of pharmacological activity, but the absorption and transport characteristics in vivo is unclear. The experiment using Caco-2 cell model, with apigenin as internal standard substance, using the method for the determination of drug concentration by HPLC, were studied at different concentrations and absorption transport characteristics of respectively adding different types of protein inhibitors. Data were analyzed by Q test, the results show that low, middle, high concentration of P(app)(BL-AP)/ P(app)(AP-BL) = 1.38 < 1.5, respectively adding different types of protein inhibitors, compared with the control group of P(app)(BL-AP)/ P(app)(AP-BL), there were no significant differences. Calycosin absorption may mainly passive transport, also involved in active transport mechanism, the transport may not be affected by the P-protein, MRP2 protein, SGLT protein.

[Studies on effects of calycosin-7-O-ß-D-glucoside on prim-O-glucosylcimifugin and cimifugin in vivo pharmacokinetics].

Study on the effects of Astragali Radix main active flavone calycosin-7-O-ß-D-glucoside on Saposhnikoviae Radix main active ingredients prim-O-glucosylcimifugin and cimifugin, a UPLC-MS/MS method for simultaneous determination of prim-O-glucosylcimifugin and cimifugin in rat plasma was established, and the comparative pharmacokinetics of prim-O-glucosylcimifugin and cimifugin after oral administration of prim-O-glucosylcimifugin and calycosin-7-O-ß-D-glucoside-prim-O-glucosylcimifugin to rats were carried out, which might be conductive in exploring the rationality of Astragali Radix - Saposhnikoviae Radix herb couple. Twelve male SD rats were divided into two groups. Prim-O-glucosylcimifugin and cimifugin in rat plasma of different time points after oral administration of prim-O-glucosylcimifugin and calycosin-7-O-ß-D-glucoside - prim-O-glucosylcimifugin to rats were determinated. And the main pharmacokinetic parameters were investigated using DAS 3. 2. 4. The established method was rapid, accurate and sensitive for simultaneous determination of prim-O-glucosylcimifugin and cimifugin in rat plasma. The analysis was performed on a Waters Acquity BEH C18 column (2.1 mm x 100 mm, 1.7 µm) with the mixture of acetonitrile and 0.1% formic acid/water as mobile phase, and the gradient elution at a flow rate of 0.3 mL x min(-1). The analytes were detected by tandem mass spectrometry with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM) mode. Compared with prim-O-glucosylcimifugin group, the AUC(0-t)., and AUC(0-∞) of p-O-glucosylcimifugin as well as the C(max) of cimifugin significantly increased (P < 0.05) in calycosin-7-O-ß-D-glucoside-prim-O-glucosylcimifugin group. Calycosin-7-O-ß-D-glucoside could enhance the absorption of prim-O-glucosylcimifugin and cimifugin and improve the bioavailability, explaining preliminarily the rationality of Astragali Radix-Saposhnikoviae Radix herb couple.

[Studies on effects of Achyranthes bidentata on tongsaimai pellets main active ingredients chlorogenic acid, isoliquiritin, harpagoside and glycyrrhizin in vivo pharmacokinetics].

To study on the effects of Achyranthes bidentata on Tongsaimai pellets main active ingredients chlorogenic acid, isoliquiritin, harpagoside and glycyrrhizin in rats in vivo pharmacokinetic behaviors, a method for the simultaneous determination of chlorogenic acid, isoliquiritin, harpagoside and liquiritigenin in rat plasma was established by UPLC-MS/MS. The analysis was performed on a waters Acquity BEH C18 column (2.1 mm x 100 mm, 1.7 microm) with the mixture of acetonitrile and 0.1% formic acid/water as mobile phase, and the gradient elution at a flow rate of 0.3 mL x min(-1). The analytes were detected by tandem mass spectrometry with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM) mode. It turned out that the analytes of Tongsaimai pellets groups C(max) and AUC(Q-infinity) values were higher than that with A. bidentata group, and the C(max) values of chlorogenic acid had significantly difference (P < 0.05), the AUC(0-infinity) values of chlorogenic acid and glycyrrhizin had significantly difference (P < 0.05); The T(max) and CL values of two groups had no significantly difference. Results showed that the established method was specific, rapid, accurate and sensitive for the studies of Tongsaimai pellets four main active ingredients in rat in vivo pharmacokinetic, and A. bidentata have varying degrees of effects on Tongsaimai pellets four main active ingredients in rat in vivo pharmacokinetic behaviors.

Surgical Treatment of Brucellar Cervical Epidural Abscess.

OBJECTIVES: Brucellar cervical epidural abscess (CEA) is a rare condition with potentially permanent neurological damage if left untreated. This study aims to define the clinical presentation of brucellar CEA and evaluate the outcome of surgical treatment, specifically decompression and fusion surgery. The findings will contribute to understanding whether all patients with brucellar CEA could benefit from this surgical intervention. METHODS: A retrospective study on brucellar spondylitis was conducted at the First Hospital of Jilin University from August 2018 to August 2022. During this period, a total of 37 patients were diagnosed with brucellar spondylitis at the hospital. Out of the 37 cases, six patients (16.2%) were confirmed to have CEA through cervical magnetic resonance imaging examination and serology test results.. RESULTS: Six patients were diagnosed with brucellar CEA (16.2%), of whom 5 successfully underwent anterior cervical decompression and fusion surgery. One patient had a large prevertebral abscess that could only be drained. In combination with effective antibiotic therapy, the clinical performance of the 5 patients who underwent surgery improved after the surgery. The remaining one patient required delayed surgery due to instability of the cervical spine. The follow-up period of all the 6 patients was 6 months. CONCLUSIONS: Brucellosis should be considered as a potential cause of CEA, especially in endemic areas. Timely detection and effective management of this condition are crucial in order to minimize the associated morbidity and mortality. For patients with detectable brucellar CEA, we recommend decompression and fusion surgery.

Embryotropic actions of follistatin: paracrine and autocrine mediators of oocyte competence and embryo developmental progression.

Despite several decades since the birth of the first test tube baby and the first calf derived from an in vitro-fertilised embryo, the efficiency of assisted reproductive technologies remains less than ideal. Poor oocyte competence is a major factor limiting the efficiency of in vitro embryo production. Developmental competence obtained during oocyte growth and maturation establishes the foundation for successful fertilisation and preimplantation embryonic development. Regulation of molecular and cellular events during fertilisation and embryo development is mediated, in part, by oocyte-derived factors acquired during oocyte growth and maturation and programmed by factors of follicular somatic cell origin. The available evidence supports an important intrinsic role for oocyte-derived follistatin and JY-1 proteins in mediating embryo developmental progression after fertilisation, and suggests that the paracrine and autocrine actions of oocyte-derived growth differentiation factor 9, bone morphogenetic protein 15 and follicular somatic cell-derived members of the fibroblast growth factor family impact oocyte competence and subsequent embryo developmental progression after fertilisation. An increased understanding of the molecular mechanisms mediating oocyte competence and stage-specific developmental events during early embryogenesis is crucial for further improvements in assisted reproductive technologies.

Enhancement by Glycyrrhizae Radix of hepatic metabolism of hypaconitine, a major bioactive and toxic component of Aconiti Laterlis Radix, evaluated by HPLC-TQ-MS/MS analysis.

Glycyrrhizae Radix (GR) is often prescribed together with Aconiti Laterlis Radix (ALR) (a so-called compatible drug pair) in traditional Chinese medicinal practice to reduce toxicity of ALR. However, the mechanisms involved remain to be addressed. In this study, the metabolic interactions between GR-ALR drug pair were investigated for the first time. First, an HPLC-TQ-MS/MS method was developed to analyze hypaconitine, a major bioactive and toxic component of ALR, in rat liver S9. Then the in vitro metabolic rates of hypaconitine by different rat liver S9 were compared using the established method. The experiments were designed in four groups: pure hypaconitine (group I) and ALR extract (group II) incubated with liver S9 of normal rats, and pure hypaconitine (group III) and ALR extract (group IV) incubated with liver S9 of GR-pretreated rats. When incubated for more than 4 h, the metabolic rates of hypaconitine in group III were significantly higher than those in group I, and when incubated for more than 2 h, the metabolic rates of hypaconitine in group IV were significantly higher than those in group II, suggesting that GR can enhance metabolic rate of hypaconitine, the mechanism of which might be related to hepatic metabolizing enzyme induction by GR.

[Application of oral micro-carrier drug delivery system in studies on traditional Chinese medicine].

Drug-loading micro-particles are a targeted, positioned and controlled-release drug delivery carrier with a wide application prospect. Various micro-carrier drug delivery systems have their own advantages in promoting absorption, improving stability, targeting and controlled release. Accordingly, it is of far-reaching significance for the studies on micro carrier drug delivery systems to build oral traditional Chinese medicine (TCM) compound micro-carrier drug delivery systems with effective TCM components and effective fractions. This article introduces several features and advantages of oral micro-carrier drug delivery systems, and summarizes their application in the field of TCMs.

[Advance in studies on gut microbiota in de-glycosylation of traditional Chinese medicine glycosides].

Glycosides are important active components in traditional Chinese medicine (TCM). Their pharmacological activity, pharmacokinetic characteristics and in vivo existence become hotspots of current studies. The metabolic pathways of these glycosides are de-glycosylation mainly mediated by gut microbiota. After glycosides were metabolized into aglycones, they could be absorbed more easily and show better pharmacological effects. In this article, we reviewed the main glycosidase in gut microbiota which helps metabolize TCM glycosides, relevant bacterial strains which generate glycosidase, as well as the de-glycosylated metabolic pathways of the representative glycosides, on the basis of gut microbiota's important roles in in vivo metabolism and efficacy of TCM glycosides. We also preliminarily solved problems in studies on de-glycosylation of TCM glycosides.

[Application of spectrum-effect relationship in Chinese medicine research and related thinking].

Fingerprint technology is the key technology in modern Chinese medicine research, while spectrum-effect relationship research is the advanced stage of fingerprint research. Spectrum-effect relationship research can reveal the relationship between fingerprint and pharmacological effect through multiple statistical analyses, which can be used in Chinese medicine research. Spectrum-effect relationship has been used in many areas of Chinese medicine research, such as effective basis of single and compound Chinese medicine research, component compatibility research, processing mechanism research, pharmacological effect forecast research, technology optimization research, and so on. This paper systematically reviewed the application of spectrum-effect relationship in Chinese medicine research, and indicated some problems in spectrum-effect relationship research. At last, the authors give an outlook of the future of spectrum-effect relationship research.

Can e-commerce reduce urban CO2 emissions? Evidence from National E-commerce Demonstration Cities policy in China.

The existing studies ignore the potential impact of e-commerce on CO2 emissions. Based on panel data of 284 cities at the prefecture level and above in China from 2003 to 2019, we regard National E-commerce Demonstration Cities (NEDC) policy as a quasi-natural experiment and empirically examine the impact and mechanism of NEDC policy on urban CO2 emissions by using multi-period difference-in-difference (DID) model and mediating effect model. The results show that, under the premise of satisfying parallel trends, the NEDC policy significantly reduces urban CO2 emissions. Compared with the non-pilot cities, the NEDC policy leads to decreases in urban CO2 emissions by 0.83%. The result still holds after a series of robustness tests, which include placebo test, propensity score matching (PSM) DID estimation, and instrumental variable estimation. The NEDC policy reduces urban CO2 emissions through promoting industrial structure upgrading, green technology innovation, and economic agglomeration. Heterogeneity analysis shows that the reduction effect of NEDC policy on urban CO2 emissions is stronger in non-western cities, larger scale cities, and resource-based cities.