AIM To observe the effects of melatonin on acute and chronic injuries induced by oxygen and glucose deprivation (OGD) in co-cultured neuron and glia and to explore the probable mechanisms of melatonin in antagonizing the injuries. METHODS The injury model of cultured neuron and co-cultured neuron and glia was made by administration of sodium dithionite and glucose-deprived Earles solution. In neuron and glia co-culture, two different models, acute injury model at the phase of OGD and chronic injury model after 'reperfusion' were established. The levels of nitric oxide (NO) and the activity of lactate dehydrogenase (LDH) were measured by Griess reagent and LDH kits respectively. The content of malondialdehyde (MDA) was determined by TBA method. Cell viability was analyzed using colorimetric MTT assay. RESULTS Melatonin increased the level of NO at the concentration of 10 -6 , 10 -7 mol?L -1 and decreased the level of MDA content elevated by OGD at the concentration of 10 -6 , 10 -7 , 10 -8 mol?L -1 in vitro cultured cortical neurons. In the chronic injury model after 'reperfusion' melatonin (10 -6 , 10 -7 , 10 -8 mol?L -1 ) significantly decreased LDH activity and increased MTT value in neurons and glia co-cultured. But in the acute injury model, melatonin obviously increased LDH activity and decreased MTT value. CONCLUSION Melatonin protection for neuron from injuries induced by oxygen and glucose deprivation may be related to increase in the level of NO and decrease in the content of MDA. Melatonin can antagonize the injury in the chronic injury model after 'reperfusion', but exaggerate the injury in the acute injury model. These may be all related to its antioxidant action. Our results also suggest that melatonin may probably inhibit activation of microglia.

Aim To observe the effect and primary mechanism of arctigenin ( ARG) in C6 rat glioma. At the same time, to investigate the effect of ARG com-bined with temozolomide. Methods C6 glioma rat model was established, and 90 rats were divided into six groups, which were subcutaneously administered with model, low and high ARG (0. 05 and 0. 1 mg· kg-1 , sc) , temozolomide (20 mg·kg-1 , p. o. ) , low ARG combined with temozolomide(TMZ / ARG 0. 05) and high ARG combined with temozolomide ( TMZ /ARG 0. 1 ) . The tumor specimens of brain were col-lected after tumor graft. Proliferating cell nuclear anti-gen ( PCNA ) , glial fibrillary acidic protein ( GFAP ) and CD40 in tumor specimens were determined by im-munohistochemistry. Results ① Compared with the model group, the tumor sizes of rats in the arctigenin treatment groups were decreased ( P<0. 05 ) . ②ARG
significantly decreased PCNA and CD40 expression ( P<0. 05 ) and increased GFAP expression ( P<0. 05 ) .③ Compared with model group, arctigenin combined with temozolomide decreased the tumor sizes ( P <0. 01 ) , and the tumor inhibition rate was higher than that of the arctigenin and temozolomide. At the same time, arctigenin combined with temozolomide de-creased PCNA and CD40 expression ( P <0. 01 ) and increased GFAP expression ( P <0. 05 ) , which was better than arctigenin and temozolomide. Conclusion Arctigenin inhibits rat glioma growth, and synergizes with temozolomide, which may be associated with in-hibiting PCNA and CD40 expression and strengthening GFAP expression.

This study investigated the effect of arctigenin (Arc) on the cell activation, cytokines expression, proliferation, and cell-cycle distribution of mouse T lymphocytes. Mouse lymphocytes were prepared from lymph node and treated with Phorbol-12-myristate-13-acetate (PMA)/Ionimycin (Ion) and/or Arc. CD69, CD25, cytokines, proliferation and cell cycle were assayed by flow cytometry. The results showed that, at concentrations of less than 1.00 micromol x L(-1), Arc expressed non-obvious cell damage to cultured lymphocytes, however, it could significantly down-regulate the expression of CD69 and CD25, as well as TNF-alpha, IFN-gamma, IL-2, IL-4, IL-6 and IL-10 on PMA/Ion stimulated lymphocytes. At the same time, Arc could also inhibit the proliferation of PMA/Ion-activated lymphocytes and exhibited lymphocyte G 0/G1 phase cycle arrest. These results suggest that Arc possesses significant anti-inflammatory effects that may be mediated through the regulation of cell activation, cytokines expression and cell proliferation.

The traditional experimental teaching mode of forensic science and biological evidence is mostly confined to experimental operation, which is not capable of cultivating students' comprehensive quality and post competency. Therefore, it is urgent to seek an innovative teaching and training mode. At present, the experimental teaching of forensic science and biological evidence is dominated by teachers. There are some problems, such as insufficient training of students' scientific thinking and innovation ability, single teaching and evaluation model, and disconnection from the practical application. This paper proposes an experimental teaching design scheme of forensic science and biological evidence based on post competency training. The course is implanted in the framework of simulated cases, and the virtual simulation experiment platform and group discussion learning method are used to achieve a training model oriented by social needs and centered on students. In the preliminary study on the students who were trained in this mode of selected sections, we found that, compared with traditional teaching, the time for students to complete the prescribed experimental operation in this teaching mode was shortened by 4 minutes on average, and the average score of theoretical course test case analysis questions was increased by 1.5 points. In conclusion, the instructional design of the experiment teaching forensic science and biological evidence can effectively improve students' post-competency, and it deserves further exploration and application.

OBJECTI VE To optimize the extraction technology of the leaves of Dimocarpus longan according to flavonoids and phenolic acids. METHODS The contents of gallic acid ，protocatechuic acid ，ethyl gallate ，quercetin，luteolin and kaempferol in the leaves of D. longan were determined by HPLC. Based on single factor test ，with the ethanol volume fraction ，solid-liquid ratio and extraction time as factors ，using comprehensive scores of the contents of above six components as indexes ，the extraction technology of the leaves of D. longan was optimized by Box-Behnken response surface methodology. RESULTS The optimal extraction technology included ethanol volume fraction of 100％，solid-liquid ratio of l ∶ 7（g/mL），extraction time of 90 min， extraction temperature of 80 ℃. After 3 times of validation tests ，the average comprehensive score was 97.54（RSD＝0.33％，n＝ 3），relative error of which with predicted score （99.05）was 1.55％. CONCLUSIONS Box-Behnken response surface methodology combined with multi-index comprehensive score can be used for the extraction technology of the leaves of D. longan ，and the optimized extraction technology is stable and feasible.

OBJECTIVE To establish the quality standard of the leaves of Litchi chinensis Sonn.. METHODS The identification of medicinal properties, microscopic characteristics, TLC and content determination method of the leaves of Litchi chinensis Sonn. was conducted. The moisture, total ash, acid insoluble ash and extract of the leaves of Litchi chinensis Sonn. were determined according to Chinese Pharmacopoeia(Volume IV), 2020. RESULTS The leaves of Litchi chinensis Sonn. under forest exhibited specific properties in characteristics, microscopic features and TLC results. The moisture content of the medicinal materials was 2.66%-6.42%, the total ash content was 2.96%-4.52%, the acid insoluble ash content was 0.17%-0.94%, the water soluble extract was 15.38%-19.87%, and the alcohol soluble extract was 24.94%-30.33%. The eight components of gallic acid, protocatechin, catechin, epicatechin, rutin, astragalin, quercetin and kaempferol had a good linear relationship in 0.003 3-0.052 0 mg·mL-1, 0.006 9-0.109 6 mg·mL-1, 0.013 0-0.208 0 mg·mL-1, 0.057 5-0.920 0 mg·mL-1, 0.013 4-0.213 6 mg·mL-1, 0.013 2-0.211 2 mg·mL-1, 0.002 9-0.045 6 mg·mL-1, 0.003 6-0.056 8 mg·mL-1(r>0.999). The average sample recovery rate was 97.43%-102.97% and the RSD was 1.70%-2.90%. CONCLUSION The established quality standard of the leaves of Litchi chinensis Sonn. medicinal material has good specificity, accuracy and reproducibility, which can be used for quality control research of the leaves of Litchi chinensis Sonn..

Objective To investigate the active ingredients of Jingfang Baidu San for the prevention and treatment of COVID-19 by using network pharmacology and molecular docking, and to provide references for clinical applications. Methods The chemical constituents and action targets of all medicinal materials in Jingfang Baidu San were retrieved from TCMSP. Uniprot database was used to search the corresponding genes of targets. Cytoscape software was used to construct the network of medicinal materials-compounds-targets for visualization. The target proteins of COVID-19 were searched by disease databases. The intersection of both was considered to be analyzed to establish the protein-protein interaction (PPI) network by STRING database. GO function enrichment analysis and KEGG pathway enrichment analysis were performed through Metascape database to predict its mechanism. The effective strength of core constituents on preventing COVID-19 was calculated by molecular docking method. Results A total of 159 effective ingredients and 277 potential targets were obtained in Jingfang Baidu San within the given screening conditions [oral bioavailability (OB) ≥30%; drug-like (DL) ≥ 0.18], including 55 core targets with the intersection of 273 targets of COVID-19. According to the results of GO and KEGG enrichment analysis performed on the core targets, 1376 GO items and 136 KEGG pathways were obtained, involving infectious diseases, cancer, cell progress, immune system, signaling pathways etc. The results of molecular docking indicated strong binding capacity between the core ingredients and SARS-CoV-2 3CL hydrolase or angiotensin-converting enzyme II (ACE2). The hydrogen binding and hydrophobic effect were the main forms of the interaction. Conclusion The active ingredients in Jingfang Baidu San can inhibit the binding between SARS-CoV-2 protein and ACE2, thus regulating multiple targets and signal pathways, which plays a role in the prevention and the treatment of COVID-19.

OBJECTIVE To study the metabolites derived from the ethanol extract from the leaves of Dimocarpus longan preliminarily in rats in vivo ，and to provide reference for elucidating the possible metabolic mechanism of the leaves of D. longan in lowering blood glucose . METHODS Ultra high performance liquid chromatography quadrupole time -of-flight mass spectrometry （UPLC-Q-TOF-MS/MS） was adopted by taking ethanol extract of D. longan leaves，the feces and urine of rats at 0-72 h and 0-48 h after intragastric administration of 33.8 g/kg ethanol extract of D. longan leaves（by extract ），the feces and urine of rats at the corresponding time after intragastric administration of normal saline （blank control ） as samples . The accurate relative molecular weight ，formula and fragment information of the compounds were collected ， and the compounds were speculated and i dentified by matching with the database and spectrum library of the instrument ，and comparing with the reference substance and relevant literature . RESULTS A total of eight compounds were identified in urine and feces of rats ，including 2 prototype components and 6 metabolites. Three compounds （including two prototype components as quercetin ，luteolin and one metabolite as luteolin or kaempferol） in feces of rats were identified ；five compounds （all metabolites ） in urine of rats were identified ，involving metabolites of quercetin ，luteolin or kaempferol . Metabolites mainly included the products of methylation ，glucuronidation and oxidation. CONCLUSIONS After intragastric administration ，the ethanol extract from the leaves of D. longan is mainly metabolized in rats through methylation ，glucuronidation and other pathways . The identified compounds are mostly metabolites of quercetin and luteolin .