基于类药有效组分特征图谱的中药复方质量表征模式研究

目的以开心散为研究载体,建立基于类药有效组分特征图谱的中药复方质量表征模式。方法采用东莨菪碱造模致SD大鼠记忆障碍,灌胃给予开心散提取物,取含药血清;同时采用改良的外翻肠囊法,制备开心散小肠吸收液,测定HPLC特征图谱,并与开心散提取物HPLC特征图谱进行对比分析。结果筛选出开心散类药有效组分中14个化学成分,鉴定了其中的5个特征成分,进而采用血清药理方法对所筛选的类药有效组分进行药效验证,并进一步建立类药有效组分特征图谱,形成基于类药有效组分特征图谱的开心散质量表征模式。结论所建立的基于类药有效组分特征图谱的中药复方质量表征模式,科学、合理、可行,更能体现中药复方质量特性,可作为中药复方质量控制研究的一种新思路与方法。

Identification of Potential Flavonoid Inhibitors of the SARS-CoV-2 Main Protease 6YNQ:A Molecular Docking Study

Objective Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the causative agent for coronavirus disease 2019(COVID-19),is responsible for the recent global pandemic.As there are no effective drugs or vaccines available for SARS-CoV-2,we investigated the potential of flavonoids against SARS-CoV-2 main protease 6YNQ.Methods In silico molecular simulation study against SARS-CoV-2 main protease 6YNQ.Results Among the 21 selected flavonoids,rutin demonstrated the highest binding energy(−8.7 kcal/mol)and displayed perfect binding with the catalytic sites.Conclusions Our study demonstrates the inhibitory potential of flavonoids against SARS-CoV-2 main protease 6YNQ.These computational simulation studies support the hypothesis that flavonoids might be helpful for the treatment of COVID-19.

Limitations of the use of MTT assay for screening in drug discovery

The 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide （MTT） assay is a routine cell viability assay for cell proliferation and cytotoxicity, which is widely used in many fields, especially in screening for drug discovery. However, this assay exhibits limitations in the presence of particular compounds and under certain assay conditions, which may yield false screening results. For example, polyphenols that are extracted from natural sources can react with MTT in the absence of living cells and thus interfere with the screening results. We measured the absorbance of 15 polyphenols extracted from green tea and showed that the phenolic hydroxyl groups in the polyphenols are responsible for the reduction of MTT to formazan. When three or more phenolic hydroxyl groups were present on a conjugated polyphenol, a significantly increased MTT reduction was observed. Moreover, the type of medium also had an effect on the absorbance value, in the following order： ct-MEM ＋ 10% FBS〉 a-MEM〉DMEM/F12〉PBS. The absorbance of the MTT assay recorded at 570 nm is more sensitive than that measured at 595 nm. These results will improve the cell-based assay of polyphenols and clarify the limitations of the MTT assay as a method of screening in drug discovery.

Comparative pharmacophore modeling of human adenosine receptor A1 and A3 antagonists

Adenosine receptors are promising therapeutic targets in drug discovery. In this study, three-dimensional pharmacophore mod- els of human adenosine receptor A1 and A3 antagonists were developed based on 26 and 23 diverse compounds, respectively. The best A1 pharmacophore model （A1-Hopyl） consists of four features： one hydrogen bond donor, one hydrophobic point and two ring aromatics, while the best A3 pharmacophore model （A3_Hopyl） also has four features： one hydrogen bond ac- ceptor, one hydrophobic point and two ring aromatics. The correlation coefficients were 0.840 for A1 test set with 146 diverse compounds and 0.827 for A3 test set with 238 diverse compounds. In the simulated virtual screening experiments, high en- richment factors of 6.51 and 6.90 were obtained for A1_Hopyl and A3_Hopyl models, respectively. Moreover, two models also showed high subtype-selectivity in the simulated virtual screening experiments. These results could be helpful for the dis- covery of novel potent and selective A1 and A3 antagonists.