Rapid screening of bioactive compounds from natural products by integrating 5-channel parallel chromatography coupled with on-line mass spectrometry and microplate based assays

A high throughput method was developed for rapid screening and identification of bioactive compounds from traditional Chinese medicine, marine products and other natural products. The system, integrated with five-channel chromatographic separation and dual UV–MS detection, is compatible with in vitro 96-well microplate based bioassays. The stability and applicability of the proposed method was validated by testing radical scavenging capability of a mixture of seven known compounds (rutin, dihydroquercetin, salvianolic acid A, salvianolic acid B, glycyrrhizic acid, rubescensin A and tangeretin). Moreover, the proposed method was successfully applied to the crude extracts of traditional Chinese medicine and a marine sponge from which 12 bioactive compounds were screened and characterized based on their anti-oxidative or anti-tumor activities. In particular, two diterpenoid derivatives, agelasine B and (−)-agelasine D, were identified for the first time as anti-tumor compounds from the sponge Agelas mauritiana, showing a considerable activity toward MCF-7 cells (IC₅₀ values of 7.84 ± 0.65 and 10.48 ± 0.84 μM, respectively). Our findings suggested that the integrated system of 5-channel parallel chromatography coupled with on-line mass spectrometry and microplate based assays can be a versatile and high efficient approach for the discovery of active compounds from natural products.     

Optimising key performance indicator adherence with application to emergency department congestion

Many operational queueing systems must adhere to systems of Key Performance Indicators (KPIs), each comprising a waiting time limit and a level of compliance specifying the minimal fraction of customers that must meet the standard. KPIs are frequently employed as measures of system performance in health care settings. The primary flaw with KPIs is that they represent a system of constraints with no objective function. KPIs say nothing about customers who exceed their limit, so long as such occurrences are sufficiently rare, when in fact customers who miss their time limit in a health care setting are of greater importance, not lesser. We address this flaw by minimising the mean number of customers present who have exceeded their respective limits; we consider also weighted averages of the numbers in excess for each class. We then show that one logical service discipline to achieve this goal is the Accumulating Priority Queueing (APQ) discipline. We carry out numerical examples to investigate the utility of our method. We then apply the optimisation approach to the case of an Emergency Department in Southern Ontario, Canada.     

Analysis of active components of rhinoceros, water buffalo and yak horns using two-dimensional electrophoresis and ethnopharmacological evaluation

Cornu Rhinoceri Asiatici (rhinoceros horn, RH), Cornu Bubali (water buffalo horn, WBH), and Cornu Bovis grunniens (yak horn, YH) are traditional Chinese medicine (TCM), and have been used in China for thousands of years. In this study, ethnopharmacological experiments were used to evaluate and verify the traditional efficacies of horns. Area under curve (AUC) was used to quantify the pharmacological efficacy strength of three horns. Two-dimensional electrophoresis (2-DE) was used to analyze the protein components in horns, as a result, 14 common protein spots in rhinoceros horn, water buffalo horn, and yak horn electrophoresis gels were found by image analysis. Then linear regression analysis was used to establish the correlation between pharmacological efficacies and components in the horns, and five potential active components were selected from the 14 common protein spots. Finally, two protein spots from five were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this study, a simple method to construct correlation between components and efficacy strength was explored by linear regression analysis, which could be applied to screen potential active components of animal horns.     

Rapid identification of chemical compositions in callicarpa kwangtungensis Chun by ultra‐high‐performance liquid chromatography with Q Exactive hybrid quadrupole orbitrap high‐resolution accurate mass spectrometry

Callicarpa kwangtungensis Chun is a traditional Chinese medicine that has various therapeutic effects. Despite its wide use in Chinese medicine, the study is still quite limited, especially its chemical compositions. In this research, an ultra‐high‐pressure liquid chromatography coupled with Q Exactive hybrid quadrupole‐orbitrap high‐resolution accurate mass spectrometry tandem mass spectrometry method was utilized to analyze its chemical compositions for the first time. As a result, a total of 124 compounds, including 20 phenylethanoid glycosides, 31 flavonoids, 36 organic acids, 26 terpenoids and 11 phenols, were identified or tentatively characterized in 30 min. Among them, 49 compounds, including 5 phenylethanoid glycosides, 12 flavonoids, 16 organic acids, 12 terpenoids, and 4 phenols, were identified in Callicarpa kwangtungensis Chun for the first time. Besides, the fragmentation pathways were also discussed. This research established a rapid and reliable method to analyze the chemical compositions of complicated herb without the process of isolation, and provide abundant information on the chemical material basis for further bioactivity and quality control studies.     

An ultra high performance liquid chromatography with tandem mass spectrometry method for simultaneous determination of thirteen components extracted from Radix Puerariae in rat plasma and tissues: Application to pharmacokinetic and tissue distribution study

A rapid and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for simultaneous determination of thirteen bioactive components (gallic acid, protocatechuic acid, puerarin, p‐hydroxycinnamic acid, daidzin, ononin, daidzein, naringenin, genistein, apigenin, formononetin, biochanin A, and β‐sitosterol) of Radix Puerariae extract in rat plasma and tissues. The plasma and tissues samples were pretreated by protein precipitation extraction, and umbelliferone and rutin were used as internal standards. Sample separation was performed on a ZORBAX RRHD Eclipse plus C₁₈ column (2.1 mm × 50 mm, 1.8 µm, Agilent) with a mobile phase consisting of methanol–water (containing 0.1% formic acid). The mass spectrometry analysis was conducted in positive and negative ionization modes with multiple reaction monitoring. The lower limit of quantitation range for the 13 analytes was 0.2?35 ng/mL. The intra‐ and inter‐day precision of all the analytes were less than 10.92%, with an accuracy ranging from ?13.10 to 11.96%. Both the recovery and matrix effect were within acceptable limits. This method was successfully applied to pharmacokinetic and tissue distribution study of the 13 bioactive components in rats after oral administration of R. Puerariae extract.     

Separation of acteoside and linarin from Buddlejae Flos by high‐speed countercurrent chromatography and their anti‐inflammatory activities

Buddleja officinalis Maxim., a deciduous, flowering shrub, is used as a traditional Chinese medicine; the bioactivity of B. officinalis is primarily due to flavonoids and phenylethanoid glycosides. In the study, acteoside and linarin were successfully isolated from B. officinalis by high‐speed countercurrent chromatography with a two‐phase solvent system composed of ethyl acetate: n‐butanol: water (5:0.8:5, v/v/v). The purities of acteoside and linarin were determined to be 97.3 and 98.2%, respectively, using one‐step high‐speed countercurrent chromatography separation. The chemical structures of the two compounds were identified by electrospray ionization‐mass spectrometry and nuclear magnetic resonance. After separation, the anti‐inflammatory effects of the two compounds were evaluated using lipopolysaccharide‐induced human umbilical vein endothelial cells. Acteoside and linarin inhibited the expression of nitric oxide, tumor necrosis factor α and interleukin 1β, which demonstrated that acteoside and linarin possessed anti‐inflammatory activity.     

Comprehensive evaluation of the antioxidant capacity of Sceptridium ternatum using multiple colorimetric methods and 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography analysis

Sceptridium ternatum is a medicinal herb with multiple health benefits. However, its antioxidant activity and active components have not been clarified. In this study, the antioxidant capacity of S. ternatum was comprehensively investigated using multiple colorimetric methods and 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography analysis. First, the phenolic content, flavonoid content, and radical scavenging ability of S. ternatum were parallelly determined using colorimetric methods performed in 96‐well microplates. The flavonoid content, rather than the phenolic content, was highly correlated with its antioxidant activity. Sceptridium ternatum was shown to be a rich source of flavonoids, with a highest flavonoid yield of 3.44 ± 0.11 mg/g. Subsequently, 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography experiment and quadrupole time‐of‐flight mass spectrometry analyses were carried out for rapid screening of the individual antioxidants. A total of 14 O‐glycosyl flavonoids with quercetin or kaempferol aglycone have been characterized. Particularly, quercetin 3‐O‐rhamnoside‐7‐O‐glucoside exhibited the most potent antioxidant ability. Its half‐maximal effective concentrations for scavenging 1,1‐diphenyl‐2‐picrylhydrazyl and 2,2?‐azino‐bis (3‐ethylbenzthiazoline‐6‐sulfonic acid) radicals were 70.55 ± 2.69 and 106.90 ± 1.76 µg/mL, respectively, which were comparable with those of l ‐ascorbic acid. Our results indicated that the combined colorimetric and chromatographic methods provided a practical strategy for the discovery of bioactive compounds from natural products.     

Combination of c oxidase subunit I based deoxyribonucleic acid barcoding and HPLC techniques for the identification and quality evaluation of Pheretima aspergillum

This study aimed to identify Pheretima aspergillum (Guang‐Pheretima) and its adulterants using the cytochrome c oxidase subunit I based deoxyribonucleic acid barcoding technology, and further to evaluate their quality using an optimized high‐performance liquid chromatography method. For deoxyribonucleic acid barcoding identification, the Kimura‐2‐Parameter model was used to analyze genetic distance, and phylogenetic neighbor‐joining tree was constructed for species identification of 20 labeled Guang‐Pheretima samples. A high‐performance liquid chromatography method was developed for the simultaneous determination of seven nucleoside components for quality evaluation. Compared with the GenBank database, 10 samples were identified as real Guang‐Pheretima (P. aspergillum), and the others as the adulterants‐Metaphire magna. The maximum intraspecific genetic distances of c oxidase subunit I sequence for P. aspergillum were smaller than the minimum interspecific genetic distances between P. aspergillum and M. magna. Ten P. aspergillum and 10 M. magna samples were clearly clustered in the neighbor‐joining tree. The contents of seven nucleosides components in P. aspergillum were significantly higher than that in its adulterant‐M. magna. The incidence of adulterants for Guang‐Pheretima was high (up to 50%) with an alarming quality. This study provided a powerful idea for the quality evaluation of other highly valuable plant‐ or animal‐derived products for safety concerns to avoid misidentification.     

Quality assessment of raw and baked Aucklandia lappa Decne. by color measurement and fingerprint analysis

Aucklandia lappa Decne. has been used as a traditional Chinese herb for thousands of years in treating various kinds of disorders. According to the Chinese Pharmacopoeia, there are two kinds of processed products, raw and baked Aucklandia lappa Decne., which have different therapeutic effect in clinical application. In this study, based on color measurement and fingerprint analysis, the method to assess the quality of these two processed products was established. In color measurement, the reference ranges of color parameters (L^*, a^*, and b^*), standard color difference values, and mathematical prediction functions of these two processed products were obtain after the color was measured by a spectrophotometer. Meanwhile, high‐performance liquid chromatography fingerprints of these two processed products were established, where there were 12 peaks recognized as the common peaks in both processed products, in which two peaks were identified as costunolide and dehydrocostus lactone, and these two processed products were classified with chemometrics analysis subsequently. Furthermore, the correlation between color parameters and sample compositions was explored and the contents of costunolide and dehydrocostus lactone were determined simultaneously by high‐performance liquid chromatography. Consequently, an integral method including color measurement, high‐performance liquid chromatography fingerprint with chemometrics analysis, and quantitative determination was established.     

The Effects of Prolonged Storage on ARPE-19 Cells Stored at Three Different Storage Temperatures

This study aimed to investigate how prolonged storage of adult retinal pigment epithelial (ARPE-19) cell sheets affects cell metabolism, morphology, viability, and phenotype. ARPE-19 cell sheets were stored at three temperatures (4 °C, 16 °C, and 37 °C) for three weeks. Metabolic status and morphology of the cells were monitored by sampling medium and examining cells by phase-contrast microscopy, respectively, throughout the storage period. Cell viability was analyzed by flow cytometry, and phenotype was determined by epifluorescence microscopy after the storage. Lactate production and glucose consumption increased heavily, while pH dropped considerably, through storage at 37 °C compared to 4 °C and 16 °C. During storage, morphology started to deteriorate first at 4 °C, then at 37 °C, and was maintained the longest at 16 °C. Viability of the cells after three weeks of storage was best preserved at 16 °C, while cells stored at 4 °C and 37 °C had reduced viability. Dedifferentiation indicated by reduced expression of retinal pigment epithelium-specific protein 65 (RPE65), zonula occludens protein 1 (ZO-1), and occludin after three weeks of storage was noticed in all experimental groups compared to control. We conclude that storage temperature affects the metabolic status of ARPE-19 cells and that 16 °C reduces metabolic activity while protecting viability and morphology.