Development and validation of a high-performance thin-layer chromatographic method for the quantitative analysis of vitexin in Passiflora foetida herbal formulations

© 2019 Dehon et al. Introduction: Formative evaluations of clinical teaching for emergency medicine (EM) faculty are limited. The goal of this study was to develop a behaviorally-based tool for evaluating and providing feedback to EM faculty based on their clinical teaching skills during a shift. Methods: We used a three-phase structured development process. Phase 1 used the nominal group technique with a group of faculty first and then with residents to generate potential evaluation items. Phase 2 included separate focus groups and used a modified Delphi technique with faculty and residents, as well as a group of experts to evaluate the items generated in Phase 1. Following this, residents classified the items into novice, intermediate, and advanced educator skills. Once items were determined for inclusion and subsequently ranked they were built into the tool by the investigators (Phase 3). Results: The final instrument, the Faculty Shift Card, is a behaviorally-anchored evaluation and feedback tool used to facilitate feedback to EM faculty about their teaching skills during a shift. The tool has four domains: teaching clinical decision-making; teaching interpersonal skills; teaching procedural skills; and general teaching strategies. Each domain contains novice, intermediate, and advanced sections with 2-5 concrete examples for each level of performance. Conclusion: This structured process resulted in a well-grounded and systematically developed evaluation tool for EM faculty that can provide real-time actionable feedback to faculty and support improved clinical teaching

Prevalence of Comorbidities Associated With Type 2 Diabetes Mellitus In Ksa: A Cross-Sectional Study

Objective: To determine the prevalence of comorbidities associated with type 2 diabetes mellitus among the Saudi adult population. Methods: A cross-sectional study design will be employed to investigate the prevalence of comorbidities associated with Type 2 Diabetes Mellitus (T2DM) within the Kingdom of Saudi Arabia (KSA) population. This design allows for the collection of data at a single point in time, providing insights into the existing relationship between T2DM and comorbidities.Results: The study included 601 participants. The most frequent body mass index BMI value among study participants was overweight 25-29.9 kg/m2 (n= 196, 33%), followed by Normal 18.5-24.9 kg/m2 (n= 177, 29%). The frequent gender among study participants was male years (n= 356, 59%) and female (n= 245, 41%). The most frequent age among study participants was 40-50 years (n= 145, 24%), followed by 18-28 years (n= 140, 23%). The most frequent marital status among study participants was married (n= 360, 60%), followed by single (n= 160, 27%). The perceived physical activity per week among study participants, most of whom did not do any activity (n=231,38%) followed one-time activity (n=98,16%). Conclusion: The results showed that most of the study participants were overweight according to their BMI. The majority of patients had normal blood pressure. Most of the participants suffer from diabetes. In addition, most of the participants do not do any activity, and the majority of participants are non-smokers

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

The Interaction of Human Glutathione Transferase GSTA1-1 with Reactive Dyes

Human glutathione transferase A1-1 (hGSTA1-1) contributes to developing resistance to anticancer drugs and, therefore, is promising in terms of drug-design targets for coping with this phenomenon. In the present study, the interaction of anthraquinone and diazo dichlorotriazine dyes (DCTD) with hGSTA1-1 was investigated. The anthraquinone dye Procion blue MX-R (PBMX-R) appeared to interact with higher affinity and was selected for further study. The enzyme was specifically and irreversibly inactivated by PBMX-R, following a biphasic pseudo-first-order saturation kinetics, with approximately 1 mol of inhibitor per mol of the dimeric enzyme being incorporated. Molecular modeling and protein chemistry data suggested that the modified residue is the Cys112, which is located at the entrance of the solvent channel at the subunits interface. The results suggest that negative cooperativity exists upon PBMX-R binding, indicating a structural communication between the two subunits. Kinetic inhibition analysis showed that the dye is a competitive inhibitor towards glutathione (GSH) and mixed-type inhibitor towards 1-chloro-2,4-dinitrobenzene (CDNB). The present study results suggest that PBMX-R is a useful probe suitable for assessing by kinetic means the drugability of the enzyme in future drug-design efforts

GC quantitative analysis of benzyl isothiocyanate in Salvadora persica roots extract and dental care herbal products

An accurate, sensitive, precise and simple method was developed utilizing Gas Chromatography for the quantitative analysis of benzyl isothicyanate in Siwak extract and dental care herbal products claimed to contain Siwak. Rtx (30.0 m × 0.25 mm ID, 25 µm thickness) column was used and helium as carrier gas at a flow rate of 0.74 mL/min. The retention time of standard benzyl isothicyanate was 13.470 min under the described conditions. Linear regression data analysis indicated a good linear relationship between peak height measurement and concentration of benzyl isothiocyanate in the range of 10–50 µg/ml (R2 = 0.9971). The regression equation was y = 11,471x. The developed GC method was subjected to validation requirements set by the ICH for precision, accuracy, and robustness. The entitled GC analyses expected to be valuable for the determination of benzyl isothiocyanate in Siwak extracts and other formulations containing Siwak extract. The amount of benzyl isothiocyanate reflects the efficacy of the products. Keywords: S. persica, Benzyl isothiocyanate, GC, ICH guidelines, Quantitativ

Probing the Role of the Conserved Arg174 in Formate Dehydrogenase by Chemical Modification and Site-Directed Mutagenesis

The reactive adenosine derivative, adenosine 5′-O-[S-(4-hydroxy-2,3-dioxobutyl)]-thiophosphate (AMPS-HDB), contains a dicarbonyl group linked to the purine nucleotide at a position equivalent to the pyrophosphate region of NAD+. AMPS-HDB was used as a chemical label towards Candida boidinii formate dehydrogenase (CbFDH). AMPS-HDB reacts covalently with CbFDH, leading to complete inactivation of the enzyme activity. The inactivation kinetics of CbFDH fit the Kitz and Wilson model for time-dependent, irreversible inhibition (KD = 0.66 ± 0.15 mM, first order maximum rate constant k3 = 0.198 ± 0.06 min−1). NAD+ and NADH protects CbFDH from inactivation by AMPS-HDB, showing the specificity of the reaction. Molecular modelling studies revealed Arg174 as a candidate residue able to be modified by the dicarbonyl group of AMPS-HDB. Arg174 is a strictly conserved residue among FDHs and is located at the Rossmann fold, the common mononucleotide-binding motif of dehydrogenases. Arg174 was replaced by Asn, using site-directed mutagenesis. The mutant enzyme CbFDHArg174Asn was showed to be resistant to inactivation by AMPS-HDB, confirming that the guanidinium group of Arg174 is the target for AMPS-HDB. The CbFDHArg174Asn mutant enzyme exhibited substantial reduced affinity for NAD+ and lower thermostability. The results of the study underline the pivotal and multifunctional role of Arg174 in catalysis, coenzyme binding and structural stability of CbFDH

Investigation of antioxidant compounds in commercial pomegranate molasses products using matrix-solid phase dispersion extraction coupled with HPLC

Pomegranate is a well known fruit for its unique flavor, taste and health benefits. The medicinal properties of this fruits directly associated with the phenolic content present, with great anti-oxidant potential. The research is intended to develop matrix solid phase dispersion method (MSPD) and HPLC quantification of four major anti-oxidant marker constituents (vitamin C, gallic acid, rutin & ellagic acid) in pomegranate molasses samples. The effects of several important experimental parameters like type of dispersant, sample-dispersant ratio, solvents and its volume, time of extraction were investigated. A C18 column with the specification (5 µm, 250 × 4.0 mm) was used for the separation. A gradient flow of mobile phase was selected after many trials containing 0.1%, v/v solution of orthophosphoric acid and acetonitrile. The flow rate was 1.0 mL/min; and the chromatograms were recorded at 254 nm. The validation parameters, like linearity (r2 = 0.9985, 0.9965, 0.9925 & 0.9986), accuracy (100.3, 99.5, 100.9 & 101.9%), intra-day precision (%RSD = 1.09, 1.02, 1.26 & 0.97), inter-day precision (%RSD = 1.32, 0.83, 1.07, & 1.15) LOD (0.07, 4.50, 0.45 & 0.40 µg/mL), LOQ (0.095, 9.50, 0.85 & 9.5 µg/mL) and robustness (% RSD = 0.92, 0.76, 0.81 & 0.83) respectively for vitamin C, gallic acid, rutin & ellagic acid, were found satisfactory as per ICH guidelines. Keywords: MSPD, HPLC-UV, Pomegranate molasses, Validation, Quality contro

Carduus edelbergii Rech. f. Mediated Fabrication of Gold Nanoparticles; Characterization and Evaluation of Antimicrobial, Antioxidant and Antidiabetic Potency of the Synthesized AuNPs

Background: Due to the high expense, less effectiveness and more side effects of available synthetic medicine, the researchers and communities are focusing on phyto-based natural bioactive compounds, which are considered safer for the treatment of syndromes and chronic diseases. Aim: The current project was aimed to determine the phytochemicals constituents available in the aerial parts of methanol extract of Carduus edelbergii via GC-MS, fabrication of AuNPs mediated with the mentioned extract; characterization and evaluation of antimicrobial, antioxidant and antidiabetic potency of the synthesized AuNPs. Methods: Confirmation of green synthesis of AuNPs, functional groups responsible for the reduction in Au+, size and crystallinity, morphology and quantity of gold (Au) were carried out by Ultraviolet-Visible (UV-Vis) spectroscopy, Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and dispersive X-ray (EDX), respectively, whereas in vitro antioxidant characteristics were assessed by DPPH and ABTS assays. Wistar albino rats were used to test the anti-diabetic properties of the methanol extract and AuNPs. Results: GC-MS revealed that the diluted methanol extract of Carduus edelbergii consists of about 19 chemical constituents. Among the identified compounds, the 13-Docosenoic acid, methyl ester, (Z)—has the highest concentration (38.16%), followed by 9-Octadecenoic acid, methyl ester, (E)—(15.72%) and n-Hexadecanoic acid (15.07%). Methanol extract and its fabricated nanoparticles showed significant antioxidant and antimicrobial activities. In vivo antidiabetic study revealed a noteworthy (p < 0.05) decline in body weight and HDL and elevated concentration of blood glucose, bilirubin, creatinine, urea, triglyceride, VLDL, LDL, ALP, ALT and AST in diabetic control. The said changes were recovered significantly (p < 0.05) by treatment of diabetic rats with methanol extract (150 and 300 mg/Kg BW) and AuNPs of Carduus edelbergii (5 and 10 mg/Kg BW). Conclusion: The green synthesized AuNPs exhibit significant antioxidant, antimicrobial and antidiabetic characteristics

Modeling, Molecular Dynamics Simulation, and Mutation Validation for Structure of Cannabinoid Receptor 2 Based on Known Crystal Structures of GPCRs

The cannabinoid receptor 2 (CB2) plays an important role in the immune system. Although a few of GPCRs crystallographic structures have been reported, it is still challenging to obtain functional transmembrane proteins and high resolution X-ray crystal structures, such as for the CB2 receptor. In the present work, we used 10 reported crystal structures of GPCRs which had high sequence identities with CB2 to construct homology-based comparative CB2 models. We applied these 10 models to perform a prescreen by using a training set consisting of 20 CB2 active compounds and 980 compounds randomly selected from the National Cancer Institute (NCI) database. We then utilized the known 170 cannabinoid receptor 1 (CB1) or CB2 selective compounds for further validation. Based on the docking results, we selected one CB2 model (constructed by β1AR) that was most consistent with the known experimental data, revealing that the defined binding pocket in our CB2 model was well-correlated with the training and testing data studies. Importantly, we identified a potential allosteric binding pocket adjacent to the orthosteric ligand-binding site, which is similar to the reported allosteric pocket for sodium ion Na⁺ in the A_2AAR and the δ-opioid receptor. Our studies in correlation of our data with others suggested that sodium may reduce the binding affinities of endogenous agonists or its analogs to CB2. We performed a series of docking studies to compare the important residues in the binding pockets of CB2 with CB1, including antagonist, agonist, and our CB2 neutral compound (neutral antagonist) XIE35-1001. Then, we carried out 50 ns molecular dynamics (MD) simulations for the CB2 docked with SR144528 and CP55940, respectively. We found that the conformational changes of CB2 upon antagonist/agonist binding were congruent with recent reports of those for other GPCRs. Based on these results, we further examined one known residue, Val113^3.32, and predicted two new residues, Phe183 in ECL2 and Phe281^7.35, that were important for SR144528 and CP55940 binding to CB2. We then performed site-directed mutation experimental study for these residues and validated the predictions by radiometric binding affinity assay

Production, Bioprocessing and Anti-Proliferative Activity of Camptothecin from Penicillium chrysogenum, “An Endozoic of Marine Sponge, Cliona sp.”, as a Metabolically Stable Camptothecin Producing Isolate

Exploring the metabolic potency of fungi as camptothecin producers raises the hope of their usage as an industrial source of camptothecin, due to their short-life span and the feasibility of metabolic engineering. However, the tiny yield and loss of camptothecin productivity of fungi during storage and sub-culturing are challenges that counteract this approach. Marine fungi could be a novel source for camptothecin production, with higher yield and reliable metabolic sustainability. The marine fungal isolate Penicillium chrysogenum EFBL # OL597937.1 derived from the sponge “Cliona sp.” has been morphologically identified and molecularly confirmed, based on the Internal Transcribed Spacer sequence, exhibiting the highest yield of camptothecin (110 μg/L). The molecular structure and chemical identity of P. chrysogenum derived camptothecin has been resolved by HPLC, FTIR and LC-MS/MS analyses, giving the same spectroscopic profiles and mass fragmentation patterns as authentic camptothecin. The extracted camptothecin displayed a strong anti-proliferative activity towards HEP-2 and HCT-116 (IC50 values 0.33–0.35 µM). The yield of camptothecin was maximized by nutritional optimization of P. chrysogenum with a Plackett-Burman design, and the productivity of camptothecin increased by 1.8 fold (200 µg/L), compared to control fungal cultures. Upon storage at 4 °C as slope culture for 8 months, the productivity of camptothecin for P. chrysogenum was reduced by 40% compared to the initial culture. Visual fading of the mycelial pigmentation of P. chrysogenum was observed during fungal storage, matched with loss of camptothecin productivity. Methylene chloride extracts of Cliona sp. had the potency to completely restore the camptothecin productivity of P. chrysogenum, ensuring the partial dependence of the expression of the camptothecin biosynthetic machinery of P. chrysogenum on the chemical signals derived from the sponge, or the associated microbial flora. This is the first report describing the feasibility of P. chrysogenum, endozoic of Cliona sp., for camptothecin production, along with reliable metabolic biosynthetic stability, which could be a new platform for scaling-up camptothecin production