Presence of T3SS (exoS, exoT, exoU and exoY), susceptibility pattern and MIC of MDR-Pseudomonas aeruginosa from burn wounds.

INTRODUCTION: The emergence of resistance is a major public health and clinical issue, particularly in pathogens causing nosocomial infections. Recently, there is the emergence of Pseudomonas aeruginosa resistance to different broad-spectrum antibiotics. METHODOLOGY: The current study was designed to find out the prevalence of multi-drug resistant (MDR) P. aeruginosa in burn patients, the antibiotic susceptibility pattern of MDR Pseudomonas, and to determine the Minimum Inhibitory Concentration (MIC) of the effective antimicrobials. The assessment of virulence genes (exoT, exoS, exoY and exoU) was also achieved through PCR. In the current study wound swabs were collected from 160 burn patients from two burn units (MTI-Govt. Lady Reading Hospital and MTI-Khyber Teaching Hospital). RESULTS: Out of these 160 samples, 26 samples (16.25%) were positive for P. aeruginosa. Per patients, one isolate was included in the current study. Antibiotic susceptibility pattern showed all P. aeruginosa isolates were 100% resistant to amoxicillin-clavulanic acid, 84.62% resistance to Cefepime, and Ceftazidime, and 76.92% resistance to Amikacin, Aztreonam, and Ciprofloxacin. Whereas the lowest resistance was observed to Imipenem and Piperacillin-Tazobactam (53.85%), Colistin Sulfate (23.08%), and Polymyxin-B (15.38%). Regarding the prevalence of MDR, 22 (84.61%) isolates out of 26 were found to be MDR-P. aeruginosa. For MDR-P. aeruginosa, the MIC range was 1-2 µg/mL against Polymyxin-B, 2-8 µg/mL against Colistin sulfate, 16-1024 µg/mL against Imipenem and 128-1024 µg/mL against Piperacillin-Tazobactam. 100% of the isolates carried exoT, 88.46% carried exoY, and 57.69% and 38.46% carried exoU and exoS, respectively. CONCLUSIONS: These findings further emphasize the need for antibiotic discipline and to follow the recommended hospital antibiotic policy to prevent the proliferation of MDR strains of P. aeruginosa in the community.

Facile synthesis of water-soluble silver nanoclusters for the photocatalytic degradation of dyes by multivariate optimization approach.

In this study, silver nanoclusters protected by the natural tripeptide ligand (GSH@Ag NCs) were constructed for photocatalytic dye degradation. The ultrasmall GSH@Ag NCs were found to exhibit a remarkably high degradation capability. Aqueous solutions of the hazardous organic dye Erythrosine B (Ery. B) and Rhodamine B (Rh. B) were subjected to degradation in the presence of Ag NCs under solar light and white-light LED irradiation. The degradation efficiency of GSH@Ag NCs was evaluated using UV-vis spectroscopy, where Erythrosine B showed considerably high degradation of 94.6% compared to Rhodamine B, which was degraded by 85.1%, corresponding to a 20 mg L-1 degradation capacity in 30 min respectively under solar exposure. Moreover, the degradation efficacy for the above-mentioned dyes demonstrated a dwindling trend under white-light LED irradiation, attaining 78.57 and 67.923% degradation under the same experimental conditions. The astoundingly high degradation efficiency of GSH@Ag NCs under solar-light irradiation was due to the high I of 1370 W for solar light versus 0.07 W for LED light, along with the formation of hydroxyl radicals HO˙ on the catalyst surface initiating degradation due to oxidation.

Novel silver-morphine-functionalized polypropylene (AgPP-mrp) nanocomposite for the degradation of dye removal by multivariate optimization approach.

As a novel adsorbent, an opioid silver-morphine-functionalized polypropylene was synthesized through a one-pot reaction at room temperature and successfully used for the simple one-pot photocatalytic degradation catalyst of methyl orange removal from wastewater. UV spectral analysis reveals a special reference to the excitation of surface plasmon resonance as the main characteristic of the polymer-Ag nanocomposite in toluene solution peak at 420 nm in AgPP-mrp catalyst. The 1H NMR spectrum showed no sign of Ag NP peaks revealing small size distribution in the channels of morphine-functionalized polypropylene polymer. The morphology of silver nanoparticle-doped polymer through scanning electron microscopy (SEM-EDX) reveals PP-mrp with continuous matrix and Ag NPs (0.87 wt%). Furthermore, photocatalytic degradation of methyl orange was investigated on AgPP-mrp catalyst spectrophotometrically under solar irradiation in waste effluent, demonstrating high degradation efficiency. According to experimental findings, silver nanoparticles (AgPP-mrp) achieved high degradation capacities of 139 mg/g equivalent to 97.4% of photodegradation in a little period of time (35 min), as associated with previously stated materials and follow pseudo-second-order kinetic degradation tail of a high regression coefficient (R2 = 0.992). The suggested techniques offer a linear reaction for MO over the pH range of 1.5 to 5 and a degradation temperature of 25 to 60 °C. Central composite design and response surface methodology statistics recommend pH of the reaction medium and time as important variables for methyl orange degradation on AgPP-mrp photocatalytic. AgPP-mrp on the photocatalytic phenomenon based on heterojunction catalytic design producing electron holes (e-), as well as superoxides for the successful degradation of methyl orange.

Ginger ring compounds as an inhibitor of spike binding protein of alpha, beta, gamma and delta variants of SARS-CoV-2: An in-silico study.

The available drugs against coronavirus disease 2019 (COVOD-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are limited. This study aimed to identify ginger-derived compounds that might neutralize SARS-CoV-2 and prevent its entry into host cells. Ring compounds of ginger were screened against spike (S) protein of alpha, beta, gamma, and delta variants of SARS-CoV-2. The S protein FASTA sequence was retrieved from Global Initiative on Sharing Avian Influenza Data (GISAID) and converted into ".pdb" format using Open Babel tool. A total of 306 compounds were identified from ginger through food and phyto-databases. Out of those, 38 ring compounds were subjected to docking analysis using CB Dock online program which implies AutoDock Vina for docking. The Vina score was recorded, which reflects the affinity between ligands and receptors. Further, the Protein Ligand Interaction Profiler (PLIP) program for detecting the type of interaction between ligand-receptor was used. SwissADME was used to compute druglikeness parameters and pharmacokinetics characteristics. Furthermore, energy minimization was performed by using Swiss PDB Viewer (SPDBV) and energy after minimization was recorded. Molecular dynamic simulation was performed to find the stability of protein-ligand complex and root-mean- square deviation (RMSD) as well as root-mean-square fluctuation (RMSF) were calculated and recorded by using myPresto v5.0. Our study suggested that 17 out of 38 ring compounds of ginger were very likely to bind the S protein of SARS-CoV-2. Seventeen out of 38 ring compounds showed high affinity of binding with S protein of alpha, beta, gamma, and delta variants of SARS-CoV-2. The RMSD showed the stability of the complex was parallel to the S protein monomer. These computer-aided predictions give an insight into the possibility of ginger ring compounds as potential anti-SARS-CoV-2 worthy of in vitro investigations.

Structure-based in silico design and in vitro acaricidal activity assessment of Acacia nilotica and Psidium guajava extracts against Sarcoptes scabiei var. cuniculi.

Infestation by Sarcoptes scabiei var. cuniculi mite causes scabies in humans and mange in animals. Alternative methods for developing environmentally friendly and effective plant-based acaricides are now a priority. The purpose of this research was the in silico design and in vitro evaluation of the efficacy of ethanol extracts of Acacia nilotica and Psidium guajava plant leaves against S. scabiei. Chem-Draw ultra-software (v. 12.0.2.1076.2010) was used to draw 36 distinct compounds from these plants that were employed as ligands in docking tests against S. scabiei Aspartic protease (SsAP). With docking scores of - 6.50993 and - 6.16359, respectively, clionasterol (PubChem CID 457801) and mangiferin (PubChem CID 5281647) from A. nilotica inhibited the targeted protein SsAP, while only beta-sitosterol (PubChem CID 222284) from P. guajava interacted with the SsAP active site with a docking score of - 6.20532. Mortality in contact bioassay at concentrations of 0.25, 0.5, 1.0, and 2.0 g/ml was determined to calculate median lethal time (LT50) and median lethal concentration (LC50) values. Acacia nilotica extract had an LC50 value of 0.218 g/ml compared to P. guajava extract, which had an LC50 value of 0.829 g/ml at 6 h. These results suggest that A. nilotica extract is more effective in killing mites, and these plants may have novel acaricidal properties against S. scabiei. Further research should focus on A. nilotica as a potential substitute for clinically available acaricides against resistant mites.

In Vitro, Ex Vivo, and In Vivo Evaluation of Nanoparticle-Based Topical Formulation Against Candida albicans Infection.

Ketoconazole is commonly used in the treatment of topical fungal infections. The therapy requires frequent application for several weeks. Systemic side effects, allergic reactions, and prolonged treatment are often associated with non-compliance and therapy failure. Hence, we developed an optimized topical antifungal gel that can prolong the release of drug, reduce systemic absorption, enhance its therapeutic effect, and improve patient compliance. Ketoconazole-loaded PLGA nanoparticles were prepared by the emulsion/solvent evaporation method and were characterized with respect to colloidal properties, surface morphology, and drug entrapment efficiency. The optimized ketoconazole-loaded PLGA nanoparticles and commercially available silver nanoparticles were incorporated into a Carbopol 934P-NF gel base. This arrangement was characterized and compared with commercially available 2% ketoconazole cream to assess physical characteristics of the gel, in vitro drug release, ex vivo skin permeation and retention, and in vivo studies on Wister male albino rats. The results showed that polymeric PLGA nanoparticles were very effective in extending the release of ketoconazole in our optimized formulation. Nanoparticles were smooth, spherical in shape, and below 200 nm in size which is consistent with the data obtained from light scattering and SEM images. The ex vivo data showed that our gel formulation could strongly reduce drug permeation through the skin, and more than 60% of the drug was retained on the upper surface of the skin in contrast to 38.42% of the commercial cream. The in vivo studies showed that gel formulation could effectively treat the infection. This study demonstrates that our topical gel could be effective in sustaining the release of drug and suggests its potential use as a possible strategy to combat antifungal-resistant Candida albicans.

Elucidation of correlation between SARS-CoV-2 RdRp and N gene cycle threshold (Ct) by RT-PCR with age and gender.

BACKGROUND: Coronavirus disease 2019 (COVID19) caused by the new severe acute respiratory syndrome coronavirus 2 (SARSCoV2) is a global public health emergency. Age and gender are two important factors related to the risk and outcome of various diseases. Cycle threshold (Ct) value is believed to have relation with age and gender. OBJECTIVE: This study has been conducted to investigates the association between SARS-CoV-2 cycle threshold to age and gender of COVID-19 patients, to investigate whether the population-wide change of SARSCoV2 RTPCR Ct value over time is corelated to the number of new COVID19 cases and to investigate the dynamic of RdRp and N genes. METHODS: 72,811 individuals from second wave of COVID19, were observed in current study at Pure Health Lab, Mafraq Hospital, Abu Dhabi, UAE. RESULTS: 15,201/72,811 (21 %) positivity was observed. COVID-19 were more prevalent in males (59.35%) as compared to female (40.65%). The Positivity rate were significantly higher in Male than in Female cases (p-Value = 0.04). The Ct values for both targets of all the samples were ranged from 4.57 to 29.73. Longitudinal analysis showed significant increased during the study period from starting to end as were hypothesized. Interestingly, both the targets (RdRp and N) were present in age < 1 year. Which may indicate that mutated strains are not prevalent in children's < 1 year. CONCLUSION: There was no statistically significant difference in viral loads in between age-groups. Males were tending to higher viral load compared to females. The findings have implications for preventive strategies.

TLR-2 Germ Line Variants as a Risk for Obesity in Local Pakistani Population.

BACKGROUND: Obesity is increasing rapidly affecting half billion adult's population. Pathophysiology of obesity involves low grade inflammation sustained by Toll like receptor 2 (TLR-2) the innate immune adapters. This study was conducted for detection and association of TLR-2 gene mutations with obesity. METHODS: In this case-control study 228 individuals with obesity and 228 controls were enrolled based on Body Mass Index (BMI) ≥25 and 18-24 kg/m2 respectively. The variations in TLR-2 gene were detected by Sanger sequencing. These identified TLR-2 variants were further analyzed in silico for change in miRNA binding and mRNA strucutre. RESULTS: Four novel single base substitutions (153688371 T >C, 153702295 T >C, 153703504 T >C and 153705074 C >A) were identified in exon 3 and 4 of TLR-2 gene affecting splice site and poly-A tail. The genotypic and allelic frequencies of the variants were strongly associated with increasing obesity susceptibility. Only variant 153703504 T >C was significantly associated with preobesity. Despite variations in gene sequence, no change in miRNA binding except for variant 153688371 T >C of Exon 3 where a novel binding site for hsa-miR-4523 was created. Furthermore, mRNA stability and secondary structure were also compromised in identified variants. CONCLUSION: All detected variants of TLR-2 gene were significantly associated with and posed risk for development of obesity. Furthermore, in silico analysis revealed generation of new miRNA (hsa-miR-4523) binding site and change in mRNA structure/stability which needs to be further investigated for possible role in altering TLR-2 gene regulation/expression in obesity.

Preparation and Characterization of Hydrophilic Polymer Based Sustained-Release Matrix Tablets of a High Dose Hydrophobic Drug.

The objective of this study was the preparation and characterization of a sustained-release matrix tablet containing a high-dose hydrophobic drug and its comparison with marketed products. In the present study, HPMC was applied as the matrix-forming polymer for the sustained release of clarithromycin (500 mg). The compatibility of clarithromycin and excipients was studied using a binary mixture approach and compatible excipients were selected. Matrix tablets were prepared using the high-shear wet granulation technique. Tablets were compressed using oblong (19 mm), shallow concave punches, under a compression weight of 900 mg/tablet. The flow of granules was evaluated by determining their bulk density, tapped density, angle of repose, Hausner ratio, and Car's index. Compressed tablets were tested for their physical parameters, mechanical characteristics, drug content, and in vitro drug release, as per United States Pharmacopeia (USP). Clarithromycin is a drug having poor water solubility and showed compatibility with all the excipients used in the formulation of polymeric matrix tablets. FTIR spectra of clarithromycin, before and after being subjected to the stress conditions, confirmed the compatibility of clarithromycin and other ingredients of the matrix tablets. All the formulations exhibited good rheological characteristics and all the parameters related to flow showed results in the acceptable range. Physically, matrix tablets were smooth and shiny, without any surface defects. Weight variation (±5%) and drug content of the tablets (95-102%) were within the pharmacopeial limits. HPMC successfully sustained the drug release for 24 h. It is concluded from the study that dissolution rate of clarithromycin can be sustained using hydrophilic polymer (HPMC) as a release-controlling agent.

Elucidation of molecular mechanism for colistin resistance among Gram-negative isolates from tertiary care hospitals.

Antimicrobial resistance is a growing concern of global public health. The emergence of colistin-resistance among carbapenem-resistant (CPR) Gram-negative bacteria causing fear of pan-resistance, treatment failure, and high mortality across the globe. AIM: To determine the genotypic colistin-resistance mechanisms among colistin-resistant (CR)Gram-negative clinical isolates along with genomic insight into hypermucoviscous(hv)-CR-Klebsiella pneumoniae. METHODS: Phenotypic colistin-resistance via broth-microdilution method. PCR-based detection of plasmid-mediated colistin resistance genes(mcr-1,2,3). Characterization of selected hvCR-K. pneumoniae via Whole-genome sequencing. RESULTS: Phenotypic colistin-resistance was 28% among CPR-Gram-negative isolates of which 90% of CR-isolates displayed MDR profile with overall low plasmid-mediated colistin resistance (mcr-2 = 9.4%;mcr-3 = 6%). Although K. pneumoniae isolates showed the highest phenotypic colistin-resistance (51%) however, relatively low plasmid-mediated gene-carriage (mcr-2 = 11.5%;mcr-3 = 3.4%) pointed toward other mechanisms of colistin-resistance. mcr-negative CR-K. pneumoniae displaying hv-phenotype were subjected to WGS. In-silico analysis detected 7-novel mutations in lipid-A modification genes includes eptA(I38V; V50L; A135P), opgE(M53L; T486A; G236S), and arnD(S164P) in addition to several non-synonymous mutations in lipid-A modification genes conferring resistance to colistin. Insertion of 6.6-kb region harboring putative-PEA-encoding gene(yjgX) was detected for the first time in K. pneumoniae (hvCRKP4771). In-silico analysis further confirmed the acquisition of not only MDR determinants but several hypervirulent-determinants displaying a convergent phenotype. CONCLUSION: overall high prevalence of phenotypic colistin resistance but low mcr-gene carriage suggested complex chromosomal mediated resistance mechanism especially in K. pneumoniae isolates. The presence of novel mutations in lipid-A modification genes and the acquisition of putative-PEA-encoding gene by hvCR-K. pneumoniae points toward the role of chromosomal determinants conferring resistance to colistin in the absence of mcr-genes.

Rotavirus gastroenteritis in Pakistan, 2018: updated disease burden.

OBJECTIVE: Rotavirus A (RVA) is a significant cause of severe diarrheal illness and one of the common causes of death in children under the age of five. This study was aimed at detecting the prevalence of RVA in Pakistan after rotavirus vaccines were introduced. Fecal samples were obtained from 813 children from different hospitals in Rawalpindi and Islamabad, Pakistan, from January 2018 to December 2018. To obtain additional information from the parents / guardians of the children, a standard questionnaire was used. RESULTS: Using an enzyme-linked immunosorbent assay kit (ELISA), rotavirus antigen was detected and ELISA positive samples were subjected to reverse transcription PCR (RT-PCR). The findings showed 22% prevalence of RVA in children with acute gastroenteritis (AGE) via ELISA and 21% prevalence via RT-PCR in children with AGE. There was no statistically significant difference between gender, age and RVA infections. The winter, spring and fall/autumn seasons were statistically significant for RVA prevalence. CONCLUSION: The present study will provide post vaccine prevalence data for the health policy makers. The implementation of rotavirus vaccines, along with adequate nutrition for babies, clean water supply and maternal hygienic activities during infant feeding, is recommended. Furthermore, continuous surveillance is mandatory in the whole country to calculate the disease burden caused by RVA.

Coronavirus Pandemic: a major public health crisis for the developed and developing world.

Pandemic of novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections in China is now become global public health crisis. At present 87.64% of the world is infected by this deadly illness. The risk from this epidemic depends on the nature of the virus, including how well it transmits from person to person, and the complications resulting from this current illness. The novel coronavirus has killed thousands of people in China and other countries as well; its rate of mortality is increasing day by day. There is an urgent need to control the virus by developing vaccine or any other antiviral drugs to save the world from this deadly viral infection.

COVID-19 Pandemic: A Serious Threat for Public Mental Health Globally.

Deep emotion traumas in societies around the globe are overcome by extreme human catastrophes such as natural disasters, social crises, war conflicts and infectious virus induced pandemic diseases, etc., can lead to enormous stress-related disorders. The current ongoing pandemic known as COVID-19 caused by novel Corona virus first appeared in Wuhan, city of China and then rapidly spread in the whole world. It has affected various frontiers of lives and caused numerous psychiatric problems like nervousness, post-traumatic stress disorder (PTSD), fear and uncertainty, panic attacks, depression, obsessive compulsory disorder, xenophobia and racism, etc. Globally COVID-19 has persuaded public mental health crisis. Furthermore, inadequate resources of public mental health services in several countries are discussed in this review, which will be further straighten by the upcoming increase in demand for mental health services due to the COVID-19 pandemic. All mental health sciences including Psychiatry can play a very important role in the comfort of COVID-19 infected individuals and their relatives, healthcare providers and society. We need to learn more about psychological and psychiatric features of COVID-19 from the perceptions of public and global mental health in order to cope up the present deteriorating situation caused by the SARS-CoV-2 pandemic.

Experimental and mechanism study: Partially hydrolyzed polyacrylamide gel degradation and deplugging via ultrasonic waves and chemical agents.

Partially hydrolyzed Polyacrylamide (PHPAM) crosslinked by Cr+3 is frequently applied to plug thief zone for the better water management in matured oil reservoir. However, PHPAM gel may certainly cause inevitable formation damage nearby the wellbore. Although various kinds of chemical agents, such as hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), and chlorine dioxide (ClO2) were employed to mitigate the nearby wellbore damage. But, huge financial investment, poor degelation efficiency, environmentally insecure, corrosion problem, and long time span requirement persuade researchers to look for other effective technique. In this connection, ultrasonic waves is characterized by reliable, environment friendly, and cost effective technology. Current work involves comparative study of PHPAM gel degradation by the individual means of chemical agent and ultrasonic waves. Subsequently, the best-performed ultrasonic parameters and well-performed chemical agent were used independently and then simultaneously to deplug (PHPAM gel) the core sample. Results showed that 20 KHz frequency (1000 W) effectively reduced gel viscosity from original (2495 mPa.s) to 1.37 mPa.s after 10 min irradiation. This degradation is attributed to cavitation, heat energy, and hydroxyl radical (HO∙). However, after 2 min further exposure, the viscosity grew back to 3.29 mPa.s (18 KHz), 1.42 mPa.s (20 KHz), and 3.74 mPa.s (25 KHz). This adverse behavior is owing to hydroxyl radical (HO∙) annihilation. In chemical treatment, H2O2 among other chemicals efficiently degelled the PHPAM gel's original viscosity to 2.64 mPa.s after 24 h reaction. Similarly, NaOCl and ClO2 brought down original viscosity to 6.5 mPa.s and 159 mPa.s respectively. SEM of the samples before and after treatment was performed for the better understanding of PHPAM gel morphology. Considering dynamic experiment, maximum 23.5% and 19.80% damaged permeability recovery (30 × 10-3 µm2 gas permeability) were obtained by applying ultrasonic waves (20 KHz, 1000 W, and 100 min irradiation) and chemical agent (H2O2) respectively. Permeability recovery was further increased to 40.90% by the simultaneous application of ultrasonic waves and chemical agent.

Antinociceptive, antioxidant and phytochemical studies of Pakistani medicinal plants.

The aim of the current study was to evaluate the antinociceptive activity of the selected Pakistani medicinal plants (Chenopodium botrys, Micromeria biflora and Teucrium stocksianum) in-vivo followed by their antioxidant potential against 1,1-diphenyl-2-picrylhidrazyl (DPPH) in-vitro. The results demonstrated profound antinociceptive effect of both the crude methanolic extract of Chenopodium botrys (CBM) and subsequent aqueous fraction (CBW) of C. botrys with 80.76% and 84% pain relief in acetic acid induced writhing test at 100 mg/kg i.p respectively. Similarly the crude methanolic extract of Micromeria biflora (MBM) and its subsequent aqueous fraction (MBW) with 66.46% 78.08% pain reversal in acetic acid induced writhing test respectively at 100mg/kg i.p. However, the crude methanolic extract and isolated water fraction of Teucrium stocksianum (TS) did not show any significant effect at test doses. Both the crude extracts and aqueous fractions of selected medicinal plants exhibited marked scavenging effects on DPPH and therefore strongly support the antinociceptive activity. Phytochemical analysis indicated the presence of various classes of natural products (alkaloids, terpenoids, flavonoids etc.) and thus the current finding can be attributed to the presence of these compounds. In short, our findings provide a strong scientific background to the folk uses C. botrys and M. biflora in the management of various painful conditions.

Effect of vanadium contamination on the framework and micropore structure of ultra stable Y-zeolite.

Y-zeolites are the main component of fluid catalytic cracking (FCC) catalyst for conversion of crude petroleum to products of high demand including transportation fuel. We investigated effects of vanadium which is present as one of the impurities in FCC feedstock on the framework and micropore structure of ultra-stable (US) Y-zeolite. The zeolite samples were prepared and characterized using standard techniques including: (1) X-ray diffraction, (2) N2 adsorption employing non local density functional theory method, NLDFT, (3) Transmittance and Pyridine FTIR, (4) Transmittance electron microscopy (TEM), and (5) (27)Al and (29)Si MAS-NMR. Results revealed that in the presence of steam, vanadium caused excessive evolution of non inter-crystalline mesopores and structural damage. The evolved mesopore size averaged about 25.0nm at 0.5wt.% vanadium loading, far larger than mesopore size in zeolitic materials with improved hydrothermal stability and performance for FCC catalyst. A mechanism of mesopore formation based on accelerated dealumination has been proposed and discussed. Vanadium immobilization experiments conducted to mitigate vanadium migration into the framework clearly showed vanadium is mobile at reaction conditions. From the results, interaction of vanadium with the passivator limits and decreases mobility and activity of vanadium into inner cavities of the zeolite capable of causing huge structure breakdown and acid sites destruction. This study therefore deepens insight into the causes of alteration in activity and selectivity of vanadium contaminated catalyst and hints on a possible mechanism of passivation in vanadium passivated FCC catalyst.

Antioxidant profile of constituents isolated from Polygonatum verticillatum rhizomes.

The purpose of the current study was to estimate the antioxidant profile of two compounds, diosgenin and santonin, isolated from Polygonatum verticillatum rhizomes. Stable free radical, 2, 2-diphenyl-1-picrylhydrazyl and reducing power assays were employed for this purpose. The results showed profound free radical scavenging effect of both diosgenin and santonin in a concentration-dependent manner. The calculated half maximal inhibitory concentration (IC50) values for both diosgenin and santonin was 65.80 and 50.03 µg/ml, respectively. Similarly, in reducing power assay, diosgenin and santonin exhibited marked quenching effect. The corresponding IC50 values for both the compounds were 62.10 and 46.40 µg/ml, respectively. In conclusion, both the isolated compounds have strong antioxidant potential, which is consistent with the results of the extracts of the plant.