Antibacterial and synergistic activity of 6ß-hydroxy-3-oxolup-20(29)-en-28-oic acid (6ß-hydroxy betunolic acid) isolated from Schumacheria castaneifolia vahl.

Multi- drug resistant microbial pathogens are a serious global health problem and thus new antibacterial agents, which are effective both alone and in combination with traditional antibiotics, are urgently needed. Hence, the objective of the present study was to investigate the antibacterial activity of 6ß-hydroxy-3-oxolup-20(29)-en-28-oic acid (6ß-hydroxy betunolic acid) isolated from the bark of Schumacheria castaneifolia and its effect when combined with oxacillin. Antibacterial potential of 6ß-hydroxy betunolic acid alone was performed using broth micro dilution assay against sixteen bacterial strains which included eight standard strains [Staphylococcus aureus (ATCC 29213 and ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 35218 and ATCC 25922), carbapenemase producing Kebsiella pneumonia (ATCC BAA 1705), carbapenemase non-producing K. pneumonia (ATCC BAA 1706) and Pseudomonas aeruginosa (ATCC 27853)] and four strains each of clinically isolated meropenem resistant Acinetobactor sp. and methicillin resistant S. aureus (MRSA) which were included in the urgent threat list and serious threat list, respectively in 2019 by the Centers for Disease Control and Prevention in the United States. Its effect when combined with oxacillin was tested against S. aureus (ATCC 29213) and MRSAs using a checkerboard dilution method. The results indicated that 6ß-hydroxy betunolic acid had antibacterial activity against the tested Gram positive organisms with MICs ranging from 16 to 32 mg L-1 (MIC of oxacillin and meropenem ranged from 0.25-16 and 0.03-128 mg L-1 respectively). The high MIC values (>1024 mg L-1) of 6ß-hydroxy betunolic acid against Gram negative strains indicated a likely lack of activity. Further, 6ß-hydroxy betunolic acid exhibited synergistic effect with oxacillin against Staphylococcus aureus (0.49) and showed an additive effect against all the tested MRSAs. The present study suggested that the antibacterial activity of the 6ß-hydroxy betunolic acid is restricted to Staphylococcus isolates and possibly Enterococcus faecalis. Further testing on different types of Gram positives and identification of the exact mechanism of action would be of importance.

Modification of a designed amphipathic cell-penetrating peptide and its effect on solubility, secondary structure, and uptake efficiency.

The development of safe and efficient nonviral gene delivery carriers has received a great deal of attention in the past decade. A class of amphipathic peptides has shown to be able to cross cell membranes and deliver cargo to the intracellular environment. Here, we introduce an 18-mer amphipathic peptide, C6M1, as a modified version of peptide C6 for short interfering RNA (siRNA) delivery. The importance of tryptophan residues and the effect of peptide sequence modification on its solubility, secondary structure, cytotoxicity, and uptake efficiency were investigated. The solubility of C6M1 in aqueous solutions was greatly enhanced compared to that of C6, confirmed by surface tension and anilinonaphthalene-8-sulfonic acid fluorescence measurements. C6M1 had a random/helical structure in water with the ability to attain a helical conformation in the presence of anionic components or membrane-mimicking environments. The modification significantly reduced the cytotoxicity of the peptide, making it a safer carrier for siRNA delivery. C6M1 was also found ∼90% more efficient than C6 in delivering Cy3-labeled siRNA in Chinese hamster ovary cells.

Multiscale modeling of the cellular uptake of C6 peptide-siRNA complexes.

In gene therapy utilising short interfering RNA (siRNA), delivery of the siRNA therapeutics to the target site is a major obstacle, due to low cellular uptake. Efficient delivery systems such as cell penetrating peptides (CPPs) are in the forefront for the development of efficient, safe, non-viral gene delivery. The C6 peptide series are a class of synthetic CPPs, developed specifically for the delivery of siRNA. This series of peptides are derivatives of the original C6 peptide, modified to increase cellular uptake and efficiency. In this study, multiscaled computational simulations of these peptides were performed in aqueous media, interrogating the relationship between the structure and behaviour. All atom molecular dynamic (MD) simulation results show that all CPPs show stable α-helical amphipathic secondary structures. Furthermore, docking calculations indicate that the C6 peptides can fit into the major groove of the siRNA double-helix, and once filled, could bind randomly along the minor grooves and to other, previously bound peptides. Coarse grained MD simulations were also used to generate free energy profiles for the dimerization of peptides, and binding of the peptide to siRNA. Simulation results confirm that all peptides favour binding to siRNA, they however, also favour dimerization. This affinity for aggregation may trigger the formation of larger complexes with siRNA and enhance the cellular uptake. These results indicate the capacity of C6 peptides as efficient delivery vehicles. As expected the amino acid sequence plays a crucial role in the helicity, peptide self-assembly, interaction of peptide with cell membrane and formation of stable siRNA-CPP complex.

Doxorubicin Loaded Magnesium Oxide Nanoflakes as pH Dependent Carriers for Simultaneous Treatment of Cancer and Hypomagnesemia.

Doxorubicin (DOX) is an anticancer drug commonly used in treating cancer; however, it has severe cytotoxicity effects. To overcome both the adverse effects of the drug and mineral deficiency (i.e., hypomagnesemia) experienced by cancer patients, we have developed magnesium oxide (MgO) nanoflakes as drug carriers and loaded them with DOX for use as a targeted drug delivery (TDD) system for potential application in cancer therapy. The synthesis employed herein affords pure, highly porous MgO nanoparticles that are void of the potentially harmful metal contaminants often discussed in the literature. Purposed for dual therapy, the nanoparticles exhibit an impressive 90% drug loading capacity with pH dependent drug releasing rates of 10% at pH 7.2, 50.5% at pH 5.0, and 90.2% at pH 3. Results indicate that therapy is achievable via slow diffusion where MgO nanoflakes degrade (i.e., dissolve) under acidic conditions releasing the drug and magnesium ions to the cancerous region. The TDD system therefore minimizes cytotoxicity to healthy cells while supplying magnesium ions to overcome hypomagnesemia.

Targeted lung cancer screening selects individuals at high risk of cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD) is a major cause of morbidity and mortality in populations eligible for lung cancer screening. The aim of this study was to determine whether a brief CV risk assessment, delivered as part of a targeted community-based lung cancer screening programme, was effective in identifying individuals at high risk who might benefit from primary prevention. METHODS: The Manchester Lung Screening Pilot consisted of annual low dose CT (LDCT) over 2 screening rounds, targeted at individuals in deprived areas at high risk of lung cancer (age 55-74 and 6-year risk ≥1.51%, using PLCOM2012 risk model). All participants of the second screening round were eligible to take part in the study. Ten-year CV risk was estimated using QRISK2 in participants without CVD and compared to age (±5 years) and sex matched Health Survey for England (HSE) controls; high risk was defined as QRISK2 score ≥10%. Coronary artery calcification (CAC) was assessed on LDCT scans and compared to QRISK2 score. RESULTS: Seventy-seven percent (n=920/1,194) of screening attendees were included in the analysis; mean age 65.6 ± 5.4 and 50.4% female. QRISK2 and lung cancer risk (PLCOM2012) scores were correlated (r = 0.26, p < 0.001). Median QRISK2 score was 21.1% (IQR 14.9-29.6) in those without established CVD (77.6%, n = 714/920), double that of HSE controls (10.3%, IQR 6.6-16.2; n = 714) (p < 0.001). QRISK2 score was significantly higher in those with CAC (p < 0.001). Screening attendees were 10-fold more likely to be classified high risk (OR 10.2 [95% CI 7.3-14.0]). One third (33.7%, n = 310/920) of all study participants were high risk but not receiving statin therapy for primary CVD prevention. DISCUSSION: Opportunistic CVD risk assessment within a targeted lung cancer screening programme is feasible and is likely to identify a very large number of individuals suitable for primary prevention.

Trends in the Binding of Cell Penetrating Peptides to siRNA: A Molecular Docking Study.

The use of gene therapeutics, including short interfering RNA (siRNA), is limited by the lack of efficient delivery systems. An appealing approach to deliver gene therapeutics involves noncovalent complexation with cell penetrating peptides (CPPs) which are able to penetrate the cell membranes of mammals. Although a number of CPPs have been discovered, our understanding of their complexation and translocation of siRNA is as yet insufficient. Here, we report on computational studies comparing the binding affinities of CPPs with siRNA, considering a variety of CPPs. Specifically, seventeen CPPs from three different categories, cationic, amphipathic, and hydrophobic CPPs, were studied. Molecular mechanics were used to minimize structures, while molecular docking calculations were used to predict the orientation and favorability of sequentially binding multiple peptides to siRNA. Binding scores from docking calculations were highest for amphipathic peptides over cationic and hydrophobic peptides. Results indicate that initial complexation of peptides will likely occur along the major groove of the siRNA, driven by electrostatic interactions. Subsequent binding of CPPs is likely to occur in the minor groove and later on bind randomly, to siRNA or previously bound CPPs, through hydrophobic interactions. However, hydrophobic CPPs do not show this binding pattern. Ultimately binding yields a positively charged nanoparticle capable of noninvasive cellular import of therapeutic molecules.

A Study on Cytotoxic and Apoptotic Potential of a Triterpenoid Saponin (3-O-α-L-Arabinosyl Oleanolic Acid) Isolated from Schumacheria castaneifolia Vahl in Human Non-Small-Cell Lung Cancer (NCI-H292) Cells.

Lung cancer is the major cause of cancer death among men. A number of natural compounds have proven to be useful in the treatmet of lung cancer. This study was aimed to determine cytotoxic and apoptotoic effects of a natural compound 3-O-α-L-arabinosyl oleanolic acid (3-O-L-AO) isolated from Schumacheria castaneifolia in non-small-cell lung cancer (NCI-H292) cells. Cytotoxic effects of 3-O-L-AO were determined by Sulforhodamine B (SRB) assay and apoptotic effects were tested by evaluating (a) apoptotsis related morphological changes, (b) caspase 3/7 activity, and (c) expression of Bax, p53, and survivin genes. Oxidative stress markers (reactive oxygen species (ROS), glutathione-S-transferase (GST), and glutathione (GSH)) were also analysed in 3-O-L-AO treated NCI-H292 cells. 3-O-L-AO exerted potent cytotoxic effects in NCI-H292 cells while being less cytotoxic to normal lung (MRC-5) cells. Exposure to 3-O-L-AO caused upregulation of Bax and p53 and downregulation of survivin in NCI-H292 cells. Activation of caspase 3/7 and morphological features related to apoptosis further confirmed 3-O-L-AO induced apoptosis. Furthermore, elevated ROS and GST levels and decreased GSH levels suggested 3-O-L-AO can induce apoptosis, possibly causing oxidative stress in NCI-H292 cells. Overall results suggest that 3-O-L-AO can be considered as an effective anticancer agent for the treatment of lung cancer.

Microorganisms and heavy metals associated with atmospheric deposition in a congested urban environment of a developing country: Sri Lanka.

The presence of bacteria and heavy metals in atmospheric deposition were investigated in Kandy, Sri Lanka, which is a typical city in the developing world with significant traffic congestion. Atmospheric deposition samples were analyzed for Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb which are heavy metals common to urban environments. Al and Fe were found in high concentrations due to the presence of natural sources, but may also be re-suspended by vehicular traffic. Relatively high concentrations of toxic metals such as Cr and Pb in dissolved form were also found. High Zn loads can be attributed to vehicular emissions and the wide use of Zn coated roofing materials. The metal loads in wet deposition showed higher concentrations compared to dry deposition. The metal concentrations among the different sampling sites significantly differ from each other depending on the traffic conditions. Industrial activities are not significant in Kandy City. Consequently, the traffic exerts high influence on heavy metal loadings. As part of the bacterial investigations, nine species of culturable bacteria, namely; Sphingomonas sp., Pseudomonas aeruginosa, Pseudomonas monteilii, Klebsiella pneumonia, Ochrobactrum intermedium, Leclercia adecarboxylata, Exiguobacterium sp., Bacillus pumilus and Kocuria kristinae, which are opportunistic pathogens, were identified. This is the first time Pseudomonas monteilii and Ochrobactrum intermedium has been reported from a country in Asia. The culturable fraction constituted ~0.01 to 10%. Pigmented bacteria and endospore forming bacteria were copious in the atmospheric depositions due to their capability to withstand harsh environmental conditions. The presence of pathogenic bacteria and heavy metals creates potential human and ecosystem health risk.

Antidiabetic Properties, Bioactive Constituents, and Other Therapeutic Effects of Scoparia dulcis.

This review discusses the antidiabetic activities of Scoparia dulcis as well as its antioxidant and anti-inflammatory properties in relation to the diabetes and its complications. Ethnomedical applications of the herb have been identified as treatment for jaundice, stomach problems, skin disease, fever, and kidney stones, reproductory issues, and piles. Evidence has been demonstrated through scientific studies as to the antidiabetic effects of crude extracts of S. dulcis as well as its bioactive constituents. The primary mechanisms of action of antidiabetic activity of the plant and its bioactive constituents are through α-glucosidase inhibition, curbing of PPAR-γ and increased secretion of insulin. Scoparic acid A, scoparic acid D, scutellarein, apigenin, luteolin, coixol, and glutinol are some of the compounds which have been identified as responsible for these mechanisms of action. S. dulcis has also been shown to exhibit analgesic, antimalarial, hepatoprotective, sedative, hypnotic, antiulcer, antisickling, and antimicrobial activities. Given this evidence, it may be concluded that S. dulcis could be promoted among the masses as an alternative and complementary therapy for diabetes, provided further scientific studies on the toxicological and pharmacological aspects are carried out through either in vivo or clinical means.

Controlled release of diclofenac sodium in glycolipid incorporated micro emulsions.

The effect of the glycolipid, hexadecyl-ß-d-glucopyranoside, incorporated in microemulsions (ME(1)) towards the enhancement of skin absorption and skin permeation of Diclofenac sodium (DS(2)) was evaluated. A Franz diffusion cell with a piece of pig's ear epidermis indicated that the optimized ME formulation with glycolipid (0.05wt%) exhibited significantly higher permeability than the conventional formulations. The releasing profiles of DS from ME formulations exhibited first order release kinetics resembling a diffusion controlled release model for the first 8h. Incorporating hexadecyl-ß-D glucopyranoside in ME formulations shows significant potential as a delivery vehicle in the cosmetics and pharmaceutical industry.

Non-Boolean computing with nanomagnets for computer vision applications.

The field of nanomagnetism has recently attracted tremendous attention as it can potentially deliver low-power, high-speed and dense non-volatile memories. It is now possible to engineer the size, shape, spacing, orientation and composition of sub-100 nm magnetic structures. This has spurred the exploration of nanomagnets for unconventional computing paradigms. Here, we harness the energy-minimization nature of nanomagnetic systems to solve the quadratic optimization problems that arise in computer vision applications, which are computationally expensive. By exploiting the magnetization states of nanomagnetic disks as state representations of a vortex and single domain, we develop a magnetic Hamiltonian and implement it in a magnetic system that can identify the salient features of a given image with more than 85% true positive rate. These results show the potential of this alternative computing method to develop a magnetic coprocessor that might solve complex problems in fewer clock cycles than traditional processors.

Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system.

A novel, efficient delivery system for iron (Fe2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30nm and with a negative zeta potential (-38mV). The in vitro release studies showed a prolonged release profile for 96h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2.The initial burst release upto 8h followed zero order kinetics at all three pH values. All the release profiles beyond 8h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed.

Natural Carriers for siRNA Delivery.

This review is based on carriers of natural origin such as polysaccharides, proteins, and cell derived entities which have been used for delivery of siRNA. To realize the therapeutic potential of a delivery system, the role of the carrier is of utmost importance. Historical aspects of viral vectors, the first carriers of genes are briefly outlined. Chitosan, one of the extensively experimented carriers, alginates and other polysaccharides have shown success in siRNA delivery. Peptides of natural origin and mimics thereof have emerged as another versatile carrier. Exosomes and mini cells of cellular origin are the newest entrants to the area of siRNA delivery and probably the closest one can get to a natural carrier. In many of the carriers, modifications have provided better efficiency in delivery. The salient features of the carriers and their advantages and disadvantages are also reviewed.

Bacteriophage degradation of Klebsiella K44 polysaccharide: an n.m.r. study and chemical proof of the position of the acetate group.

Bacteriophages (phi) have been used to degrade polysaccharides into oligosaccharides containing one or more of their repeating units. The capsular polysaccharide from Klebsiella K44 contains an acetate group, and n.m.r. spectroscopy and chemical methods have been employed to prove its linkage to O-6 of the 4-linked glucose residue. Phage phi 44 was shown to be an alpha-glucosidase not influenced by the acetate moiety and thus able to depolymerize the polysaccharide into pentasaccharide repeating units, some of which contained acetate on O-6 of the reducing glucose residue. The two oligosaccharides were studied by 1H- and 13C-n.m.r. spectroscopy, and their spectra were compared with those of the native and the deacetylated polysaccharide. 13C-n.m.r. was a useful tool for locating the 6-linked acetate, the position of which was confirmed by the method of temporary protection using methyl vinyl ether. The importance of using bacteriophages to obtain oligosaccharides is highlighted by the better results obtained with the oligosaccharide in comparison to the polysaccharide, both in n.m.r. spectroscopy and the temporary protection method.

Escherichia coli serotype K44: an acidic capsular polysaccharide containing two 2-acetamido-2-deoxyhexoses.

The structure of the capsular polysaccharide from Escherichia coli O8:K44 (A):H- (K44 antigen) has been established using the techniques of methylation, beta-elimination, deamination, and Smith degradation. N.m.r. spectroscopy (13C and 1H) was used extensively to establish the nature of the anomeric linkages of the polysaccharide and of oligosaccharides derived through degradative procedures. The K antigen is comprised of repeating units of the linear tetrasaccharide shown. This acidic polysaccharide represents the first instance of an E. coli K antigen in this series (group A) that has been found to contain two different 2-acetamido-2-deoxyhexoses.

Novel oligosaccharides obtained by bacteriophage degradation of the polysaccharide from Klebsiella serotype K26.

Bacteriophage phi 26 was used to depolymerize the polysaccharide of Klebsiella K26, yielding three oligosaccharides. The major product was the heptasaccharide repeating unit, with one of the minor products being the fourteen-sugar oligosaccharide corresponding to two repeating units. The other minor product was unusual since it was a hexasaccharide devoid of the terminal, pyruvate-containing galactose unit present in the side chain of the normal repeating unit. Phage phi 26 was shown to act as a beta-galactosidase, and hence it may have the ability to remove the terminal beta-galactose residue in the side chain.

Chemical and functional properties of fibre concentrates obtained from by-products of coconut kernel.

The coconut kernel residues obtained after extraction of coconut milk (MR) and virgin coconut oil (VOR) were analysed for their potential as dietary fibres. VOR was defatted and treated chemically using three solvent systems to isolate coconut cell wall polysaccharides (CCWP). Nutritional composition of VOR, MR and CCWPs indicated that crude fibre, neutral detergent fibre, acid detergent fibre and hemicelluloses contents were higher in CCWPs than in VOR and MR. MR contained a notably higher content of fat than VOR and CCWPs. The oil holding capacity, water holding capacity and swelling capacity were also higher in CCWPs than in VOR and MR. All the isolates and MR and VOR had high metal binding capacities. The CCWPs when compared with commercially available fibre isolates, indicated improved dietary fibre properties. These results show that chemical treatment of coconut kernel by-products can enhance the performance of dietary fibre to yield a better product.

PM(10)-bound polycyclic aromatic hydrocarbons: biological indicators, lung cancer risk of realistic receptors and 'source-exposure-effect relationship' under different source scenarios.

Cancer has become a critical health issue in the world heritage city Kandy, Sri Lanka. Polycyclic aromatic hydrocarbons (PAHs), one of persistent organic pollutants, in the atmosphere may be a major etiological factor in lung carcinogenicity. Over the very high concentrations of ambient air PAHs reported in Kandy, this paper is focused on setting priorities to control human exposure to PAHs in prevention of cancer. On re-appraisal of the classical indicator benzo(a)pyrene (B[a]P) for atmospheric PAHs-related carcinogenicity, B[a]P failed to reflect the toxicity completely and may not be the sole indicator for risk assessment studies in complex multi-sourced urban environments. The excess lifetime lung cancer risks of atmospheric PAHs with 'less than lifetime exposure' were assessed based on both 'B[a]P toxic equivalents' and 'B[a]P surrogate epidemiological' approach of risk quantification, over emissions characterized urban, suburban, and rural areas of Kandy. In urban heavy traffic areas, PAH-related additional cancer burden has been 942 million(-1) over 30 y of exposure. Over the whole study area, ∑p-PAHs show strong correlation (r=0.8) to the predicted risk levels. While the urban and suburban predicted cancer risk levels could not show significant correlation to their emission sources indicating the real complexity in mega urban environments, the rural lung cancer risk levels correlated perfectly with the source, firewood combustion. Policy decisions on environment and health could be based on established correlations among 'emission sources-exposures-health effects'. The priority for "analysis of options and policy formulation to reduce inhalation PAHs exposure of population in Kandy" was considered "moderate to high".