Inhibitory Effect of Nepeta deflersiana on Climax Bacterial Community Isolated from the Oral Plaque of Patients with Periodontal Disease

Background: The red-complex bacteria are one of the most significant complexes found simultaneously in subgingival plaque next to the periodontal pocket. The current antibacterial treatment is not adequate, and multidrug resistance to it is developing. Henceforth, the antibacterial effect of the ethanolic extract of Nepeta deflersiana was put to test against red-complex bacteria in patients with chronic periodontitis. Methods: Well diffusion and micro broth dilution procedure by Alamar blue were applied to assess the zone of inhibition (ZOI), the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC). Anti-virulence efficacies of the plant extract that comprise of adherence and formation of biofilms were examined by the process of adherence and biofilm production assay. Results: The crude extract of Nepeta deflersiana exhibited significant inhibitory outcome against periodontopathic bacteria with noteworthy MIC (0.78–3.12 mg/mL), inhibitory zone (12–20 mm), as well as MBC (3.12–12.50 mg/mL). The N. deflersiana extract inhibited bacterial adhesion ranging from 41% to 52%, 53% to 66%, and 60% to 79% at the given MIC × 0.5, MIC × 1, and MIC × 2 in succession. Substantial suppression was also developed in the biofilm production of the investigated periodontopathic strains following exposure to numerous concentrations of N. deflersianan extract for a period of 24 and 48 h. Conclusion: These outcomes divulge a new concept that N. deflersiana extract can be utilized to manufacture valuable antibacterial compounds to treat chronic and acute periodontitis. This identifies N. deflersiana as an essential natural source for future drug development.     

Chemical Elicitors-Induced Variation in Cellular Biomass,Biosynthesis of Secondary Cell Products,and Antioxidant System in Callus Cultures of Fagonia indica

Fagonia indica is a rich source of pharmacologically active compounds. The variation in the metabolites of interest is one of the major issues in wild plants due to different environmental factors. The addition of chemical elicitors is one of the effective strategies to trigger the biosynthetic pathways for the release of a higher quantity of bioactive compounds. Therefore, this study was designed to investigate the effects of chemical elicitors, aluminum chloride (AlCl₃) and cadmium chloride (CdCl₂), on the biosynthesis of secondary metabolites, biomass, and the antioxidant system in callus cultures of F. indica. Among various treatments applied, AlCl₃ (0.1 mM concentration) improved the highest in biomass accumulation (fresh weight (FW): 404.72 g/L) as compared to the control (FW: 269.85 g/L). The exposure of cultures to AlCl₃ (0.01 mM) enhanced the accumulation of secondary metabolites, and the total phenolic contents (TPCs: 7.74 mg/g DW) and total flavonoid contents (TFCs: 1.07 mg/g DW) were higher than those of cultures exposed to CdCl₂ (0.01 mM) with content levels (TPC: 5.60 and TFC: 0.97 mg/g) as compared to the control (TPC: 4.16 and TFC: 0.42 mg/g DW). Likewise, AlCl₃ and CdCl₂ also promoted the free radical scavenging activity (FRSA; 89.4% and 90%, respectively) at a concentration of 0.01 mM, as compared to the control (65.48%). For instance, the quantification of metabolites via high-performance liquid chromatography (HPLC) revealed an optimum production of myricetin (1.20 mg/g), apigenin (0.83 mg/g), isorhamnetin (0.70 mg/g), and kaempferol (0.64 mg/g). Cultures grown in the presence of AlCl₃ triggered higher quantities of secondary metabolites than those grown in the presence of CdCl₂ (0.79, 0.74, 0.57, and 0.67 mg/g). Moreover, AlCl₃ at 0.1 mM enhanced the biosynthesis of superoxide dismutase (SOD: 0.08 nM/min/mg-FW) and peroxidase enzymes (POD: 2.37 nM/min/mg-FW), while CdCl₂ resulted in an SOD activity up to 0.06 nM/min/mg-FW and POD: 2.72 nM/min/mg-FW. From these results, it is clear that AlCl₃ is a better elicitor in terms of a higher and uniform productivity of biomass, secondary cell products, and antioxidant enzymes compared to CdCl₂ and the control. It is possible to scale the current strategy to a bioreactor for a higher productivity of metabolites of interest for various pharmaceutical industries.     

Efficacy of Phytochemicals Derived from Avicennia officinalis for the Management of COVID-19: A Combined In Silico and Biochemical Study

The recent coronavirus disease 2019 (COVID-19) pandemic is a global threat for healthcare management and the economic system, and effective treatments against the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus responsible for this disease have not yet progressed beyond the developmental phases. As drug refinement and vaccine progression require enormously broad investments of time, alternative strategies are urgently needed. In this study, we examined phytochemicals extracted from Avicennia officinalis and evaluated their potential effects against the main protease of SARS-CoV-2. The antioxidant activities of A. officinalis leaf and fruit extracts at 150 µg/mL were 95.97% and 92.48%, respectively. Furthermore, both extracts displayed low cytotoxicity levels against Artemia salina. The gas chromatography–mass spectroscopy analysis confirmed the identifies of 75 phytochemicals from both extracts, and four potent compounds, triacontane, hexacosane, methyl linoleate, and methyl palminoleate, had binding free energy values of −6.75, −6.7, −6.3, and −6.3 Kcal/mol, respectively, in complexes with the SARS-CoV-2 main protease. The active residues Cys145, Met165, Glu166, Gln189, and Arg188 in the main protease formed non-bonded interactions with the screened compounds. The root-mean-square difference (RMSD), root-mean-square fluctuations (RMSF), radius of gyration (Rg), solvent-accessible surface area (SASA), and hydrogen bond data from a molecular dynamics simulation study confirmed the docked complexes′ binding rigidity in the atomistic simulated environment. However, this study′s findings require in vitro and in vivo validation to ensure the possible inhibitory effects and pharmacological efficacy of the identified compounds.     

Crystal engineering using anilic acids and dipyridyl compounds through a new supramolecular synthon

The anilic acids, 2,5-dihydroxy-1,4-benzoquinone (1a), 2,5-dibromo-3,6-dihydroxy-1,4-benzoquinone (bromanilic acid; 1b), 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid; 1c), and 2,5-dicyano-3,6-dihydroxy-1,4-benzoquinone (cyananilic acid; 1d), were cocrystallized with rigid organic ligands containing two pyridine rings, 2,4-bipyridine (2a), 4,4'-bipyridine (2b), 1,2-bis(2-pyridyl)ethylene (3a), 1,2-bis(4-pyridyl)ethylene (3b), 2,2'-dipyridylacetylene (4a), 3,3'-dipyridylacetylene (4b), and 4,4'-dipyridylacetylene (4c). Fourteen complexes 5-18 were obtained as single crystals, and their crystal structures were successfully determined by X-ray analysis. All complexes except those with 2a are 1:1 and are composed of an infinite linear or zigzag tape structure, the formation of which is ascribed to intermolecular O-H...N, N(+)-H...O, or N(+)-H...O(-) hydrogen bonds or a combination of these between the anilic acids and the dipyridyl compounds. In the complexes 5 and 6, no infinite tape structure is observed although the molecular units connected by a similar hydrogen-bonding pattern are formed. For the 1:1 complexes, we have found two types of stacking arrangements, segregated stacks (7, 9, 12-15, 18) and alternated ones (8, 10, 11, 16, 17). In the complexes of 1c with the series of dipyridylacetylenes 4 (14, 15, 17), the neutral, dication, and monocaction states are formed depending on the nitrogen positions, which can be attributed to the different basicity of the pyridyl groups.     

A convenient synthetic route to a useful synthon: 4-bromo-2-pyridinecarboxaldehyde

We have developed a novel four-step method to synthesise 4-bromo-2-pyridinecarboxaldehyde, from 2-picoline-N-oxide via 4-nitro-2-pyridinecarboxaldehyde, under mild reaction conditions.     

Integrin clustering in two and three dimensions

Integrins are transmembrane proteins that allow cells to bind to their external environment. They are the primary regulators of cell-matrix interactions, with direct roles in cell motility and signaling, which in turn regulate numerous physiological processes. Under common experimental conditions, integrins tend to cluster for sturdy and effective binding to extracellular matrix molecules. These clusters often evolve into focal adhesions, which regulate downstream signaling. However, integrin clusters are more pronounced and have longer lifetimes in two-dimensional assays than in more realistic three-dimensional environments. While a number of models and theoretical approaches have focused on integrin binding and diffusion, the reasons for the differences between two- and three-dimensional clustering have remained elusive. In this study, we model an individual cluster attached to a two-dimensional collagen film and attached to collagen fibers of various sizes in three-dimensional matrices. We then discuss how our results explain differences in size and lifetime, and how they hint at reasons for other differences between the two environments. Further, we make predictions regarding the stability of clusters based on different overall intracellular conditions. Our results show good agreement with experiments and provide a quantitative basis for understanding how matrix dimensionality and structure regulate integrin behavior in environments that mimic in vivo conditions.     

Effects of Hall current on unsteady MHD flows of a second grade fluid

The aim of this present paper is to construct exact solutions corresponding to the motion of magnetohydrodynamic (MHD) fluid in the presence of Hall current, due to cosine and sine oscillations of a rigid plate as well as those induced by an oscillating pressure gradient. A uniform magnetic field is applied transversely to the flow. By using Fourier sine transform steady state and transient solutions are presented. These solutions satisfy the governing equations and all associated initial and boundary conditions. The results for a hydrodynamic second grade fluid can be obtained as a limiting case when B ₀ → 0 and for a Newtonian fluid when α ₁ → 0.     

A New Cycloartane Glycoside from the Aerial Part of Astragalus grahamianus

Chemistry of Natural Compounds - A new 9,19-cyclolanostane type arabinoside, 16,23;22,25-diepoxy-3β,22,23,24-tetrahydroxy-9,19-cyclolanostane-3-O-α-L-arabinopyranoside (1), together with...     

Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride-THF-methanol system. The alcohols are obtained in 70–92% yields in 2–5 hours, in a pure state. This two-step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.     

Isomeric yield ratios for the natNd(γ, xn) 139m,g; 141m,gNd reactions in the bremsstrahlung energy region from 45 to 60 MeV

The independent isomeric yield ratios (IR) for the ^139m,gNd and the ^141m,gNd isomeric pairs produced from the ^natNd(γ, xn) reactions were determined by the activation and the off-line γ-ray spectrometric technique at the end-point bremsstrahlung energies of 45, 50, 55, and 60 MeV in the 100 MeV electron Linac of the Pohang accelerator laboratory, Korea. The present IR for the ^141m,gNd isomeric pair were compared with those from the literature measured by the bremsstrahlung and the neutron to examine the role of excitation energy. The obtained IR for the ^139m,gNd and the ^141m,gNd isomeric pairs from ^natNd(γ, xn) reactions were compared with those from the ¹⁴¹Pr(p, x), the ^natCe(³He, x), and the ¹³⁶Ce(α, n) reactions to examine the role of parameters in entrance channel i.e. excitation energy and the effect of the input angular momentum. The present IR of ^139m,gNd and ^141m,gNd were compared with those calculated by using the TALYS 1.4 code as well as those from the literature data of above mentioned reactions.