Integrated spectroscopic and computational analyses unravel the molecular interaction of pesticide azinphos-methyl with bovine beta-lactoglobulin.

Organophosphorus are typically hazardous chemicals used in the pharmaceutical, agricultural, and other industries. They pose a serious risk to human life and can be fatal upon direct exposure. Hence, studying the interaction between such compounds with proteins is crucial for environmental, health, and food safety. In this study, we investigated the interaction mechanism between azinphos-methyl (AZM) and ß-lactoglobulin (BLG) at pH 7.4 using a combination of biophysical techniques. Intrinsic fluorescence investigations revealed that BLG fluorescence was quenched in the presence of increasing AZM concentrations. The quenching mechanism was identified as static, as evidenced by a decrease in the fluorescence quenching constant (1.25 × 104, 1.18 × 104, and 0.86 × 104 M-1) with an increase in temperatures. Thermodynamic calculations (ΔH > 0; ΔS > 0) affirmed the formation of a complex between AZM and BLG through hydrophobic interactions. The BLG's secondary structure was found to be increased due to AZM interaction. Ultraviolet -visible spectroscopy data showed alterations in BLG conformation in the presence of AZM. Molecular docking highlighted the significant role of hydrophobic interactions involving residues such as Val43, Ile56, Ile71, Val92, Phe105, and Met107 in the binding between BLG and AZM. A docking energy of -6.9 kcal mol-1, and binding affinity of 1.15 × 105 M-1 suggest spontaneous interaction between AZM and BLG with moderate to high affinity. These findings underscore the potential health risks associated with the entry of AZM into the food chain, emphasizing the need for further consideration of its impact on human health.

Binding of a Drug (Colchicine) to L-Asparaginase Enzyme Using Multispectroscopic, Thermodynamics, and Simulation Studies: Possible Implication in Acute Lymphoblastic Leukemia Treatment.

The research aims to elucidate how drug interactions affect the activity of L-asparaginase (L-ASNase), an essential enzyme in cancer treatment, especially for acute lymphoblastic leukemia (ALL). Understanding these interactions is crucial for optimizing treatment effectiveness and reducing adverse effects. This study explores the intricate molecular interactions and structural dynamics of L-ASNase upon binding with colchicine. Fluorescence quenching experiments were conducted at various temperatures (298, 303, and 310 K), revealing notable interactions between L-ASNase and colchicine. These interactions were characterized by a reduction in fluorescence intensity and a blue shift in emission maxima. Additional analyses, including the determination of Stern-Volmer quenching constants (KSV), bimolecular quenching rate constants (kq), and thermodynamic parameters, indicated a static quenching mechanism with moderate binding affinities (Ka: 1.40-2.71 × 104 M-1) across different temperatures. Thermodynamic study suggested positive enthalpy and entropy changes (ΔH° = -10.26 kcal mol-1; ΔS° = -14.19 cal mol-1 K-1), suggesting a spontaneous reaction with negative ΔG° values (-5.86 to -6.03 kcal mol-1). FRET measurements supported optimal distances (r and Ro) for FRET occurrence, reinforcing the static quenching mechanism. Molecular docking further supported these findings, revealing a 1:1 stoichiometric binding ratio for L-ASNase:colchicine and elucidating specific binding orientations and interactions critical for complex stability. Subsequent molecular dynamics simulations spanning 100 ns underscored the stability of the L-ASNase-colchicine complex, with minimal deviations observed in key structural parameters such as RMSD, RMSF, Rg, and SASA. Additionally, spectroscopic analyses, including circular dichroism (CD), synchronous fluorescence, and 3D fluorescence provided insights into the conformational changes and alterations in the microenvironment of aromatic amino acid residues in L-ASNase upon colchicine binding. Moreover, L-ASNase activity was slightly reduced by 25% in the presence of colchicine. This comprehensive investigation sheds light on the molecular intricacies of the L-ASNase-colchicine complex, advancing our understanding of drug-target interactions and offering potential avenues for therapeutic applications.

Study of Amiloride Binding to Human Serum Albumin: Insights from Thermodynamic, Spectroscopic, and Molecular Docking Investigations.

This study was undertaken to investigate the interaction between the sodium channel blocker amiloride (AML) and human serum albumin (HSA). A combination of multi-spectroscopic techniques and computational methods were employed to identify the AML binding site on HSA and the forces responsible for the formation of the HSA-AML complex. Our findings revealed that AML specifically binds to Sudlow's site II, located in subdomain IIIA of HSA, and that the complex formed is stabilized using van der Waals hydrogen-bonding and hydrophobic interactions. FRET analysis showed that the distance between AML and Trp214 was optimal for efficient quenching. UV-Vis spectroscopy and circular dichroism indicated minor changes in the structure of HSA after AML binding, and molecular dynamics simulations (MDS) conducted over 100 ns provided additional evidence of stable HSA-AML-complex formation. This study enhances understanding of the interaction between AML and HSA and the mechanism responsible.

Assessment of the Anticancer Effect of Chlorojanerin Isolated from Centaurothamnus maximus on A549 Lung Cancer Cells.

The goal of this study was to assess the anticancer efficacy of chlorojanerin against various cancer cells. The effects of chlorojanerin on cell cytotoxicity, cell cycle arrest, and cell apoptosis were examined using MTT assay, propidium iodide staining, and FITC Annexin V assay. RT-PCR was employed to determine the expression levels of apoptosis-related genes. Furthermore, docking simulations were utilized to further elucidate the binding preferences of chlorojanerin with Bcl-2. According to MTT assay, chlorojanerin inhibited the proliferation of all tested cells in a dose-dependent manner with a promising effect against A549 lung cancer cells with an IC50 of 10 µM. Cell growth inhibition by chlorojanerin was linked with G2/M phase cell cycle arrest in A549 treated cells. Flow cytometry analysis indicated that the proliferation inhibition effect of chlorojanerin was associated with apoptosis induction in A549 cells. Remarkably, chlorojanerin altered the expression of many genes involved in apoptosis initiation. Moreover, we determined that chlorojanerin fit into the active site of Bcl-2 according to the molecular docking study. Collectively, our results demonstrate that chlorojanerin mediated an anticancer effect involving cell cycle arrest and apoptotic cell death and, therefore, could potentially serve as a therapeutic agent in lung cancer treatment.

In Silico Identification of Novel Derivatives of Rifampicin Targeting Ribonuclease VapC2 of M. tuberculosis H37Rv: Rifampicin Derivatives Target VapC2 of Mtb H37Rv.

The emergence of multi-drug-resistant Mycobacterium tuberculosis (Mtb) strains has rendered many of the currently available anti-TB drugs ineffective. Hence, there is a pressing need to discover new potential drug targets/candidates. In this study, attempts have been made to identify novel inhibitors of the ribonuclease VapC2 of Mtb H37Rv using various computational techniques. Ribonuclease VapC2 Mtb H37Rv's protein structure was retrieved from the PDB databank, 22 currently used anti-TB drugs were retrieved from the PubChem database, and protein-ligand interactions were analyzed by docking studies. Out of the 22 drugs, rifampicin (RIF), being a first-line drug, showed the best binding energy (-8.8 Kcal/mol) with Mtb H37Rv VapC2; hence, it was selected as a parent molecule for the design of its derivatives. Based on shape score and radial plot criteria, out of 500 derivatives designed through SPARK (Cresset®, Royston, UK) program, the 10 best RIF derivatives were selected for further studies. All the selected derivatives followed the ADME criteria concerning drug-likeness. The docking of ribonuclease VapC2 with RIF derivatives revealed the best binding energy of -8.1 Kcal/mol with derivative 1 (i.e., RIF-155841). A quantitative structure-activity relationship study revealed that derivative 1's activity assists in the inhibition of ribonuclease VapC2. The stability of the VapC2-RIF155841 complex was evaluated using molecular dynamics simulations for 50 ns and the complex was found to be stable after 10 nsec. Further, a chemical synthesis scheme was designed for the newly identified RIF derivative (RIF-155841), which verified that its chemical synthesis is possible for future in vitro/in vivo experimental validation. Overall, this study evaluated the potential of the newly designed RIF derivatives with respect to the Mtb VapC2 protein, which is predicted to be involved in some indispensable processes of the related pathogen. Future experimental studies regarding RIF-155841, including the exploration of the remaining RIF derivatives, are warranted to verify our current findings.

Investigating the binding mechanism of topiramate with bovine serum albumin using spectroscopic and computational methods.

Various spectroscopic techniques involving fluorescence spectroscopy, circular dichroism (CD), and computational approaches were used to elucidate the molecular aspects of interaction between the antiepileptic drug topiramate and the multifunctional transport protein bovine serum albumin (BSA) under physiological conditions. Topiramate quenched BSA fluorescence in a static quenching mode, according to the Stern-Volmer quenching constant (Ksv ) data derived from fluorescence spectroscopy for the topiramate-BSA complex. The binding constant was also used to calculate the binding affinity for the topiramate-BSA interaction. Fluorescence and circular dichroism experiments demonstrate that the protein's tertiary structure is affected by the microenvironmental alterations generated by topiramate binding to BSA. To establish the exact binding site, interacting residues, and interaction forces involved in the binding of topiramate to BSA, molecular modeling and simulation approaches were used. According to the Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) calculations, the average binding energy between topiramate and BSA is -421.05 kJ/mol. Topiramate was discovered to have substantial interactions with BSA, changing the structural dynamic and Gibbs free energy landscape patterns.

Spectroscopic and Molecular Docking Investigation on the Interaction of Cumin Components with Plasma Protein: Assessment of the Comparative Interactions of Aldehyde and Alcohol with Human Serum Albumin.

The interaction of the important plasma protein, human serum albumin (HSA), with two monoterpenes found in cumin oil, i.e., cuminaldehyde (4-isopropylbenzaldehyde) and cuminol (4-isopropylbenzyl alcohol), was studied in this paper. Both experimental and computational methods were utilized to understand the mechanism of binding. The UV absorption profile of HSA changes in the presence of both cuminaldehyde and cuminol, due to the interaction between HSA with both monoterpenes. The intrinsic fluorescence intensity of HSA was also quenched on the sequential addition of both ligands, due to change in the microenvironment of the fluorophore present in the former. Quenching of HSA by cuminaldehyde was much higher in comparison to that in the presence of cuminol. Fluorescence quenching data were analyzed using modified Stern-Volmer and Lineweaver-Burk methods, which suggested that the binding mechanism was of a static type for both ligands. In both cases, the binding was favored by the domination of hydrophobic as well as hydrogen bonding/Van der Waals forces. Both ligands partially unfolded the secondary structure of HSA, although the effect of cuminaldehyde was more pronounced, as compared to cuminol. The preferred binding site of cuminaldehyde and cuminol inside HSA was also the same; namely, drug binding site 1, located in subdomain IIA. The study showed that cuminaldehyde binds strongly with albumin as compared to its alcohol counterpart, which is due to the more hydrophobic nature of the former.

Identification of a Potential Inhibitor (MCULE-8777613195-0-12) of New Delhi Metallo-ß-Lactamase-1 (NDM-1) Using In Silico and In Vitro Approaches.

New Delhi metallo-ß-lactamase-1 (NDM-1), expressed in different Gram-negative bacteria, is a versatile enzyme capable of hydrolyzing ß-lactam rings containing antibiotics such as penicillins, cephalosporins, and even carbapenems. Multidrug resistance in bacteria mediated by NDM-1 is an emerging threat to the public health, with an enormous economic burden. There is a scarcity in the availability of specific NDM-1 inhibitors, and also a lag in the development of new inhibitors in pharmaceutical industries. In order to identify novel inhibitors of NDM-1, we screened a library of more than 20 million compounds, available at the MCULE purchasable database. Virtual screening led to the identification of six potential inhibitors, namely, MCULE-1996250788-0-2, MCULE-8777613195-0-12, MCULE-2896881895-0-14, MCULE-5843881524-0-3, MCULE-4937132985-0-1, and MCULE-7157846117-0-1. Furthermore, analyses by molecular docking and ADME properties showed that MCULE-8777613195-0-12 was the most suitable inhibitor against NDM-1. An analysis of the binding pose revealed that MCULE-8777613195-0-12 formed four hydrogen bonds with the catalytic residues of NDM-1 (His120, His122, His189, and Cys208) and interacted with other key residues. Molecular dynamics simulation and principal component analysis confirmed the stability of the NDM-1 and MCULE-8777613195-0-12 complex. The in vitro enzyme kinetics showed that the catalytic efficiency (i.e., kcat/Km) of NDM-1 on various antibiotics decreased significantly in the presence of MCULE-8777613195-0-12, due to poor catalytic proficiency (kcat) and affinity (Km). The IC50 value of MCULE-8777613195-0-12 (54.2 µM) was comparable to that of a known inhibitor, i.e., D-captopril (10.3 µM). In sum, MCULE-8777613195-0-12 may serve as a scaffold to further design/develop more potent inhibitors of NDM-1 and other ß-lactamases.

Antimicrobial Activity of Dihydroisocoumarin Isolated from Wadi Lajab Sediment-Derived Fungus Penicillium chrysogenum: In Vitro and In Silico Study.

Antibiotic resistance is considered a major health concern globally. It is a fact that the clinical need for new antibiotics was not achieved until now. One of the most commonly prescribed classes of antibiotics is ß-Lactam antibiotics. However, most bacteria have developed resistance against ß-Lactams by producing enzymes ß-Lactamase or penicillinase. The discovery of new ß-Lactamase inhibitors as new antibiotics or antibiotic adjuvants is essential to avoid future catastrophic pandemics. In this study, five dihydroisocoumarin: 6-methoxy mellein (1); 5,6-dihydroxymellein (2); 6-hydroxymellein (3); 4-chloro-6-hydroxymellein (4) and 4-chloro-5,6-di-hydroxymellein (5) were isolated from Wadi Lajab sediment-derived fungus Penicillium chrysogenum, located 15 km northwest of Jazan, KSA. The elucidation of the chemical structures of the isolated compounds was performed by analysis of their NMR, MS. Compounds 1-5 were tested for antibacterial activities against Gram-positive and Gram-negative bacteria. All of the compounds exhibited selective antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Bacillus licheniformis except compound 3. The chloro-dihydroisocoumarin derivative, compound 4, showed potential antimicrobial activities against all of the tested strains with the MIC value between 0.8-5.3 µg/mL followed by compound 5, which exhibited a moderate inhibitory effect. Molecular docking data showed good affinity with the isolated compounds to ß-Lactamase enzymes of bacteria; NDM-1, CTX-M, OXA-48. This work provides an effective strategy for compounds to inhibit bacterial growth or overcome bacterial resistance.

Soyasapogenol-B as a Potential Multitarget Therapeutic Agent for Neurodegenerative Disorders: Molecular Docking and Dynamics Study.

Neurodegenerative disorders involve various pathophysiological pathways, and finding a solution for these issues is still an uphill task for the scientific community. In the present study, a combination of molecular docking and dynamics approaches was applied to target different pathways leading to neurodegenerative disorders such as Alzheimer's disease. Initially, abrineurin natural inducers were screened using physicochemical properties and toxicity assessment. Out of five screened compounds, a pentacyclic triterpenoid, i.e., Soyasapogenol B appeared to be the most promising after molecular docking and simulation analysis. Soyasapogenol B showed low TPSA (60.69), high absorption (82.6%), no Lipinski rule violation, and no toxicity. Docking interaction analysis revealed that Soyasapogenol B bound effectively to all of the targeted proteins (AChE, BuChE MAO-A, MAO-B, GSK3ß, and NMDA), in contrast to other screened abrineurin natural inducers and inhibitors. Importantly, Soyasapogenol B bound to active site residues of the targeted proteins in a similar pattern to the native ligand inhibitor. Further, 100 ns molecular dynamics simulations analysis showed that Soyasapogenol B formed stable complexes against all of the targeted proteins. RMSD analysis showed that the Soyasapogenol B-protein complex exhibited average RMSD values of 1.94 Å, 2.11 Å, 5.07 Å, 2.56 Å, 3.83 Å and 4.07 Å. Furthermore, the RMSF analysis and secondary structure analysis also indicated the stability of the Soyasapogenol B-protein complexes.

The anti-hepatitis B virus and anti-hepatotoxic efficacies of solanopubamine, a rare alkaloid from Solanum schimperianum.

Chronic liver disease caused by hepatitis B virus (HBV) remains an important health issue. Though there are effective HBV-polymerase inhibitors (e.g., lamivudine), their prolonged use leads to emergence of drug-resistant (polymerase mutant) strains. Several herbal formulations and phytochemicals have been therefore, reported as potential anti-HBV agents with no sign of resistance in experimental and clinical settings. In this study, we assessed the anti-HBV as well as hepatoprotective salutations of solanopubamine, a rare alkaloid isolated from S. schimperianum. In cultured HepG2.2.15 cells, solanopubamine showed marked anti-HBV activity in a time and dose-dependent manner. Solanopubamine (30 µM) efficiently inhibited HBsAg and HBeAg expressions by 66.5%, 70.5%, respectively as compared to 82.5% and 86.5% respective inhibition by lamivudine (2 µM) at day 5. Molecular docking analyses of solanopubamine revealed formations of stable complexes with lamivudine-sensitive as well as lamivudine-resistant polymerase through interactions of catalytic 'YMDD/YIDD' motif residues. Moreover, solanopubamine attenuated DCFH-induced oxidative and apoptotic damage and restored HepG2 cell viability by 28.5%, and downregulated caspase-3/7 activations by 33%. Further docking analyses of solanopubamine showed formation of stable complexes with caspase-3/7. Taken together, our data demonstrates promising anti-HBV and anti-hepatotoxic therapeutic potential of solanopubamine, and warrants further molecular and pharmacological studies.

Quinoline yellow dye stimulates whey protein fibrillation via electrostatic and hydrophobic interaction: A biophysical study.

Amyloid fibril formation of proteins is associated with a number of neurodegenerative diseases. Several small molecules can accelerate the amyloid fibril formation in vitro and in vivo. However, the molecular mechanism of amyloid fibrillation is still unclear. In this study, we investigated how the food dye quinoline yellow (QY) induces amyloid fibrillation in α-lactalbumin (α-LA), a major whey protein, at pH 2.0. We used several spectroscopy techniques and a microscopy technique to explore how QY provokes amyloid fibrillation in α-LA. From turbidity and Rayleigh light scattering experiments, we found that QY promotes α-LA aggregation in a concentration-dependent manner; the optimal concentration for α-LA aggregation was 0.15 to 10.00 mM. Below 0.1 mM, no aggregation occurred. Quinoline yellow-induced aggregation was a rapid process that escaped the lag phase, but it depended on the concentrations of both α-LA and QY. We also demonstrated that aggregation switched the secondary structure of α-LA from α-helices to cross-ß-sheets. We then confirmed the amyloid-like structure of aggregated α-LA by transmission electron microscopy measurements. Molecular docking and simulation confirmed the stability of the α-LA-QY complex due to the formation of 1 hydrogen bond with Lys99 and 2 electrostatic interactions with Arg70 and Lys99, along with hydrophobic interactions with Leu59 and Tyr103. This study will aid in our understanding of how small molecules induce aggregation of proteins inside the stomach (low pH) and affect the digestive process.

Crosstalk of plant growth regulators protects photosynthetic performance from arsenic damage by modulating defense systems in rice.

Salicylic acid (SA) is a well-known plant growth regulator, which participates in many physiological processes of plants under normal and stressful conditions. In this study, we investigated the impact of SA supplementation on the components of ascorbate-glutathione cycle and glyoxalase system, photosynthesis and growth of rice (Oryza sativa) plants subjected to arsenic (As) stress. Plants grown with As exhibited enhanced As uptake, increased oxidative stress, and photosynthesis and growth inhibition. Application of SA promoted photosynthesis and growth in plants with or without As stress by improving plant defense systems and reducing oxidative stress through interaction with ethylene and nitric oxide (NO). SA acted as an ethylene antagonist, reducing stress ethylene formation under As stress, while NO formation was induced. This resulted in coordinated control over the antioxidant defense systems and enhanced As tolerance, protecting photosynthesis and growth from As-induced damage. The study showed that positive responses of SA in promoting photosynthesis and growth under As stress were the result of its interplay with ethylene and NO, enhanced capacity of defense systems to reduce oxidative stress. The crosstalk of SA with ethylene and NO will be useful in augmenting the performance of rice plants under As stress.

Box-Behnken Design (BBD)-Based Optimization of Microwave-Assisted Extraction of Parthenolide from the Stems of Tarconanthus camphoratus and Cytotoxic Analysis.

Parthenolide, a strong cytotoxic compound found in different parts of Tarchonanthus camphoratus which motivated the authors to develop an optimized microwave-assisted extraction (MEA) method using Box-Behnken design (BBD) for efficient extraction of parthenolide from the stem of T. camphoratus and its validation by high-performance thin-layer chromatography (HPTLC) and cytotoxic analysis. The optimized parameters for microwave extraction were determined as: 51.5 °C extraction temperature, 50.8 min extraction time, and 211 W microwave power. A quadratic polynomial model was found the most suitable model with R2 of 0.9989 and coefficient of variation (CV) of 0.2898%. The high values of adjusted R2 (0.9974), predicted R2 (0.9945), and signal-to-noise ratio (74.23) indicated a good correlation and adequate signal, respectively. HPTLC analyzed the parthenolide (Rf = 0.16) content in T. camphoratus methanol extract (TCME) at λmax = 575 nm and found it as 0.9273% ± 0.0487% w/w, which was a higher than expected yield (0.9157% w/w). The TCME exhibited good cytotoxicity against HepG2 and MCF-7 cell lines (IC50 = 30.87 and 35.41 µg/mL, respectively), which further supported our findings of high parthenolide content in TCME. This optimized MAE method can be further applied to efficiently extract parthenolide from marketed herbal supplements containing different Tarconanthus species.

Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp.

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-ß-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.

Cytotoxicity and molecular docking analysis of racemolactone I, a new sesquiterpene lactone isolated from Inula racemosa.

CONTEXT: Traditionally, Inula racemosa Hook. f. (Asteraceae) has been reported to be effective in cancer treatment which motivated the authors to explore the plant for novel anticancer compounds. OBJECTIVE: To isolate and characterize new cytotoxic phytoconstituents from I. racemosa roots. MATERIALS AND METHODS: The column chromatography of I. racemosa ethyl acetate extract furnished a novel sesquiterpene lactone whose structure was established by NMR (1D/2D), ES-MS and its cytotoxic properties were assessed on HeLa, MDAMB-231, and A549 cell lines using MTT and LDH (lactate dehydrogenase) assays. Further, morphological changes were analyzed by flow cytometry, mitochondrial membrane potential, AO-EtBr dual staining, and comet assay. Molecular docking and simulation were performed using Glide and Desmond softwares, respectively, to validate the mechanism of action. RESULTS: The isolated compound was identified as racemolactone I (compound 1). Amongst the cell lines tested, considerable changes were observed in HeLa cells. Compound 1 (IC50 = 0.9 µg/mL) significantly decreased cell viability (82%) concomitantly with high LDH release (76%) at 15 µg/mL. Diverse morphological alterations along with significant increase (9.23%) in apoptotic cells and decrease in viable cells were observed. AO-EtBr dual staining also confirmed the presence of 20% apoptotic cells. A gradual decrease in mitochondrial membrane potential was observed. HeLa cells showed significantly increased comet tail length (48.4 µm), indicating broken DNA strands. In silico studies exhibited that compound 1 binds to the active site of Polo-like kinase-1 and forms a stable complex. CONCLUSIONS: Racemolactone I was identified as potential anticancer agent, which can further be confirmed by in vivo investigations.

Treatment of nitric oxide supplemented with nitrogen and sulfur regulates photosynthetic performance and stomatal behavior in mustard under salt stress.

Nitric oxide (NO) is a hormone that connects numerous reactions in plant cells under normal and environmental stress conditions. The application of 100 µM NO as sodium nitroprusside (SNP; NO donor) applied individually or in combination with N or S in different combinations (i.e. 100 mg N or S kg-1 soil applied at the time of sowing [100 N + 100S]0d or with split, 50 mg N or S kg-1 soil at the time of sowing and similar dose at 20 d after sowing [50 N + 50S]0d + [50 N + 50S]20d ) was tested to alleviate salt stress in mustard (Brassica juncea L.). Application of 100 µM NO plus split application of N and S more significantly promoted stomatal behavior, photosynthetic and growth performance in the absence of salt stress and maximally alleviated effects of salt stress through increased N- and S-use efficiency, proline and antioxidant system. The combined application of N and S at the time of sowing was lesser effective in promoting photosynthesis and growth under salt or no salt stress conditions in presence or absence of NO. The study suggests that salt stress effects on the photosynthetic performance are mitigated more efficiently when NO was applied together with the split application of N and S given at two stages, and the photosynthetic activity was promoted under salt stress through increased N and S assimilation and antioxidant system. This strategy may be adopted in agricultural system for overcoming salt stress effects on performance of mustard.

Quinoline yellow (food additive) induced conformational changes in lysozyme: a spectroscopic, docking and simulation studies of dye-protein interactions.

Quinoline yellow (QY) is a synthetic yellow dye widely used as a coloring agent for various foodstuffs. In the current study, we have examined the role of QY on the aggregation propensity of hen egg-white lysozyme (HEWL) under physiological conditions. The dye induced conformational changes in HEWL leading to aggregate formation were identified by circular dichroism (CD), turbidity analysis, fluorescence measurement and microscopic (TEM) imaging. Molecular docking and molecular dynamics simulation studies were also employed to strengthen binding and aggregation results. Our results indicate that 25-100 µM of QY induces aggregation in HEWL, while lower QY concentrations (5 and 10 µM) does not have any effect on the aggregation propensity of HEWL. The kinetics of HEWL aggregation demonstrate nucleation independent aggregation of HEWL without lag phase. On the other hand, far UV-CD analysis illustrated the loss of α-helical structure with the increasing concentration of QY. TEM results also support the formation of aggregate structures in HEWL when exposed to QY. Molecular docking and simulation studies revealed that the HEWL-QY complex is stable as compared to individual entities. In silico analysis also illustrated that QY-induced aggregation of HEWL proceeds through the formation of hydrogen bonds, electrostatic (Pi-Anion) and Pi-Sulfur interactions. The above-mentioned results highlight the possible detrimental effect by food additive dyes, particularly in protein misfolding.

Ethephon mitigates nickel stress by modulating antioxidant system, glyoxalase system and proline metabolism in Indian mustard.

The role of ethylene (through application of ethephon) in the regulation of nickel (Ni) stress tolerance was investigated in this study. Ethephon at concentration of 200 µl l-1 was applied to mustard (Brassica juncea) plants grown without and with 200 mg kg-1 soil Ni to study the increased growth traits, biochemical attributes, photosynthetic efficiency, nutrients content, activities of antioxidants such as superoxide dismutase, ascorbate peroxidase, glutathione reductase, and glutathione peroxidase, glyoxalase systems and enhanced the proline metabolism. In the absence of ethephon, Ni increased oxidative stress with a concomitant decrease in photosynthesis, growth and nutrients content. However, application of ethephon positively increased growth traits, photosynthetic parameters, nutrients content and also elevated the generation of antioxidants enzymes and glyoxalase systems, proline production to combat oxidative stress. Plants water relations and cellular homeostasis were maintained through increased photosynthetic efficiency and proline production. This signifies the role of ethylene in mediating Ni tolerance via regulating proline production and photosynthetic capacity. Ethephon can be used as an exogenous supplement on plants to confer Ni tolerance. The results can be exploited to develop tolerance in plants via gene editing technology encoding enzymes responsible for proline synthesis, antioxidant defence, glyoxalase systems and photosynthetic effectiveness.

Oncoglabrinol C, a new flavan from Oncocalyx glabratus protects endothelial cells against oxidative stress and apoptosis, and modulates hepatic CYP3A4 activity.

Active herbal or natural compounds have high chemical diversity and specificity than synthetic drugs. Recently, we have validated the hypoglycemic salutation of Oncocalyx glabratus in rodent model, and demonstrated the activation of PPARα/γ by its newly ioslated flavan derivative Oncoglabrinol C (5,3'-Dihydroxyflavan 7-4'-O-digallate) in liver cells (HepG2). Here we evaluated the potential of Oncoglabrinol C against Dichlorofluorescin (DCFH) and Methylglyoxal (MGO) induced endothelial cells (HUVEC) oxidative and apoptotic damage, including activation of PXR-mediated hepatic CYP3A4. Our MTT assay showed protection of ~57% and ~63.5% HUVEC cells by 10 and 20 µg/ml doses of Oncoglabrinol C, respectively through attenuating DCFH triggered free-radicals. Also, the two doses effectively protected ~53% and ~65.5% cells, respectively by reversing MGO toxicity. In DCFH and MGO treated cells, Oncoglabrinol C (20 µg/ml) effectively downregulated caspase 3/7 activity by ~33% and ~43.5%, respectively. Moreover, in reporter gene (dual-luciferase) assay, Oncoglabrinol C (20 µg/ml) moderately activated hepatic CYP3A4. Molecular docking of Oncoglabrinol C indicated its strong interactions with cellular caspase 3/7, PPARα/γ and PXR proteins, which supported its anti-apoptotic (antagonistic) as well as pro-hypoglycemic and PXR/CYP activating (agonistic) activities. Taken together, our findings demonstrated the potential of Oncoglabrinol C in reversing the endothelial oxidative and apoptotic damage as well as in the activation of hepatic CYP3A4. This warrants further evaluations of Oncoglabrinol C and related compounds towards developing effective and safe drugs against diabetes associated cardiovascular disorders.