Lipoxygenase inhibitory synthetic derivatives of methyl gallate regulate gene expressions of COX-2 and cytokines to reduce animal model arthritis.

Mammalian lipoxygenases (LOXs) are involved in the biosynthesis of mediators of anaphylactic reactions and have been implicated in cell maturation, the pathogenesis of bronchial asthma, atherosclerosis, rheumatoid arthritis, cardiovascular diseases, Alzheimer's disease and osteoporosis. Hence LOX inhibition in chronic conditions can lead to reducing the disease progression, which can be a good target for treating these diseases. The present study deals with designing methyl gallate derivatives and their anti-inflammatory effect by in silico, in vitro and in vivo methods. Designed derivatives were docked against LOX enzyme, and molecular dynamic simulations were carried out. Following the synthesis of derivatives, in vitro LOX inhibition assay, enzyme kinetics and fluorescence quenching studies were performed. One of the derivatives of methyl gallate (MGSD 1) was demonstrated as an anti-inflammatory agent for the treatment of rheumatoid arthritis in the animal model. Amelioration of Freund's complete adjuvant (FCA)-induced arthritis by methyl gallate and its derivative with a concentration of 10-40 mg.kg-1 has been assessed in vivo in a 28-day-long study. TNF-α and COX-2 gene expression were also studied. Methyl gallate synthetic derivatives (MGSDs) inhibited LOX with an IC50 of 100 nM, 304 nM, and 226 nM for MGSD 1, MGSD 2, and MGSD 3, respectively. Fluorescence quenching methods also prove their binding characteristics, and 200 ns simulations studies showed that the RMSDs for the entire complex were less than 2.8 Å. The in vivo results showed that methyl gallate was required approximately five times diclofenac for the same level of effect, and the synthesised (MGSD 1) compound required only approximately 1/12 of diclofenac for the same level of effect in in-vivo studies. The preeminent expression of COX-2 and TNF-α genes was significantly decreased after the treatment of the methyl gallate derivative. Hence, the in vivo results showed that the referenced synthetic derivative might have more arthritis-reducing properties than the parent compound methyl gallate and is more potent than the standard drug diclofenac, with no apparent induced toxicity.

Potent phytochemicals against COVID-19 infection from phyto-materials used as antivirals in complementary medicines: a review.

BACKGROUND: Following the outbreak of the COVID-19 pandemic, there was a surge of research activity to find methods/drugs to treat it. There has been drug-repurposing research focusing on traditional medicines. Concomitantly, many researchers tried to find in silico evidence for traditional medicines. There is a great increase in article publication to commensurate the new-found research interests. This situation inspired the authors to have a comprehensive understanding of the multitude of publications related to the COVID-19 pandemic with a wish to get promising drug leads. MAIN BODY: This review article has been conceived and made as a hybrid of the review of the selected papers advertised recently and produced in the interest of the COVID-19 situation, and in silico work done by the authors. The outcome of the present review underscores a recommendation for thorough MDS analyses of the promising drug leads. The inclusion of in silico work as an addition to the review was motivated by a recently published article of Toelzer and colleagues. The in silico investigation of free fatty acids is novel to the field and it buttresses the further MDS analysis of drug leads for managing the COVID-19 pandemic. CONCLUSION: The review performed threw light on the need for MDS analyses to be considered together with the application of other in silico methods of prediction of pharmacologic properties directing towards the sites of drug-receptor regulation. Also, the present analysis would help formulate new recipes for complementary medicines.

Compounds of Citrus medica and Zingiber officinale for COVID-19 inhibition: in silico evidence for cues from Ayurveda.

BACKGROUND: The nasal carriage of SARS-CoV-2 has been reported as the key factor transmitting COVID-19. Interventions that can reduce viral shedding from the nasopharynx could potentially mitigate the severity of the disease and its contagiousness. Herbal formulation of Citrus medica and Zingiber officinale is recommended in an Ayurvedic text as a nasal rinse in the management of contagious fevers. These herbs are also indicated in the management of respiratory illnesses and have been attributed with activity against pathogenic organisms in other texts. Molecular docking studies of the phytocompounds of C. medica and Z. officinale were done to find out whether these compounds could inhibit the receptor binding of SARS-CoV-2 spike protein (S protein) as well as the angiotensin-converting enzyme 2 (ACE-2), as evidenced from their docking into binding/active sites. RESULTS: The proteins of SARS-CoV-2, essential for its entry into human cells and highly expressed in the goblet and ciliated cells of nasal epithelium, play a significant role in contagiousness of the virus. Docking studies indicated that the specific compounds present in C. medica and Z. officinale have significant affinity in silico to spike protein of virus and ACE-2 receptor in the host. CONCLUSION: In silico studies suggest that the phytochemical compounds in C. medica and Z. officinale may have good potential in reducing viral load and shedding of SARS-CoV-2 in the nasal passages. Further studies are recommended to test its efficacy in humans for mitigating the transmission of COVID-19.

Aloe emodin shows high affinity to active site and low affinity to two other sites to result consummately reduced inhibition of lipoxygenase.

Lipoxygenases (LOXs) are potential treatment targets in a variety of inflammatory conditions. It is assumed that blocking the arachidonic acid (AA) metabolism via COX inhibition by either traditional NSAIDs or selective cyclooxygenase-2 (COX-2) inhibitors could lead to the generation of pro-inflammatory leukotrienes and lipoxins via the LOX pathway, partly accounting for the side effects seen with traditional NSAIDs and selective COX-2 inhibitors. To counter this, several LOX, phospholipase A2 (PLA2) inhibitors have been reported nowadays from natural sources. Cassia angustifolia (Vahl.) is a medicinal herb belonging to the family Leguminosae and their LOX inhibitory profiles are reported in this study. Results indicate that ethyl acetate extract of Cassia leaves could inhibit LOX. MS and IR data revealed the presence of aloe emodin (270.2 m/z) in the isolated fraction. Enzyme kinetics showed that aloe emodin inhibit Lipoxygenase competitively with an IC50 of 29.49 µM. Interaction of aloe emodin with LOX was also studied using fluorescence quenching method. ITC results indicate that the interaction of LOX with aloe emodin is endothermic in nature with a stoichiometry of n = 3. In conclusion, anti-inflammatory property of the plant could be assigned to the presence of aloe emodin.

Process development for the enhanced production of bio-nematicide Purpureocillium lilacinum KU8 under solid-state fermentation.

Response surface methodology (RSM) was used to optimize the process parameters for maximizing the biomass production of Purpureocillium lilacinum KU8 using wheat bran as substrate under solid-state fermentation (SSF). The experiments of one-factor-at-a-time approach (OFAT) for central composite design (CCD) to analyze the response pattern brought out the parameters for maximum biomass production. Moisture content, yeast extract and incubation time were found to be the three significant, independent variables responsible for maximum biomass production. The biomass production was 107.46 mg/gdfs which was 1.35 times higher than that of OFAT method and 3.01 times higher than the randomly selected conditions. The optimum conditions established by RSM method for the maximum biomass production are 67.98%, 2.29% and 142.2 h respectively for moisture content, yeast extract and incubation time. The biomass thus produced had quantitatively comparable results in bio-nematicide effectiveness.

Isozymes inhibited by active site blocking: versatility of calcium indifferent hesperidin binding to phospholipase A2 and its significance.

sPLA2 is released under inflammatory conditions from neutrophils, basophils and T-cells. They cleave the cellular phospholipids leading to the release of arachidonic acid and there by provide intermediates for biosynthesis of inflammatory mediators. The focus of this study is on the interaction of hesperidin, a natural flavonoid with Group IB, IIA, and V and X isozymes of sPLA2. Affinity of hesperidin towards PLA2 isozymes was analyzed through enzymatic studies and molecular modeling. The experiments showed that hesperidin competitively inhibited PLA2 with IC50 of 5.1 µM. Molecular modeling studies revealed the association of hesperidin with the docking scores -6.90, -9.53, -5.63 and -8.29 kcal for isozymes Group IB, IIA, V and X of PLA2 respectively. Their binding energy values were calculated as -20.25, -21.63, -21.66 and -33.43 kcal for the Group IB, IIA, V and X respectively. Structural model for Group V was made by homology modeling since no structural coordinates were available. Molecular dynamics studies were carried out to evaluate the structural stability of protein ligand complex. The analyses showed that hesperidin blocked the entry of the substrate to the active site of PLA2 and it was indifferent to the differences of the isozymes. Hence, hesperidin might serve as lead for designing highly specific anti-inflammatory drugs directed to the PLA2 isozyme specific to various diseases, with IC50 value of therapeutic significance.

Surgical resection of solitary distant metastasis from locoregionally controlled advanced hypopharyngeal malignancy: A ray of hope.

Head and neck malignancies have always been challenging for the clinician, both with regards to locoregional control and distant metastasis. Aggressive approaches translate to an acceptable locoregional control, but distant failures pose a dilemma. Newer, sophisticated, imaging modalities have helped in early diagnosis of solitary metastasis, and in turn have opened up an array of interventional procedures, which to some extent improve the disease-free survival and quality of life, as was seen in the present case of locoregionally controlled advanced hypopharyngeal malignancy who presented with solitary distant metastasis. Still, diligent care needs to be taken not to aggravate the scenario with these interventions.

Novel lipoxygenase inhibitor, 1-ethenoxy-2-methylbenzene, from marine cyanobacteria Microcoleus chthonoplastes.

Lipoxygenase (LOX) inhibitors are considered to be important anti-inflammatory agents as it can control many inflammatory responses to some extent. Even though the marine bio-systems are not well explored, they are considered to be one of the promising repositories for drug lead molecules against variety of diseases. In the present study a new LOX inhibitor compound, 1-ethenoxy-2-methylbenzene, reported first time from a living system, Microcoleus chthonoplastes, has been isolated by activity guided fractionation and further structurally characterised by techniques such as FTIR, NMR and LC MS/MS. Further enzyme kinetics, isothermal titration calorimetry and molecular docking methods were used in order to get a better understanding of enzyme-ligand interactions. This exploration suggests its worthiness as a lead molecule for the development of a better anti-inflammatory drug. Its high structure-activity resemblance to cuminaldehyde from cumin seeds, which is earlier reported as a LOX inhibitor, is also established.

Hesperetin and Naringenin sensitize HER2 positive cancer cells to death by serving as HER2 Tyrosine Kinase inhibitors.

AIM: Aberrant human epidermal growth factor receptor-2 (HER2) expression and constitutive mutant activation of its tyrosine kinase domain account for tumor aggression and therapy resistance in many types of cancers with major share in breast cancer cases. HER2 specific treatment modalities still face challenges owing to the side effects and acquired resistance of available therapeutics. Recently, the anti-proliferative and pro-apoptotic potential of phytochemicals, especially of flavonoids have become increasingly appreciated as powerful chemo preventive agents. Consequently, the major goal of our study is to identify flavonoids capable of inhibiting HER2 Tyrosine Kinase (HER2-TK) activity and validate their anti-tumor activity against HER2 positive tumors. MAIN METHODS: Molecular docking studies for identifying flavonoids binding at HER2 kinase domain, ADP-Glo™ Kinase Assay for determining kinase activity, MTT assay to measure growth inhibition, various apoptotic assays and cell cycle analysis by FACS were performed. KEY FINDINGS: Among the flavonoids screened, Naringenin (NG) and Hesperetin (HP) possessed high glide scores from molecular docking studies of enzyme-inhibitor mode. The interaction analysis revealed their ability to establish stable and strong interaction at the ATP binding site of HER2-TK. These compounds also inhibited in vitro HER2-TK activity suggesting their role as HER2 inhibitors. The study also unraveled the anti-proliferative, pro-apoptotic and anti-cancerous activity of these flavonoids against HER2 positive breast cancer cell line. SIGNIFICANCE: The study identified two citrus fruit flavonoids, NG and HP as HER2-TK inhibitors and this is the first report on their potential to target preferentially and sensitize HER2 positive cancer cells to cell death.

Energetics, Thermodynamics, and Molecular Recognition of Piperine with DNA.

Piperine, the bioactive phytochemical from black pepper (Piper nigrum L.), is a nontoxic natural compound exhibiting many physiological and pharmacological properties. They include antioxidant, anti-inflammatory, antimutagenic, antitumor, antiapoptotic, antigenotoxic, antiarthritic, antifungal, antimicrobial, antidepressant, anti-HBV, and gastro-protective activities. It also enhances the bioavailability of phytochemicals and drugs. The molecular mechanism of action of piperine with DNA has not yet been addressed, while its pharmacological activities have been reported. In this work we report for the first time the interaction of piperine molecule with DNA duplex. We have carried out UV-vis absorption and fluorescence spectroscopy to confirm the binding of piperine with calf thymus DNA (ctDNA). The energetics of interaction of piperine with ctDNA was monitored by isothermal titration calorimetry (ITC). Differential scanning calorimetry (DSC) and melting temperature (Tm) analysis were also performed, confirming a minor groove mode of binding of piperine with ctDNA. The binding free energy ΔG values obtained from molecular dynamics simulation studies agree well with ITC values and reveal a sequence dependent minor groove binding exhibiting a specificity toward AT rich sequences.

Metal Ion Coordination Essential for Specific Molecular Interactions of Butea monosperma Lectin: ITC and MD Simulation Studies.

Crystal structure of Butea monosperma seed lectin (BML) was analyzed and the metal ion geometry identified. In order to understand the role of metal ions for the structural stability and ligand binding, studies of demetallized protein were carried out. Binding of different ligands like GalNAc, lactose, and galactose onto native and demetallized protein was studied by isothermal titration calorimetry as well as molecular simulation methods. Molecular dynamics was applied to the structure after removing the coordinates of metal ions, to identify the effect of demetallization in silico. Docking studies of different sugar molecules as well as the fungal α-amylase was carried out and compared the interactions in the native and apo states. It was found that metal ions are important for the ligand binding with increased affinity. However, their absence did not make any alteration to the secondary structure. Though the metal ions were not coordinated to the loops contacting the α-amylase, the absence of metal ions reduced the protein-protein binding strength due to long-range changes in irregular structures of the lectin.

The crystal structure of a lectin from Butea monosperma: insight into its glycosylation and binding of ligands.

Crystal structure of a lectin purified from Butea monosperma seeds was determined by Molecular Replacement method. Its primary structure was determined by Tandem Mass Spectroscopy and electron density maps from X-ray diffraction data. Its quaternary structure was tetrameric, formed of two monomers, α and ß, ß appearing as truncated α. The occurrence of two tetramers in the asymmetric unit of the crystal might be a consequence of asymmetric contacts due to difference in glycosylation and variable loops structures, to form an 'octamer-structure'. The crystal structure showed binding pockets for γAbu, having a proposed role in plant defense, at the interface of canonical dimer-partners. Hemagglutination studies, enzyme kinetics, isothermal titration calorimetry and molecular dynamics showed that the lectin is specific to N-acetyl d-galactosamine, galactose and lactose in decreasing order, and α-amylase inhibitor.

Cuminaldehyde as a lipoxygenase inhibitor: in vitro and in silico validation.

The search for lipoxygenase (LOX) inhibitors has been carried out for decades due to its importance in inflammatory diseases. In the present study, it was observed that the methanolic extract of Cuminum cyminum L. inhibited LOX activity. Activity-guided screening of the C. cyminum crude extracts helped the identification and isolation of cuminaldehyde as a 15-LOX inhibitor. The enzyme kinetics analysis suggested cuminaldehyde to be a competitive inhibitor and the IC 50 value derived from LB plots is 1,370 µM. Binding constants of cuminaldehyde on LOX was deduced by isothermal titration calorimetry. The combined thermodynamics and molecular modeling analyses suggested cuminaldehyde as a competitive LOX inhibitor. It is proposed from the present study that the coordinate bond between the Fe(2+) atom in the active site of the enzyme and the cuminaldehyde may be responsible for the enzyme inhibition. The study suggests that cuminaldehyde may be acting as an anti-inflammatory compound and may be therefore included in the category of leads for developing dual COX-LOX inhibitors as non-steroidal anti-inflammatory drugs (NSAIDs).

A Rare Case Report of A Young Male Patient Presenting with Osteoblastoma of the Talus.

INTRODUCTION: Osteoblastoma is a rare (incidence <1%) benign locally aggressive osteoblastic lesion of bone with rare malignant transformation. Benign osteoblastoma is the term used by Jaffe to denote an uncommon neoplasm of bone characterized by vascular osteoid and bone forming matrix rich in osteoblasts. CASE REPORT: Here we report a case of osteoblastoma of talus in eighteen year old male patient from Bijapur with complaints of pain and difficulty in walking for one year. Relevant investigations and radiographs were taken. It was treated with wide excision and bone grafting from ipsilateral ilium and talo-navicular fusion with cannulated cancellous screw fixation. Histopathology of the biopsy confirmed the diagnosis. Patient was immobilized with below knee plaster cast for six weeks later with gradual mobilization. Guarded weight bear was allowed after three months. Patient achieved satisfactory range of movements and full weight bear mobilization after six months. Symptoms relieved with no evidence of any recurrence in one year follow up. CONCLUSION: Osteoblastoma of talus is a rare benign tumor, if suspected surgical wide excision and talo-navicular fusion with cannulated cancellous screw fixation, with bone grafting is the better treatment of choice. The condition can only be confirmed after histopathological examination.

Carbohydrate binding and unfolding of Spatholobus parviflorus lectin: fluorescence and circular dichroism spectroscopic study.

Biophysical and carbohydrate binding studies have been carried out on a lectin of Spatholobus parviflorus (SPL) seeds isolated by affinity chromatography on cross-linked guar gum. It agglutinated erythrocytes of all ABO blood groups. SDS-PAGE, both in reducing and non-reducing conditions, showed two bands with MW of 29 and 31 kDa. MALDI TOF analysis revealed two peaks at 60 and 120 kDa, indicating that SPL is a hetero-dimeric tetramer. Temperature and pH stability studies revealed that SPL is a thermostable protein and its lectin activity is unaffected in the temperature range of 0-70 °C. Its activity was maximal in the pH range of 7-8. Unfolding studies with different denaturants like urea and guanidine hydrochloride indicated its globular nature and the presence of tryptophan in the highly hydrophobic area, which could be correlated to the results of fluorescence spectroscopic studies. The effect of carbohydrate binding on the lectin, shown by circular dichroism spectra, indicated the changes in its secondary and tertiary structures. SPL exerted anti-fungal activity against Aspergillus sp.

Inverted binding due to a minor structural change in berberine enhances its phospholipase A2 inhibitory effect.

Biotransformation of berberine by Rhizopus oryzae leads to its demethylation, producing hydroxyl derivatives, as revealed by Fourier Transform Infra Red spectroscopy, Nuclear Magnetic Resonance and Electro Spray Ionization-Mass Spectrometric analyses. Surface Plasmon Resonance and enzyme kinetic studies showed that biotransformed derivatives of berberine had a higher inhibitory potential than berberine towards phospholipase A(2). X-ray crystal structures demonstrated that biotransformed berberine binds to PLA(2) in an entirely different, inverted orientation with respect to the binding of berberine. This study brings out the significance of biotransformation in generation of better drug-lead compounds.

Evaluation of biotransformed berberine derivatives as anti inflammatory drugs: an in silico study.

The anti inflammatory potential of the human and microbial biotransformed derivatives of berberine were determined by molecular docking. It was revealed that almost all derivatives formed as a result of biotransformation showed increase in phospholipase A(2) binding affinity compared to berberine. The newly introduced -OH group/groups establish stronger hydrogen bonding interactions and more number of van der Waals contacts with the protein. As phospholipase A(2) is a target of anti inflammatory drugs, it might be concluded that certain biotransformed derivatives of berberine could be better anti inflammatory agents compared to berberine.

X-ray structure of a galactose-specific lectin from Spatholobous parviflorous.

A galactose-specific seed lectin from Spatholobous parviflorus (SPL) has been purified, crystallized and its X-ray structure solved. It is the first lectin purified and crystallized from the genus Spatholobus (family: Fabaceae). The crystals belong to the space group P1, with a=60.792 Å, b=60.998 Å, c=78.179 Å, α=78.68°, ß=88.62°, γ=104.32°. The data were collected at 2.04 Å resolution under cryocondition, on a MAR image-plate detector system, mounted on a rotating anode X-ray generator. The coordinates of Dolichos biflorus lectin (1lu1) were successfully used for the structure solution by molecular replacement method. The primary structure of the SPL was not known earlier and it was unambiguously visible in the electron density. S. parviflorus lectin is a hetero-dimeric-tetramer with two alpha and two beta chains of 251 and 239 residues respectively. SPL has two metal ions, Ca(2+) and Mn(2+), bound to a loop region of each chain. The SPL monomers are in jelly roll form.

Crystallization and preliminary X-ray studies of a galactose-specific lectin from the seeds of Spatholobus parviflorus.

A galactose-specific seed lectin was purified from the legume Spatholobus parviflorus and crystallized using the hanging-drop vapour-diffusion technique. The crystals belonged to space group P1, with unit-cell parameters a = 60.998, b = 60.792, c = 78.179 Å, α = 101.32, ß = 91.38, γ = 104.32°. X-ray diffraction data were collected under cryoconditions (100 K) to a resolution of 2.04 Šusing a MAR image-plate detector system mounted on a rotating-anode X-ray (Cu Kα) generator. Molecular replacement using legume-lectin coordinates as a search model gave a tetrameric structure.