Mechanistic insights into the potential role of dietary polyphenols and their nanoformulation in the management of Alzheimer's disease

Alzheimer's disease (AD) is a very common neurodegenerative disorder associated with memory loss and a progressive decline in cognitive activity. The two major pathophysiological factors responsible for AD are amyloid plaques (comprising amyloid-beta aggregates) and neurofibrillary tangles (consisting of hyperphosphorylated tau protein). Polyphenols, a class of naturally occurring compounds, are immensely beneficial for the treatment or management of various disorders and illnesses. Naturally occurring sources of polyphenols include plants and plant-based foods, such as fruits, herbs, tea, vegetables, coffee, red wine, and dark chocolate. Polyphenols have unique properties, such as being the major source of anti-oxidants and possessing anti-aging and anti-cancerous properties. Currently, dietary polyphenols have become a potential therapeutic approach for the management of AD, depending on various research findings. Dietary polyphenols can be an effective strategy to tackle multifactorial events that occur with AD. For instance, naturally occurring polyphenols have been reported to exhibit neuroprotection by modulating the Aβ biogenesis pathway in AD. Many nanoformulations have been established to enhance the bioavailability of polyphenols, with nanonization being the most promising. This review comprehensively provides mechanistic insights into the neuroprotective potential of dietary polyphenols in treating AD. It also reviews the usability of dietary polyphenol as nanoformulation for AD treatment.

Pharmacophore-Based Screening, Molecular Docking, and Dynamic Simulation of Fungal Metabolites as Inhibitors of Multi-Targets in Neurodegenerative Disorders

Neurodegenerative disorders, such as Alzheimer's disease (AD), negatively affect the economic and psychological system. For AD, there is still a lack of disease-altering treatments and promising cures due to its complex pathophysiology. In this study, we computationally screened the natural database of fungal metabolites against three known therapeutic target proteins of AD. Initially, a pharmacophore-based, drug-likeness category was employed for screening, and it filtered the 14 (A-N) best hits out of 17,544 fungal metabolites. The 14 best hits were docked individually against GSK-3β, the NMDA receptor, and BACE-1 to investigate the potential of finding a multitarget inhibitor. We found that compounds B, F, and L were immuno-toxic, whereas E, H, I, and J had a higher LD50 dose (5000 mg/kg). Among the examined metabolites, the Bisacremine-C (compound I) was found to be the most active molecule against GSK-3β (ΔG: -8.7 ± 0.2 Kcal/mol, Ki: 2.4 × 106 M-1), NMDA (ΔG: -9.5 ± 0.1 Kcal/mol, Ki: 9.2 × 106 M-1), and BACE-1 (ΔG: -9.1 ± 0.2 Kcal/mol, Ki: 4.7 × 106 M-1). It showed a 25-fold higher affinity with GSK-3β, 6.3-fold higher affinity with NMDA, and 9.04-fold higher affinity with BACE-1 than their native ligands, respectively. Molecular dynamic simulation parameters, such as RMSD, RMSF, Rg, and SASA, all confirmed that the overall structures of the targeted enzymes did not change significantly after binding with Bisacremine-C, and the ligand remained inside the binding cavity in a stable conformation for most of the simulation time. The most significant hydrophobic contacts for the GSK-3β-Bisacremine-C complex are with ILE62, VAL70, ALA83, and LEU188, whereas GLN185 is significant for H-bonds. In terms of hydrophobic contacts, TYR184 and PHE246 are the most important, while SER180 is vital for H-bonds in NMDA-Bisacremine-C. THR232 is the most crucial for H-bonds in BACE-1-Bisacremine-C and ILE110-produced hydrophobic contacts. This study laid a foundation for further experimental validation and clinical trials regarding the biopotency of Bisacremine-C.

Myco-Synthesis of Silver Nanoparticles and Their Bioactive Role against Pathogenic Microbes

Nanotechnology based on nanoscale materials is rapidly being used in clinical settings, particularly as a new approach for infectious illnesses. Recently, many physical/chemical approaches utilized to produce nanoparticles are expensive and highly unsafe to biological species and ecosystems. This study demonstrated an environmentally friendly mode of producing nanoparticles (NPs) where Fusarium oxysporum has been employed for generation of silver nanoparticles (AgNPs), which were further tested for their antimicrobial potentials against a variety of pathogenic microorganisms. The characterization of NPs was completed by UV-Vis spectroscopy, DLS and TEM, where it has been found that the NPs were mostly globular, with the size range of 50 to 100 nm. The myco-synthesized AgNPs showed prominent antibacterial potency observed as zone of inhibition of 2.6 mm, 1.8 mm, 1.5 mm, and 1.8 mm against Vibrio cholerae, Streptococcus pneumoniae, Klebsiella pneumoniae and Bacillus anthracis, respectively, at 100 µM. Similarly, at 200 µM for A. alternata, A. flavus and Trichoderma have shown zone of inhibition as 2.6 mm, 2.4 mm, and 2.1 mm, respectively. Moreover, SEM analysis of A. alternata confirmed the hyphal damage where the layers of membranes were torn off, and further EDX data analysis showed the presence of silver NPs, which might be responsible for hyphal damage. The potency of NPs may be related with the capping of fungal proteins that are produced extracellularly. Thus, these AgNPs may be used against pathogenic microbes and play a beneficial role against multi-drug resistance.

Multitargeted Virtual Screening and Molecular Simulation of Natural Product-like Compounds against GSK3β, NMDA-Receptor, and BACE-1 for the Management of Alzheimer's Disease

The complexity of Alzheimer's disease (AD) and several side effects of currently available medication inclined us to search for a novel natural cure by targeting multiple key regulatory proteins. We initially virtually screened the natural product-like compounds against GSK3β, NMDA receptor, and BACE-1 and thereafter validated the best hit through molecular dynamics simulation (MDS). The results demonstrated that out of 2029 compounds, only 51 compounds exhibited better binding interactions than native ligands, with all three protein targets (NMDA, GSK3β, and BACE) considered multitarget inhibitors. Among them, F1094-0201 is the most potent inhibitor against multiple targets with binding energy -11.7, -10.6, and -12 kcal/mol, respectively. ADME-T analysis results showed that F1094-0201 was found to be suitable for CNS drug-likeness in addition to their other drug-likeness properties. The MDS results of RMSD, RMSF, Rg, SASA, SSE and residue interactions indicated the formation of a strong and stable association in the complex of ligands (F1094-0201) and proteins. These findings confirm the F1094-0201's ability to remain inside target proteins' binding pockets while forming a stable complex of protein-ligand. The free energies (MM/GBSA) of BACE-F1094-0201, GSK3β-F1094-0201, and NMDA-F1094-0201 complex formation were -73.78 ± 4.31 kcal mol^-1, -72.77 ± 3.43 kcal mol^-1, and -52.51 ± 2.85 kcal mol^-1, respectively. Amongst the target proteins, F1094-0201 have a more stable association with BACE, followed by NMDA and GSK3β. These attributes of F1094-0201 indicate it as a possible option for the management of pathophysiological pathways associated with AD.

Elucidations of Molecular Mechanism and Mechanistic Effects of Environmental Toxicants in Neurological Disorders

Due to rising environmental and global public health concerns associated with environmental contamination, human populations are continually being exposed to environmental toxicants, including physical chemical mutagens widespread in our environment causing adverse consequences and inducing a variety of neurological disorders in humans. Physical mutagens comprise ionizing and non-ionizing radiation, such as UV rays, IR rays, X-rays, which produces a broad spectrum of neuronal destruction, including neuroinflammation, genetic instability, enhanced oxidative stress driving mitochondrial damage in the human neuronal antecedent cells, cognitive impairment due to alterations in neuronal function, especially in synaptic plasticity, neurogenesis repression, modifications in mature neuronal networks drives to enhanced neurodegenerative risk. Chemical Mutagens including alkylating agents (EMS, NM, MMS, and NTG), Hydroxylamine, nitrous acid, sodium azide, halouracils are the major toxic mutagen in our environment and have been associated with neurological disorders. These chemical mutagens create dimers of pyrimidine that cause DNA damage that leads to ROS generation producing mutations, chromosomal abnormalities, genotoxicity which leads to increased neurodegenerative risk. The toxicity of four heavy metal including Cd, As, Pb, Hg is mostly responsible for complicated neurological disorders in humans. Cadmium exposure can enhance the permeability of the BBB and penetrate the brain, driving brain intracellular accumulation, cellular dysfunction, and cerebral edema. Arsenic exerts its toxic effect by induction of ROS production in neuronal cells. In this review, we summarize the molecular mechanism and mechanistic effects of mutagens in the environment and their role in multiple neurological disorders.

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, GSK3β, 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.

Green Synthesis and Anticancer Potential of 1,4-Dihydropyridines-Based Triazole Derivatives: In Silico and In Vitro Study

A library of 1,4-dihydropyridine-based 1,2,3-triazol derivatives has been designed, synthesized, and evaluated their cytotoxic potential on colorectal adenocarcinoma (Caco-2) cell lines. All compounds were characterized and identified based on their ¹H and ¹³C NMR (Nuclear Magnetic Resonance) spectroscopic data. Furthermore, molecular docking of best anticancer hits with target proteins (protein kinase CK2α, tankyrase1, and tankyrase2) has been performed. Our results implicated that most of these compounds have significant antiproliferative activity with IC₅₀ values between 0.63 ± 0.05 and 5.68 ± 0.14 µM. Moreover, the mechanism of action of most active compounds 13ab′ and 13ad′ suggested that they induce cell death through apoptosis in the late apoptotic phase as well as dead phase, and they could promote cell cycle arrest at the G2/M phase. Furthermore, the molecular docking study illustrated that 13ad′ possesses better binding interaction with the catalytic residues of target proteins involved in cell proliferation and antiapoptotic pathways. Based on our in vitro and in silico study, 13ad′ was found to be a highly effective anti-cancerous compound. The present data indicate that dihydropyridine-linked 1,2,3-triazole conjugates can be generated as potent anticancer agents.

Lipid-Based Nanoparticle Formulation of Diallyl Trisulfide Chemosensitizes the Growth Inhibitory Activity of Doxorubicin in Colorectal Cancer Model: A Novel In Vitro, In Vivo and In Silico Analysis

Garlic’s main bioactive organosulfur component, diallyl trisulfide (DATS), has been widely investigated in cancer models. However, DATS is not suitable for clinical use due to its low solubility. The current study seeks to improve DATS bioavailability and assess its chemopreventive and chemosensitizing properties in an AOM-induced colorectal cancer model. The polyethylene glycol coated Distearoylphosphatidylcholine/Cholesterol (DSPC/Chol) comprising DATS-loaded DATSL and doxorubicin (DOXO)-encapsulated DOXL liposomes was prepared and characterized. The changes in the sensitivity of DATS and DOXO by DATSL and DOXL were evaluated in RKO and HT-29 colon cancer cells. The synergistic effect of DATSL and DOXL was studied by cell proliferation assay in the combinations of IC₁₀, IC₂₅, and IC₃₅ of DATSL with the IC₁₀ of DOXL. AOM, DATSL, and DOXL were administered to different groups of mice for a period of 21 weeks. The data exhibited ~93% and ~46% entrapment efficiency of DATSL and DOXL, respectively. The size of sham liposomes was 110.5 nm, whereas DATSL and DOXL were 135.5 nm and 169 nm, respectively. DATSL and DOXL exhibited significant sensitivity in the cell proliferation experiment, lowering their IC₅₀ doses by more than 8- and 14-fold, respectively. However, the DATSL IC₁₀, IC₂₅, and IC₃₅ showed escalating chemosensitivity, and treated the cells in combination with DOXL IC₁₀. Analysis of histopathological, cancer marker enzymes, and antioxidant enzymes revealed that the high dose of DATSL pretreatment and DOXL chemotherapy is highly effective in inhibiting AOM-induced colon cancer promotion. The combination of DATSL and DOXL indicated promise as a colorectal cancer treatment in this study. Intermolecular interactions of DATS and DOXO against numerous cancer targets by molecular docking indicated MMP-9 as the most favourable target for DATS exhibiting binding energy of −4.6 kcal/mol. So far, this is the first research to demonstrate the chemopreventive as well as chemosensitizing potential of DATSL in an animal model of colorectal cancer.

Cytotoxic Potential of Ficus palmata Extracts on Lung Cancer Cell Lines (A549)

Cancer accounts for 10 million deaths globally whereas the treatments available either have several side effects or non-effective due to multi-drug resistant property of cancer cells for long term use. Therefore, it is utmost important to find safe therapeutic drugs that have cytotoxic potentials against cancer cells. Medicinal plants are believed to have lesser side effects with huge therapeutic efficacy. One such species is Ficus palmata which is known to have several medicinal properties and great antioxidant potentials. Earlier it was reported that methanolic extract of leaves (FPLM) and aqueous extract stembark (FPBA) of this plant have decent antioxidant properties. Therefore, the anticancer potentials of these plant extracts have been evaluated in addition of hydroxyl radical scavenging property. The results shown that FPBA represents higher antioxidant (IC50 value= 242.46±11.26 µg/ml) and anticancer effects against lung cancer (A549) cell lines (IC50 value= 69.74±2.12) whereas this plant extract have lower toxicity (IC50 value= 249.61±7.31) on normal cell lines (3T3-L1) which indicate that FPBA can be a potential therapeutic option for cancer and oxidative stress. The study concluded that the stem bark aqueous extract having therapeutic properties against lung cancer. It is to be recommended that the bioactive compound responsible for its therapeutic properties need to explore against cancer cell by evaluating various other parameters such as apoptosis, cell cycle arrest, and toxic effect on cell morphology.

Oxidative Modification of Lipoproteins: A Potential Role of Oxidized Small dense LDL in Enhanced Atherogenicity

Atherosclerosis (AS) is a multifaceted inflammatory syndrome of the arterial wall to which number of mediators have been implicated in lesion progression. Triglyceride (TG)-rich lipoproteins consist of the large diversity of lipoprotein particles that fluctuate in density, size, and apolipoprotein composition. Two foremost phenotypes, on basis of size, chemical configuration, and density, of low-density-lipoprotein (LDL) have been recognized i.e., pattern A, having LDL diameter greater than 25.5nm (large buoyant LDL or lb-LDL) and pattern B, having LDL diameter less than or equal to 25.5nm (small-dense LDL or sd-LDL). Small-dense low-density-lipoprotein (sd-LDL) particles are produced by potential intravascular hydrolysis of TG-rich VLDL particles via lipoprotein lipases (LPLs), hepatic lipases (HLs) and cholesterol ester transfer protein (CETP). sd-LDL is more atherogenic due to its smaller size, increased penetration into the arterial wall, extended plasma half-life, lesser binding affinity for LDL receptors (LDL-R) as well as lower resistance to oxidative stress when equated with lb-LDL. The higher atherogenic potential of sd-LDL is due to its enhanced susceptibility to oxidation, owing to high polyunsaturated fatty acids (PUFA), low cholesterol and Apoprotein B (ApoB) content. An enhanced understanding of sd-LDL metabolism at the molecular level, transport and clearance may result in the development of sd-LDL as an independent predictive marker for AS events and may be used to maintain cholesterol homeostasis and prevent the succession of AS.

Embilica officinalis L. inhibits the growth and proliferation of Leishmania donovani through the induction of ultrastructural changes, mitochondrial dysfunction, oxidative stress and apoptosis-like cell death

Visceral leishmaniasis (VL) is caused by a protozoan parasite, Leishmania donovani (L. donovani). It affects around 1-2 million people around the world annually. There is an urgent need to investigate new medicament of it due to difficult method of drug administration, long period of treatment, high cost of the drug, adverse side-effects, low efficacy and development of parasite resistance to the available drugs. Medicinal plants have also been used for the treatment of different diseases in traditional system of medicines due to their holistic effects. The Drugs for Neglected Diseases initiative (DNDi), Geneva, Switzerland has already started the program for identification of potential medicinal plant and plant products having antileishmanial potential. Keeping all these in consideration, we planned to study the antileishmanial activity of one of the medicinal plant, Embilica officinalis L. (EO) fruit extract. EO fruit extract inhibited the growth and proliferation of promastigotes as well as intra-macrophagic amastigotes in dose-dependent manner. EO fruit extract induced morphological and ultrastructural changes in parasites as observed under Electron Microscope. It also induced the oxidative stress, mitochondrial dysfunction, DNA laddering and apotosis-like cell death in parasites. Here, we for the first time reported such a detailed mechanism of action of antileishmanial activity of EO fruit extract. Our results suggested that EO fruit extract could be used for the development of new phytomedicine against leishmaniasis.

Virtual screening of natural compounds for potential inhibitors of Sterol C-24 methyltransferase of Leishmania donovani to overcome leishmaniasis

Leishmaniasis is a neglected tropical disease caused by trypanosomatid parasite belonging to the genera Leishmania. Leishmaniasis is transmitted from one human to other through the bite of sandflies. It is endemic in around 98 countries including tropical and subtropical regions of Asia, Africa, Southern America, and the Mediterranean region. Sterol C-24 methyltransferase (LdSMT) of Leishmania donovani (L. donovani) mediates the transfer of CH3-group from S-adenosyl methionine to C-24 position of sterol side chain which makes the ergosterol different from cholesterol. Absence of ortholog in human made it potential druggable target. Here, we performed virtual screening of library of natural compounds against LdSMT to identify the potential inhibitor for it and to fight leishmaniasis. Gigantol, flavan-3-ol, and parthenolide showed the best binding affinity towards LdSMT. Further, based on absorption, distribution, metabolism, and excretion properties and biological activity prediction, gigantol showed the best lead-likeness and drug-likeness properties. Therefore, we further elucidated its antileishmanial properties. We found that gigantol inhibited the growth and proliferation of promastigotes as well as intra-macrophagic amastigotes. Gigantol exerted its antileishmanial action through the induction of reactive oxygen species in dose-dependent manner. Our study, suggested the possible use of gigantol as antileishmanial drug after further validations to overcome leishmaniasis.

Human Milk MicroRNA and Total RNA Differ Depending on Milk Fractionation

MicroRNA have been recently discovered in human milk signifying potentially important functions for both the lactating breast and the infant. Whilst human milk microRNA have started to be explored, little data exist on the evaluation of sample processing, and analysis to ensure that a full spectrum of microRNA can be obtained. Human milk comprises three main fractions: cells, skim milk, and lipids. Typically, the skim milk fraction has been measured in isolation despite evidence that the lipid fraction may contain more microRNA. This study aimed to standardize isolation of microRNA and total RNA from all three fractions of human milk to determine the most appropriate sampling and analysis procedure for future studies. Three different methods from eight commercially available kits were tested for their efficacy in extracting total RNA and microRNA from the lipid, skim, and cell fractions of human milk. Each fraction yielded different concentrations of RNA and microRNA, with the highest quantities found in the cell and lipid fractions, and the lowest in skim milk. The column‐based phenol‐free method was the most efficient extraction method for all three milk fractions. Two microRNAs were expressed and validated in the three milk fractions by qPCR using the three recommended extraction kits for each fraction. High expression levels were identified in the skim and lipid milk factions for these microRNAs. These results suggest that careful consideration of both the human milk sample preparation and extraction protocols should be made prior to embarking upon research in this area. J. Cell. Biochem. 116: 2397–2407, 2015. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Human Milk Cells and Lipids Conserve Numerous Known and Novel miRNAs, Some of Which Are Differentially Expressed during Lactation

Human milk (HM) is rich in miRNAs, which are thought to contribute to infant protection and development. We used deep sequencing to profile miRNAs in the cell and lipid fractions of HM obtained post-feeding from 10 lactating women in months 2, 4, and 6 postpartum. In both HM fractions, 1,195 mature known miRNAs were identified, which were positively associated with the cell (p = 0.048) and lipid (p = 0.010) content of HM. An additional 5,167 novel miRNA species were predicted, of which 235 were high-confidence miRNAs. HM cells contained more known miRNAs than HM lipids (1,136 and 835 respectively, p<0.001). Although the profile of the novel miRNAs was very different between cells and lipids, with the majority conserved in the cell fraction and being mother-specific, 2/3 of the known miRNAs common between cells and lipids were similarly expressed (p>0.05). Great similarities between the two HM fractions were also found in the profile of the top 20 known miRNAs. These were largely similar also between the three lactation stages examined, as were the total miRNA concentration, and the number and expression of the known miRNAs common between cells and lipids (p>0.05). Yet, approximately a third of all known miRNAs were differentially expressed during the first 6 months of lactation (p<0.05), with more pronounced miRNA upregulation seen in month 4. These findings indicate that although the total miRNA concentration of HM cells and lipids provided to the infant does not change in first 6 months of lactation, the miRNA composition is altered, particularly in month 4 compared to months 2 and 6. This may reflect the remodeling of the gland in response to infant feeding patterns, which usually change after exclusive breastfeeding, suggesting adaptation to the infant’s needs.

Human milk miRNAs primarily originate from the mammary gland resulting in unique miRNA profiles of fractionated milk

Human milk (HM) contains regulatory biomolecules including miRNAs, the origin and functional significance of which are still undetermined. We used TaqMan OpenArrays to profile 681 mature miRNAs in HM cells and fat, and compared them with maternal peripheral blood mononuclear cells (PBMCs) and plasma, and bovine and soy infant formulae. HM cells and PBMCs (292 and 345 miRNAs, respectively) had higher miRNA content than HM fat and plasma (242 and 219 miRNAs, respectively) (p < 0.05). A strong association in miRNA profiles was found between HM cells and fat, whilst PBMCs and plasma were distinctly different to HM, displaying marked inter-individual variation. Considering the dominance of epithelial cells in mature milk of healthy women, these results suggest that HM miRNAs primarily originate from the mammary epithelium, whilst the maternal circulation may have a smaller contribution. Our findings demonstrate that unlike infant formulae, which contained very few human miRNA, HM is a rich source of lactation-specific miRNA, which could be used as biomarkers of the performance and health status of the lactating mammary gland. Given the recently identified stability, uptake and functionality of food- and milk-derived miRNA in vivo, HM miRNA are likely to contribute to infant protection and development.