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1.
Structural basis of the nonribosomal codes for nonproteinogenic amino acid selective adenylation enzymes in the biosynthesis of natural products.
Kudo, F, Miyanaga, A, Eguchi, T
Journal of industrial microbiology & biotechnology. 2019;(3-4):515-536
Abstract
Nonproteinogenic amino acids are the unique building blocks of nonribosomal peptides (NRPs) and hybrid nonribosomal peptide-polyketides (NRP-PKs) and contribute to their diversity of chemical structures and biological activities. In the biosynthesis of NRPs and NRP-PKs, adenylation enzymes select and activate an amino acid substrate as an aminoacyl adenylate, which reacts with the thiol of the holo form of the carrier protein to afford an aminoacyl thioester as the electrophile for the condensation reaction. Therefore, the substrate specificity of adenylation enzymes is a key determinant of the structure of NRPs and NRP-PKs. Here, we focus on nonproteinogenic amino acid selective adenylation enzymes, because understanding their unique selection mechanisms will lead to accurate functional predictions and protein engineering toward the rational biosynthesis of designed molecules containing amino acids. Based on recent progress in the structural analysis of adenylation enzymes, we discuss the nonribosomal codes of nonproteinogenic amino acid selective adenylation enzymes.
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2.
Preoperative Considerations in Inflammatory Bowel Disease.
McKenna, NP, Lightner, AL
The Surgical clinics of North America. 2019;(6):1083-1094
Abstract
Patients with ulcerative colitis and Crohn's disease often present to surgery malnourished and on combination immunosuppression. These factors affect operation selection and postoperative outcomes. Corticosteroids have a well-established detrimental effect on postoperative outcomes, whereas the impact of biologic agents is more controversial. In a patient exposed to these medications, and in the presence of other risk factors, temporary intestinal diversion is likely the best choice. Enteral nutrition may help optimize malnourished patients at high risk of adverse postoperative outcomes.
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3.
Targeting Inflammatory Pathways in Alzheimer's Disease: A Focus on Natural Products and Phytomedicines.
Sharman, MJ, Verdile, G, Kirubakaran, S, Parenti, C, Singh, A, Watt, G, Karl, T, Chang, D, Li, CG, Münch, G
CNS drugs. 2019;(5):457-480
Abstract
Studies of the brains of Alzheimer's disease (AD) patients have revealed key neuropathological features, such as the deposition of aggregates of insoluble amyloid-β (Aβ) peptides and neurofibrillary tangles (NFTs). These pathological protein deposits, including Aβ peptides (which form senile plaques) and hyperphosphorylated tau (which aggregates into NFTs), have been assumed to be 'the cause of AD'. Aβ has been extensively targeted to develop an effective disease-modifying therapy, but with limited clinical success. Emerging therapies are also now targeting further pathological processes in AD, including neuroinflammation. This review focuses on the inflammatory and oxidative stress-related changes that occur in AD, and discusses some emerging anti-inflammatory natural products and phytomedicines. Many of the promising compounds are cytokine-suppressive anti-inflammatory drugs (CSAIDs), which target the proinflammatory AP1 and nuclear factor-κB signalling pathways and inhibit the expression of many proinflammatory cytokines, such as interleukin (IL)-1, IL-6, tumour necrosis factor-α, or nitric oxide produced by inducible nitric oxide synthase. However, many of these phytomedicines have not been tested in rigorous clinical trials in AD patients. It is not yet clear if the active compounds reach an effective concentration in the brain (due to limited bioavailability) or if they can slow down AD progression in long-term trials. The authors suggest that it is crucial for both the pharmacological and complementary medicine industries to conduct and fund those studies to significantly advance the field.
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4.
Natural Products and Obesity: A Focus on the Regulation of Mitotic Clonal Expansion during Adipogenesis.
Chang, E, Kim, CY
Molecules (Basel, Switzerland). 2019;(6)
Abstract
Obesity is recognized as a worldwide health crisis. Obesity and its associated health complications such as diabetes, dyslipidemia, hypertension, and cardiovascular diseases impose a big social and economic burden. In an effort to identify safe, efficient, and long-term effective methods to treat obesity, various natural products with potential for inhibiting adipogenesis were revealed. This review aimed to discuss the molecular mechanisms underlying adipogenesis and the inhibitory effects of various phytochemicals, including those from natural sources, on the early stage of adipogenesis. We discuss key steps (proliferation and cell cycle) and their regulators (cell-cycle regulator, transcription factors, and intracellular signaling pathways) at the early stage of adipocyte differentiation as the mechanisms responsible for obesity.
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5.
Nanoformulations of natural products for management of metabolic syndrome.
Taghipour, YD, Hajialyani, M, Naseri, R, Hesari, M, Mohammadi, P, Stefanucci, A, Mollica, A, Farzaei, MH, Abdollahi, M
International journal of nanomedicine. 2019;:5303-5321
Abstract
Metabolic syndrome is a common metabolic disorder which has become a public health challenge worldwide. There has been growing interest in medications including natural products as complementary or alternative choices for common chemical therapeutics regarding their limited side effects and ease of access. Nanosizing these compounds may help to increase their solubility, bioavailability, and promisingly enhance their efficacy. This study, for the first time, provides a comprehensive overview of the application of natural-products-based nanoformulations in the management of metabolic syndrome. Different phytochemicals including curcumin, berberine, Capsicum oleoresin, naringenin, emodin, gymnemic acid, resveratrol, quercetin, scutellarin, stevioside, silybin, baicalin, and others have been nanosized hitherto, and their nanosizing method and effect in treatment and alleviating metabolic syndrome have been reviewed and discussed in this study. It has been discovered that there are several pathways or molecular targets relevant to metabolic disorders which are affected by these compounds. Various natural-based nanoformulations have shown promising effect in treatment of metabolic syndrome, and therefore can be considered as future candidates instead of or in conjunction with pharmaceutical drugs if they pass clinical trials successfully.
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6.
The protosteryl and dammarenyl cation dichotomy in polycyclic triterpene biosynthesis revisited: has this 'rule' finally been broken?
Stephenson, MJ, Field, RA, Osbourn, A
Natural product reports. 2019;(8):1044-1052
Abstract
Covering: 1948 up to the end of 2018. The triterpene alcohols represent an important and diverse class of natural products. This diversity is believed to originate from the differential enzymatically controlled cyclisation of 2,3-oxidosqualene. It is now a well-established presumption that all naturally occurring tetra- and penta-cyclic triterpene alcohols can be rationalised by the resolution of one of two intermediary tetracyclic cations, termed the protosteryl and dammarenyl cations. Here, a discussion of typical key triterpene structures and their proposed derivation from either of these progenitors is followed by comparison with a recently reported novel pentacyclic triterpene orysatinol which appears to correspond to an unprecedented divergence from this dichotomous protosteryl/dammarenyl view of triterpene biogenesis. Not only does this discovery widen the potential scope of triterpene scaffolds that could exist in nature, it could call into question the reliability of stereochemical assignments of some existing triterpene structures that are supported by only limited spectroscopic evidence. The discovery of orysatinol provides direct experimental evidence to support considering more flexibility in the stereochemical interpretation of the biogenic isoprene rule.
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7.
Natural Compounds with Anti-BACE1 Activity as Promising Therapeutic Drugs for Treating Alzheimer's Disease.
Naushad, M, Durairajan, SSK, Bera, AK, Senapati, S, Li, M
Planta medica. 2019;(17):1316-1325
Abstract
Alzheimer's disease is a neurodegenerative disease that leads to irreversible neuronal damage. Senile plaques, composed of amyloid beta peptide, is the principal abnormal characteristic of the disease. Among the factors involved, the secretase enzymes, namely, α secretase, beta-site amyloid precursor protein-cleaving enzyme, β secretase, and γ secretase, hold consequential importance. Beta-site amyloid precursor protein-cleaving enzyme 1 is considered to be the rate-limiting factor in the production of amyloid beta peptide. Research supporting the concept of inhibition of beta-site amyloid precursor protein-cleaving enzyme activity as one of the effective therapeutic targets in the mitigation of Alzheimer's disease is well accepted. The identification of natural compounds, such as β-amyloid precursor protein-selective beta-site amyloid precursor protein-cleaving enzyme inhibitors, and the idea of compartmentalisation of the beta-site amyloid precursor protein-cleaving enzyme 1 action have caused a dire need to closely examine the natural compounds and their effectiveness in the disease mitigation. Many natural compounds have been reported to effectively modulate beta-site amyloid precursor protein-cleaving enzyme 1. At lower doses, compounds like 2,2',4'-trihydroxychalcone acid, quercetin, and myricetin have been shown to effectively reduce beta-site amyloid precursor protein-cleaving enzyme 1 activity. The currently used five drugs that are marketed and used for the management of Alzheimer's disease have an increased risk of toxicity and restricted therapeutic efficiency, hence, the search for new anti-Alzheimer's disease drugs is of primary concern. A variety of natural compounds having pure pharmacological moieties showing multitargeting activity and others exhibiting specific beta-site amyloid precursor protein-cleaving enzyme 1 inhibition as discussed below have superior biosafety. Many of these compounds, which are isolated from medicinal herbs and marine flora, have been long used for the treatment of various ailments since ancient times in the Chinese and Ayurvedic medical systems. The aim of this article is to review the available data on the selected natural compounds, giving emphasis to the inhibition of beta-site amyloid precursor protein-cleaving enzyme 1 activity as a mode of Alzheimer's disease treatment.
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8.
Terrestrial Microorganisms: Cell Factories of Bioactive Molecules with Skin Protecting Applications.
Peyrat, LA, Tsafantakis, N, Georgousaki, K, Ouazzani, J, Genilloud, O, Trougakos, IP, Fokialakis, N
Molecules (Basel, Switzerland). 2019;(9)
Abstract
It is well known that terrestrial environments host an immense microbial biodiversity. Exposed to different types of stress, such as UV radiation, temperature fluctuations, water availability and the inter- / intra-specific competition for resources, terrestrial microorganisms have been evolved to produce a large spectrum of bioactive molecules. Bacteria, archaea, protists, fungi and algae have shown a high potential of producing biomolecules for pharmaceutical or other industrial purposes as they combine a sustainable, relatively low-cost and fast-production process. Herein, we provide an overview of the different bioactive molecules produced by terrestrial microorganisms with skin protecting applications. The high content in polyphenolic and carotenoid compounds produced by several strains, as well as the presence of exopolysaccharides, melanins, indole and pyrrole derivatives, mycosporines, carboxylic acids and other molecules, are discussed in the context of their antioxidant, photo-protective and skin-whitening activity. Relevant biotechnological tools developed for the enhanced production of high added value natural products, as well as the protecting effect of some antioxidant, hydrolytic and degrading enzymes are also discussed. Furthermore, we describe classes of microbial compounds that are used or have the potential to be used as antimicrobials, moisturizers, biosurfactants, pigments, flavorings and fragrances.
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9.
Preventive and Therapeutic Effect of Ganoderma (Lingzhi) on Brain Injury.
Quan, Y, Ma, A, Yang, B
Advances in experimental medicine and biology. 2019;:159-180
Abstract
Neurological dysfunction and death are common events leading to acute and chronic neurodegenerative diseases. Neurodegenerative disorders such as Alzheimer's and Parkinson's disease account for a significant and increasing proportion of morbidity and mortality in the developed world. Ganoderma lucidum (G. lucidum, Lingzhi), one of highly nutritious and significantly effective medicinal herbs, has been used for clinical applications for thousands of years. Several researches have shown that it has a wide range of brain damage protection, such as amelioration of Alzheimer's disease, therapeutic effect on epilepsy, and the protective effect on neural cells in stroke injury. This chapter reviews the neuroprotective effects of G. lucidum and its extracts on brain injury diseases, including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, and other neurodegenerative diseases, and the potential clinical applications.
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10.
Radiation-Induced Heart Diseases: Protective Effects of Natural Products.
Musa, AE, Shabeeb, D
Medicina (Kaunas, Lithuania). 2019;(5)
Abstract
Cardiovascular diseases (CVDs) account for the majority of deaths worldwide. Radiation-induced heart diseases (RIHD) is one of the side effects following exposure to ionizing radiation (IR). Exposure could be from various forms such as diagnostic imaging, radiotherapy for cancer treatment, as well as nuclear disasters and nuclear accidents. RIHD is mostly observed after radiotherapy for thoracic malignancies, especially left breast cancer. RIHD may affect the supply of blood to heart muscles, leading to an increase in the risk of heart attacks to irradiated persons. Due to its dose-limiting consequence, RIHD has a negative effect on the therapeutic efficacy of radiotherapy. Several methods have been proposed for protection against RIHD. In this paper, we review the use of natural products, which have shown promising results for protection against RIHD.