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11.
Rongchen Dai Mengfan Liu Wan Najbah Nik Nabil Zhichao Xi Hongxi Xu 《Molecules (Basel, Switzerland)》2021,26(4)
Mycomedicine is a unique class of natural medicine that has been widely used in Asian countries for thousands of years. Modern mycomedicine consists of fruiting bodies, spores, or other tissues of medicinal fungi, as well as bioactive components extracted from them, including polysaccharides and, triterpenoids, etc. Since the discovery of the famous fungal extract, penicillin, by Alexander Fleming in the late 19th century, researchers have realised the significant antibiotic and other medicinal values of fungal extracts. As medicinal fungi and fungal metabolites can induce apoptosis or autophagy, enhance the immune response, and reduce metastatic potential, several types of mushrooms, such as Ganoderma lucidum and Grifola frondosa, have been extensively investigated, and anti-cancer drugs have been developed from their extracts. Although some studies have highlighted the anti-cancer properties of a single, specific mushroom, only limited reviews have summarised diverse medicinal fungi as mycomedicine. In this review, we not only list the structures and functions of pharmaceutically active components isolated from mycomedicine, but also summarise the mechanisms underlying the potent bioactivities of several representative mushrooms in the Kingdom Fungi against various types of tumour. 相似文献
12.
Dr. Andreas A. Bastian Dr. Maria Bastian Dr. Manuel Jäger Mark Loznik Dr. Eliza M. Warszawik Xintong Yang Dr. Nabil Tahiri Dr. Peter Fodran Prof. Dr. Martin D. Witte Anne Thoma Dr. Jens Köhler Prof. Dr. Adriaan J. Minnaard Prof. Dr. Andreas Herrmann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(36):e202200883
The continuous emergence of antimicrobial resistance is causing a threat to patients infected by multidrug-resistant pathogens. In particular, the clinical use of aminoglycoside antibiotics, broad-spectrum antibacterials of last resort, is limited due to rising bacterial resistance. One of the major resistance mechanisms in Gram-positive and Gram-negative bacteria is phosphorylation of these amino sugars at the 3’-position by O-phosphotransferases [APH(3’)s]. Structural alteration of these antibiotics at the 3’-position would be an obvious strategy to tackle this resistance mechanism. However, the access to such derivatives requires cumbersome multi-step synthesis, which is not appealing for pharma industry in this low-return-on-investment market. To overcome this obstacle and combat bacterial resistance mediated by APH(3’)s, we introduce a novel regioselective modification of aminoglycosides in the 3’-position via palladium-catalyzed oxidation. To underline the effectiveness of our method for structural modification of aminoglycosides, we have developed two novel antibiotic candidates overcoming APH(3’)s-mediated resistance employing only four synthetic steps. 相似文献
13.
Nabil Kahale 《Random Structures and Algorithms》1997,11(4):299-313
We study general geometric techniques for bounding the spectral gap of a reversible Markov chain. We show that the best bound obtainable using these techniques can be computed in polynomial time via semidefinite programming, and is off by at most a factor of order log2n, where n is the number of states. © 1997 John Wiley & Sons, Inc. Random Struct. Alg., 11 , 299–313 (1997) 相似文献
14.
15.
In an aim to prove the efficiency of polyphenols of Rosa canina fruits in promoting human health. A methanolic extract of R. canina fruits was prepared by successive maceration with solvents of increasing polarity. The polyphenol composition was analyzed by HPLC–DAD–ESI–MS. The biological activity of this extract on SH-SY5Y cells and HepG2 cells was then studied. The antioxidant activity was tested by various in vitro tests such as DPPH-radical-scavenging activity, FRAP assay, hydroxyl radical scavenging assay and total antioxidant capacity. The subacute toxicity of R. canina was tested on female rats by repeated intraperitoneal administration of various doses. The phenolic profiles showed 25 antioxidants distributed into three classes of phenolic compounds: glycosylated and agglomerated flavonoids/isoflavonoids, tannins and phenanthrenes. Qualitative phytochemical analyses showed that this extract lacks alkaloids. The methanolic extract of R. canina fruits has a total antioxidant capacity of 82.69 ± 1.18 μg EAA/mg of methanol extract and the IC50 of the methods used is in the following increasing order: FRAP assay (61.88 μg/ml), then hydroxyl radical scavenging assay (67.45 μg/ml) and then DPPH radical-scavenging activity (129.81 μg/ml). The extract of R. canina did not cause any phenotypic signs of toxicity or mortality during and after treatment. The LD50 was >5,000 mg/kg, hence, R. canina was considered nontoxic. An in vivo study proved the protective effect of R. canina against cardiac and hepato-renal toxicities. These results drew the importance of a healthy diet, where diets rich in R. canina fruits can be used as a rich natural source of antioxidants and anticarcinogenic phenolic compounds. 相似文献
16.
Dr. Andrew Ballard Dr. Stefania Narduolo Dr. Hiwa O. Ahmed Nathaniel I. Keymer Dr. Nabil Asaad Dr. David A. Cosgrove Dr. Niklaas J. Buurma Dr. Andrew G. Leach 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3661-3687
The two enantiomers of a compound often have profoundly different biological properties and thus their liability to racemisation in aqueous solutions is an important piece of information. The authors reviewed the available data concerning the process of racemisation in vivo, in the presence of biological molecules (e.g., racemase enzymes, serum albumin, cofactors and derivatives) and under purely chemical but aqueous conditions (acid, base and other aqueous systems). Mechanistic studies are described critically in light of reported kinetic data. The types of experimental measurement that can be used to effectively determine rate constants of racemisation in various conditions are discussed and the data they provide is summarised. The proposed origins of enzymatic racemisation are presented and suggest ways to promote the process that are different from processes taking place in bulk water. Experimental and computational studies that provide understanding and quantitative predictions of racemisation risk are also presented. 相似文献
17.
The diffusion of rhodamine-6G dye in ethanol is observed to be inhibited by optical pumping by a cadmium laser. The diffusion process is observed as a function of the solution temperature. The relative difference in diffusion coefficients with and without optical pumping is calculated. The effect is interpreted as being due to a stronger solvent-dye interaction in the first excited singlet state of rhodamine-6G. 相似文献
18.
Commutator inequalities associated with the polar decomposition 总被引:1,自引:0,他引:1
Fuad Kittaneh 《Proceedings of the American Mathematical Society》2002,130(5):1279-1283
Let be a polar decomposition of an complex matrix . Then for every unitarily invariant norm , it is shown that
where denotes the operator norm. This is a quantitative version of the well-known result that is normal if and only if . Related inequalities involving self-commutators are also obtained.
where denotes the operator norm. This is a quantitative version of the well-known result that is normal if and only if . Related inequalities involving self-commutators are also obtained.
19.
Rafik Aguech Nabil Lasmar Olfa Selmi 《Annals of the Institute of Statistical Mathematics》2019,71(2):389-408
Annals of the Institute of Statistical Mathematics - In this paper, we consider an unbalanced urn model with multiple drawing. At each discrete time step n, we draw m balls at random from an urn... 相似文献
20.
Norm Inequalities for Commutators of Self-adjoint Operators 总被引:3,自引:0,他引:3
Fuad Kittaneh 《Integral Equations and Operator Theory》2008,62(1):129-135
Let A, B, and X be bounded linear operators on a complex separable Hilbert space. It is shown that if A and B are self-adjoint with and for some real numbers a
1, a
2, b
1, and b
2, then for every unitarily invariant norm|||·|||,
. If, in addition, X is positive, then
. These norm inequalities generalize recent related inequalities due to Kittaneh, Bhatia-Kittaneh, and Wang-Du.
相似文献