scholarly journals Chemoenzymatic Synthesis of New Aromatic Esters of Mono- and Oligosaccharides

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1638
Author(s):  
Alina Ramona Buzatu ◽  
August E. Frissen ◽  
Lambertus A. M. van den Broek ◽  
Anamaria Todea ◽  
Marilena Motoc ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Degree Of Polymerization ◽  
Resonance Spectroscopy ◽  
Enzymatic Esterification ◽  
Alkyl Glycosides ◽  
New Class ◽  
Aromatic Esters ◽  
Novozyme 435 ◽  
Enzymatic Acylation ◽  
Derivatives Of

An efficient and convenient chemoenzymatic route for the synthesis of novel phenolic mono-, di- and oligosaccharide esters is described. Acetal derivatives of glucose, sucrose, lactose and inulin were obtained by chemical synthesis. The fully characterized pure sugar acetals were subjected to enzymatic esterification with 3-(4-hydroxyphenyl) propionic acid (HPPA) in the presence of Novozyme 435 lipase as a biocatalyst. The aromatic esters of alkyl glycosides and glucose acetal were obtained with good esterification yields, characterized by mass spectrometry (MALDI-TOF MS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR). The synthesis of aromatic esters of disaccharide acetals was successful only for the enzymatic esterification of sucrose acetal. The new chemoenzymatic route allowed the synthesis of novel aromatic esters of inulin as the inulin monoacetal monoester and diester and the inulin diacetal monoester with a polymerization degree of two, as well as the inulin monoacetal monoester with a degree of polymerization of three, were obtained by enzymatic acylation of inulin acetals with HPPA. These compounds could represent a new class of sugar ester surfactants with enhanced bioactivity, antioxidative and antimicrobial properties and with potential application in drug delivery systems.

Coordination compounds of methyl gallium hydrides

1969 ◽  
Vol 47 (4) ◽  
pp. 673-679 ◽  
Author(s):  
A. Storr ◽  
V. G. Wiebe
Keyword(s):  
Coordination Compounds ◽  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Relative Stabilities ◽  
New Class ◽  
Gallium Hydride ◽  
Derivatives Of ◽  
Gallium Compounds

Although the organo hydride derivatives of boron and aluminium are well characterized, little work has been reported on the corresponding gallium systems. The present study was initiated to determine the relative stabilities of organo gallium hydride derivatives as compared to the stabilities of the corresponding compounds of boron and aluminium. Various preparative routes in this new class of gallium compounds have been investigated. These include the use of organo mercury and organo lithium reagents in reactions with gallium hydride compounds and their halogen substituted derivatives, and also equlibration reactions between gallium hydride and organo gallium compounds. Both infrared and proton magnetic resonance spectroscopy techniques have been used extensively in following the progress of these reactions and in the characterization of the products.

scholarly journals Semisynthetic Derivatives of Selected Amaryllidaceae Alkaloids as a New Class of Antimycobacterial Agents

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6023
Author(s):  
Negar Maafi ◽  
Abdullah Al Mamun ◽  
Ondřej Janďourek ◽  
Jana Maříková ◽  
Kateřina Breiterová ◽  
...  
Keyword(s):  
Infectious Agent ◽  
Antimycobacterial Activity ◽  
Alamar Blue ◽  
Amaryllidaceae Alkaloids ◽  
New Class ◽  
Aromatic Esters ◽  
Antimycobacterial Agents ◽  
Hepatocellular Carcinoma Cell Line ◽  
Derivatives Of

The search for novel antimycobacterial drugs is a matter of urgency, since tuberculosis is still one of the top ten causes of death from a single infectious agent, killing more than 1.4 million people worldwide each year. Nine Amaryllidaceae alkaloids (AAs) of various structural types have been screened for their antimycobacterial activity. Unfortunately, all were considered inactive, and thus a pilot series of aromatic esters of galanthamine, 3-O-methylpancracine, vittatine and maritidine were synthesized to increase biological activity. The semisynthetic derivatives of AAs were screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Ra and two other mycobacterial strains (M. aurum, M. smegmatis) using a modified Microplate Alamar Blue Assay. The most active compounds were also studied for their in vitro hepatotoxicity on the hepatocellular carcinoma cell line HepG2. In general, the derivatization of the original AAs was associated with a significant increase in antimycobacterial activity. Several pilot derivatives were identified as compounds with micromolar MICs against M. tuberculosis H37Ra. Two derivatives of galanthamine, 1i and 1r, were selected for further structure optimalization to increase the selectivity index.

scholarly journals Quaternary Salts of Chitosan: History, Antimicrobial Features, and Prospects

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Douglas de Britto ◽  
Rejane Celi Goy ◽  
Sergio Paulo Campana Filho ◽  
Odilio B. G. Assis
Keyword(s):  
Physical Chemistry ◽  
Antimicrobial Activity ◽  
Drug Delivery Systems ◽  
Antimicrobial Properties ◽  
Water Soluble ◽  
Chemical Characteristics ◽  
Packaging Materials ◽  
Inhibitory Effects ◽  
Quaternary Salts ◽  
Derivatives Of

Recently, increasing attention has been paid to water-soluble derivatives of chitosan at its applications. The chemical characteristics and the antimicrobial properties of these salts can play significant role in pharmacological and food areas mainly as carriers for drug delivery systems and as antimicrobial packaging materials. In the current paper, a historical sequence of the main preparative methods, physical chemistry aspects, and antimicrobial activity of chitosan quaternized derivatives are presented and briefly discussed. In general, the results indicated that the quaternary derivatives had better inhibitory effects than the unmodified chitosan.

Antimicrobial activity and active compounds of a Rhus verniciflua Stokes extract

2018 ◽  
Vol 73 (11-12) ◽  
pp. 457-463
Author(s):  
Jinfeng Yang ◽  
Yong Soo Kwon ◽  
Myong Jo Kim
Keyword(s):  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Penicillium Oxalicum ◽  
Resonance Spectroscopy ◽  
Trichoderma Virens ◽  
Traditional Herbal Medicine ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Rhus Verniciflua Stokes ◽  
Rhus Verniciflua

Abstract The Rhus verniciflua Stokes (RVS) extract is used as a traditional herbal medicine in Southeast Asian countries such as Korea and China. In the present study, one phenolic acid and six flavonoids were isolated from an 80% ethanol RVS extract to examine their antimicrobial activities. These compounds were identified as 3′,4′,7-trihydroxyflavone (1), methyl gallate (2), gallic acid (3), fusti (4), fisetin (5), butin (6), and sulfuretin (7) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance spectroscopy. The antimicrobial activities of compounds 5 and 6 (at a dose of 16 μg/mL each) were superior to that of the control, cycloheximide (at a dose of 25 μg/mL), against Hypocrea nigricans; additionally, the activities of compounds 1 and 2 (at a dose of 8 μg/mL each) were superior to the control against Penicillium oxalicum. Also, chemical compounds 1 and 5 (at a dose of 16 μg/mL each) had higher activities than the control (25 μg/mL) against Trichoderma virens. Chemical compound 1 (at a dose of 8 μg/mL) had a similar activity to that of the control against Bacillus subtilis. The obtained results suggest that the RVS extract could be a promising food and nutraceutical source because of the antimicrobial properties of its phenolic compounds.

Synthesen von TRH-Derivaten des Typs L-Pyr-L-His-L-Pro-NH-(CH2)n-NHa (n = 4, 7,10).

1976 ◽  
Vol 31 (10) ◽  
pp. 1410-1415 ◽  
Author(s):  
Stefan Fuchs ◽  
Wolfgang Voelter
Keyword(s):  
General Structure ◽  
Biologically Active ◽  
New Class ◽  
Synthetic Routes ◽  
Derivatives Of

Synthetic routes to a new class of biologically active TRH derivatives of the general structure L—Pyr—L—His—L—Pro—NH—(CH2E)n—NH2 are described.

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