Metabolic engineering for the production of chitooligosaccharides: advances and perspectives

2018 ◽  
Vol 2 (3) ◽  
pp. 377-388 ◽  
Author(s):  
Meixi Ling ◽  
Jianghua Li ◽  
Guocheng Du ◽  
Long Liu

Chitin oligosaccharides (CTOs) and its related compounds chitosan oligosaccharides (CSOs), collectively known as chitooligosaccharides (COs), exhibit numerous biological activities in applications in the nutraceutical, cosmetics, agriculture, and pharmaceutical industries. COs are currently produced by acid hydrolysis of chitin or chitosan, or enzymatic techniques with uncontrollable polymerization. Microbial fermentation by recombinant Escherichia coli, as an alternative method for the production of COs, shows new potential because it can produce a well-defined COs mixture and is an environmentally friendly process. In addition, Bacillus subtilis, a nonpathogenic, endotoxin-free, GRAS status bacterium, presents a new opportunity as a platform to produce COs. Here, we review the applications of COs and differences between CTOs and CSOs, summarize the current preparation approaches of COs, and discuss the future research potentials and challenges in the production of well-defined COs in B. subtilis by metabolic engineering.

2020 ◽  
Vol 13 (12) ◽  
pp. 479
Author(s):  
Márcio Rodrigues ◽  
Ana Clara Lopes ◽  
Filipa Vaz ◽  
Melanie Filipe ◽  
Gilberto Alves ◽  
...  

Thymus mastichina has the appearance of a semishrub and can be found in jungles and rocky lands of the Iberian Peninsula. This work aimed to review and gather available scientific information on the composition and biological properties of T. mastichina. The main constituents of T. mastichina essential oil are 1,8-cineole (or eucalyptol) and linalool, while the extracts are characterized by the presence of flavonoids, phenolic acids, and terpenes. The essential oil and extracts of T. mastichina have demonstrated a wide diversity of biological activities. They showed antibacterial activity against several bacteria such as Escherichia coli, Proteus mirabilis, Salmonella subsp., methicillin-resistant and methicillin-sensitive Staphylococcus aureus, Listeria monocytogenes EGD, Bacillus cereus, and Pseudomonas, among others, and antifungal activity against Candida spp. and Fusarium spp. Additionally, it has antioxidant activity, which has been evaluated through different methods. Furthermore, other activities have also been studied, such as anticancer, antiviral, insecticidal, repellent, anti-Alzheimer, and anti-inflammatory activity. In conclusion, considering the biological activities reported for the essential oil and extracts of T. mastichina, its potential as a preservative agent could be explored to be used in the food, cosmetic, or pharmaceutical industries.


2015 ◽  
Vol 51 (7) ◽  
pp. 733-750 ◽  
Author(s):  
V. G. Doroshenko ◽  
V. A. Livshits ◽  
L. G. Airich ◽  
I. S. Shmagina ◽  
E. A. Savrasova ◽  
...  

2017 ◽  
Vol 66 (4) ◽  
pp. 484-493 ◽  
Author(s):  
Niranjan Koirala ◽  
Ramesh Prasad Pandey ◽  
Nguyen Huy Thuan ◽  
Gopal Prasad Ghimire ◽  
Hye Jin Jung ◽  
...  

1969 ◽  
Vol 115 (4) ◽  
pp. 733-739 ◽  
Author(s):  
M. Cole

1. A method is given for the preparation of penicillin acylase by using Escherichia coli N.C.I.B. 8743 and a strain selected for higher yield. The enzyme is associated with the bacterial cells and removes the side chains of penicillins to give 6-amino-penicillanic acid and a carboxylic acid. 2. The rates of penicillin deacylation indicated that p-hydroxybenzylpenicillin was the best substrate, followed in diminishing order by benzyl-, dl-α-hydroxybenzyl-, 2-furylmethyl-, 2-thienylmethyl-, d-α-aminobenzyl-, n-propoxymethyl- and isobutoxymethyl-penicillin. Phenylpenicillin and dl-α-carboxybenzylpenicillin were not substrates and phenoxymethyl-penicillin was very poor. 3. Amides and esters of the above penicillins were also substrates for the deacylation reaction, as were cephalosporins with a thienylmethyl side chain. 4. For the deacylation of 2-furylmethylpenicillin at 21° the optimum pH was 8·2. The optimum temperature was 60° at pH7. 5. By using selection A of N.C.I.B. 8743 and determining reaction velocities by assaying yields of 6-amino-penicillanic acid in a 10min. reaction at 50° and pH8·2, the Km for benzylpenicillin was found to be about 30mm and the Km for 2-furylmethylpenicillin, about 10mm. The Vmax. values were 0·6 and 0·24μmole/min./mg. of bacterial cells respectively.


2018 ◽  
Vol 9 ◽  
Author(s):  
Luan L. Chu ◽  
Dipesh Dhakal ◽  
Hee J. Shin ◽  
Hye J. Jung ◽  
Tokutaro Yamaguchi ◽  
...  

2020 ◽  
Vol 24 (22) ◽  
pp. 2665-2693
Author(s):  
Dipayan Mondal ◽  
Pankaj Lal Kalar ◽  
Shivam Kori ◽  
Shovanlal Gayen ◽  
Kalpataru Das

Indole moiety is often found in different classes of pharmaceutically active molecules having various biological activities including anticancer, anti-viral, anti-psychotic, antihypertensive, anti-migraine, anti-arthritis and analgesic activities. Due to enormous applications of indole derivatives in pharmaceutical chemistry, a number of conventional synthetic methods as well as green methodology have been developed for their synthesis. Green methodology has many advantages including high yields, short reaction time, and inexpensive reagents, highly efficient and environmentally benign over conventional methods. Currently, the researchers in academia as well as in pharmaceutical industries have been developing various methods for the chemical synthesis of indole based compounds via green approaches to overcome the drawbacks of conventional methods. This review reflects the last ten years developments of the various greener methods for the synthesis of indole derivatives by using microwave, ionic liquids, water, ultrasound, nanocatalyst, green catalyst, multicomponent reaction and solvent-free reactions etc. (please see the scheme below). Furthermore, the applications of green chemistry towards developments of indole containing pharmaceuticals and their biological studies have been represented in this review.


2019 ◽  
Vol 16 (5) ◽  
pp. 709-729 ◽  
Author(s):  
Muhammad A. Rashid ◽  
Aisha Ashraf ◽  
Sahibzada S. Rehman ◽  
Shaukat A. Shahid ◽  
Adeel Mahmood ◽  
...  

Background:1,4-Diazepines are two nitrogen containing seven membered heterocyclic compounds and associated with a wide range of biological activities. Due to its medicinal importance, scientists are actively involved in the synthesis, reactions and biological evaluation of 1,4-diazepines since number of decades.Objective:The primary purpose of this review is to discuss the synthetic schemes and reactivity of 1,4- diazepines. This article also describes biological aspects of 1,4-diazepine derivatives, that can be usefully exploited for the pharmaceutical sector.Conclusion:This review summarizes the abundant literature on synthetic routes, chemical reactions and biological attributes of 1,4-diazepine derivatives. We concluded that 1,4-diazepines have significant importance due to their biological activities like antipsychotic, anxiolytic, anthelmintic, anticonvulsant, antibacterial, antifungal and anticancer. 1,4-diazepine derivatives with significant biological activities could be explored for potential use in the pharmaceutical industries.


2019 ◽  
Vol 16 (6) ◽  
pp. 568-577 ◽  
Author(s):  
Jainara Santos do Nascimento ◽  
João Carlos Silva Conceição ◽  
Eliane de Oliveira Silva

Coumarins are natural 1,2-benzopyrones, present in remarkable amounts as secondary metabolites in edible and medicinal plants. The low yield in the coumarins isolation from natural sources, along with the difficulties faced by the total synthesis, make them attractive for biotechnological studies. The current literature contains several reports on the biotransformation of coumarins by fungi, which can generate chemical analogs with high selectivity, using mild and eco-friendly conditions. Prompted by the enormous pharmacological interest in the coumarin-related compounds, their alimentary and chemical applications, this review covers the biotransformation of coumarins by filamentous fungi. The chemical structures of the analogs were presented and compared with those from the pattern structures. The main chemical reactions catalyzed the insertion of functional groups, and the impact on the biological activities caused by the chemical transformations were discussed. Several chemical reactions can be catalyzed by filamentous fungi in the coumarin scores, mainly lactone ring opening, C3-C4 reduction and hydroxylation. Chunninghamella sp. and Aspergillus sp. are the most common fungi used in these transformations. Concerning the substrates, the biotransformation of pyranocoumarins is a rarer process. Sometimes, the bioactivities were improved by the chemical modifications and coincidences with the mammalian metabolism were pointed out.


2020 ◽  
Vol 17 (1) ◽  
pp. 66-74
Author(s):  
Seghira Bisset ◽  
Widad Sobhi ◽  
Chawki Bensouici ◽  
Abdelhalim Khenchouche

Background: Several researches have shown that therapeutic compounds or phytochemicals from natural sources are important in the food as it is valuable in pharmaceutical industries due to their fewer side effects and potent against various diseases. Curcumin, a major polyphenol derived from turmeric spice, which used in many foods, has a wide range of biological activities, with quite a safety. Objective: The goal of this study was to investigate the antioxidant, urate-lowering, and antiinflammatory effects of pure curcumin. Methods: The antioxidant activity was evaluated for chain-breaking antioxidant effect (radicalscavenging and reducing abilities assays) and for preventive antioxidant effect with metal chelating assay, the urate-lowering was assayed on aspectrophotometer by measuring the inhibition of uric acid production by xanthine oxidase (XO) enzyme, and the anti-inflammatory effect was estimated using in vitro albumin denaturation inhibition. Results: Curcumin showed a significant and good chain-breaking antioxidant effect, both in free radical- scavenging assays (Galvinoxyl radical, ABTS, and hydroxyl radical), and in reducing abilities methods (reducing power, Cupric ion reducing antioxidant capacity and O-phenanthroline assays). In preventive antioxidant effect, assessed with the metal chelating assay, curcumin showed significant effect but with high concentration compared with standard. In the xanthine/xanthine oxidase system, curcumin significantly inhibited uric acid production (IC50=0.71 ± 0.06 mg/mL). Regarding antiinflammatory activity, curcumin showed significant inhibition of albumin denaturation with an IC50 value of 1181.69 ± 1.11μg/mL. Conclusion: These results indicated that curcumin showed promising antioxidant, anti-gout and antiinflammatory properties and might be used as potential, natural drugs against oxidative and inflammation- related diseases.


2019 ◽  
Vol 9 (3) ◽  
pp. 238-243 ◽  
Author(s):  
Emine Dede ◽  
Nusret Genc ◽  
Mahfuz Elmastas ◽  
Huseyin Aksit ◽  
Ramazan Erenler

Background: Plant in Rhododendron genus that contains phenolic compounds has been used in traditional medicine and revealed considerable biological activities. Objective: Isolation and identification of antioxidant natural products from Rhododendron ungernii. Methods: Rhododendron ungernii Trautv. flowers were collected and dried in shade. The dried flowers were extracted with methanol for 3 days. The solvent was removed by reduced pressure to yield the extract which was subjected to column chromatography (Sephadex LH-20, C18 reversed phase column) to isolate catechin-7-O-glucoside (1), quercetin-3-O-β-galactoside (2), quercetin-3-O- β-xyloside (3), farrerol (4), myricetin (5), and quercetin (6). The structures of isolated compounds were elucidated by spectroscopic methods such as 1D-NMR, 2D-NMR, and LC-TOF/MS. DPPH scavenging effect, ABTS+ scavenging activity, and reducing power (FRAP) were performed for antioxidant assays of isolated natural compounds. Results: Isolated flavonoids displayed the outstanding antioxidant activities. Catechin-7-O-glucoside (1) and quercetin-3-O-β-galactoside (2) (IC50, 3.66 µg/mL) had the most DPPH• scavenging effect among the compounds. The highest ABTS•+ scavenging activity (IC50, 1.41 µg/mL) and reducing power effect (6.05 mmol TE/g comp) were observed for myricetin (5). Conclusion: R. ungernii extract and isolated compounds could be a promising antioxidant for food and pharmaceutical industries.


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