scholarly journals The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

2020 ◽  
Vol 16 ◽  
pp. 2026-2031
Author(s):  
Sharna-kay Daley ◽  
Nadale Downer-Riley

The application of oxidative dimerization for the biomimetic synthesis of balsaminone A and ellagic acid is described. Balsaminone A is synthesized via the oxidative dimerization of 1,2,4-trimethoxynaphthalene under anhydrous conditions using CAN, PIDA in BF3 ·OEt2 or PIFA in BF3 ·OEt2 in 7–8% yields over 3 steps. Ellagic acid is synthesized from its biosynthetic precursor gallic acid, in 83% yield over 2 steps.

2019 ◽  
Author(s):  
Seth Herzon ◽  
Alan R. Healy ◽  
kevin wernke ◽  
Chung Sub Kim ◽  
Nicholas Lees ◽  
...  

<div>The clb gene cluster encodes the biosynthesis of metabolites known as precolibactins and colibactins. The clb pathway is found in gut commensal E. coli, and clb metabolites are thought to initiate colorectal cancer via DNA cross-linking. Precolibactin 886 (1) is one of the most complex isolated clb metabolites; it contains a 15-atom macrocycle and an unusual 5-hydroxy-3-oxazoline ring. Here we report confirmation of the structural assignment via a biomimetic synthesis of precolibactin 886 (1) proceeding through the amino alcohol 9. Double oxidation of 9 afforded the unstable α-ketoimine 2 which underwent macrocyclization to precolibactin 886 (1) upon HPLC purification (3% from 9). Studies of the putative precolibactin 886 (1) biosynthetic precursor 2, the model α-ketoimine 25, and the α-dicarbonyl 26 revealed that these compounds are susceptible to nucleophilic rupture of the C36–C37 bond. Moreover, cleavage of 2 produces other known clb metabolites or biosynthetic intermediates. This unexpected reactivity explains the difficulties in isolating full clb metabolites and accounts for the structure of a recently identified colibactin–adenine adduct. The colibactin peptidase ClbP deacylates synthetic precolibactin 886 (1) to form a non-genotoxic pyridone, suggesting precolibactin 886 (1) lies off-path of the major biosynthetic route.</div>


2020 ◽  
Vol 10 (4) ◽  
pp. 488-494 ◽  
Author(s):  
Venugopal Singamaneni ◽  
Sudheer Kumar Dokuparthi ◽  
Nilanjana Banerjee ◽  
Ashish Kumar ◽  
Tulika Chakrabarti

Background: Emblica officinalis Gaertn. which belongs to the family Euphorbiaceae, Terminalia chebula Retz. and Terminalia bellerica Roxb. belong to the family Combretaceae. These are well known medicinal plants with phytochemical reservoir of great medicinal values and possess a vast ethnomedical history. Objective: The aim of the present study is to isolation of major compounds and to evaluate antimutagenic potential of the ethanol extracts of these plants. Methods: The dried fruits of E. officinalis, T. bellirica and T. chebula were powdered and extracted with 95% ethanol. The ethyl acetate portions were chromatographed over silica gel to isolate major compounds. Antimutagenic activity was determined by Ames test using TA98 and TA100 strains of Salmonella typhimurium. Results: Two major known compounds, gallic acid and ellagic acid were isolated from the dried fruits of Emblica officinalis, Terminalia chebula and T. bellirica. All the three extracts counteracted the mutagenicity induced by different genotoxic compounds in a dose dependent manner. Conclusion: This study showed that ethyl acetate portion of three extracts contain two major compounds, gallic acid and ellagic acid which might be responsible for potent antimutagenic activity of these extracts.


2014 ◽  
Vol 926-930 ◽  
pp. 238-241
Author(s):  
Li Guo ◽  
Peng Wang

The effect of fermentation by Lentinus edodes hypha on active ingredient of blueberry pomace was studied, and the changes of fermentation products with protein, flavonoid and anthocyanin content were evaluated by spectrophotometric analysis. The protein content decreased slowly, and the flavonoid content in the first 66 h increased the highest level 0.09 mg/g, the anthocyanin content decreased during the first fermentation process, then increased to 0.568 mg/g at 30 h. The fermentation product of ellagic acid and gallic acid content were analyzed by using HPLC Method, the ellagic acid content decreased, and the gallic acid content increased first and then decreased, reached the highest value for the 0.310 mg/g in the first 54 h.


INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (06) ◽  
pp. 67-73
Author(s):  
M. A Shah ◽  
◽  
H. U. Patel ◽  
H.A Raj

Two chemometric methods, Inverse Least Square (ILS) and Classical Least Square (CLS), were applied for the simultaneous estimation of gallic acid, ellagic acid and curcumin in polyherbal antidiabetic formulation. Twenty mixed solutions were prepared for the chemometric calibration as training set and 10 mixed solutions were prepared as validation set. The absorbance data matrix was obtained by measuring the absorbance at 20 different wavelengths, from 241 to 279 nm with the interval of 2 nm (Δλ= 2 nm). The developed calibrations were successfully tested for three antidiabetic polyherbal formulations for their gallic acid, ellagic acid and curcumin contents. Developed methods were validated and root mean square error of precision (RMSEP) was determined. Both chemometric methods in this study can be satisfactorily used for the quantitative analysis in polyherbal dosage forms. The chemometric calculations were performed by using the chemometrics toolbox with MATLAB R2015a software.


2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500
Author(s):  
Juan A. Gayosso-De-Lucio ◽  
J. Martín Torres-Valencia ◽  
Carlos M. Cerda-García-Rojas ◽  
Pedro Joseph-Nathan

The aerial parts of Geranium potentillaefoium afforded geraniin (1), corilagin (2), gallic acid (4), methyl gallate (6), methyl brevifolincarboxylate (7), quercetin, quercetin 3- O-β-D-glucopyranoside, quercetin 3- O-β-D-[6″- O-galloyl)glucopyranoside, kaempferol, β-sitosterol 3- O-β-D-glucopyranoside and β-sitosterol, while the aerial parts of G. bellum gave the same compounds in addition to kaempferol 3- O-β-D-glucopyranoside, isolated instead of kaempferol. The substances were identified by 1D and 2D NMR spectroscopy in comparison with published data. The water decoction preparations from air-dried plant materials (2.5 g) contain ca. 4.6 % of the ellagitannin 1, envisaging that when such decoction is ingested (250 mL), a therapeutic dose of ca. 36 mg of the antitumor ellagic acid (3) may be incorporated into the organism.


Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 986
Author(s):  
Benta Natânia Silva Figueiredo ◽  
Marcello Otake Sato ◽  
Laiane Teixeira Sousa Moura ◽  
Sandra Maria Botelho Mariano ◽  
Tarso da Costa Alvim ◽  
...  

The current study evaluated the anthelmintic effect of different extracts of Leucaena leucocephala, Parkia platycephala, and Senna alata on trichostrongylid eggs and infective larvae and determined the potential active components of each plant. Dried and macerated plant material was concentrated using rotaevaporation to obtain the crude extract (CE), followed by solvent partitioning to obtain hexanic (HexE), acetatic (AcE), and butanolic (BuE) extracts used for phytochemical analysis and anthelmintic efficacy testing in vitro. All the crude and partitioned extracts tested showed inhibition activity in the hatching of trichostrongylid eggs. Larvicidal efficacy was observed at CE concentrations of 2.5, 5.0, and 7.5 mg/mL for P. platycephala and S. alata. However, L. leucocephala CE did not significantly reduce the number of living larvae in the tested concentrations. Chromatographic analysis revealed several active metabolites; gallic acid, ellagic acid, naringin, morin, and kaempferol on AcE of P. platycephala; gallic acid, rutin, and ellagic acid on BuE of P. platycephala; and gallic acid and naringin on BuE of L. leucocephala. The extracts of P. platycephala, L. leucocephala, and S. alata leaves showed egg hatching inhibition and larvicidal activity, probably produced by tannins and flavonoids, which may act alone or by synergism.


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