Anticholinesterase activity of endemic plant extracts from Soqotra

A total of 30 chloroform and methanol extracts from the following endemic Soqotran plants Acridocarpus socotranus Olive, Boswellia socotranao Balf.fil, Boswellia elongata Balf. fil., Caralluma socotrana N. Br, Cephalocroton socotranus Balf.f, Croton socotranus Balf. fil.., Dendrosicycos socotrana Balf.f., Dorstenia gigas Schweinf. ex Balf. fil., Eureiandra balfourii Cogn. & Balf. fil., Kalanchoe farinaceae Balf.f, Limonium sokotranum (Vierh) Radcl. Sm), Oldenlandia pulvinata, Pulicaria diversifolia( Balf. and Pulicaria stephanocarpa Balf. were screened for their acetylcholinesterase inhibitory activity by using in vitro Ellman method at 50 and 200 μg/ml concentrations. Chloroform extracts of Croton socotranus, Boswellia socotrana, Dorstenia gigas, and Pulicaria stephanocarpa as well as methanol extracts of Eureiandra balfourii exhibited inhibitory activities higher than 50 % at concentration of 200 μg. At a concentrations of 50 μg, the chloroform extract of Croton socotranus exhibited an inhibition of 40.6 %.Key words: plant extracts, acetylcholinesterase inhibitors, Soqotra, Alzheimer’s diseas

Anti-Inflammatory activity of a polyphenolic extract from Arabidopsis thaliana in in vitro and in vivo models of Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder and the primary form of dementia in the elderly. One of the main features of AD is the increase in amyloid-beta (Aβ) peptide production and aggregation, leading to oxidative stress, neuroinflammation and neurodegeneration. Polyphenols are well known for their antioxidant, anti-inflammatory and neuroprotective effects and have been proposed as possible therapeutic agents against AD. Here, we investigated the effects of a polyphenolic extract of Arabidopsis thaliana (a plant belonging to the Brassicaceae family) on inflammatory response induced by Aβ. BV2 murine microglia cells treated with both Aβ25⁻35 peptide and extract showed a lower pro-inflammatory (IL-6, IL-1β, TNF-α) and a higher anti-inflammatory (IL-4, IL-10, IL-13) cytokine production compared to cells treated with Aβ only. The activation of the Nrf2-antioxidant response element signaling pathway in treated cells resulted in the upregulation of heme oxygenase-1 mRNA and in an increase of NAD(P)H:quinone oxidoreductase 1 activity. To establish whether the extract is also effective against Aβ-induced neurotoxicity in vivo, we evaluated its effect on the impaired climbing ability of AD Drosophila flies expressing human Aβ1⁻42. Arabidopsis extract significantly restored the locomotor activity of these flies, thus confirming its neuroprotective effects also in vivo. These results point to a protective effect of the Arabidopsis extract in AD, and prompt its use as a model in studying the impact of complex mixtures derived from plant-based food on neurodegenerative diseases

One-pot synthesis of organophosphate monoesters from alcohols

AbstractA one-pot procedure for the phosphorylation of alcohols provides the corresponding phosphate monoesters in improved yields. The protocol features the use of tetrabutylammonium hydrogen phosphate and trichloroacetonitrile, followed by purification of the crude product by flash chromatography on silica gel. The final step, cation exchange chromatography, affords the organophosphates as ammonium salts that are usually required for biochemical applications. The mechanism appears to be phosphate rather than alcohol activation by trichloroacetonitrile

In vitro anticancer evaluation of novel triphenyltin(IV) compounds with some N-acetyl-S-naphthoquinonylcysteine derivatives

Triphenyltin(IV) compounds with naphthoquinone derivatives containing N-acetylcysteine, N-acetyl-S-(3,4-dihydro-3,4-dioxo-1-naphthyl)cysteine (1,2-NQC), 1, and N-acetyl-S-(1,4-dihydro-1,4-dioxo-2-naphthyl)cysteine (1,4-NQC), 2, were synthesized and characterized by elemental microanalysis, IR, multinuclear (H-1, C-13, Sn-119) NMR spectroscopy as well as HR-ESI mass spectrometry. With the aim of in vitro anticancer activity determination of ligand precursors and novel synthesized organotin(IV) compounds against human cervix adenocarcinoma (HeLa), human colon carcinoma (HT-29) and melanoma carcinoma cell line (B16F10), MTT colorimetric assay method was applied. The results indicate that synthesized compounds exhibited remarkable antiproliferative activity toward all tested cell lines with IC50 in the range from 0.17 to 0.87 mu M. Complex 1 showed the greatest activity against HT-29 cells, with IC50 value of 0.21 +/- 0.01 mu M, 119 times better than cisplatin, while complex 2 demonstrated the highest activity toward HeLa cells, IC50 = 0.17 +/- 0.01 mu M, which is similar to 26 times better than cisplatin

(Z)-2-[(4-Methyl­phen­yl)sulfon­yl]-1,2-diphenyl­ethene­selenol

In the title compound, C21H18O2SSe, the dihedral angle between the cis phenyl rings is 64.3 (1)° and those between the toluene and the phenyl rings are 21.1 (2) and 72.0 (1)°, respectively. An intra­molecular Se—H⋯O hydrogen bond occurs. In the crystal, mol­ecules are connected by C—H⋯O hydrogen bonds and weak C—H⋯π inter­actions help to consolidate the crystal packing

Squalene and amentoflavone from Antidesma laciniatum

Squalene, (2E, 7x,11x)-phyt-2-en-1-ol and amentoflavone have been isolated from the extract of the leaves of Antidesma laciniatum. Their structures were elucidated using spectroscopic methods. This is the first report of these compounds from Antidesma species.   KEY WORDS: Antidesma laciniatum, Euphorbiaceae, Squalene, Amentoflavone, (2E, 7x,11x)-Phyt-2-en-1-ol  Bull. Chem. Soc. Ethiop. 2006, 20(2), 325-328

A multiplex approach of MS, 1D-, and 2D-NMR metabolomicsin plant ontogeny A case study on Clusia minor L. organs (leaf, flower, fruit, and seed)

Introduction The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives. Objectives The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages. Material and Methods In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC-MS and 1H- and heteronuclear multiple-bond correlation (HMBC)-NMR-based metabolomics. Results This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5-hydroxy-8-methyltocotrienol (8.5 μg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 μg/mg f.w.). Nemorosone and 5-hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5-hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 μg/mg f.w. Seeds as typical storage organ were rich in sugars and omega-6 fatty acids. Conclusion To the best of our knowledge, this is the first report on a comparative 1D-/2D-NMR approach to assess compositional differences in ontogeny studies compared with LC-MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed

Enzymatic C–C-Coupling Prenylation: Bioinformatics – Modelling – Mechanism – Protein-Redesign – Biocatalytic Application

The functional role of isoprenoids and especially enzymatic prenylation in nature and human application is briefly covered, with the focus on bioinformatical, mechanistical and structural aspects of prenyltransferases and terpene synthases. These enzymes are as yet underrepresented but perspectively useful biocatalysts for C–C couplings of aromatic and isoprenoid substrates. Some examples of the successful use in chemoenzymatic synthesis are given including an application for the otherwise difficult synthesis of Kuhistanol A. Computational structure-based site-directed mutagenesis can be used for rational enzyme redesign to obtain altered substrate and product specificities, which is demonstrated for terpene cyclases

Computational Studies and Biosynthesis of Natural Products with Promising Anticancer Properties

We present an overview of computational approaches for the prediction of metabolic pathways by which plants biosynthesise compounds, with a focus on selected very promising anticancer secondary metabolites from floral sources. We also provide an overview of databases for the retrieval of useful genomic data, discussing the strengths and limitations of selected prediction software and the main computational tools (and methods), which could be employed for the investigation of the uncharted routes towards the biosynthesis of some of the identified anticancer metabolites from plant sources, eventually using specific examples to address some knowledge gaps when using these approaches