Mohamed S. Abdelfattah

Mansoquinone: Isolation and structure elucidation of new antibacterial aromatic polyketides from terrestrial Streptomyces Sp. Eg5

The cultivation of terrestrial Streptomyces Sp. Eg5 delivered two new aromatic polyketides, 2-butyryl-1,8-dihydroxy-3-methylanthraquinone (2), or mansoquinone, and 2-acetyl-1,8-dihydroxy-3-methyl-anthra-quinone (3) along with the known 2-ethyl-1,8-dihydroxy-3-methylanthraquinone (1). The structure of mansoquinone (2) was elucidated using detailed spectral (1H and 13C NMR, 1H–1H COSY, HSQC, HMBC and HRMS) analysis. This is the first report of the isolation of 3 from natural source. Mansoquinone (2) exhibited moderate antibacterial activities against Escherichia coli, Bacillus subtilis and Staphylococcus aureus.

Profiling the chemical content of Ficus lyrata extracts via UPLC-PDA-qTOF-MS and chemometrics

This study attempts to elucidate the secondary metabolite profiles of Ficus lyrata leaves and fruits grown in Egypt. Non-targeted metabolite profiling via ultra performance liquid chromatography (UPLC)-qTOF-MS was used to identify various chemical classes in F. lyrata fruits and leaves (i.e. flavonoids, phenolic acids and fatty acids) analysed by chemometrics. A total of 72 metabolites were evaluated via a UPLC-qTOF-MS-based metabolomic study. Seventeen flavonoids were characterised and tentatively identified with the main constituents being catechins/procyanidins, O- and C-linked flavonoid glycosides. The major procyanidins were dimers and trimers comprising (epi)catechin and (epi)afzelechin units, whereas the predominant flavones were C-glycosides of luteolin and apigenin. Aside from these major flavonoid classes, a group of benzoic acids, caffeoylquinic acids, fatty acid and sphingolipids were also annotated. This study provides the most complete map for polyphenol distribution in F. lyrata leaves and fruits and the basis for future investigation of its fruits nutritional value or possible nutraceutical uses.

Isolation and Crystal Structure of a new Anthraquinone Derivative from Actinomycete

A new anthraquinone derivative, 1,5-dihydroxy-3,4-dimethoxy-2-methylanthraquinone (1), was isolated from Streptomyces sp. Eg8. The structure and absolute configuration of 1 were established by X-ray crystallographic analysis. The crystal is monoclinic, space group P21/c with a = 7.1789 (4) Å, b = 17.4365 (10) Å, c = 11.1363 (6) Å, β = 102.378 (2)°, and Z = 4.

A new bioactive aminophenoxazinone alkaloid from a marine-derived actinomycete.

Chemical investigation of the marine Streptomyces sp. Eg25 led to the isolation of one new natural 2-aminophenoxazin-3-one-8-carboxylic acid methyl ester named maroxazinone (1) as well as the known compounds elloxazinone A (2), exfoliazone (3), carboxyexfoliazone (4), elloxazinone B (5) and venezueline D (6). The chemical structures of the isolated compounds were deduced from extensive studies of NMR (1H and 13C NMR, 1H–1H COSY, HMQC and HMBC) and mass spectra. The cytotoxic activities of the new maroxazinone (1) and venezueline D (6) against breast carcinoma cell line (MCF7), liver carcinoma cell line (HEPG2) and colon carcinoma cell line (HCT116) were investigated.

Marine actinomycete crude extracts with potent TRAIL-resistance overcoming activity against breast cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent, as it can kill tumor cells selectively. In our search of bioactive natural products to overcome TRAIL-resistance, we isolated 47 actinomycete strains from different sediments and seawater samples collected from the Red Sea coast in Egypt and found four crude extracts (EGY1, EGY3, EGY24 and EGY34) displaying TRAIL sensitizing activity in the resistant breast cancer cell line MDA-MB-231. None of these crude extracts exhibited cytotoxic effect on normal mouse embryonic fibroblasts (MEF), with the exception of EGY34. Analysis of the signaling pathways underlying the sensitization of MDA-MB-231 cells to TRAIL-induced apoptosis, by western blotting, revealed that all crude extracts facilitated initiator caspase‑8/-10 activation upon TRAIL stimulation, but that in addition, EGY3 and EGY34, alone, induced strong ER-stress activation, with the appearance of BiP in the cytosolic extracts. Our results pave the way to the discovery and the development of marine-derived drugs for cancer therapy.

Cytotoxic activity of alkyl benzoate and fatty acids from the red sea sponge Hyrtios erectus

Abstract The chemical investigation of the methylene chloride fraction of marine sponge Hyrtios erectus led to the isolation of the known oxysterol (2) along with a new alkyl benzoate compound identified by spectroscopic methods (NMR and MS) as 4′-methylheptyl benzoate (1), whilst the n-butanol fraction afforded the known indole 3-carbaldehyde and β-carboline derivatives. Moreover, the hexane fraction was analysed by GC–MS for their fatty acids (FAs). A total of 17 FAs with chain lengths between 14 and 25 carbons were identified. Methyl-branched FAs are predominated suggesting the presence of bacterial symbionts in the H. erectus sponge. Furthermore, compounds 1 and 2 displayed significant cytotoxicity against breast adenocarcinoma (MCF-7) with IC50 values of 2.4 and 3.8 μM, respectively, since compound 2 was also shown to have potent cytotoxic effect against hepatocellular carcinoma cells (HepG 2) with IC50 value of 1.3 μM.