Ehab A. Ragab

A new monoterpene glucoside and complete assignments of dihydroflavonols of Pulicaria jaubertii: potential cytotoxic and blood pressure lowering activity

Abstract One new monoterpene glucoside and five dihydroflavonols were isolated for the first time from the aerial parts of Pulicaria jaubertii and identified as p-menthane-2-O-β-D-glucopyranoside [1], dihydroquercetin (taxifolin) [2], 7,3′-di-O-methyltaxifolin [3], 3′-O-methyltaxifolin [4], 7-O-methyltaxifolin (padmatin) [5] and 7-O-methyl-dihydrokampferol (7-O-methylaromadenderin) [6]. The structures of these compounds were unambiguously assigned on the basis of NMR spectroscopic data (1H, 13C, DEPT, HSQC, HMBC) and MS analysis. 2D-NMR methods required revision of assignments of H-6 and H-8 for dihydroflavonol compounds. Possible cytotoxic activity as well as blood pressure (BP) lowering activity were tested. The alcoholic extract showed cytotoxic activity against prostate carcinoma (PC-3), breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG-2) human cell lines with IC50 19.1, 20.0 and 24.1 μg, respectively. The higher dose levels of the alcoholic extract significantly reduced normal BP of rats in a dose-dependent manner.

A new flavan-3-ol dimer from Ficus spragueana leaves and its cytotoxic activity

Background: Isolation and structure elucidation of flavan-3-ol constituents from the leaves of Ficus spragueana and their cytotoxic activity. Materials and Methods: Different open silica gel column chromatographic techniques with different solvent systems were used for the separation of the constituents of the ethyl acetate-soluble fraction of the alcoholic extract of Ficus spragueana leaves. The structures of these compounds were assigned on the basis of spectroscopic analyses and comparison with literature data. MTT colorimetric assay method (Viability assay) was used for the evaluation of cytotoxic activity of compound 1 against human breast cancer (MCF-7) and human liver cancer (HepG2) cell lines. Results: The isolation of one flavan-3-ol dimer and was identified as (-)-afzelechin-(4α→8)-epicatechin 1, and two flavan-3-ol monomers and were identified as (-)-epiafzelechin 2 and (-)-epicatechin 3. Compound 1 was relatively inactive against human breast cancer (MCF-7) cell line at the tested concentrations as compared with the standard. However, at a concentration (50 ΅g) it was found to give inhibition upon the proliferation of examined human liver (HepG2) tumor cell line. Conclusions: Compound 1 is a new flavan-3-ol dimer and it showed a potent cytotoxic activity against human liver (HepG2) tumor cell line.

New Phytochemical Constituent and Bioactivities of Horwoodia dicksoniae and Rumex cyprius.

Background: Many plants growing in Saudi Arabia are used in folk medicine for treatment of several diseases. Objective: Information of the chemical constituents and biological activities of plants is desirable for the discovery of therapeutic agents and discovering the actual value of folkloric remedies. Materials and Methods: The compounds were isolated and purified using silica gel column chromatography and preparative high-performance liquid chromatography-diode array detector (HPLC-DAD) Method. The alcoholic extracts of these plants were evaluated for biological activities. Results: Isolation and characterization of 1-feruloyl-β-D-glucopyranoside (1) as well as new secondary metabolite tryptophan methyl ester (2) were isolated for the 1st time from the Horwoodia dicksoniae. The three flavones were isolated from Rumex cyprius identified as isoorientin (3), vitexin (4), and Cynarosid (5). The structures of these compounds were characterized by nuclear magnetic resonance and mass spectrometry analysis and comparing with literature. The compounds were isolated and purified using silica gel column chromatography and preparative HPLC-DAD Method. The alcoholic extracts of these plants were evaluated for antimicrobial activities against two Gram-positive bacteria, two Gram-negative bacteria, and four pathogenic fungi. Both plants showed good activities against Syncephalastrum racemosum and Streptococcus pneumoniae with minimal inhibitory concentrations (MICs) 0.98 and 1.95 μg/mL, respectively. H. dicksoniae showed good activity against Aspergillus fumigates with an MIC 1.95 μg/mL. The two extracts showed also effective free radical scavenging activities in the 1,1-diphenyl-2-picrylhydrazyl assay. H. dicksoniae exhibited remarkable cytotoxic activity against Human breast cancer mammary cancer cells-7, Human liver cancer human hepatoma carcinoma cells-2, and human lung carcinoma (A-549) cell lines. Conclusions: It was suggested that further work should be carried out to isolate, purify, and characterize the active constituents responsible for the activity of these plants. SUMMARY New secondary metabolite Tryptophane methyl ester as well as 1-feruloyl-β-D-glucopyranoside were isolated for the first time from the HD. Isoorientin, vitexin and Cynarosid were isolated from RC. HD exhibited good activity against Aspergillus fumigates with an MIC 1.95 μg mL-1. HD showed significant cytotoxic activity against Human breast cancer (MCF-7), Human liver cancer (HepG-2) and Human lung carcinoma (A-549) cell lines.