Chemical characterization, antioxidant and cytotoxic activities of the methanolic extract of Hymenocrater longiflorus grown in Iraq.

Hymenocrater longiflorus was collected from northern Iraq, and the chemical composition and antioxidant and cytotoxic activities of this plant were investigated. Ten compounds detected by HPLC-ESI/MS were identified as flavonoids and phenolic acids. The free radical scavenging activity of the 70% methanol extract was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The antioxidant activities of the extract may be attributed to its polyphenolic composition. The cytotoxicity of the plant extract against the osteosarcoma (U2OS) cell line was assessed with the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The extract significantly reduced the viability of cells in a concentration- and time-dependent manner. Cells were arrested during the S-phase of the cell cycle, and DNA damage was revealed by antibodies against histone H2AX. The apoptotic features of cell shrinkage and decrease in cell size were also observed. Western blot analysis revealed cleavage of poly (ADP-ribose)-polymerase 1 (PARP-1), in addition to increases in the proteins p53, p21, and γ-H2AX. Collectively, our findings demonstrate that the H. longiflorus extract is highly cytotoxic to U2OS cells, most likely due to its polyphenolic composition.

Assessing the anti-tumour properties of Iraqi propolis in vitro and in vivo.

The study was designed to evaluate anti-tumour properties of Iraqi propolis collected from Mosul region (M) on HL-60 and HCT-116 cell lines and on HCT-116 in vivo. M induced an inhibitory effect against the proliferation of HL-60 and colony potential of HCT-116 cells. The apoptosis in HL-60 cells was associated with down-regulation of Bcl-2 and activation of Bax, while in HCT-116 cells, necrotic features were observed; size of cells was dramatically increased by swelling of cytoplasm and loss of membrane integrity, cell rupture and release of cellular contents. Analysis of BrdU/DNA cell cycle in both cell lines showed that M induced cell cycle perturbations in both BrdU positive and BrdU negative cells. The exposure of HL-60 to M caused γ-H2AX in a dose dependent manner and was associated with induction of apoptosis. The experiments in HCT-116 tumor-bearing mice showed that oral administration of propolis at doses that caused no detectable toxicity was associated with a decrease in mitotic cells and an increase in endoreduplications, increased p53 and decreased Ki-67 expression of cells in tumor sections. This study provides the rationale to investigate the potential beneficial effect of propolis in the diet of patients receiving anti-cancer therapies.

Chemical characterization of Iraqi propolis samples and assessing their antioxidant potentials.

Propolis samples, collected from different geographical locations in Iraq (Baghdad, Dahuk, Mosul and Salah ad-Din), were analyzed and assessed for their anti-oxidant activity. Concentrations of phenolic compounds (flavonoids, phenolic acids and their esters) in propolis were estimated using high performance liquid chromatography coupled to electrospray mass spectrometry. Thirty-eight different compounds were identified and 33 of them were polyphenols. Other compounds were tentatively identified as clerodane diterpenoids, and one was considered unknown. Semi-quantitative measurements showed that phenolic acids and their esters were the predominant constituents in propolis extracts, followed by flavones and flavonols, and then flavanones and dihydroflavonols. Propolis samples were further spectrophotometrically characterized using the Folin-Ciocalteu reagent for the determination of total phenolic compounds. The free radical scavenging activities of propolis samples were also evaluated by using the 2,2-diphenyl-1-picrylhydrazyl assay. The results revealed that propolis extracts exhibited strong free radical scavenging activity.