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BACKGROUND: Origanum majorana L., belonging to the Lamiaceae family, has great potential and has been used as a folk medicine against asthma, indigestion, headache and rheumatism; in addition, the essential oils of this plant have been used widely in the food industry. Plant materials have been harvested from the Medicinal and Aromatic Plant Field of Gaziosmanpasa University. Air-dried plant materials were boiled in water, filtered, and the solvent part subsequently extracted with hexane and ethyl acetate. The chromatographic method was applied to the ethyl acetate extract to isolate bioactive secondary metabolites, the structures of which were elucidated by spectroscopic techniques: basically one-dimensional and two-dimensional nuclear magnetic resonance and quadrupole time-of-flight liquid chromatography. Antiproliferative and antioxidant activities of isolated secondary metabolites were determined. RESULTS: 5,6,3 ′ -Trihydroxy-7,8,4 ′ -trimethoxyflavone, hesperetin, hydroquinone, arbutin and rosmarinic acid were isolated from the water-soluble ethyl acetate extract of aerial parts of O. majorana. Antioxidant activities of isolated compounds and water-soluble ethyl acetate extract were investigated using assays of DPPH • ,A BTS •+ , reducing power and total phenolic content. Antiproliferative activities of the isolated compounds and plant extracts were investigated against C6 and HeLa cell lines using BrdU cell proliferation enzyme-linked immunosorbent assay and xCELLigence assay, respectively. Both hesperetin and hydroquinone were determined to have stronger antiproliferative activities against C6 and HeLa cells than the other isolated compounds and 5-fluorouracil. CONCLUSION: The results showed that the extract and isolated compounds exhibited significant antioxidant activities. Hence this plant has the potential to be a natural antioxidant in the food industry and an anticancer drug. © 2015 Society of Chemical Industry Supporting information may be found in the online version of this article.

dienyl)pyridine 11 and 3-(3-(pyridine-3-yl)propa-1,2-dienyl)pyridine 17 and the acetylenes 5, 12 and 16 wereobtainedbyreductionofthecorrespondingpropargylicacetates 3, 10and 15bySamarium(II)iodide in the presence of Pd(0). Base-promoted isomerisation of acetylene 12 provided allene 11 in a yield of 80%. 1-(Pentafluorophenyl)-3-phenylprop-2-yn-1-ol 2 was prepared from phenylacetylene and pentafluorobenzaldehyde. The condensation of nicotinaldehyde with trimethylsilylacetylene gave the 3-(trimethylsilyl)-1-(pyridine-3-yl)prop-2-yn-1-ol 7. The removal of the silyl group of 7 to acetylene 8 was done in basic conditions. The Pd catalysed condensation of the acetylene 8 with iodobenzene gave 3-phenyl-1-(pyridine-3-yl)prop-2-yn-1-ol 9. The Pd catalysed condensation of 8 with 3-bromopyridine gave the 1,3-dipyridin-3-yl-prop-2-yn-1-ol 14. The propargylic alcohols 2, 9 and 14were converted to the acetates 3, 10 and 15 with acetic anhydride-pyridine.

The conversion of 4-pyridyl propargylic alcohols 1 to the ( E )-propenones 3 and propynones 2 occurs under mild reaction conditions, pyridinium chloride in methanol at room temperature. (Z)-4-Pyridyl propenones 11 are detected as initial products when large substituents such as trimethylsilyl, tert -butyl and phenyl are attached at C-3 of the propynols and these ( Z )-enones 11 are isomerised to the ( E )-isomers 3 under the reaction conditions. In the presence of deuterated solvent, both hydrogens at the double bond of enone 3d are deuterated. An allenol is proposed as intermediate whose preferential protonation occurs at the less hindered side giving the (Z)-enone. The propargylic alcohols, pyridin-2-yl 12 and quinolin-4-yl 5 , are converted to ( E )-enones 13 and 7 , respectively.

Stereoselective synthesises are described for naphthalene and tetralin derivatives. Hexabromo 2 and 3, monomethoxy 7, dimethoxy 6, dihydroxy 4 and dinitroxy 10 derivatives of tetralin have been obtained. Base-promoted elimination reactions of 6 and 4 provided monomethoxy 8 and 9 and diepoxy 5 naphthalenes respectively. The structures of these products were determined by 1H and 13C NMR spectra, mass spectra and micro analysis.