Propolis is a gummy material produced by honey bees to protect their hives and currently has drawn the attention of researchers due to its broad clinical use. It has been reported, based only on observations, that honey bees also collect other non-vegetation substances such as paint or asphalt/tar to make propolis. Therefore, propolis samples were collected from bee hives in Riyadh and Al-Bahah...

In the present study, a simple and sensitive methodology based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography with quadrupole mass detection (GC-qMSD), was developed and optimized for the determination of volatile (VOCs) and semi-volatile (SVOCs) compounds from different alcoholic beverages: wine, beer and whisky. Key experimental fa...

Epicuticular leaf waxes of Ginkgo biloba, Magnolia grandiflora and Liriodendron tulipifera contain homologous series of hydrocarbons, wax esters, benzyl acyl esters, aldehydes, primary alcohols, and fatty acids. None of these lipid classes is found to contain any main component dominating. In addition to these usual wax lipids, in G. biloba leaf wax a secondary alcohol namely nonacosan-10-ol (1...

 Caffeic acid phenethyl ester(CAPE) suppresses the growth of transformed cells such as human breast cancer cells, hepatocarcinoma , myeloid leukemia, colorectal cancer cells, fibrosarcoma, glioma and melanoma. A group of heterocyclic esters of caffeic acid was synthesized using Mitsunobu reaction and the esters were subjected to further structural modification by electrooxidation of the catecho...

a most effective and less energy demanding method of producing fatty esters, diol esters, by esterifying fatty acids, with neopentyl and ethylenglycol alcohols in the presence of an acidic ion exchange resin catalyst(polyestyrendivinylbenzensulfated) was investigated at elevated temperature. in this process an azeotroping agent, toluene, was used to facilitate continuous removal of water by dis...

The biosynthesis of antibiotic 1233A (F-244) was studied by feeding 13C-labeled precursors to the producing organism, Scopulariopsis sp. F-244. 13C NMR spectroscopy established that 1233A is derived from 4 methionines and 7 acetates. Seven acetates are condensed to form a hexaketide and 4 methyl residues from methionine are introduced into the main skeleton. The beta-lactone is derived from the...

A convenient zinc(II) chloride-catalyzed regioselective propargylation/amination/cycloisomerization process has been developed for the synthesis of substituted pyrrole derivatives from propargylic acetates, enoxysilanes and primary amines. Various aromatic and aliphatic propargylic acetates participate well in the reaction, providing the propargylation/amination/cycloisomerization products in g...