HBF4 Catalysed Nucleophilic Substitutions of Propargylic Alcohols

The activity of HBF4 (aqueous solution) as a catalyst in propargylation reactions is presented. Diverse types of nucleophiles were employed in order to form new C–O, C–N and C–C bonds in technical acetone and in air. Good to excellent yields and good chemoselectivities were obtained using low acid loading (typically 1 mol-%) under simple reaction conditions

Determinants of personal exposure to fine particulate matter (PM2.5) in adult subjects in Hong Kong

202308 bcchAccepted ManuscriptRGCOthersFocused Innovations Scheme of the; Hong Kong Environmental Protection Department; Vice-Chancellor's Discretionary Fund; Faculty of Arts and Social Sciences, Carleton University; Chinese University of Hong KongPublishe

Estimation of personal exposure to fine particles (PM2.5) of ambient origin for healthy adults in Hong Kong

202308 bcchAccepted ManuscriptRGCOthersHong Kong Environmental Protection Department; Chinese University of Hong KongPublishe

In vitro cytotoxicity of (-)-EGCG octaacetate on MDAMB-231 and SKHep-1 human carcinoma cells: A pharmacological consideration on prodrug design

Esterification of acetate with generic pharmaceutical compound has been commonly employed to produce ester prodrug for improving its potency when compared with the mother compound. Acetate, on the other hand, has been recognized to have inhibitory effect on the respiratory biochemistry. Here we demonstrate that acetate at a concentration of 400 mu M exhibited significant growth inhibitory activity on two human cancer cell lines, the MDAMB-231 breast cancer and the SKHep-1 hepatoma cell lines. To establish the ester prodrug with multi-acetate ester conjugates as our experimental model, one molecule of (-)-epigallocatechin gallate was required to conjugate with eight molecules of acetate forming the corresponding (-)-epigallocatechin gallate octaacetate prodrug. Chemical structure of this epigallocatechin gallate octaacetate ester prodrug was confirmed by both C-13 and H-1 nuclear magnetic resonance spectra and mass spectrometry. Further cytotoxic assay using both MDAMB-231 and SKHep-1 human carcinoma cell lines showed that acetate at a concentration of 400 mu M exhibits an additional cytotoxic effect with (-)-epigallocatechin gallate at a concentration of 50 mu M, although the additional effect was not as high as (-)-epigallocatechin gallate octaacetate ester prodrug alone at a concentration of 50 mu M. Our results thus raise a pharmacological consideration of using multi-acetate conjugate as the ester prodrug where the release of free acetate by esterase could be part of the explanation for the improved in vitro cytotoxicity