Quantitative structure activity relationship (QSAR) of piperine analogsfor bacterial NorA efflux pump inhibitors

Quantitative structure activity relationship (QSAR) analysis of piperine analogs as inhibitors of efflux pump NorA from Staphylococcus aureus has been performed in order to obtain a highly accurate model enabling prediction of inhibition of S. aureus NorA of new chemical entities from natural sources as well as synthetic ones. Algorithm based on genetic function approximation method of variable selection in Cerius2 was used to generate the model. Among several types of descriptors viz., topological, spatial, thermodynamic, information content and E-state indices that were considered in generating the QSAR model, three descriptors such as partial negative surface area of the compounds, area of the molecular shadow in the XZ plane and heat of formation of the molecules resulted in a statistically significant model with r

Trichosporon beigelli esterase (TBE): a versatile esterase for the resolution of economically important racemates

A hydrolase producing strain Trichosporon beigelli esterase (TBE) isolated from local cottage cheese in its native form has displayed versatility and high efficacy in the kinetic resolution of a wide range of economically important substrates, which include racemic secondary alcohols, such as 1-(6-methoxy-2-naphthyl)ethanol (E � 316), 1-(3,4-methylenedioxyphenyl)ethanol and pentanol(E � 180 and 156 resp.), and alkyl esters of carboxylic acids such as ibuprofen (E � 340), 2-(benzylthio)propanoic acid (E � 1000). In other substrates such as in the primary alcohol 2-(6-methoxy-2-naphthyl)propan-1-ol and carboxylic acids such as 2-(5-bromo-6-methoxy-2-naphthyl)propanoic acid, 2-(2-naphthyloxy)propanoic acid, and substituted 2-thiopropanoic acids, it displayed moderate to low selectivity. Commercial lipases such as CCL, PPL, and PSL were also used in the resolution of the substrates for comparative studies