4 nitrophenyl butyrate p npb

Horseradish peroxidase (HRP) (reagent grade), Candida antarctica lipase (CALB), 2-methylimidazole, phosphate buffer saline (1×), 1,2,3-trihydroxybenzene (THB, ACS reagent), and 4-nitrophenyl butyrate (p-NPB) were purchased from Sigma-Aldrich. Zinc nitrate hexahydrate (99.998%) and hydrogen peroxide (29–32% wt) were purchased from Alfa Aesar. Cytochrome c from horse heart was purchased from Biodee Corporation. All the other reagents are of analytic grade.

Materials: Lipase from Candida rugosa Type VII (specific activity of 724 U mg⁻¹; 1 U corresponds to the amount of enzyme, which hydrolyzes 1 microequivalent of fatty acid from a triglyceride per hour at pH 7.2 and 37 °C), bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT), (hydroxypropyl)methyl cellulose (HPMC) (3600–5500 cP), lauric acid as well as the iodoacetamido-TEMPO, and 4-Nitrophenyl butyrate (p-NPB) were obtained from Sigma, Darmstadt, Germany. The spin probe 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Hydroxy-TEMPO), the spin-labelled doxylated derivatives 5-doxyl stearic acid (5-(1-oxyl-2,2-dimethyl-oxazolidin) stearic acid; 5-DSA), 16-doxyl stearic acid (16-DSA), 12-doxyl methyl stearate (12-DMS), 10-doxyl nonadecane (10-DN), 5-doxyl decane (5-DD), and the spin label 4-(2-iodoacetamido)-2,2,6,6-tetramethyl-1-piperidinyloxy (4-(2-iodoacetamido)-TEMPO) were obtained from Sigma, Darmstadt, Germany. All other reagents were of the highest commercially available purity.

Porcine pancreatic lipase (PPL, type II), 4-nitrophenyl butyrate (p-NPB), porcine pancreatic cholesterol esterase, oleic acid, phosphatidylcholine, cholesterol, sodium taurocholate hydrate, sodium chenodeoxycholate, sodium glycodeoxycholate, orlistat, epigallocatechin gallate (EGCG), cholestyramine resin, cinnamyl acetate, eugenol, kaempferol, trans-cinnamaldehyde, trans-cinnamic acid, phlorizidin, epicatechin, catechin, 4-hydroxybenzoic acid, gallic acid, and HMG-CoA reductase assay kits (CS 1090) were purchased from Sigma-Aldrich Co., St. Louis, MO, USA. Total cholesterol test kits (BXC0261) were purchased from Fortress Diagnostics, UK, and total bile acid kits (BQ 042A-EALD) were purchased from Bio-Quant Co. (San Diego, CA, USA). All the other chemical reagents used in this study were of analytical grade.