title: TLC bioautographic method for detecting lipase inhibitors.
abstract: BACKGROUND
  Bioautographic assays using TLC play an important role in the search for active compounds from plants. A TLC bioautographic assay has previously been established for the detection of acetylcholinesterase inhibitors but not for lipases.
  
  
  OBJECTIVE
  Development of a TLC bioautographic method for detecting lipase inhibitors in plant extracts.
  
  
  METHODS
  After migration of the plant extracts, the TLC plate was sprayed with α-naphtyl acetate and enzyme solutions before incubation at 37°C for 20 min. Finally, the solution of Fast Blue B salt was sprayed onto the TLC plate giving a purple background colouration.
  
  
  RESULTS
  Lipase inhibitors were visualised as white spots on the TLC plates. Orlistat (a known lipase inhibitor) inhibited lipase down to 0.01 µg. Methanolic extracts of Camellia sinensis (L.) kuntz and Rosmarinus officinalis L after migration on TLC gave enzymatic inhibition when applied in amounts of 82 and 56 µg, respectively. On the other hand the methanolic extract of Morus alba leaves did not exhibit any lipase inhibitory activity.
  
  
  CONCLUSIONS
  The screening test was able to detect lipase inhibition by pure reference substances and by compounds present in complex matrices, such as plant extracts.
authors.affiliation: Department of Biochemistry, Faculty of Agriculture, Fayoum University, Fayoum, Egypt. ash01@fayoum.edu.eg
authors.forename: Abdel Moniem Sadek
authors.initials: AM
authors.lastname: Hassan
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry*; D002855:Chromatography, Thin Layer / Q000379:methods; D003116:Color; D004789:Enzyme Activation; D057075:Enzyme Assays / Q000379:methods*; D004791:Enzyme Inhibitors / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D007783:Lactones / Q000737:chemistry; D008049:Lipase / Q000037:antagonists & inhibitors*; D000432:Methanol / Q000737:chemistry; D031625:Morus / Q000737:chemistry; D009284:Naphthols / Q000737:chemistry; D000077403:Orlistat; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry; D012015:Reference Standards; D027542:Rosmarinus / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D007783:Lactones; D009284:Naphthols; D010936:Plant Extracts; D012997:Solvents; C027876:alpha-naphthyl acetate; D000077403:Orlistat; D008049:Lipase; D000432:Methanol