TLC bioautographic method for detecting lipase inhibitors

Area of Science:

• Natural Product Chemistry
• Biochemistry
• Analytical Chemistry

Background:

• Bioautographic assays using thin-layer chromatography (TLC) are crucial for identifying bioactive plant compounds.
• Existing TLC bioautographic methods are established for acetylcholinesterase inhibitors but lack a standardized approach for lipase inhibitors.

Purpose of the Study:

• To develop and validate a novel TLC bioautographic method for the detection and screening of lipase inhibitors within plant extracts.
• To establish a reliable method for identifying natural compounds with lipase inhibitory potential.

Main Methods:

• Plant extracts were separated using TLC.
• TLC plates were subsequently incubated with α-naphtyl acetate and lipase enzyme solution.
• Lipase inhibition was visualized using Fast Blue B salt, resulting in a purple background with white spots indicating inhibitor presence.

Main Results:

• The developed TLC bioautographic method successfully visualized lipase inhibitors as white spots against a purple background.
• Orlistat, a known lipase inhibitor, demonstrated inhibition at concentrations as low as 0.01 µg.
• Methanolic extracts of Camellia sinensis (82 µg) and Rosmarinus officinalis (56 µg) exhibited lipase inhibitory activity, while Morus alba showed no activity.

Conclusions:

• The developed TLC bioautographic assay is effective for detecting lipase inhibition from both pure reference compounds and complex plant matrices.
• This method provides a valuable screening tool for discovering novel lipase inhibitors from natural sources.