Evaluation of p-Nitrophenyl butyrate based bioautographic method for the identification of lipase inhibitors from the unexplored plant sources

Abstract

Plants are the source of different lipase inhibitors and have complex matrices. Lipase inhibitors from plant matrices can be directly detected on Bioautograms. In this study, a p-Nitrophenyl butyrate based bioautography was evaluated for the identification of lipase inhibitors from unexplored plants. Most of the unexplored plants were found to be positive for the lipase inhibitory activity. Leaf extracts of Lantana camara and Sorghum bicolor showed dark blue spots, whereas the floral extract of Lantana camara and seed extract of Areca catechu showed faint blue spots on the bioautogram suggesting the presence of higher or lower levels of lipase inhibitory activities respectively. Floral extract of Delonix regia showed the lipase inhibitory activity as a faint blue spot on the bioautogram which was not detected by the spectrophotometry. Hence, false negatives and false positives can be avoided with bioautography. Bioautographic assay was successfully validated by checking the lipase inhibitory activities in the blue spots.