Urease inhibitory constituents from Daphne retusa

Abstract

The bioassay-guided fractionation of Daphne retusa Hemsl. has led to the isolation of a new aryl tetrahydronaphthalene lignan derivative named as daphnretusic acid (1), along with six new source compounds such as 5,7-dihydroxyflavone (2), 7-hydroxyflavone (3), 6-methoxyflavone (4), (+) pinoresinol (5), (+) sesamin (6), and β-sitosterol-3-O-β-D-glucopyranoside (7). Their structures were elucidated by ¹H NMR, ¹³C NMR, 1D, 2D NMR, UV, IR, and EIMS analyses. All the fractions (n-hexane, CHCl₃, AcOEt, CH₃OH, and water) and pure compounds (1–7) were subjected to the assay of urease and α-chymotrypsin inhibitory activities. Chloroform and methanol soluble fractions showed moderate urease inhibition. Compound 2 exhibited significant urease inhibition with IC₅₀ value 60.4 ± 0.72 μM, whereas compounds 1 and 3–7 remained inactive during urease inhibition and α-chymotrypsin bioassays.

Keywords::

• Daphne retusa
• Thymeleaceae
• flavones
• urease inhibitors
• α-chymotrypsin enzyme

Acknowledgments

Authors of manuscript greatly acknowledge the financial support of the Dean, Faculty of Science, University of Karachi for this research.