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New Enzyme Inhibitory Constituents from Tribulus longipetalus

Muhammad Akram Naveed, Naheed Riaz, Muhammad Saleem, Sara Mussadiq, Bushra Jabeen, Muhammad Ashraf, Ayesha Shaukat, Malik Munir Ahmed and Abdul Jabbar

Department of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan

Department of Biochemistry and Biotechnology, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan

Abstract: Normal and reversed phasechromatographic purification of the chloroform soluble fraction of the methanolic extract of Tribulus longipetalus led to the isolation of a new tyramine amide, longipetalamide (1), two new benzocoumarins, longipetalasin A (8-n-propyl-threo-1 ¢ S ,2 ¢ S -dihydroxy-5-methoxy-5a,9a-benzocoumarin; 2) and B (8-n-propyl-threo-1 ¢ S ,2 ¢ S -dihydroxy-5,10-dimethoxy-5a,9a-benzocoumarin; 3) together with 1,2,3-propantriyl trioleate (4), crotamide A (5), stigmasterol (6), (25S)-5α-furustan-22-methoxy-3β,26-diol (7), neotigogenin (8), tigogenin (9), methyl 4-hydroxyphenyl acetate (10) and 2-O-methylinositol (11). All the isolates (1-11) were characterized by using UV, IR, 1D- ( 1H and 13C), 2D-NMR (HSQC, HMBC, COSY) spectroscopy, mass spectrometry (EI-MS, HR-EI-MS, FAB-MS, HR-FAB-MS) and in comparison with the data reported in literature. The compounds 1-11 were evaluated for their enzyme inhibition studies against α-glucosidase, lipoxygenase (LOX), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and found that 2 and 3 were the significant inhibitors of enzyme α-glucosidase with IC 50 values 94.17 ± 0.09 and 85.65 ± 0.08 µM, respectively.

Keywords: Tribulus longipetalus ; Secondary Metabolites; Isolation; Characterization; Enzyme Inhibition. © 2015 ACG Publications. All rights reserved.