α-Glucosidase inhibitory activity of compounds isolated from the twig and leaf extracts of Desmos dumosus
Virayu Suthiphasilp,
Tharakorn Maneerat,
Raymond J. Andersen,
Brian O. Patrick,
Stephen G. Pyne,
Surat Laphookhieo
Affiliations
Virayu Suthiphasilp
Center of Chemical Innovation for Sustainability (CIS), School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand
Tharakorn Maneerat
Center of Chemical Innovation for Sustainability (CIS), School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand; Medicinal Plant Innovation Center of Mae Fah Luang University, Chiang Rai 57100, Thailand
Raymond J. Andersen
Department of Earth, Ocean & Atmospheric Sciences, University of British Columbia, 2036 Main Mall, V6T 1Z1 Vancouver, BC, Canada; Department of Chemistry, University of British Columbia, 2036 Main Mall, V6T 1Z1 Vancouver, BC, Canada
Brian O. Patrick
Department of Chemistry, University of British Columbia, 2036 Main Mall, V6T 1Z1 Vancouver, BC, Canada
Stephen G. Pyne
School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, 2522, Australia
Surat Laphookhieo
Center of Chemical Innovation for Sustainability (CIS), School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand; Medicinal Plant Innovation Center of Mae Fah Luang University, Chiang Rai 57100, Thailand; Corresponding author.
Four new compounds, (+)-(2S)-desmosdumosone (1), (+)-(2R)-7,8-dimethoxy-5-hydroxyflavanone (7), (+)-(2R)-7-methoxychamanetin (9), and (+)-(1ˊR,2ˊR)-phebalosin (18), and 25 known compounds were isolated from the twig and leaf extracts of Desmos dumosus. Compounds (±)-7 and (±)-9 were isolated as racemates and their enantiomers were separated by chiral HPLC. Their structures were elucidated by spectroscopic methods as well as comparisons made from the literature. The absolute configuration of (+)-(1ʹR,2ʹR)-18 was established by X-ray diffraction analysis using Cu Kα radiation and electronic circular dichroism (ECD) spectoscopy. In contrast, the absolute configuration of compounds (+)-(2S)-1, (+)-(2R)-7, and (+)-(2R)-9 were identified by comparing their ECD spectra and specific rotations with those of reported known compounds. Compounds 9, 11, 13, 14, 22, 25, and 28 showed α-glucosidase inhibitory activities with IC50 values ranging from 5.3-52.7 μM, much better than that of standard control (acarbose, IC50 value 83.5 μM). Compound 13 was the most active with an IC50 value of 5.3 μM.
