In vitro evaluation of potential bitterness-masking terpenoids from the Canada goldenrod (Solidago canadensis)
- J Nat Prod. 2014 Jul 25;77(7):1739-43. doi: 10.1021/np5001413.
- 1. Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University , 500 W. 12th Avenue, Columbus, Ohio 43210, United States.
In a screening of extracts of selected Plants native to Ohio against the human bitterness receptor hTAS2R31, a chloroform-soluble Extract of the aerial parts of Solidago canadensis (Canada goldenrod) was determined to have hTAS2R31 antagonistic activity and, thus, was fractionated for isolation of potential bitterness-masking agents. One new labdane diterpenoid, solidagol (1), and six known Terpenoids, including two labdane Diterpenoids (2 and 3), three clerodane Diterpenoids (6β-angeloyloxykolavenic acid, 6β-tigloyloxykolavenic acid, and crotonic acid), and a triterpenoid (longispinogenin), were isolated. Among these compounds, 3β-acetoxycopalic acid (2) was found to be the first member of the labdane diterpene class shown to have inhibitory activity against hTAS2R31 activation (IC50 8 μM). A homology model of hTAS2R31 was constructed, and the molecular docking of 2 to this model indicated that this diterpenoid binds well to the active site of hTAS2R31, whereas this was not the case for the closely structurally related compound 3 (sempervirenic acid). The content of 2 in the chloroform-soluble portion of the methanolic Extract of S. canadensis was up to 2.24 g/100 g dry weight, as determined by HPLC.