In Vitro Evaluation of Potential Bitterness-Masking Terpenoids from the Canada Goldenrod (Solidago canadensis)

Abstract

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.

Reactivity of (3-Methylpentadienyl)iron(1+) Cation: Late-stage Introduction of a (3-Methyl-2Z,4-pentadien-1-yl) Side Chain

“… 135, 114 and 20 ppm respectively. These chemical shifts are characteristic of a 3-methyl-2Z,4-pentadienyl group [2][3][4][5] . This was found to be in sharp contrast to the chemical shifts reported 9 for H14 ( 6.37 ppm) C14, C15 and the dienyl methyl C16 ( 141.7, 111.1 and 12.1 ppm) of the sidechain of heteroscyphic acid methyl ester.…”

“…It should be noted that attempts at reduction of the 5 using H 2 and a poisoned catalyst were unsuccessful. As part of our interest in the application of organoiron complexes to organic synthesis 7 , we have examined the reactivity the (3-methylpentadienyl)Fe(CO) 2 PPh 3 + cation (6, Scheme 2) with nucleophiles as a means for late-stage introduction of the 3-methyl-2Z,4-pentadienyl sidechain 8 . Scheme 1.…”

Techniques for the analysis of pentacyclic triterpenoids in medicinal plants

“…used HPLC to assay on a RP C 18 column with a column temperature of 30°C, flow rate of 1 mL/min, mobile phase consisting of 0.1% aqueous formic acid, and acetonitrile containing 0.1% formic acid to quantitatively analyze nine triterpenoid saponins simultaneously . An HPLC–DAD coupled with MS identification was also developed to explore the inhibitory activity of extracts obtained from the aerial parts of Solidago canadensis (longispinogenin, 6β‐angeloyloxykolavenic acid, 6β‐tigloyloxykolavenic acid, and crotonic acid) against human bitterness receptor hTAS2R31 in vitro , in which HPLC–DAD–MS allowed the precise quantification and identification of pentacyclic triterpenes in extracts to solve the dose issue of bioavailable substances.…”

Comparison of Polyphenol Profile and Antimutagenic and Antioxidant Activities in Two Species Used as Source of Solidaginis herba – Goldenrod

“…This diverse terpenoid profile includes: sesquiterpenoids with germacrene D (two isomers), b-epi-bicyclosesquiphellandrene and other such as bicyclogermacrene, gemacrene B, 6-epia-cubebene, 6-epi-b-cubebene, predominant constituents; [10] [11] diterpenoidsmainly furan containing cis-clerodanes, 6b-angeloyloxykolavenic acid, 6b-tigloyloxykolavenic acid, and crotonic acid [11] [12] but also labdane diterpenoids: 9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 13-epi-9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 15,16-epoxylabdane-7,13-diene-6,16-dione, 15ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, 13-epi-15-ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, deoxysolidagenone, solidagenone, 15,16-epoxylabdane-7,13-diene-6,15-dione; solidagol, 3b-acetoxycopalic acid, sempervirenic acid [12][13] as well as a triterpenoids: longispinogenin, [12] 3b-[(3R)-acetoxyhexadecanoyloxy]lup-20(29)-ene, 3b-(3-ketohexadecanoyloxy)lup-20(29)-ene, 3b-[(3R)-acetoxyhexadecanoyloxy]-29-norlupan-20-one, and 3b-(3-ketohexadecanoyloxy)-29-norlupan-20-one. This diverse terpenoid profile includes: sesquiterpenoids with germacrene D (two isomers), b-epi-bicyclosesquiphellandrene and other such as bicyclogermacrene, gemacrene B, 6-epia-cubebene, 6-epi-b-cubebene, predominant constituents; [10] [11] diterpenoidsmainly furan containing cis-clerodanes, 6b-angeloyloxykolavenic acid, 6b-tigloyloxykolavenic acid, and crotonic acid [11] [12] but also labdane diterpenoids: 9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 13-epi-9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 15,16-epoxylabdane-7,13-diene-6,16-dione, 15ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, 13-epi-15-ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, deoxysolidagenone, solidagenone, 15,16-epoxylabdane-7,13-diene-6,15-dione; solidagol, 3b-acetoxycopalic acid, sempervirenic acid [12][13] as well as a triterpenoids: longispinogenin, [12] 3b-[(3R)-acetoxyhexadecanoyloxy]lup-20(29)-ene, 3b-(3-ketohexadecanoyloxy)lup-20(29)-ene, 3b-[(3R)-acetoxyhexadecanoyloxy]-29-norlupan-20-one, and 3b-(3-ketohexadecanoyloxy)-29-norlupan-20-one.…”

“…The lipophilic hexane fractions contained terpenoids which were preliminarily identified on the basis of their mass spectra and fragmentation patterns with reference to the literature. This diverse terpenoid profile includes: sesquiterpenoids with germacrene D (two isomers), b-epi-bicyclosesquiphellandrene and other such as bicyclogermacrene, gemacrene B, 6-epia-cubebene, 6-epi-b-cubebene, predominant constituents; [10] [11] diterpenoidsmainly furan containing cis-clerodanes, 6b-angeloyloxykolavenic acid, 6b-tigloyloxykolavenic acid, and crotonic acid [11] [12] but also labdane diterpenoids: 9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 13-epi-9,13,15,16-bisepoxylabdane-7-ene-6, 15-dione; 15,16-epoxylabdane-7,13-diene-6,16-dione, 15ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, 13-epi-15-ethoxy-9,13,15,16-bisepoxylabdane-7-ene-6-one, deoxysolidagenone, solidagenone, 15,16-epoxylabdane-7,13-diene-6,15-dione; solidagol, 3b-acetoxycopalic acid, sempervirenic acid [12] [13] as well as a triterpenoids: longispinogenin, [12] 3b-[(3R)-acetoxyhexadecanoyloxy]lup-20(29)-ene, 3b-(3-ketohexadecanoyloxy)lup-20(29)-ene, 3b-[(3R)-acetoxyhexadecanoyloxy]-29-norlupan-20-one, and 3b-(3-ketohexadecanoyloxy)-29-norlupan-20-one. [6] In Vitro Antioxidant Activity…”