Inhibition of [3H]-LSD binding to 5-HT7 receptors by flavonoids from Scutellaria lateriflora.
The hot water and 70% ethanol extracts of dried mad-dog skullcap (Scutellaria lateriflora) both bound to the 5-HT(7) receptor, with 87.2 +/- 6.2% and 56.7 +/- 1.3% inhibition of [(3)H]-LSD binding to the receptor at 100 microg/mL, respectively. The on-line analysis of a 70% ethanol extract by HPLC-UV/MS resulted in the identification of five flavones (1-5). Fractionation of the ethanol extract resulted in the isolation of three flavone-glucuronides (6-8) and a flavanone-glucuronide (9), including one new compound, lateriflorin (5,6,-dihydroxy-7-glucuronyloxy-2'-methoxyflavone) (8). The structure of 8 was determined by NMR ((1)H NMR, (13)C NMR, and NOESY experiments) and MS analysis. From the results obtained in the testing of the pure compounds, it is evident that the activity on the 5-HT(7) receptor is at least partly due to the presence of flavonoids. Scutellarin and ikonnikoside I showed the highest inhibition of [(3)H]-LSD binding with IC(50) values of 63.4 and 135.1 microM, respectively.
Gafner
Stefan
S
Tom's of Maine, 302 Lafayette Center, P.O. Box 710, Kennebunk, Maine 04043, USA. stefang@tomsofmaine.com
Bergeron
Chantal
C
Batcha
Laura L
LL
Reich
Jesse
J
Arnason
John T
JT
Burdette
Joanna E
JE
Pezzuto
John M
JM
Angerhofer
Cindy K
CK
D002478:Cells, Cultured / Q000187:drug effects; D047309:Flavones; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010946:Plants, Medicinal / Q000737:chemistry*; D011985:Receptors, Serotonin / Q000187:drug effects*; D031363:Scutellaria / Q000737:chemistry*; D012702:Serotonin Antagonists / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014707:Vermont
D047309:Flavones; D005419:Flavonoids; C031182:LSD receptor; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; C043562:flavone