Phytochemistry of cimicifugic acids and associated bases in Cimicifuga racemosa root extracts.
BACKGROUND
Earlier studies reported serotonergic activity for cimicifugic acids (CA) isolated from Cimicifuga racemosa. The discovery of strongly basic alkaloids, cimipronidines, from the active extract partition and evaluation of previously employed work-up procedures has led to the hypothesis of strong acid/base association in the extract.


OBJECTIVE
Re-isolation of the CAs was desired to permit further detailed studies. Based on the acid/base association hypothesis, a new separation scheme of the active partition was required, which separates acids from associated bases.


METHODS
A new 5-HT(7) bioassay guided work-up procedure was developed that concentrates activity into one partition. The latter was subjected to a new two-step centrifugal partitioning chromatography (CPC) method, which applies pH zone refinement gradient (pHZR CPC) to dissociate the acid/base complexes. The resulting CA fraction was subjected to a second CPC step. Fractions and compounds were monitored by (1)H NMR using a structure-based spin-pattern analysis facilitating dereplication of the known acids. Bioassay results were obtained for the pHZR CPC fractions and for purified CAs.


RESULTS
A new CA was characterised. While none of the pure CAs was active, the serotonergic activity was concentrated in a single pHZR CPC fraction, which was subsequently shown to contain low levels of the potent 5-HT(7) ligand, N(omega)-methylserotonin.


CONCLUSIONS
This study shows that CAs are not responsible for serotonergic activity in black cohosh. New phytochemical methodology (pHZR CPC) and a sensitive dereplication method (LC-MS) led to the identification of N(omega)-methylserotonin as serotonergic active principle.
Gödecke
Tanja
T
UIC/NIH Center for Botanical Dietary Supplements Research, Department of Medicinal Chemistry and Pharmacognosy and PCRPS, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA.
Nikolic
Dejan
D
Lankin
David C
DC
Chen
Shao-Nong
SN
Powell
Sharla L
SL
Dietz
Birgit
B
Bolton
Judy L
JL
van Breemen
Richard B
RB
Farnsworth
Norman R
NR
Pauli
Guido F
GF
D000818:Animals; D016466:CHO Cells; D002109:Caffeic Acids / Q000737:chemistry*; D031885:Cimicifuga / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010648:Phenylacetates / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
D002109:Caffeic Acids; D010648:Phenylacetates; D010936:Plant Extracts; C116092:cimicifugic acid