Acetoxyvalerenic acid

Quality Control of Valerianae Radix by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy.[Pubmed:29121679]

Planta Med. 2018 Apr;84(6-07):442-448.

(Acetoxy-)valerenic acid and total essential oil content are important quality attributes of pharmacy grade valerian root (Valerianae radix). Traditional analysis of these quantities is time-consuming and necessitates (harmful) solvents. Here we investigated an application of attenuated total reflection Fourier transform infrared spectroscopy for extractionless analysis of these quality attributes on a representative sample comprising 260 wild-crafted individuals covering the Central European taxonomic diversity of the Valeriana officinalis L. s. l. species aggregate with its three major ploidy cytotypes (i.e., di-, tetra- and octoploid). Calibration models were built by orthogonal partial least squares regression for quantitative analysis of (acetoxy-)valerenic acid and total essential oil content. For the latter, we propose a simplistic protocol involving apolar extraction followed by gas chromatography as a reference method for multivariate calibration in order to handle the analysis of samples taken from individual plants. We found good predictive ability of chemometric models for quantification of valerenic acid, Acetoxyvalerenic acid, total sesquiterpenoid acid, and essential oil content with a root mean squared error of cross-validation of 0.064, 0.043, and 0.09 and root mean squared error of prediction of 0.066, 0.057, and 0.09 (% content), respectively. Orthogonal partial least squares discriminant analysis revealed good discriminability between the most productive phenotype (i.e., the octoploid cytotype) in terms of sesquiterpenoid acids, and the less productive ones (i.e., di- and tetraploid). All in all, our results demonstrate the application of attenuated total reflection Fourier transform infrared spectroscopy for rapid, extractionless estimation of the most important quality attributes of valerian root and minimally invasive identification of the most productive phenotype in terms of sesquiterpenoid acids.

Pharmacokinetics of valerenic acid after single and multiple doses of valerian in older women.[Pubmed:20878691]

Phytother Res. 2010 Oct;24(10):1442-6.

Insomnia is a commonly reported clinical problem with as many as 50% of older adults reporting difficulty in falling and/or remaining asleep. Valerian (Valeriana officinalis) is a commonly used herb that has been advocated for promoting sleep. Valerenic acid is used as a marker for quantitative analysis of valerian products with evidence of pharmacological activity relevant to the hypnotic effects of valerian. The objective of this study was to determine the pharmacokinetics of valerenic acid in a group of elderly women after receiving a single nightly valerian dose and after 2 weeks of valerian dosing. There was not a statistically significant difference in the average peak concentration (C(max)), time to maximum concentration (T(max)) area under the time curve (AUC), elimination half-life (T(1/2)) and oral clearance after a single dose compared with multiple dosing. There was considerable inter- and intra-subject variability in the pharmacokinetic parameters. C(max) and AUC deceased and T(1/2) increased with increased body weight. The variability between the capsules was extremely low: 2.2%, 1.4% and 1.4%, for hydroxyvalerenic acid, Acetoxyvalerenic acid and valerenic acid, respectively. In conclusion, large variability in the pharmacokinetics of valerenic acid may contribute to the inconsistencies in the effect of valerian as a sleep aid.

Transport of a GABAA receptor modulator and its derivatives from Valeriana officinalis L. s. l. across an in vitro cell culture model of the blood-brain barrier.[Pubmed:18704879]

Planta Med. 2008 Sep;74(11):1338-44.

The roots and rhizome of Valeriana officinalis L . s. l. are therapeutically used for their sedative and sleep-enhancing effects. Some of the active compounds found in commonly used extracts are the sesquiterpenic acids, especially valerenic acid, which was recently identified as a GABA (A) receptor modulator. To interact with this receptor in the brain, substances such as valerenic acid and its derivatives Acetoxyvalerenic acid and hydroxyvalerenic acid have to cross the blood-brain barrier (BBB). The aim of our study was to obtain BBB permeability data of these compounds for the first time and to elucidate possible transport pathways across our BBB in vitro model. Transport of valerenic acid, Acetoxyvalerenic acid and hydroxyvalerenic acid was compared with the permeability of the GABA (A) modulator diazepam, which is known to penetrate into the central nervous system transcellularly by passive diffusion. Experiments were carried out with an established Transwell in vitro model based on the human cell line ECV304. Results indicated clearly that all three acids permeated significantly slower than diazepam. The ranking was confirmed in group studies as well as in single-substance studies after normalization to diazepam. Valerenic acid (1.06 +/- 0.29 microm/min, factor 0.03 related to diazepam) was the slowest to permeate in the group study, followed by hydroxyvalerenic acid (2.72 +/- 0.63 microm/min, factor 0.07 related to diazepam) and Acetoxyvalerenic acid (3.54 +/- 0.58 microm/min, factor 0.09 related to diazepam). To elucidate the contribution of the paracellular transport, studies were performed at different tightness status of the cell layers reflected by different transendothelial electrical resistance (TEER) values. Results showed an exponential correlation between transport and TEER for all three acids, whereas diazepam permeated TEER independently. In summary, it is hypothesized that the investigated compounds from Valeriana officinalis L. S. L. can probably only pass through the BBB by a still unknown transport system and not transcellularly by passive diffusion.

Modulation of GABAA receptors by valerian extracts is related to the content of valerenic acid.[Pubmed:18095218]

Planta Med. 2008 Jan;74(1):19-24.

Valeriana Officinalis L . is a traditionally used sleep remedy, however, the mechanism of action and the substances responsible for its sedative and sleep-enhancing properties are not fully understood. As we previously identified valerenic acid as a subunit-specific allosteric modulator of GABAA receptors, we now investigated the relation between modulation of GABAA receptors by Valerian extracts of different polarity and the content of sesquiterpenic acids (valerenic acid, Acetoxyvalerenic acid). All extracts were analysed by HPLC concerning the content of sesquiterpenic acids. GABAA receptors composed of alpha 1, beta 2 and gamma 2S subunits were expressed in Xenopus laevis oocytes and the modulation of chloride currents through GABAA receptors (IGABA) by Valerian extracts was investigated using the two-microelectrode voltage clamp technique. Apolar extracts induced a significant enhancement of IGABA, whereas polar extracts showed no effect. These results were confirmed by fractionating a highly active ethyl acetate extract: again fractions with high contents of valerenic acid exhibited strong receptor activation. In addition, removal of sesquiterpenic acids from the ethyl acetate extract led to a loss of I (GABA) enhancement. In conclusion, our data show that the extent of GABAA receptor modulation by Valerian extracts is related to the content of valerenic acid.

Preserved pharmacological activity of hepatocytes-treated extracts of valerian and St. John's wort.[Pubmed:16041642]

Planta Med. 2005 Jul;71(7):592-8.

The two herbal extracts valerian (Valeriana officinalis L.) and St. John's wort (Hypericum perforatum L.) were studied for their metabolic changes upon incubation with freshly prepared rat hepatocytes and subsequently analysed phytochemically as well as pharmacologically in vitro. Quantitative HPLC analysis of valerian extracts revealed considerable metabolic activities with regard to sesquiterpenes and iridoids. The amount of Acetoxyvalerenic acid decreased 9-fold, while that of hydroxyvalerenic acid correspondingly increased 9-fold due to O-deacetylation. The valepotriates didrovaltrate, isovaltrate and valtrate decreased 2-, 18- and 16-fold, respectively. However, the binding affinities of the incubated extracts to the benzodiazepine and picrotoxin binding site of the GABA (A) receptor were quite similar to those of the non-incubated extracts. Neither valerenic acids nor valepotriates exhibited any significant effect on the two binding sites when tested as single compounds. Therefore, either other constituents represent the active ones or multiple compounds are necessary for the observed inhibitory and allosteric effects at the GABA (A) receptor. Extracts of St. John's wort were less potently metabolised than valerian. The amount of pseudohypericin and the main flavonoids (hyperoside, rutin, isoquercitrin, quercitrin, quercetin and I3,II8-biapigenin) slightly decreased during the 4-h incubation period. Both the antagonist effect at the corticotropin-releasing factor (CRF) type 1 receptor and the binding inhibition at the 5-HT transporter were attenuated during the metabolic treatment. The reduced antagonist effect correlates with the decreasing amount of pseudohypericin known to be a CRF (1) receptor antagonist. In conclusion, the incubation of plant extracts with freshly prepared rat hepatocytes represents a useful approach to study the pharmacological action of metabolised plant extracts. The consistent pharmacological activity of both valerian and St. John's wort is concordant with the known clinical efficacy of pharmacological activities.

In vitro activity of commercial valerian root extracts against human cytochrome P450 3A4.[Pubmed:15367385]

J Pharm Pharm Sci. 2004 Aug 12;7(2):265-73.

PURPOSE: Valerian root ( Valeriana officinalis L.) has been used since antiquity as a medicinal herb. Recent studies have found that certain herbal products used concomitantly with conventional therapeutic products can markedly affect drug disposition. METHODS: The in vitro effect of aliquots from 14 commercially available single-entity and blended products containing valerian root on cytochrome P450 CYP3A4-mediated metabolism and P-glycoprotein transport has been determined with aqueous, ethanol and acetonitrile extracts. RESULTS: Hydroxyvalerenic acid, Acetoxyvalerenic acid and valerenic acid content was analyzed and wide variation was found between samples and compared to the concentrations noted on the product labels. Valerian extracts from the products tested also exhibited a marked capacity to inhibit cytochrome P450 3A4-mediated metabolism and P-glycoprotein transport based upon the ATPase assay. CONCLUSIONS: There is wide variation between commercially available samples of valerian root. The findings from this study suggest that valerian root may have an initial inhibitory effect when taken with therapeutic products. Further work is warranted to determine whether valerian root can affect other CYP450 isozymes and how the results of this in vitro investigation can be extrapolated to in vivo situations.

Cytotoxic potential of valerian constituents and valerian tinctures.[Pubmed:23195845]

Phytomedicine. 1998 May;5(3):219-25.

Underground parts of three Valeriana species, namely V. officinalis L. s.l., V. wallichii DC. (V. jatamansi Jones), and V. edulis Nutt. ex Torr & Gray ssp. procera (H.B.K.) F. G. Meyer (V. mexicana DC.), are used in phytotherapy because of their mild sedative properties. Characteristic constituents of these species, which are regarded also as the active principles, were tested for cytotoxicity against GLC(4), a human small-cell lung cancer cell line, and against COLO 320, a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. Valepotriates of the diene type (valtrate, isovaltrate and acevaltrate) displayed the highest cytotoxicity, with IC50 values of 1-6 muM, following continuous incubation. The monoene type valepotriates (didrovaltrate and isovaleroxyhydroxydidrovaltrate) were 2- to 3-fold less toxic. Baldrinal and homobaldrinal, decomposition products of valepotriates, were 10- to 30-fold less toxic than their parent compounds. Isovaltral had a higher cytotoxicity than its parent compound isovaltrate. Valerenic acids (valerenic acid, Acetoxyvalerenic acid, hydroxyvalerenic acid and methyl valerenate), which are characteristic for V. officinalis, had a low toxicity with IC(50) values between 100 and 200 muM. Freshly prepared and stored tinctures, prepared from roots and rhizomes of the three valerian species, were analysed for valepotriates, baldrinals and valerenic acids, and also tested for cytotoxicity. There was a clear relationship between the valepotriate contents of the freshly prepared tinctures and their toxicity. Upon storage, valepotriates decomposed, which was reflected in a significant reduction of the cytotoxic effect.