Valerenic Acids Research Articles

Chemical Diversity of Wild-Growing and Cultivated Common Valerian (Valeriana officinalis L. s.l.) Originating from Poland.

Common valerian is a medicinal plant. The underground organs of this species are used as a mild sedative and sleeping aid. Poland is one of the largest producers of this raw material in Europe, with local cultivar 'Lubelski' as a primary cultivated form. Although valerian is the subject of more or less deliberate selection carried out by farmers, it is still genetically unstable. The aim of this study was to determine the diversity of the 'Lubelski' cultivar originating from four regions of Poland (forms: L1-L4) in relation to wild-growing populations of the species. The plants were assessed in terms of the mass of underground organs and the content of valerenic acids and essential oils (EOs). The content of valerenic acids was determined using HPLC, whereas the content of EOs was determined using hydrodistillation. The composition of EOs was assessed using GC-MS GC-FID. The ploidy level of the analyzed objects was determined as well. Wild-growing populations (diploids) were characterized by lower masses of underground organs and lower contents of valerenic acid than cultivated forms (tetraploids). However, they produced higher contents of EOs. All the cultivated forms were strongly diversified with respect to the analyzed traits, including the mass of the roots (CV 49-75%), the content of valerenic acids (CV 18-55%), and the content of EOs (CV 28-57%). A total of 44 compounds were identified in the EOs. The dominant compound of both wild-growing populations and the 'Lubelski' forms were: α-fenchene, bornyl acetate, and valerenal. Among 'Lubelski' forms, the most interesting seems to be the L2 form, which was characterized by a relatively high yield and high content of valerenic acids and EOs. Thus, it appears to be a promising source of objects for further valerian cultivar improvement.

Induction and submerged cultivation of Valeriana jatamansi adventitious root cultures for production of valerenic acids and its derivatives

In vitro adventitious roots were induced from leaves of Valeriana jatamansi to assess their potential as a sustainable alternative to extract pharmaceutically important phytoconstituents. Among the different media used, a significantly (p ≤ 0.05) high root induction (90%) was achieved on Schenk and Hildebrandt (SH) medium fortified with 9.84 µM indole-3-butyric acid (IBA). In addition, various process parameters i.e. IBA concentration, sucrose and medium strength were also optimized under submerged cultivation. The maximum fresh root biomass (144.09 ± 11.36 g/L) with a high relative growth rate (2.01 ± 0.04) and growth index (13.41) was achieved in half-strength SH medium having 2% sucrose and 4.92 µM IBA. Further, a significantly high yield of total valerenic acid derivatives [1525.14 µg/g dry weight (DW)] was recorded in adventitious roots as compared to donor plant parts. Individually, valerenic acid (506.27 µg/g DW) was accumulated higher in plant rhizomes, while acetoxyvalerenic (534.91 µg/g DW) and hydroxyl valerenic acid (919.57 µg/g DW) in adventitious roots. Interestingly, hydroxy valerenic acid was unmeasurable in donor plant parts. The phenolic compounds were also found maximum in adventitious roots (451.85 µg/g DW) with the dominance of pharmaceutically important kaempferol and rutin. A substantial increase in phytochemicals was evident at subsequent culture stages with shortened in vitro cultivation cycle (2 months) than field-grown plants (24 months). Moreover, adventitious roots also accumulated 0.059% essential oil with patchouli alcohol (24%) as a key constituent. Conclusively, an enriched metabolic profile and substantially shorter growth cycle under submerged cultivation undoubtedly demonstrated the potential of induced V. jatamansi adventitious roots as a feasible source of phytoconstituents. In vitro adventitious roots induced leaf of Valeriana jatamansi showed improved metabolic profile and shorter cultivation cycle, thereby exhibiting potential as a sustainable alternative for extraction of industrially important phytoconstituents.

Development of high-performance thin-layer chromatography method for herbals identification in extemporaneous oral solution

The preparation of extemporal medicines in store includes carrying out intrapharmacy quality control and stability studies. Since there is no single analytical method that ideally suited for all drugs, for each formulation depend on its composition and analytical goal, appropriate quality control methods should be developed. The object of analysis was pediatric oral solution with sedative action that contains Valerian tincture, Motherwort tincture, and sodium bromide.The purpose of research was the development of simple, specific and reproducible methods of active herbal ingredients identification formulated into oral solution.Materials and methods. The high-performance thin-layer chromatography (HPTLC) was used as the method for analysis. It was performed on 200 × 100 mm silica gel 60 F 254 HPTLC glass plates (Merck, Germany). Standard solutions and samples were applied onto the plate as bands 8.0 mm wide using spray-on technique with Automatic TLC sampler ATS 4; the development was made in saturated Automatic developing chamber ADC 2, temperature and the relative humidity were 23 °C and 33 % respectively; the derivatization was performed using Chromatogram Immersion Device; the documentation was conducted using Visualizer with visionCATS software (CAMAG, Switzerland).As a result two HPTLC identification methods have been developed for valerenic acids that are specific for Valerian tincture and flavonoids that are specific for Motherwort tincture. Thus, the sample preparation has been developed, the optimal chromatographic conditions have been chosen, the acceptance criteria have been proposed, and the reference chromatograms have been shown. Valerenic acids of oral solution were determined in mobile phase: cyclohexane, ethyl acetate, acetic acid (60:38:2); the derivatization of plates was performed through dipping with Anisaldehyde-sulfuric acid reagent and heated to 100 °C for 3 min; documentation was performed after derivatization under white light and UV 366 nm. Flavonoids of oral solution were determined in mobile phase: ethylacetate, methyl ethyl ketone, formic acid, water (5:3:1:1); the derivatization of plates was performed through dipping with Natural Products/PEG reagents, heated to 100 °C for 3 min before dipping; documentation was performed after derivatization under UV 366 nm.Conclusions. The developed methods can be used for identification of oral solution, and for stability study with the purpose of determination of its storage conditions and shelf-life.

Ionic liquid-assisted micellar extraction for the quantitative determination of sesquiterpenic acids in Valeriana officinalis L. (Caprifoliaceae)

ABSTRACTA series of hydrophilic ionic liquids (ILs) were investigated as extractants for the quantitative determination of valerenic and acetoxyvalerenic acids in Valerianae radix. The influence of different factors, e.g. type of cation and anion, alkyl chain length, concentration, temperature, extraction time and solid–liquid ratio, was investigated. The results obtained showed that the extraction yield is strongly dependent on the cation type. The best outcome was obtained with IL capable of forming micelles in aqueous solution, e.g. 1-decyl-3-methylimidazolium chloride. As a result, an alternative protocol for the quantification of sesquiterpenic acids in valerian was developed and validated.

Neuroprotective effect of Tagara, an Ayurvedic drug against methyl mercury induced oxidative stress using rat brain mitochondrial fractions.

BackgroundMethyl mercury (MeHg), an important environmental toxicant is implicated in neurological disorders such as Hunter-Russell syndrome and Autism. Therefore, the present work is in search of new drugs that can alleviate MeHg toxicity. In this connection, Tagara, an ayurvedic drug is used for assessing its neuro protective effect against MeHg toxicity.MethodsIn the present study, we assessed the phytochemical contents of Tagara by colorimetric and HPLC analyses. The neuroprotective effect of Tagara on MeHg induced neurotoxicity was measured in terms of viability by MTT assay and oxidative stress in terms of catalase activity, glutathione and thiobarbituric acid reactive substance levels. Further, the chelating effect of Tagara towards MeHg was performed to identify the molecular mechanism. Statistical analysis was done by statistical package for social sciences (SPSS) version 16.0.ResultsThe results demonstrated that Tagara contains significant amounts of phenols and flavonoids. Also, HPLC analysis of Tagara revealed the presence of essential oils such as hydroxyvalerenic and valerenic acids. Our results demonstrated that exposure of rat brain mitochondrial fractions to MeHg resulted in a dose dependent death in MTT assay and IC50 value was found to be 10 μM. However, a 250 μg dose of Tagara effectively prevented MeHg induced mitochondrial damage. The oxidative stress caused by MeHg results in elevated levels of reactive oxygen species as evidenced by elevated TBARS (Thiobarbituric acid-reactive substances) levels and diminished catalase enzyme activity and glutathione content. However, Tagara at 250 μg concentration offsets these alterations caused by MeHg. Further, Tagara also diminished GSH oxidation caused by MeHg, confirming its chelating effect, one of the molecular mechanisms that triggers protection against oxidative damage.ConclusionOur results revealed that MeHg induced toxicity is predominantly mediated through oxidative stress mechanism and the propensity of Tagara to abolish such reactions. Hence, we propose that Tagara with a source of potential neuroprotectants may be a useful approach to alleviate MeHg associated neurotoxicity.

Contents of essential oil, valerenic acids and extractives in different parts of the rootstock of medicinal valerian (Valeriana officinalis L. s.l.)

In 2008, a breeding project was started with the aim to develop one or several varieties of Valeriana officinalis L. s.l. with a coarse root system and reliable ingredient contents according to the pharmacopoeia. It was initially assumed that a negative relationship between the adventitious root thickness and the ingredient contents exist.Therefore, the clones of four genotypes, differing in root fineness and ingredient content, were cultivated. The rootstocks were carefully harvested by hand in autumn and the rootstock components, rhizomes and roots, were separated. The roots were assigned to four diameter groups and the lateral roots were separated from the adventitious roots after drying. The analyses of the valerenic acids, essential oil and formerly listed extractives were conducted according to the current European Pharmacopoeia.In general for the investigated genotypes, the highest contents of valerenic acids and essential oil are located in the adventitious roots, followed by the lateral roots and the rhizomes. In contrast to the other ingredients, the extractives content of the rhizomes are comparatively high. Differences in the investigated ingredient contents and the different root thicknesses are not detectable.The investigation indicates how important careful harvesting and preparation of the rootstock are to conserve the existing ingredients. In addition, the different ingredient contents of the adventitious and lateral roots are not expected to decrease ingredient contents of the root drug when lateral roots and thin adventitious roots are lost during root cleaning and preparation. The study also shows that despite initial assumptions, thicker roots did not result in a decline of ingredient contents.

Efficient plant regeneration, genetic fidelity and high-level accumulation of two pharmaceutical compounds in regenerated plants of Valeriana officinalis L.

An efficient regeneration system via adventitious shoot formation was developed in Valeriana officinalis, an important medicinal species. Regeneration response was significantly influenced by the type and concentrations of plant growth regulators as well as callus morphology. Optimum values for adventitious shoot–buds induction in both leaf and petiole explants were obtained when organogenic calli with compact, nodular and yellowish green phenotype was cultured in MS medium supplemented with 9.30μM Kn and 2.26μM 2,4-D. Well-developed shoots was achieved on a hormone-free half strength (1/2) MS basal medium. In vitro rooting of elongated shoots was tried on 1/2 MS medium supplemented with various concentrations of α-naphthalene acetic acid (NAA) or indole-3-butyric acid (IBA). IBA at a concentration of 2.46μM was found to be the best rooting treatment, which promoted the highest frequency of rooting (98%). Successful acclimatization of rooted plantlets was achieved in potting medium containing 5:1 mixture of peat and perlite with 95.34% survival rate. The contents of valtrate and valerenic acid in biomass extracts from petiole-derived plants were significantly (P<0.05) higher than leaf-derived plants as well as the seed-raised field-grown plants. Maximum valtrate (6.98mgg−1 DW) and valerenic acids (3.02mgg−1 DW) contents were quantified in root tissue of petiole-derived plants raised on medium with higher concentration of Kn (9.30μM) in combination with 2.26μM 2,4-D. Random amplified polymorphic DNA (RAPD) analysis indicated no evidence of genetic variation in the tissue culture-raised plants. The results suggest that the tissue culture-raised V. officinalis plants are capable of producing higher content of secondary metabolites under optimum in vitro conditions than that under natural wild growth conditions.

Valerian extract characterized by high valerenic acid and low acetoxy valerenic acid contents demonstrates anxiolytic activity

Valerian is one of the most commonly used herbal remedies for the treatment of insomnia and anxiety. Valerian extracts allosterically modulate GABAA receptors, an action related to valerenic acid, which is one of the active compounds determined from pharmacological studies. Derivatives of valerenic acid, i.e. acetoxy valerenic acid or hydroxy valerenic acid, do not allosterically modulate GABAA receptors, but they bind to identical binding sites. Therefore, the question arises whether they might interfere with the effects of valerenic acid. Two valerian extracts were tested in the elevated plus maze test and the tail suspension test for anxiolytic and antidepressive activity, respectively. Reference substances were diazepam (1.0mg/kg) and imipramine (30mg/kg). The extracts were standardized to the identical total amounts of the acids (0.1; 0.5; 1.0 and 2.0mg/kg), i.e. valerenic and acetoxy valerenic acid, but the ratio between the acids was different (12:1 and 1:1.5). The extract with the ratio 12:1 prolonged the time spent on the open arm significantly when 0.5mg/kg was applied. Of the other extract, with the ratio 1:1.5, four times that amount was required (2.0mg/kg). Both of the tested extracts did not show any antidepressive effect, rather the other way around, the extract with the ratio 1:1.5 prolonged the immobility phase. However, since the core body temperature was reduced by the 1.0 and 2.0mg/kg extract dose, the prolongation may be related to the temperature phenomenon and is not indicative of a specific depressive action. In conclusion, the anxiolytic activity of the valerian extract seems rather related to valerenic acid and, moreover, standardization with respect to the total amount of valerenic acids, i.e. valerenic acid together with acetoxy valerenic acid, is misleading.

Micellar LC Separation of Sesquiterpenic Acids and Their Determination in Valeriana officinalis L. Root and Extracts

A simple micellar liquid chromatography (MLC) method was developed and validated according to ICH Guidelines for the determination of sesquiterpenic acids (valerenic, hydroxyvalerenic, and acetoxyvalerenic acids) in root and rhizome extract from Valeriana officinalis L. and valerian dry hydroalcoholic extract. Samples were analyzed on Nucleosil C18 column (, 5 μm) using an isocratic mobile phase which consisted of Brij 35 (5% (w/v) aqueous solution; pH by phosphoric acid) and 1-butanol (6% (v/v)); UV detection was at 220 nm. Micellar mobile phase using allows to fully separate valerenic acids within 25 minutes. Linearity for hydroxyvalerenic, acetoxyvalerenic, and valerenic acids was 1.9–27.9, 4.2–63.0, and 6.1–91·3 μg.mL−1, and limit of detection was 0.14, 0.037, and 0.09 μg·mL−1, respectively. Intraday and interday precisions were not less than 2% for all investigated compounds. The proposed method was found to be reproducible and convenient for quantitative analysis of sesquiterpenic acids in valerian root and related preparations.

Enhanced production of valerenic acids and valepotriates by in vitro cultures of Valeriana officinalis L.

Valerian (Valeriana officinalis L.) is an important medicinal plant that is widely exploited for its roots and rhizomes which contain valepotriates and valerenic acids (with putative pharmacological activities). Thus root proliferation of valerian is very important. The aim of this study was to establish a practical tissue culture method for rapid and large-scale induction of V. officinalis L. roots with high capacity for production of valerian phytomedicine. Explants derived from leaves, petioles, and root segments (both basal and apical) of four months aged plantlets were cultured on MS basal medium supplemented with different concentrations (0.625-5 µM) of auxin and cytokinin hormones. Then accumulation of valerenic acids and valepotriates in developed root cultures was studied to find the best yielding conditions. Maximum valerenic acids (0.84%) and valepotriates contents (7.41%) were quantified in roots developed on petiole explants and in roots formed on root basal segments in medium supplemented with 1.25 μM and 0.625 μM indole-3-acetic acid, respectively. These values were significantly (P<0.05) higher than those in roots from basal and apical root segments without plant growth regulators as control. The highest average number (29.00) of directly formed roots developed on leaf explants in media supplemented with 5 μM α- naphthalene acetic acid. Also maximum number of indirectly developed roots (30.05) was observed on root apical segments in media containing 2.5 μM α- naphthalene acetic acid. These results suggest that besides the applied plant growth regulators, the type of primary explant is also relevant for biosynthetic capacity of these metabolites in root cultures.

Content of Essential Oil and Valerenic Acids in Valerian (Valeriana offcinalis L.) Roots at the Selected Developmental Phases

The content of essential oil and valerenic acids and the yield of roots were analyzed in valerian cultivar ‘Polka’ and strain no. 4 during the nine following phases: the beginning of vegetation, spring rosette, pedicel development, the beginning of flowering, full bloom, seed harvest, three weeks after the seed harvest, fall rosette, and after the first frost. The yield of valerian roots was different at the investigated phases and in years of cultivation, while tested genotypes produced similar root yields. The highest contents of essential oil and valerenic acids were obtained at different phases by the tested genotypes: strain no. 4 in full bloom (1.3% and 0.266%, respectively) and cultivar ‘Polka’ three weeks after seed harvest (1.25%) and during seed harvest (0.218%). The lowest contents of the investigated substances were detected at the beginning of growth and after the first frost in both genotypes. The obtained results revealed significant differences in essential oil and valerenic acids content, which depend on genotype, plant age, harvest time and the year of cultivation. The results suggest that higher amounts of valerenic acids could be obtained in the second year of cultivation over the period from full bloom (0.278%) to fall rosette phase (0.316%).

Experimental design on supercritical extraction of essential oil from valerian roots and study of optimal conditions

Supercritical CO 2 extraction from valerian ( Valeriana officinalis L.) roots was studied. The objective of this study was to optimize the independent process parameters (temperature, pressure, dynamic time and modifier volume) in order to attain the highest yield of the essential oil and valerenic acids as the desired compounds. The process optimization was based on a simplex centroid design (mixture design), coupled with the statistical and graphical analysis of the results. Due to the features of mixture method and to the proper ratios of four independent variables, the optimal points were in the range of temperature (37 °C), pressure (24.3–25.0 MPa), dynamic time (19–24 min) and modifier volume (100–200 μl).

Changes in valerenic acids content of valerian root ( Valeriana officinalis L. s.l.) during long-term storage

Dried valerian ( Valeriana officinalis) root powder was stored at 5, 14 and 30 °C under low, moderate and high humidity conditions for 6 months, and the level of the valerenic acids monitored on a monthly basis. From an initial moisture content of 5 g/kg, the moisture level during storage decreased in root powder stored at low humidity and increased during storage at high humidity, with the effect greatest at 30 °C. The concentration of valerenic acid significantly decreased over time and was affected by temperature and humidity with the loss greatest at 30 °C in low humidity. Acetoxyvalerenic acid also decreased over time but with greatest loss at 30 °C and high humidity. Hydroxyvalerenic acid was not detected in the fresh sample but was present in all stored samples and tended to reflect the decrease in acetoxyvalerenic acid. The concentration of total valerenic acids essentially mirrored the change in valerenic acid. It is concluded that maximum retention of valerenic acids would be achieved by storing valerian at a temperature lower than about 14 °C with humidity not a great concern. If storage is to occur at higher temperatures, retention of valerenic acids is favoured by storage under a high humidity but such a recommendation is not considered practical due to the risk of microbial growth and increasing difficulty of postharvest handling of moist material.

Characteristics of Extracted Valerenic Acids From Valerian (Valeriana Officinalis) Root by Supercritical Fluid Extraction Using Carbon Dioxide

The extraction of valerenic acids from valerian root by supercritical fluid extraction using CO2 under different operating conditions was compared to extraction by percolation using 70% ethanol. The yield of total valerenic acids under pressures of 10–20 MPa and temperatures of 40–50°C was about 85% of that achieved by percolation, while the addition of 5% ethanol or methanol as a modifier to the CO2 resulted in the same yield as percolation. Moreover, maximal extraction was achieved in the faster time of 20 minutes and resulted in a more highly concentrated extract than obtained by percolation which would aid the manufacturing of liquid or dried products. Further studies on a larger scale would clarify the use of this technique commercially.

Chemical Fingerprinting of Valeriana Species: Simultaneous Determination of Valerenic Acids, Flavonoids, and Phenylpropanoids Using Liquid Chromatography with Ultraviolet Detection

The roots and rhizomes of various valeriana species are currently used as a sleeping aid or mild sedative. A liquid chromatography method has been developed that permits the analysis of chlorogenic acid, lignans, flavonoids, valerenic acids, and valpotrates in various valerian samples. The best results were obtained with a Phenomenex Luna C18(2) column using gradient elution with a mobile phase consisting of water and 0.05% phosphoric acid and 2-100% acetonitrile-methanol (1 + 1) with 0.05% phosphoric acid. The flow rate was 0.8 mL/min and ultraviolet detection was at 207, 225, 254, 280, and 325 nm. Different valerian species and commercial products showed remarkable quantitative variations. Chlorogenic acid (0.2-1.2%), 3 lignans, linarin (0.002-0.24%), and valepotriates were detected in all the valeriana species analyzed. Highest amounts of valerenic acids were detected in V. officinalis L., trace amounts in V. sitchensis, and none in the other species analyzed.

Effect of postharvest handling on valerenic acids content of fresh valerian (Valeriana officinalis) root

AbstractValerian (Valeriana officinalis) is a medicinal herb native to Europe and North Asia, the roots and rhizomes of which are used as a sedative for nervous tension, sleeplessness, anxiety and stress. The impact of washing and drying on the valerenic acids concentration in valerian roots was investigated. The valerenic acids content of roots that were washed, soaked or cut prior to drying was not significantly different from that of whole valerian roots that were dried without washing, but cutting markedly decreased the drying time. Increasing the drying temperature from 15 to 70 °C reduced drying time by 176 h, with a 23% loss of valerenic acids from 15 to 40 °C. A further 36% loss occurred from 40 to 50 °C but no further significant change was evident at higher temperatures. The use of a heat pump dryer reduced the drying time at 40 °C by 25% compared with a hot air drier operated at the same temperature with no significant difference in the level of valerenic acids. There was no significant change in the level of valerenic acids in fresh whole roots held at ambient conditions for 10 days but a considerable decrease in water content. Hence valerian growers can separate or soak roots prior to washing and can store fresh roots before drying without concern over loss of valerenic acids. However, drying at the lowest feasible temperature is recommended. Copyright © 2005 Society of Chemical Industry

Use of Solid‐Phase Extraction for Improving HPLC Assays of Triterpene Glycosides in Gotu Kola (Centella asiatica), Parthenolide in Feverfew (Tanacetum parthenium), and Valerenic Acids in Valerian (Valeriana officinalis)

The use of solid‐phase extraction (SPE) for solving interference problems observed in simple HPLC assays involving nutraceuticals is demonstrated. Anion‐exchange SPE is used to remove an interfering compound coeluting with the triterpene glycoside madecassoside in gotu kola (Centella asiatica). C18 SPE is used to remove an interfering compound coeluting with parthenolide in feverfew (Tanacetum parthenium), and as a general cleanup for valerenic acids in valerian (Valeriana officinalis). In each case, use of a single ultrasonically assisted extraction was verified by comparing the results with multiple extractions.

Preserved Pharmacological Activity of Hepatocytes-Treated Extracts of Valerian and St. John's Wort

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.

Normal and reversed-phase TLC determination of rosmarinic and valerenic acids

The chromatographic properties of valerenic and rosmarinic acids have been studied by normal- and reversed-phase TLC with eight mobile phases (methanol-water, ethanol-water, propanol-water, acetonitrile-water, acetonitrile-methanol, THF-water, acetonitrile-buffer, and methanol-buffer) in which the concentration of organic modifier was varied from 0 to 100% ( v/v ). The retention of the compounds and the impact on their chromatographic behavior of the solvents used in the mobile phases are discussed. The dependence of the R F of valerenic and rosmarinic acids on buffer solution pH was also investigated.

Retention properties of rosmarinic and valerenic acids on an amino-modified hydrophilic layer

The chromatographic properties of rosmarinic and valerenic acids have been studied on an amino stationary phase with eight binary mobile phases (methanol-water, ethanol-water, propanol-water, acetonitrile-water, acetonitrile-methanol, THF-water, acetonitrile-buffer, and methanol-buffer) in which the concentration of organic modifier was varied from 0 to 100% ( v/v ). The retention of the compounds and the impact on their chromatographic behavior of the solvents used as mobile phases are discussed. The dependence of the R F of valerenic and rosmarinic acids on buffer solution pH was also investigated.