Hypericum perforatum--chemical profiling and quantitative results of St. John's Wort products by an improved high-performance liquid chromatography method

Dietary supplements and medicinal plants in urolithiasis: diet, prevention, and cure

BACKGROUND

Urolithiasis has been a major health concern for centuries, primarily owing to the limited treatment options in the physician's armamentarium. However, various studies have underscored a lesser incidence of urolithiasis in cohorts predominantly consuming fruits and vegetables. This article aims to review various dietary plants, medicinal herbs and phytochemicals in the prevention and management of urolithiasis.

METHODS

To provide context and evidence, relevant publications were identified on Google Scholar, PubMed and Science-Direct using keywords such as urolithiasis, nephrolithiasis, urolithiasis, renal stones, phytochemicals and dietary plants.

RESULTS

Growing bodies of evidence suggest the incorporation of plant-based foods, medicinal and herbal supplements, and crude drugs containing phytochemicals into the staple diet of people. The anti-urolithiatic activity of these plant bioactives can be attributed to their antioxidant, antispasmodic, diuretic, and inhibitory effect on the crystallization, nucleation and crystal aggregation effects. These mechanisms would help alleviate the events and symptoms that aid in the development and progression of renal calculi. In addition, it will also avoid the exacerbation of secondary disorders like inflammation and injury, which can initiate a vicious circle in turn worsening the disease progression.

CONCLUSION

In conclusion, the results presented in the review demonstrate the promising role of various dietary plants, medicinal and herbal supplements, and phytochemicals in preventing and managing the precipitation of uroliths. However, more conclusive and cogent evidence from preclinical and clinical studies is required to substantiate their safety, efficacy and toxicity profiles in humans.

Hyperforin: A natural lead compound with multiple pharmacological activities

Hypericum perforatum L. (Clusiaceae), commonly known as St. John's wort, has a rich historical background as one of the oldest and most widely studied herbal medicines. Hyperforin is the main antidepressant active ingredient of St. John's wort. In recent years, hyperforin has attached increasing attention due to its multiple pharmacological activities. In this review, the information on hyperforin was systematically summarized. Hyperforin is considered to be a lead compound with diverse pharmacological activities including anti-depression, anti-tumor, anti-dementia, anti-diabetes and others. It can be obtained by extraction and synthesis. Further pharmacological studies and more precise detection methods will help develop a value for hyperforin. In addition, structural modification and pharmaceutical preparation technology will be beneficial to promoting the research progress of hyperforin based innovative drugs. Although these works are full of known and unknown challenges, researchers are still expected to make hyperforin play a greater value.

Proteomic and Metabolomic Revealed Differences in the Distribution and Synthesis Mechanism of Aroma Precursors in Yunyan 87 Tobacco Leaf, Stem, and Root at the Seedling Stage

Tobacco, as an important cash crop and model plant, has been the subject of various types of research. The quality of flue-cured tobacco products depends on the compound collection of tobacco leaves, including pigments, carbohydrates, amino acids, polyphenols, and alkaloid aroma precursors. The present study investigates tobacco seedling organs (leaf, stem, and root) with the assistance of label-free proteomic technology and untargeted metabonomic technology. We analyzed 4992 proteins and 298 metabolites obtained in the leaf, stem, and root groups and found that there were significant differences in both primary and secondary metabolism processes involved in aroma precursor biosynthesis, such as carbohydrate metabolism, energy metabolism, and amino acid biosynthesis, and phenylpropanoid, flavonoid, and alkaloid biosynthesis. The findings showed that the contents of alkaloid metabolites such as nornicotine, anatabine, anatalline, and myosmine were significantly higher in tobacco roots than in leaves and stems at the seedling stage.

Optimization of Light Intensity, Temperature, and Nutrients to Enhance the Bioactive Content of Hyperforin and Rutin in St. John's Wort

St. John’s wort (Hypericum perforatum L.) is a medicinal plant that alleviates depression and other disorders due to its abundance of active ingredients. Hyperforin, rutin, and melatonin are the main active, and important, ingredients in St. John’s wort that alleviate depression. In order to investigate the optimal conditions for accumulating these active ingredients, design of experiments and response surface methodology (RSM) was employed in this study. Two-month-old St John’s wort plants were cultivated in growth chambers at varying temperatures, light intensities, and nutrient solution concentrations before analysis by HPLC, for determining differences in hyperforin, rutin, and melatonin content. The results showed that hyperforin and rutin contents were significantly influenced by temperature (18–23 °C) and light intensity (49–147 μmol m⁻² s⁻¹ photosynthetic photon flux density (PPFD)), whereas Hoagland’s nutrient solution concentration (25–75%) had little effect. The accumulation of melatonin might not be influenced by cultivation conditions. Light intensity and temperature are easily controlled environmental factors in artificial cultivation, both of which are related to secondary metabolite production in the plant. Based on RSM, the optimal conditions for the accumulation of hyperforin and rutin were obtained. The maximum content of hyperforin was 5.6 mg/g, obtained at a temperature of 19 °C, a nutrient solution concentration of 45%, and a light intensity of 49 μmol m⁻² s⁻¹ PPFD. The maximum content of rutin was 3.8 mg/g obtained at a temperature of 18 °C, a nutrient solution concentration of 50%, and a light intensity of 147 μmol m⁻² s⁻¹ PPFD. This evaluation of suitable conditions for the accumulation of bioactive compounds in St. John’s wort can be applied to plant factories on a large scale.

Evaluation of the Effect of Topical Hypericum perforatum Oil on Excisional Palatal Wound Healing in Rabbits

Aim: The aim of this study was to evaluate the effect of Hypericum perforatum (HP) oil on wound-healing process in rabbit palatal mucosa. Materials and Methods: Thirty-six New Zealand albino rabbits were randomly allocated to following groups; (1) HP oil (test, n = 18) and (2) olive oil (control, n = 18). Palatinal excisional wounds were created and the oils were topically applied (0.1 ml, 30 s, twice a day). Gingival biopsies were excised, and analyzed for re-epithelialization (RE) and granulation tissue maturation (GTM) on days 3, 7, and 14 after surgery. Levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) were assessed using the immunohistochemical method. Apoptotic cells (ACs) were evaluated using TUNEL staining. Enzyme-linked immunosorbent assay was used to assess tissue catalase (CAT) and malondialdehyde (MDA) levels. Results: RE and GTM were completed earlier in the HP oil group than in the control group. The number of positively stained cells/vessels was higher in olive oil than in the test group on day 3 for FGF-2 and on days 3 and 7 for VEGF (p < 0.05). In contrast, on day 14, a higher number of vessels was observed in the HP oil group than in the control group. HP oil treatment reduced the number of ACs compared to olive oil (p < 0.05), but the difference during the healing period did not reach significance. Tissue CAT and MDA levels between groups were not different, and also the results were the same when the levels were analyzed by the evaluated time periods (p > 0.05). Conclusions: The results of this study demonstrated that topical HP oil treatment did not provide an additional benefit to its base, olive oil, in the early phase of secondary wound healing.

Optimized and Validated HPLC Analysis of St. John's Wort Extract and Final Products by Simultaneous Determination of Major Ingredients

Aim of this work was to develop a validated high performance liquid chromatography method for the analysis of extracts and final products of St. John's wort, according to international guidelines for bioanalytical method validation. Chromatographic separation was performed on a C18 column with a combination of gradient and isocratic steps; the mobile phase composed of ammonium acetate solution (pH 4.5; 10 mM), acetonitrile and methanol. Quantification and method validation was performed using extract spiked with external reference standards of chlorogenic acid, rutin, hyperoside, isoquercitrin, quercetin and hypericin. Validation study revealed that trans-chlorogenic acid is partially transformed into its cis-isomer during analysis. The method showed good linearity, precision and accuracy. Hyperforin was completely unstable. All other ingredients were stable at -18°C and after three freeze-thaw cycles, while stability of most ingredients was limited at room temperature and 4 - 8°C; quercetin was the most unstable one. The major ingredients of methanolic extracts, infusions and final products of Hypericum perforatum were completely resolved and quantified. Beyond its potential usefulness in the analysis of St. John's wort products, this study addresses the issue of validation from the perspective of the field of bioanalysis and reveals the wealth of critical information which can be derived.

Quality control of Hypericum perforatum L. analytical challenges and recent progress

Objectives

The most widely applied qualitative and quantitative analytical methods in the quality control of Hypericum perforatum extracts will be reviewed, including routine analytical tools and most modern approaches.

Key findings

Biologically active components of H. perforatum are chemically diverse; therefore, different chromatographic and detection methods are required for the comprehensive analysis of St. John's wort extracts. Naphthodianthrones, phloroglucinols and flavonoids are the most widely analysed metabolites of this plant. For routine quality control, detection of major compounds belonging to these groups seems to be sufficient; however, closer characterization requires the detection of minor compounds as well.

Conclusions

TLC and HPTLC are basic methods in the routine analysis, whereas HPLC-DAD is the most widely applied method for quantitative analysis due to its versatility. LC-MS is gaining importance in pharmacokinetic studies due to its sensitivity. Modern approaches, such as DNA barcoding, NIRS and NMR metabolomics, may offer new possibilities for the more detailed characterization of secondary metabolite profile of H. perforatum extracts.

Chemometrics: A new scenario in herbal drug standardization

Chromatography and spectroscopy techniques are the most commonly used methods in standardization of herbal medicines but the herbal system is not easy to analyze because of their complexity of chemical composition. Many cutting-edge analytical technologies have been introduced to evaluate the quality of medicinal plants and significant amount of measurement data has been produced. Chemometric techniques provide a good opportunity for mining more useful chemical information from the original data. Then, the application of chemometrics in the field of medicinal plants is spontaneous and necessary. Comprehensive methods and hyphenated techniques associated with chemometrics used for extracting useful information and supplying various methods of data processing are now more and more widely used in medicinal plants, among which chemometrics resolution methods and principal component analysis (PCA) are most commonly used techniques. This review focuses on the recent various important analytical techniques, important chemometrics tools and interpretation of results by PCA, and applications of chemometrics in quality evaluation of medicinal plants in the authenticity, efficacy and consistency.

Effects of herbal supplements on the bioactivation of chemotherapeutic agents

OBJECTIVES

The aim of this study was to investigate the impact of commercially available, over-the-counter herbal supplements (St John's wort, black cohosh and ginger root extract) on the metabolic activation of tamoxifen and irinotecan.

METHODS

Co-incubation of each drug and supplement combination over a range of concentrations was conducted in human liver microsomes and the decrease in the rate of active metabolite formation was monitored using high-performance liquid chromatography tandem mass spectrometry. Data was analysed using non-linear regression analysis and Dixon plots to determine the dominant mechanism of inhibition and to estimate the Ki and IC50 values of the commercial supplements.

KEY FINDINGS

The data suggest that black cohosh was the strongest inhibitor tested in this study for both CYP450 and carboxyesterase mediated biotransformation of tamoxifen and irinotecan, respectively, to their active metabolites. St John's wort was a stronger inhibitor compared with ginger root extract for tamoxifen (CYP mediated pathway), while ginger root extract was a stronger inhibitor compared with St John's wort for the carboxyesterase mediated pathway.

CONCLUSIONS

Commercially available supplements are widely used by patients and their potential impact on the efficacy of the chemotherapy is often unknown. The clinical significance of these results needs to be evaluated in a comprehensive clinical trial.

Identification and biosynthesis of acylphloroglucinols in Hypericum gentianoides

Species of the genus Hypericum contain a rich array of unusual polyketides, however, only a small proportion of the over 450 Hypericum species, other than the popular medicinal supplement St. John's Wort (Hypericum perforatum), have even been chemically characterized. Hypericum gentianoides, a small annual used medicinally by Cherokee Americans, contains bioactive acylphloroglucinols. Here, we identify acylphloroglucinol constituents of H. gentianoides and determine a potential pathway to their synthesis. Liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) and HPLC-UV indicate that the level of accumulation and profile of acylphloroglucinols in H. gentianoides vary little seasonally when grown in a greenhouse, but do vary with development and are highly dependent on the accession, highlighting the importance of the selection of plant material for study. We identify the chemical structures of the nine prevalent polyketides, based on LC/ESI-MS and hybrid quadrupole orthogonal time-of-flight (Q-TOF) mass spectrometry; these metabolites include one monomeric phlorisobutyrophenone (PIB) derivative and eight dimeric acylphloroglucinols. Q-TOF spectrometry was used to identify eight additional PIB derivatives that were not detected by LC/ESI-MS. These data lead us to propose that diacylphloroglucinols are synthesized via modification of PIB to yield diverse phloroglucinol and filicinic acids moieties, followed by dimerization of a phloroglucinol and a filicinic acid monomer to yield the observed complement of diacylphloroglucinols. The metabolomics data from H. gentianoides are accessible in plant metabolomics resource (PMR) (http://www.metnetdb.org/pmr), a public metabolomics database with analysis software for plants and microbial organisms.

Flavonoid glycosides and naphthodianthrones in the sawfly Tenthredo zonula and its host-plants, Hypericum perforatum and H. hirsutum

Larvae of the sawfly Tenthredo zonula are specialized on Hypericum. Whether the sawfly is able to sequester plant metabolites was unknown. Aerial materials of Hypericum perforatum and H. hirsutum, as well as dissected larvae and prepupae of T. zonula, were analyzed by HPLC to determine the presence and content of flavonoid glycosides (rutin, hyperoside, isoquercitrin, and quercitrin) and naphthodianthrones (pseudohypericin and hypericin). All flavonoid glycosides were detected in both Hypericum species, with hyperoside as major compound in H. perforatum (ca. 1.7 μmol/g fresh weight, FW) and isoquercitrin in H. hirsutum (0.7 μmol/g FW). Naphthodianthrones were present at low concentrations (0.02 μmol/g FW) in the former, and almost undetected in the latter species. In the body parts (i.e., hemolymph, digestive tract, salivary glands, or miscellaneous organs) of T. zonula, the surveyed compounds were detected more frequently in prepupae than in larvae. The compounds were not present in every sample, and flavonoid glycosides especially occurred in highly variable amounts, with maximal concentrations of 41 μg rutin/prepupa in salivary glands, 8 μg hyperoside/prepupa in hemolymph (= 0.36 μmol/g FW), 32 μg isoquercitrin/prepupa in salivary glands, and 63 μg quercitrin/larva in miscellaneous organs (mainly composed of the integument). We conclude that flavonoid glycosides are sequestered since they were detected in organs other than the digestive tract of larvae, and because prepupae are a non-feeding stage. The naphthodianthrone pseudohypericin, but not hypericin, occurred generally in the digestive tract (up to 0.25 μg/larva). Both naphthodianthrones and related unidentified compounds, but not flavonoid glycosides, were found in the larval excrement. The highly variable distributions of flavonoid glycosides and naphthodianthrones in T. zonula larvae and prepupae make it difficult to determine the ecological significance of these metabolites.

Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L

BACKGROUND

The St John's Wort (Hypericum perforatum; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.

RESULTS

An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC50 of 0.52 μg/ml), NO scavenging (6.11 μg/ml), superoxide scavenging (1.86 μg/ml), lipid peroxidation (0.0079 μg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.

CONCLUSION

LC-MS technique has been successfully applied for a quick separation and identification of the major components of H. perforatum fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, H. perforatum preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).

The Quality of Commercially Available Herbal Products

Herbal products are believed to be safe as they are naturally occurring, however, this is a misconception. Currently, there are many herbal products which are not manufactured under the Good Manufacturing Practice (GMP) guidelines and hence the quality of the product is not controlled. Quality can be assessed by evaluation of data on levels of either active constituent(s) or chemical markers indicative of origin of plant material. Assessment of published data on levels of quality of herbal medicinal products revealed that only a percentage of the total number of products investigated were found to contain the levels of markers as stated on the label, and others had widely varying levels of constituents. Thus few products complied with acceptable quality control standards. Herbal products are increasingly self-prescribed for the treatment of minor ailments. Patients relying on herbal products for therapeutic effects may expose themselves to either low doses of active constituents causing insufficient effects or alternatively take higher levels than expected, with the increased risk of toxicity or adverse effects, or be affected by the inadvertent inclusion of unexpected components with associated potential health risks.

A Semiquantitative FIA-ESI-MS Method for the Rapid Screening of Hypericum perforatum Crude Extracts

A method based on FIA-ESI-MS has been developed to profile the major constituents of Hypericum perforatum extracts. The objective was to obtain simultaneous semi-quantitative data on hypericin, chlorogenic acid, rutin, quercitrin, quercetin and hyperforin contents for a high-throughput screening of the raw plant material. The principal drawback of FIA-ESI analysis of complex mixtures involves ion suppression effects: the ionization of some components of the mixture can be severely suppressed by ionization of others. The results show that this problem can be alleviated using a new approach to generate calibration curves.

Matrix-free UV-laser desorption/ionization (LDI) mass spectrometric imaging at the single-cell level: distribution of secondary metabolites of Arabidopsis thaliana and Hypericum species

The present paper describes matrix-free laser desorption/ionisation mass spectrometric imaging (LDI-MSI) of highly localized UV-absorbing secondary metabolites in plant tissues at single-cell resolution. The scope and limitations of the method are discussed with regard to plants of the genus Hypericum. Naphthodianthrones such as hypericin and pseudohypericin are traceable in dark glands on Hypericum leaves, placenta, stamens and styli; biflavonoids are also traceable in the pollen of this important phytomedical plant. The highest spatial resolution achieved, 10 microm, was much higher than that achieved by commonly used matrix-assisted laser desorption/ionization (MALDI) imaging protocols. The data from imaging experiments were supported by independent LDI-TOF/MS analysis of cryo-sectioned, laser-microdissected and freshly cut plant material. The results confirmed the suitability of combining laser microdissection (LMD) and LDI-TOF/MS or LDI-MSI to analyse localized plant secondary metabolites. Furthermore, Arabidopsis thaliana was analysed to demonstrate the feasibility of LDI-MSI for other commonly occurring compounds such as flavonoids. The organ-specific distribution of kaempferol, quercetin and isorhamnetin, and their glycosides, was imaged at the cellular level.

Chemical constituents of Hypericum adenotrichum Spach, an endemic Turkish species

The present study was conducted out to determine hyperforin, hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, quercitrin, quercetin, kaempferol, apigenin-7-O-glucoside and amentoflavone contents of Hypericum adenotrichum, an endemic plant species to Turkey. The aerial parts representing a total of 30 individuals were collected at full flowering, dried at room temperature and assayed for secondary metabolite concentrations by HPLC. All of the chemicals were detected at various levels except for hyperforin. This is the first report on polar chemistry of this endemic species.

Hypericum in infection: Identification of anti-viral and anti-inflammatory constituents

The Iowa Center for Research on Botanical Dietary Supplements seeks to optimize Echinacea, Hypericum, and Prunella botanical supplements for human-health benefit, emphasizing antiviral, anti-inflammatory and anti-pain activities. This mini-review reports on ongoing studies on Hypericum. The Center uses the genetically diverse, well-documented Hypericum populations collected and maintained at the USDA-ARS North Central Regional Plant Introduction Station (NCRPIS), and the strength of research in synthetic chemistry at Iowa State University to tap natural diversity, to help discover key constituents and interactions among constituents that impact bioactivity and toxicity. The NCRPIS has acquired more than 180 distinct populations of Hypericum, with a focus on Hypericum perforatum L. (Hypericaceae), representing about 13% of currently recognized taxa. Center chemists have developed novel synthetic pathways for key flavones, acyl phloroglucinols, hyperolactones and a tetralin that have been found in Hypericum, and these compounds are used as standards and for bioactivity studies. Both light-dependent and light-independent anti-viral activities have been identified by using bioactivity-guided fractionation of H. perforatum and a HIV-1 infection test system. Our Center has focused on light-independent activity, potentially due to novel chemicals, and polar fractions are undergoing further fractionation. Anti-inflammatory activity has been found to be light-independent, and fractionation of a flavonoid-rich extract revealed four compounds (amentoflavone, chlorogenic acid, pseudohypericin and quercetin) that interacted in the light to inhibit lipopolysaccharide-induced prostaglandin E(2) activity. The Center continues to explore novel populations of H. perforatum and related species to identify constituents and interactions of constituents that contribute to potential health benefits related to infection.

Characterizing the metabolic fingerprint and anti-inflammatory activity of Hypericum gentianoides

In this paper we characterize the metabolic fingerprint and first reported anti-inflammatory activity of Hypericum gentianoides. H. gentianoides has a history of medical use by Native Americans, but it has been studied very little for biological activity. High-performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) analyses of a methanol extract show that H. gentianoides contains a family of over nine related compounds that have retention times, mass spectra, and a distinctive UV absorption spectra characteristic of certain acyl-phloroglucinols. These metabolites are abundant relative to other secondary products present in H. gentianoides, accounting for approximately 0.2 g per gram of dry plant tissue. H. gentianoides methanol extracts and a specific semipreparative HPLC fraction from these extracts containing the putative acyl-phloroglucinols reduce prostaglandin E 2 synthesis in mammalian macrophages.

1H NMR determination of hypericin and pseudohypericin in complex natural mixtures by the use of strongly deshielded OH groups

The (1)H NMR spectra of the commercially available compounds hypericin and its derivative pseudohypericin in CD(3)OH solutions indicate significantly deshielded signals in the region of 14-15 ppm. These resonances are attributed to the peri hydroxyl protons OH(6), OH(8) and OH(1), OH(13) of hypericins which participate in a strong six-membered ring intramolecular hydrogen bond with CO(7) and CO(14), respectively, and therefore, they are strongly deshielded. In the present work, we demonstrate that one-dimensional (1)H NMR spectra of hypericin and pseudohypericin, in Hypericum perforatum extracts show important differences in the chemical shifts of the hydroxyl groups with excellent resolution in the region of 14-15 ppm. The facile identification and quantification of hypericin and its derivative compound pseudohypericin was achieved, without prior HPLC separation, for two H. perforatum extracts from Greek cultivars and two commercial extracts: a dietary supplement, and an antidepressant medicine. The results were compared with those obtained from UV-vis and LC/MS measurements.

Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS

The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. For the on-line NMR detection, the analytes eluted from column were trapped one by one onto separate SPE cartridges, and hereafter transported into the NMR flow-cell. LC/DAD/SPE/NMR and LC/UV/MS allowed the characterization of constituents of Greek H. perforatum, mainly naphtodianthrones (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, quercitrin, isoquercitrin, hyperoside, astilbin, miquelianin, I3,II8-biapigenin) and phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid). Two phloroglucinols (hyperfirin and adhyperfirin) were detected for the first time, which have been previously reported to be precursors in the biosynthesis of hyperforin and adhyperforin.

Possible drug-metabolism interactions of medicinal herbs with antiretroviral agents

Herbal medicines are widely used by HIV patients. Several herbal medicines have been shown to interact with antiretroviral drugs, which might lead to drug failure. We have aimed to provide an overview of the modulating effects of Western and African herbal medicines on antiretroviral drug-metabolizing and transporting enzymes, focusing on potential herb-antiretroviral drug interactions. Echinacea, garlic, ginkgo, milk thistle, and St. John's wort have the potential to cause significant interactions. In vitro and in vivo animal studies also indicated other herbs with a potential for interactions; however, most evidence is based on in vitro studies. Further pharmacokinetic studies to unveil potential Western and especially African herb-antiretroviral drug interactions are urgently required, and the clinical significance of these interactions should be assessed.

Clinical assessment of effects of botanical supplementation on cytochrome P450 phenotypes in the elderly: St John's wort, garlic oil, Panax ginseng and Ginkgo biloba

OBJECTIVES

Elderly patients are more likely to ingest prescription medications concurrently with botanical supplements, and may therefore be vulnerable to herb-drug interactions. Phytochemical-mediated modulation of cytochrome P450 (CYP) activity may underlie many herb-drug interactions. Some evidence suggests that CYP activity may decrease in the elderly. If so, herb-mediated changes in CYP activity may take on greater clinical relevance in this population. In this study, single timepoint, phenotypic metabolic ratios were used to determine whether long-term supplementation of St John's wort, garlic oil, Panax ginseng, and Ginkgo biloba affected CYP1A2, CYP2D6, CYP2E1 or CYP3A4 activity in elderly subjects.

METHODS

Twelve healthy volunteers between the ages of 60 and 76 years (mean age 67 years) were randomly assigned to receive each botanical supplement for 28 days followed by a 30-day washout period. Probe drug cocktails of midazolam, caffeine, chlorzoxazone and debrisoquine were administered before and at the end of supplementation. Pre- and post-supplementation phenotypic ratios were determined for CYP3A4, CYP1A2, CYP2E1 and CYP2D6 using 1-hydroxymidazolam/midazolam serum ratios (1-hour), paraxanthine/caffeine serum ratios (6-hour), 6-hydroxychlorzoxazone/chlorzoxazone serum ratios (2-hour) and debrisoquine urinary recovery ratios (8-hour), respectively. The content of purported 'active' phytochemicals was determined for each supplement.

RESULTS

Comparisons of pre- and post-St John's wort phenotypic ratios revealed significant induction of CYP3A4 (approximately 140%) and CYP2E1 activity (approximately 28%). Garlic oil inhibited CYP2E1 activity by approximately 22%. P. ginseng inhibition of CYP2D6 was statistically significant, but the magnitude of the effect (approximately 7%) did not appear to be clinically relevant. None of the supplements tested in this study appeared to affect CYP1A2 activity.

CONCLUSIONS

Elderly subjects, like their younger counterparts, are susceptible to herb-mediated changes in CYP activity, especially those involving St John's wort. Pharmacokinetic herb-drug interactions stemming from alterations in CYP activity may adversely affect drug efficacy and/or toxicity. When compared with earlier studies that employed young subjects, the data suggest that some age-related changes in CYP responsivity to botanical supplementation may exist. Concomitant ingestion of botanical supplements with prescription medications, therefore, should be strongly discouraged in the elderly.

A high-performance liquid chromatography with electrochemical detection for the determination of total hypericin in extracts of St. John's Wort

An HPLC method for the quantitation of hypericin using a new and sensitive amperometric detection is presented. Hypericin was eluted isocratically using a mobile phase consisting of ammonium acetate, methanol and acetonitrile. The oxidation was carried out with a glassy carbon electrode at a potential of + 1.1 V vs. an Ag-AgCl-KCl reference electrode. Under the conditions described, hypericin was separated at a retention time (Rt) of 12 min. Linearity was obtained over the range 0.035-1.30 microg/mL (r = 0.9994). The limit of detection was determined to be 0.010 ng on-column for hypericin. The method was applied to the determination of total hypericin (hypericin, pseudohypericin, protohypericin and protopseudohypericin) in extracts of St. John's wort using hypericin as an external standard. The protoforms were converted into hypericin and pseudohypericin by subjecting the sample to artificial light prior to chromatographic analysis. For the evaluation of total hypericin, the peak areas of pseudohypericin (Rt 3.7 min) and hypericin (Rt 12.0 min) were combined. The relative standard deviation in analysing samples containing Hypericum ranged from 2.5 to 5.4%.

Development and evaluation of methods for determination of naphthodianthrones and flavonoids in St. John's wort

Several major constituents in St. John's wort were determined for a homogenized plant sample. Three extraction techniques were evaluated: Soxhlet extraction, pressurized-fluid extraction (PFE), and sonication extraction. Levels of nine constituents (chlorogenic acid, rutin, hyperoside, isoquercitrin, quercitrin, quercetin, amentoflavone, pseudohypericin, and hypericin) were measured using liquid chromatography with ultraviolet/visible absorbance, mass spectrometric, and fluorescence detection. Levels of total naphthodianthrones determined by liquid chromatography (LC) with absorbance detection at 590 nm were compared with levels determined by direct spectrophotometry at the same wavelength. Additionally, the methods described in this paper were applied to several brands of St. John's wort finished products.

Effect of eluent pH on the HPLC-UV analysis of hyperforin from St. John's Wort (Hypericum perforatum L.)

The effect of the pH of the mobile phase in HPLC analysis of hyperforin was investigated. Working with an extract of St. John's Wort (Hypericum perforatum L.) that is rich in hyperforin, significant differences were observed in conventional chromatograms depending on whether the mobile phase was acidic or alkaline. Chromatogram changes were paralleled by changes in the UV spectrum of the hyperforin peak. The structural changes in hyperforin occur in the chromatographic column itself, as has been confirmed by UV spectroscopy performed on a sample of purified hyperforin, which showed that the UV spectrum is indeed dependent on the pH of its environment.

Issues related to botanicals

Herbal product studies cannot be considered scientifically valid if the product tested was not authenticated and characterized in order to ensure reproducibility in the manufacturing of the product in question. Many studies refer to the use of standardized material, but in reality they are referring to chemical standardization. While chemical standardization is important, its utility is limited when the starting material is not well characterized botanically. Although the resulting studies are sound with respect to the actual product tested, adequate authentication of the product cannot be compared to other products on the market. Also, a comparison of one study to another cannot be made due to inconsistencies in the identity of the botanical matrix. The tools needed for authentication of the field plant material also depend on the plant and process involved. This could be as straightforward as botanical/morphological identification or as elaborate as genetic or chemical profiling. Authenticated raw material is the basic starting point for the development of a botanical product. However, harvesting, storing, processing and formulating methods may dramatically affect the quality and consistency of the final product by altering the desired marker components or by increasing the possibility of unwanted contaminants. Thus, validated methods to ensure quality control in manufacturing and storage are required tools for optimal efficacy and safety of the products. These controls are also critical for the evaluation of pharmacological, toxicological and clinical studies of the botanical supplements.

Phytochemical analysis and genetic characterization of six Hypericum species from Serbia

The secondary metabolite contents and genetic profiles of six Hypericum species (H. barbatum Jacq., H. hirsutum L., H. linarioides Bosse, H. maculatum Crantz, H. rumeliacum Boiss. and H. tetrapterum Fries), collected from different locations in Serbia, have been analyzed. Methanol extracts of the aerial parts of the plants were obtained by accelerated solvent extraction (ASE) at 40 degrees C and 100 bar, and analyzed for five pharmacologically important standard constituents (hyperoside, quercitrin, pseudohypericin, hyperforin and hypericin) by LC-MS/MS. The highest content of hypericin and pseudohypericin was observed in the H. barbatum extract, while the highest content of hyperforin and quercitrin was found in the H. tetrapterum extract and the highest content of hyperoside in the H. maculatum extract. A literature survey shows that the above six Hypericum species, with the exception of H. maculatum, have not been previously genetically profiled. In order to correlate the chemical constituents of the species under investigation with their genetic factors, genetic profiling of these species was undertaken using the random amplification of polymorphic DNA (RAPD) and single sequence repeat (SSR) profiles of the above selected plants. Among the 52 random primers used for the initial screening, only 10 yielded polymorphic RAPD profiles. A total of 111 polymorphic markers were generated using these primers. The SSR analysis shows that 8 out of the 10 primers used were polymorphic. The correlation among the species under investigation using the two genetic markers was performed using Jaccuard's coefficients of similarity and a high correlation (r=0.99) was obtained. The main conclusion from the above data is that there exists a stronger correlation for secondary metabolite contents with RAPD data than with SSR data among the six Hypericum species from Serbia.

Toxicity and drug interactions associated with herbal products: ephedra and St. John's Wort

Health care providers are being increasingly confronted with the use of herbal medications by their patients. It is imperative that patients be questioned regarding herbal preparation use and that health care providers become familiar with these agents. Research into the active components and mechanisms of action of various herbals is ongoing [350]. Long-range studies need to be performed to follow patients for efficacy or toxicity in chronic use [351,352]. Adverse reactions to herbal remedies should be reported to the FDA MedWatch at http://www.fda.gov/medwatch. As withany therapeutic agent, risk of use must always be weighed against potential benefits.

Phytochemical profiling of New and Old World Hypericum (St. John's Wort) species

Botanical extracts of Hypericum perforatum L. (common St. John's Wort) are used in the USA and in Europe as a treatment for mild to moderate depression, although controversy surrounds the identity of the active constituent(s). RP-HPLC with photodiode array detection was used to separate and quantify nine compounds of pharmacological interest in extracts from 74 taxa of Hypericum native to the Old and New World. Chemical profiles of these constituents may be used to distinguish extracts of H. perforatum from those of other species of Hypericum, and to indicate species that may be of interest for further phytochemical investigation.

Chromatographic performance of a new polar poly(ethylene glycol) bonded phase for the phytochemical analysis of Hypericum perforatum L

The aim of this study was to evaluate the chromatographic performance of a poly(ethylene glycol) (PEG) stationary phase for the HPLC analysis of the secondary metabolites (chlorogenic acid, flavonoids, phloroglucinols and naphthodianthrones) in methanolic extracts of Hypericum perforatum L. (St. John's Wort) flowering tops, herbal medicinal products and dietary supplements. A fast and reliable method was developed. The analyses were carried out on a Supelco Discovery HS PEG column (150 mm x 4.6 mm i.d., 5 microm). A gradient mobile phase, composed of 0.1 M aqueous acetic acid solution (pH 2.8) and methanol-acetonitrile (5:4, v/v), was used. The flow rate was 1 mL/min. The photodiode array detector monitored the eluent at 270 (for chlorogenic acid, flavonoids and phloroglucinols) and 590 nm (for naphthodianthrones). The column was maintained at room temperature. The total running time was 40 min. The method was validated and showed good linearity, precision, accuracy, sensitivity and specificity. Through the above described phytochemical markers, this technique allowed the unequivocal identification and standardization of H. perforatum plant material and phytoproducts. The quantification data highlighted the fact that the products on sale, in particular those labeled as dietary supplements, varied widely in the quantitative composition of the active constituents. The developed method could be considered suitable for the quality control of H. perforatum herb and derivatives.

Phytochemical Assays of Commercial Botanical Dietary Supplements

The growing popularity of botanical dietary supplements (BDS) has been accompanied by concerns regarding the quality of commercial products. Health care providers, in particular, have an interest in knowing about product quality, in view of the issues related to herb-drug interactions and potential side effects. This study assessed whether commercial formulations of saw palmetto, kava kava, echinacea, ginseng and St. John's wort had consistent labeling and whether quantities of marker compounds agreed with the amounts stated on the label. We purchased six bottles each of two lots of supplements from nine manufacturers and analyzed the contents using established commercial methodologies at an independent laboratory. Product labels were found to vary in the information provided, such as serving recommendations and information about the herb itself (species, part of the plant, marker compound, etc.) With regard to marker compound content, little variability was observed between different lots of the same brand, while the content did vary widely between brands (e.g. total phenolic compounds in Echinacea ranged from 3.9-15.3 mg per serving; total ginsenosides in ginseng ranged from 5.3-18.2 mg per serving). Further, the amounts recommended for daily use also differed between brands, increasing the potential range of a consumer's daily dose. Echinacea and ginseng were the most variable, while St. John's wort and saw palmetto were the least variable. This study highlights some of the key issues in the botanical supplement market, including the importance of standardized manufacturing practices and reliable labeling information. In addition, health care providers should keep themselves informed regarding product quality in order to be able to appropriately advise patients utilizing both conventional and herbal medicines.

Development of a high-performance liquid chromatographic method with electrochemical detection for the determination of hyperforin

An HPLC method with electrochemical detection for the determination of hyperforin extracts without using additional sample precleaning has been developed and validated. The hyperforin solutions were separated isocratically using a mobile phase consisting of 10% ammonium acetate buffer (0.5 M, pH 3.7)-MeOH-acetonitrile (10:40:50, v/v) at a flow rate of 0.8 mL/min. Hyperforin was detected amperometrically with a glassy carbon electrode at a potential of +1.1 V versus Ag/AgCl/3 M potassium chloride reference electrode. Under these conditions, a plot of integrated peak area versus concentration of hyperforin was found to be linear over the range of 0.054-5.4 microg/mL, with a relative standard deviation of 2.2-8.6%. The limit of detection was 0.050 ng on column. The determination of the hyperforin content in a commercially available St. John's Wort preparation exhibited a mean content of 1.56 mg. Recovery experiments led to a mean recovery rate of 97 +/- 5.8%. The proposed method is not time-consuming, sensitive and reproducible and is therefore suitable for routine analysis of hyperforin in herbal medicinal products.

Characterization of supercritical fluid extracts of St. John’s Wort (Hypericum perforatum L.) by HPLC–MS and GC–MS

Supercritical fluid extracts (carbon dioxide without modifiers) of St. John's Wort (Hypericum perforatum L., Clusiaceae) were analyzed by GC-MS, HPLC-DAD and HPLC-DAD-MS. Besides the dominating phloroglucinols hyperforin (36.5 +/- 1.1%) and adhyperforin (4.6 +/- 0.1%), the extracts mainly contained alkanes (predominantly nonacosane), fatty acids and wax esters. The apolar components tended to accumulate in a waxy phase resting a top of the hyperforin-enriched phase. No components of higher polarity like naphthodianthrones were found. A set of hyperforin oxidation products was detected and tentatively assigned using HPLC-MS.

Development of a high-performance-liquid-chromatographic method for the determination of biapigenin in biorelevant media

A new precise, rapid and selective high-performance-liquid-chromatographic (HPLC) method has been developed to quantify biapigenin in St. John's Wort (SJW) preparations and to investigate its release characteristics in the dissolution test using both compendial and biorelevant media. Experiments were carried out on a LiChroCart 125-4, RP-18 (5 microm) column, using gradient elution at a flow rate of 1 ml/min. The binary mobile phase consisted of solvent A (acetic acid, 5:100, w:w) and B (a mixture of acetonitrile and methanol (3:1, v:v)). Detection was performed at a wavelength of 270 nm using a photodiodearray detector. The limit of detection was 0.05 microg/ml, the injection volume 20 microl. Five SJW preparations were chosen to determine the amount of biapigenin in the dosage form and to investigate their release characteristics. Best results in terms of release as well as discriminating the tested products were obtained, using fed state simulated intestinal fluid (FeSSIF), where over 80% of biapigenin was dissolved after 20 min comparing to 70% using simulated gastric fluid sine pepsin (SGF(sp)) as compendial medium. Experiments in fasted state simulated intestinal fluid (FaSSIF) show 80% release of biapigenin within 80 min.

Use of an on-line, precolumn photochemical reactor in high-performance liquid chromatography of naphthodianthrones in Hypericum perforatum preparations

A method has been developed for the determination of naphthodianthrones in Hypericum perforatum L. extracts and phytopharmaceutical preparations by high-performance liquid chromatography combined with on-line, precolumn photochemical conversion followed by photodiode-array detection. The chromatographic separation was performed on a C18 column under isocratic reversed-phase conditions. An on-line, precolumn photochemical reactor equipped with a knitted PTFE reaction coil around a visible light source was used in order to transform the light sensitive naphthodianthrones, protohypericin and protopseudohypericin, very easily into the non-protoforms, hypericin and pseudohypericin, respectively. Two UV chromatograms (photochemical reactor "on" and "off") were compared and were quite useful in characterizing the sample. Validation studies demonstrated that this HPLC method is simple, rapid, reliable and reproducible. The time-consumptive manual irradiation of the samples is omitted by this automated on-line irradiation step. The developed method was successfully applied to the quality control of Hypericum perforatum L. extracts and its phytopharmaceutical preparations.

Clinic at the health food store? Employee recommendations and product analysis

STUDY OBJECTIVES

To determine what products health food store employees recommend for depression, to analyze the content of these products based on label claims, and to evaluate employee statements or recommendations for accuracy and safety.

METHODS

Twelve health food stores were selected for the study. One investigator approached an employee in each store and asked what they recommended for depression plus five additional questions regarding product use. Thirteen products containing St. John's wort were purchased and analyzed for hypericin and pseudohypericin content using high-performance liquid chromatography (HPLC). Total hypericin content was calculated by adding the values for hypericin and pseudohypericin.

RESULTS

All 12 health food store employees recommended a St. John's wort supplement for treatment of depression. Furthermore, numerous comments made by employees regarding St. John's wort and the treatment of depression were unsafe and inaccurate. The HPLC analysis revealed that no product contained +/- 10% of the stated label claim for hypericin content, and two products contained 0% hypericin. The total hypericin content (hypericin plus pseudohypericin) of only two products was within +/- 10% of the label claim for hypericin.

CONCLUSIONS

Health food store employees offer health care advice regarding treatment of depression with dietary supplements without proper scientific and medical training. Their comments could cause significant harm to customers. In addition, the inconsistencies of dietary supplement content continue to raise concern for individuals who use these agents as medical treatment.