Query: St. John's wort

Relevant passages:
Herbal infusions as a source of calcium, magnesium, iron, zinc and copper in human nutrition. <=SEP=> The study material consisted of five herbs: chamomile (flowers), mint (leaves), St John's wort (flowers and leaves), sage (leaves) and nettle (leaves), sourced from three producers. The calcium, magnesium, iron, zinc and copper contents were determined for both dried herb samples and prepared infusions, and the extraction rates were calculated. Mineral components were determined using atomic absorption spectrometry. Analysis showed that the contents of individual elements in herbs and infusions depended on the type of raw material, as well as on its origin. Moreover, it was found that iron penetrated the herbal infusions to the lowest degree (4.4-12.4%), while copper did so to the highest (26.7-50.7%). It is felt that in average consumption the herbal infusions are not important as calcium, magnesium, iron, zinc and copper sources in human nutrition.

The influence of Aspalathus linearis (Rooibos) and dihydrochalcones on adrenal steroidogenesis: quantification of steroid intermediates and end pro... <=SEP=> The steroid hormone output of the adrenal gland is crucial in the maintenance of hormonal homeostasis, with hormonal imbalances being associated with numerous clinical conditions which include, amongst others, hypertension, metabolic syndrome, cardiovascular disease, insulin resistance and type 2 diabetes. Aspalathus linearis (Rooibos), which has been reported to aid stress-related symptoms linked to metabolic diseases, contains a wide spectrum of bioactive phenolic compounds of which aspalathin is unique. In this study the inhibitory effects of Rooibos and the dihydrochalcones, aspalathin and nothofagin, were investigated on adrenal steroidogenesis. The activities of both cytochrome P450 17α-hydroxylase/17,20 lyase and cytochrome P450 21-hydroxylase were significantly inhibited in COS-1 cells. In order to study the effect of these compounds in H295R cells, a human adrenal carcinoma cell line, a novel UPLC-MS/MS method was developed for the detection and quantification of twenty-one steroid metabolites using a single chromatographic separation. Under both basal and forskolin-stimulated conditions, the total amount of steroids produced in H295R cells significantly decreased in the presence of Rooibos, aspalathin and nothofagin. Under stimulated conditions, Rooibos decreased the total steroid output 4-fold and resulted in a significant reduction of aldosterone and cortisol precursors. Dehydroepiandrosterone-sulfate levels were unchanged, while the levels of androstenedione (A4) and 11β-hydroxyandrostenedione (11βOH-A4) were inhibited 5.5 and 2.3-fold, respectively. Quantification of 11βOH-A4 showed this metabolite to be a major product of steroidogenesis in H295R cells and we confirm, for the first time, that this steroid metabolite is the product of the hydroxylation of A4 by human cytochrome P450 11β-hydroxylase. Taken together our results demonstrate that Rooibos, aspalathin and nothofagin influence steroid hormone biosynthesis and the flux through the mineralocorticoid, glucocorticoid and androgen pathways, thus possibly contributing to the alleviation of negative effects arising from elevated glucocorticoid levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

Acute neurocognitive effects of epigallocatechin gallate (EGCG). <=SEP=> Green tea is reported to have wide ranging beneficial health outcomes across epidemiological studies, which have been attributed to its flavonoid content. We investigated whether the flavonoid epigallocatechin gallate (EGCG) modulates brain activity and self-reported mood in a double-blind, placebo controlled crossover study. Participants completed baseline assessments of cognitive and cardiovascular functioning, mood and a resting state electroencephalogram (EEG) before and then 120 min following administration of 300 mg EGCG or matched placebo. EGCG administration was associated with a significant overall increase in alpha, beta and theta activity, also reflected in overall EEG activity, more dominant in midline frontal and central regions, specifically in the frontal gyrus and medial frontal gyrus. In comparison to placebo the EGCG treatment also increased self-rated calmness and reduced self rated stress. This pattern of results suggests that participants in the EGCG condition may have been in a more relaxed and attentive state after consuming EGCG. This is in keeping with the widespread consumption of green tea for its purported relaxing/refreshing properties. The modulation of brain function due to EGCG is deserving of further controlled human studies. Copyright Â© 2011 Elsevier Ltd. All rights reserved.

Consumption of Hibiscus sabdariffa L. aqueous extract and its impact on systemic antioxidant potential in healthy subjects. <=SEP=> BACKGROUND: To evaluate health benefits attributed to Hibiscus sabdariffa L. a randomized, open-label, two-way crossover study was undertaken to compare the impact of an aqueous H. sabdariffa L. extract (HSE) on the systemic antioxidant potential (AOP; assayed by ferric reducing antioxidant power (FRAP)) with a reference treatment (water) in eight healthy volunteers. The biokinetic variables were the areas under the curve (AUC) of plasma FRAP, ascorbic acid and urate that are above the pre-dose concentration, and the amounts excreted into urine within 24 h (Ae(0-24) ) of antioxidants as assayed by FRAP, ascorbic acid, uric acid, malondialdehyde (biomarker for oxidative stress), and hippuric acid (metabolite and potential biomarker for total polyphenol intake). RESULTS: HSE caused significantly higher plasma AUC of FRAP, an increase in Ae(0-24) of FRAP, ascorbic acid and hippuric acid, whereas malondialdehyde excretion was reduced. Furthermore, the main hibiscus anthocyanins as well as one glucuronide conjugate could be quantified in the volunteers' urine (0.02% of the administered dose). CONCLUSION: The aqueous HSE investigated in this study enhanced the systemic AOP and reduced the oxidative stress in humans. Furthermore, the increased urinary hippuric acid excretion after HSE consumption indicates a high biotransformation of the ingested HSE polyphenols, most likely caused by the colonic microbiota. Copyright © 2012 Society of Chemical Industry.

Bioavailability study of a polyphenol-enriched extract from Hibiscus sabdariffa in rats and associated antioxidant status. <=SEP=> The aqueous extracts of Hibiscus sabdariffa have been commonly used in folk medicine. Nevertheless, the compounds or metabolites responsible for its healthy effects have not yet been identified. The major metabolites present in rat plasma after acute ingestion of a polyphenol-enriched Hibiscus sabdariffa extract were characterized and quantified in order to study their bioavailability. The antioxidant status of the plasma samples was also measured through several complementary antioxidant techniques. High-performance liquid chromatography coupled to time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) was used for the bioavailability study. The antioxidant status was measured by ferric reducing ability of plasma method, thiobarbituric acid reactive substances assay, and superoxide dismutase activity assay. Seventeen polyphenols and metabolites have been detected and quantified. Eleven of these compounds were metabolites. Although phenolic acids were found in plasma without any modification in their structures, most flavonols were found as quercetin or kaempferol glucuronide conjugates. Flavonol glucuronide conjugates, which show longer half-life elimination values, are proposed to contribute to the observed lipid peroxidation inhibitory activity in the cellular membranes. By contrast, phenolic acids appear to exert their antioxidant activity through ferric ion reduction and superoxide scavenging at shorter times. We propose that flavonol-conjugated forms (quercetin and kaempferol) may be the compounds responsible for the observed antioxidant effects and contribute to the healthy effects of H. sabdariffa polyphenolic extract. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanism of action of stinging nettles. <=SEP=> OBJECTIVE: Inadvertent exposure to the ubiquitous weed, Urtica dioica, called "stinging nettles" produces an immediate stinging and burning sensation on the skin. This investigation evaluates the structural effect that stinging nettle spicules may have on the clinical manifestation of these symptoms. This hypothesis was investigated by exposing murine skin to stinging nettles and then evaluating the skin using electron microscopy. It was hypothesized that the mechanism of action of stinging nettles is both biochemical and mechanical, which may have clinical significance regarding treatment for acute exposure. METHODS: Fresh post-mortem dermis samples from the carcasses of genetically modified hairless mice were brushed under the stem and leaf of a stinging nettle plant, mimicking the clinical method of exposure a patient might experience. Another set of mouse skin samples was obtained but not exposed to the nettles. Both sets of skin samples were imaged with scanning electron microscopy. RESULTS: The skin samples that were not exposed to nettle leaves were uniform, with occasional striated hairs on the skin surface and no nettle spicules. The skin samples exposed to nettle leaves showed many smooth nettle spicules piercing the skin surface. A few spicules retained their bases, which appear empty of any liquid contents. CONCLUSIONS: The mechanism of action of stinging nettles dermatitis appears to be both biochemical and mechanical. Impalement of spicules into the skin likely accounts for the mechanical irritation in addition to the known adverse chemical effects of stinging nettles. Further investigation of treatment modalities is warranted. Copyright © 2011 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. <=SEP=> PURPOSE: To determine the effects of therapy with Urtica dioica for symptomatic relief of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). MATERIAL AND METHODS: A 6-month, double-blind, placebo-controlled, randomized, partial crossover, comparative trial of Urtica dioica with placebo in 620 patients was conducted. Patients were evaluated using the International Prostate Symptom Score (IPSS), the maximum urinary flow rate (Qmax), postvoid residual urine volume (PVR), Serum Prostatic- Specific Antigen (PSA), testosterone levels, and prostate size. At the end of 6-month trial, unblinding revealed that patients who initially received the placebo were switched to Urtica dioica. Both groups continued the medication up to 18 months. RESULTS: 558 patients (90%) completed the study (287/305, 91% in the Urtica dioica group, and 271/315, 86% in the placebo group). By intention- to-treat analysis, at the end of 6-month trial, 232 (81%) of 287 patients in the Urtica dioica group reported improved LUTS compared with 43 (16%) of 271 patients in the placebo group (P < 0.001). Both IPSS and Qmax showed greater improvement with drug than with placebo. The IPSS went from 19.8 down to 11.8 with Urtica dioica and from 19.2 to 17.7 with placebo (P = 0.002). Peak flow rates improved by 3.4 mL/s for placebo recipients and by 8.2 mL/s for treated patients (P < 0.05). In Urtica dioica group, PVR decreased from an initial value of 73 to 36 mL (P < 0.05). No appreciable change was seen in the placebo group. Serum PSA and testosterone levels were unchanged in both groups. A modest decrease in prostate size as measured by transrectal ultrasonography (TRUS) was seen in Urtica dioica group (from 40.1 cc initially to 36.3 cc; P < 0.001). There was no change in the prostate volume at the end of study with placebo. At 18-month follow-up, only patients who continued therapy, had a favorable treatment variables value. No side effects were identified in either group. CONCLUSION: In the present study, Urtica dioica have beneficial effects in the treatment of symptomatic BPH. Further clinical trials should be conducted to confirm these results before concluding that Urtica dioica is effective.

Emerging issues associated with HIV patients seeking advice from health food stores. <=SEP=> OBJECTIVES: To ascertain the recommendations, training and education of health food store employees and determine how they communicate the costs, benefits and risks associated with natural health products for the HIV/AIDS community. METHODS: Four male research assistants, posing as asymptomatic HIV-positive individuals, inquired of employees of all retail health food stores in a major Canadian city as to what is recommended for their condition. The research assistants asked about product costs, side effects, potential drug interactions and efficacy. They also inquired as to employee education related to Complementary and Alternative Medicine (CAM) and noted whether employees asked about which conventional medications they were taking and whether they recommended that the subjects seek physician or CAM provider advice. RESULTS: A total of 32 stores were included. Eight store employees (25%) offered no advice; eight (25%) inquired whether the subjects were currently taking medications; six (19%) suggested visiting a physician; and eight (25%) suggested visiting a CAM provider. A total of 36 different products (mean 2.3 per employee) were recommended with considerable variability in product evidence and cost. The education of the employees varied from postgraduate education (n=3), to undergraduate degree (n=3), college level (n=5) in CAM, or no formal education in CAM (n=21). CONCLUSION: There was considerable heterogeneity in advice on natural food products provided by employees of natural food stores and, in general, these individuals had limited formal training in CAM. The products they recommended had limited evidence supporting their efficacy and in some instances were potentially harmful and had considerable costs. The findings of this study support the need to further examine how best to regulate this growing component of the health care system.

Health information provided by retail health food outlets. <=SEP=> Alternative health practices have become increasingly popular in recent years. Many patients visit specific complementary practitioners, while others attempt to educate themselves, trusting advice from employees at local health food stores or the Internet. Thirty-two retail health food stores were surveyed on the nature of the information provided by their staff. A research assistant visited the stores and presented as the mother of a child in whom Crohn's disease had been diagnosed. Seventy-two per cent (23 of 32) of store employees offered advice, such as to take nutritional and herbal supplements. Of the 23 stores where recommendations were made, 15 (65%) based their recommendation on a source of information. Fourteen of the 15 stores using information sources used the same reference book. This had a significant impact on the recommendations; the use of nutritional supplements was favoured. In conclusion, retail health food stores are not as inconsistent as hypothesized, although there are many variances in the types of supplements recommended for the same chronic disease.