Phytochemical Assays of Commercial Botanical Dietary Supplements

Application to Butterbur Products of a Suggested Daily Intake-Based Safety Evaluation of Individual Herbal Supplements with Cytochrome P450 Expression as a Major Index

The present paper first proposes a method for ensuring the safety of commercial herbal supplements, termed the suggested daily intake-based safety evaluation (SDI-based safety evaluation). This new method was inspired as a backward analog of the acceptable daily intake (ADI) derivation from the no observed adverse effect level (NOAEL), the basis of food additive risk analysis; namely, rats are dosed with individual herbal supplement products at the SDI for human use multiplied by 100 (the usual uncertainty factor value) per body weight for 8 d. The primary endpoint is the sign of adverse effects on liver, especially gene expression of cytochrome P450 (CYP) isoforms. The proposed method was then applied to three butterbur (Petasites hybridus) products without pyrrolizidine alkaloids but lacking clear safety information. Results showed that two oily products markedly enhanced the mRNA expression of CYP2B (>10-fold) and moderately enhanced that of CYP3A1 (<4-fold) with liver enlargement. These products also caused the renal accumulation of alpha 2-microglobulin. One powdery product showed no significant effect on liver and kidney. The large difference in effects of products was due to the difference in chemical composition revealed by liquid chromatography-mass spectroscopy. The oily and the powdery products required attention in terms of safety and effectiveness, respectively. Finally, the results from the SDI-based safety evaluation of butterbur and other herbal supplement products were grouped into four categories and cautionary notes were discussed. The SDI-based safety evaluation of their products by herbal supplement operators would contribute to safe and secure use by consumers.

Review of the recent developments in metabolomics-based phytochemical research

Phytochemicals are important bioactive components present in natural products. Although the health benefits of many food products are well-known and accepted as a common knowledge, the identity of the main bioactive molecules and the mechanism by which they interact in the body of human are often unknown. It was only in the last 30 years when the field of metabolomics had matured that the identification of such molecules with bioactivity has been made possible through the development of instruments to separate and computational techniques to characterize complex samples. This in turn has enabled in vitro studies to quantify the biological activity of the respective phytochemical either in mice models or in humans. In this review, the importance of key dietary phytochemicals such as phenolic acids, flavonoids, carotenoids, resveratrol, curcumin, and capsaicinoids are discussed together with their potential functions for human health. Untargeted metabolomics, in particular, liquid chromatography mass spectrometry, is the most used method to isolate, identify and profile bioactive compounds in the study of phytochemicals in foods. The application of metabolomics in drug discovery is a common practice nowadays and has boosted the drug and/or supplement manufacturing sector.HighlightsPhytochemicals are beneficial compounds for human healthPhytochemicals are plant-based bioactive and obtainable from natural productsUntargeted metabolomics has boosted the discovery of phytochemicals from foodTargeted metabolomics is key in the authentication and screening of phytochemicalsMetabolomics of phytochemicals is reshaping the road to drug and supplement manufacture.

Multifaceted Factors Causing Conflicting Outcomes in Herb-Drug Interactions

Metabolic enzyme and/or transporter-mediated pharmacokinetic (PK) changes in a drug caused by concomitant herbal products have been a primary issue of herb and drug interactions (HDIs), because PK changes of a drug may result in the alternation of efficacy and toxicity. Studies on HDIs have been carried out by predictive in vitro and in vivo preclinical studies, and clinical trials. Nevertheless, the discrepancies between predictive data and the clinical significance on HDIs still exist, and different reports of HDIs add to rather than clarify the confusion regarding the use of herbal products and drug combinations. Here, we briefly review the underlying mechanisms causing PK-based HDIs, and more importantly summarize challenging issues, such as dose and treatment period effects, to be considered in study designs and interpretations of HDI evaluations.

Measurement of the S-adenosyl methionine (SAMe) content in a range of commercial veterinary SAMe supplements

OBJECTIVES

To measure the percentage of the stated amount of S-adenosyl methionine present in a range of commercially available S-adenosyl methionine supplements for veterinary use.

METHOD

Sixty-four samples of products containing S-adenosyl methionine marketed to support liver function were obtained from five manufacturers via three commercial wholesalers. The amount of S-adenosyl methionine in each product was measured using high-pressure liquid chromatography.

RESULTS

There were greater than threefold variation in the percentage of measured S-adenosyl methionine compared to the stated amount on the packaging which was significantly (P < 0 · 001) related to the product group being measured.

CLINICAL SIGNIFICANCE

Differences in received dose of S-adenosyl methionine between different products were marked and this could have a profound influence on studies that evaluate any variation in absorption of S-adenosyl methionine between different product formulations, the effectiveness of S-adenosyl methionine-based products in clinical cases or when translating the results of studies that have used a specific S-adenosyl methionine product to those produced by a different manufacturer.

Quantification of phenylpropanoids in commercial Echinacea products using TLC with video densitometry as detection technique and ANN for data modelling

INTRODUCTION

Echinacea preparations are among the most popular herbal remedies worldwide. Although it is generally assigned immune enhancement activities, the effectiveness of Echinacea is highly dependent on the Echinacea species, part of the plant used, the age of the plant, its location and the method of extraction.

OBJECTIVE

The aim of this study was to investigate the capacity of an artificial neural network (ANN) to analyse thin-layer chromatography (TLC) chromatograms as fingerprint patterns for quantitative estimation of three phenylpropanoid markers (chicoric acid, chlorogenic acid and echinacoside) in commercial Echinacea products.

MATERIAL AND METHODS

By applying samples with different weight ratios of marker compounds to the system, a database of chromatograms was constructed. One hundred and one signal intensities in each of the TLC chromatograms were correlated to the amounts of applied echinacoside, chlorogenic acid and chicoric acid using an ANN.

RESULTS

The developed ANN correlation was used to quantify the amounts of three marker compounds in Echinacea commercial formulations. The minimum quantifiable level of 63, 154 and 98 ng and the limit of detection of 19, 46 and 29 ng were established for echinacoside, chlorogenic acid and chicoric acid respectively.

CONCLUSION

A novel method for quality control of herbal products, based on TLC separation, high-resolution digital plate imaging and ANN data analysis has been developed. The method proposed can be adopted for routine evaluation of the phytochemical variability in Echinacea formulations available in the market.

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.

Conducting systematic reviews of complementary and alternative medicine: common pitfalls

Systematic reviews (SRs) are considered the best tools for summarizing the evidence for or against the effectiveness of health care interventions. The principles and methods of SRs apply equally to both, mainstream and complementary/alternative medicine (CAM). Certain challenges are, however, more commonly encountered in CAM or even specific to it; this article is aimed at raising awareness of these among systematic reviewers. When searching for literature, specific issues relating to specialist databases, indexing, access, foreign language studies, and certain forms of publication bias need to be considered. Researchers also need to be aware of the difficulties of comparing CAM studies and address the variability between studies. CAM modalities are highly diversified and great variations exist in the standardization of herbal products and other dietary supplements. Individualization of treatment as well as different classifications of disease and different diagnostic methods need to be addressed. Expectation bias is high in CAM, and finding appropriate controls and blinding are often challenging. It is important that these issues are taken into account early on in the planning stages of an SR so that proper consideration can be given to the search strategies, inclusion/exclusion criteria and methods of analysis with the overall aim of reducing bias.

No effect of acute, single dose oral administration of Momordica charantia Linn., on glycemia, energy expenditure and appetite: a pilot study in non-diabetic overweight men

AIM OF THE STUDY

Momordica charantia Linn. Cucurbitaceae (MC), has been used to treat glycemic impairment in humans for centuries. The objective of this study was to determine the acute effect of MC on postprandial glucose levels, energy expenditure/fuel mixture and appetite in overweight men.

MATERIALS AND METHODS

Five healthy overweight men were supplemented on three randomized conditions where (1) no MC (placebo), (2) 50 mg/kg body weight (MC50) or (3) 100 mg/kg body weight of freeze dried MC were administered orally prior to a 75 g oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were measured before and during the OGTT. Energy expenditure as well as carbohydrate and lipid oxidation rates were measured by indirect calorimetry. Visual analogue scales were used to rate appetite profile.

RESULTS

Plasma glucose and insulin levels significantly increased during the OGTT (p < or =0.05) but no significant difference was observed between experimental conditions. Energy expenditure, carbohydrate and lipid oxidation rates as well as appetite profile did not differ between experimental conditions.

CONCLUSIONS

These results suggest that from an acute standpoint, a freeze dried MC extraction in its present dose form does not affect plasma glucose/insulin levels, energy expenditure, substrate mixture and appetite scores following an oral glucose load in non-diabetic overweight men.

Identification of methysticin as a potent and non-toxic NF-kappaB inhibitor from kava, potentially responsible for kava's chemopreventive activity

Nuclear factor-kappaB (NF-kappaB) is a transcription factor that plays an essential role in cancer development. The results of our recent chemopreventive study demonstrate that kava, a beverage in the South Pacific Islands, suppresses NF-kappaB activation in lung adenoma tissues, potentially a mechanism responsible for kava's chemopreventive activity. Methysticin is identified as a potent NF-kappaB inhibitor in kava with minimum toxicity. Other kava constituents, including four kavalactones of similar structures to methysticin, demonstrate minimum activities in inhibiting NF-kappaB.

Beneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to estrogen or androgen content

OBJECTIVE

To examine the estrogenic and androgenic activity of Lepidium meyenii (Maca) and its effect on the hormonal profile and symptoms in postmenopausal women.

DESIGN

Fourteen postmenopausal women completed a randomized, double-blind, placebo-controlled, crossover trial. They received 3.5 g/day of powered Maca for 6 weeks and matching placebo for 6 weeks, in either order, over a total of 12 weeks. At baseline and weeks 6 and 12 blood samples were collected for the measurement of estradiol, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin, and the women completed the Greene Climacteric Scale to assess the severity of menopausal symptoms. In addition, aqueous and methanolic Maca extracts were tested for androgenic and estrogenic activity using a yeast-based hormone-dependent reporter assay.

RESULTS

No differences were seen in serum concentrations of estradiol, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin between baseline, Maca treatment, and placebo (P > 0.05). The Greene Climacteric Scale revealed a significant reduction in scores in the areas of psychological symptoms, including the subscales for anxiety and depression and sexual dysfunction after Maca consumption compared with both baseline and placebo (P < 0.05). These findings did not correlate with androgenic or alpha-estrogenic activity present in the Maca as no physiologically significant activity was observed in yeast-based assays employing up to 4 mg/mL Maca extract (equivalent to 200 mg/mL Maca).

CONCLUSIONS

Preliminary findings show that Lepidium meyenii (Maca) (3.5 g/d) reduces psychological symptoms, including anxiety and depression, and lowers measures of sexual dysfunction in postmenopausal women independent of estrogenic and androgenic activity.

Dietary supplement polypharmacy: an unrecognized public health problem?

Excessive and inappropriate use of medications, or 'polypharmacy', has been recognized as a public health problem. In addition, there is growing use of dietary supplements in the United States; however, little is known about the patterns of supplement use. Recent reports in the literature of cases of excessive or inappropriate use of herbal dietary supplements leading to the term 'polyherbacy'. The clinical vignettes described in this article highlight the need for further research on the nature and extent of multiple and inappropriate dietary supplement use or 'dietary supplement polypharmacy'. Clinical interviewing and population surveys both address this issue in complementary ways, and provide a further understanding of dietary supplement use patterns.

Supplementation With Goldenseal (Hydrastis canadensis), but not Kava Kava (Piper methysticum), Inhibits Human CYP3A Activity In Vivo

The effects of goldenseal (Hydrastis canadensis) and kava kava (Piper methysticum) supplementation on human CYP3A activity were evaluated using midazolam (MDZ) as a phenotypic probe. Sixteen healthy volunteers were randomly assigned to receive either goldenseal or kava kava for 14 days. Each supplementation phase was followed by a 30-day washout period. MDZ (8 mg, per os) was administered before and after each phase, and pharmacokinetic parameters were determined using standard non-compartmental methods. Comparisons of pre- and post-supplementation MDZ pharmacokinetic parameters revealed significant inhibition of CYP3A by goldenseal (AUC(0-infinity), 107.9+/-43.3 vs 175.3+/-74.8 ng x h/ml; Cl/F/kg, 1.26+/-0.59 vs 0.81+/-0.45 l/h/kg; T(1/2), 2.01+/-0.42 vs 3.15+/-1.12 h; Cmax, 50.6+/-26.9 vs 71.2+/-50.5 ng/ml). MDZ disposition was not affected by kava kava supplementation. These findings suggest that significant herb-drug interactions may result from the concomitant ingestion of goldenseal and CYP3A substrates.

The Potency of Immunomodulatory Herbs May Be Primarily Dependent upon Macrophage Activation

Standardized extracts of Echinacea, cat's claw, and saw palmetto were each evaluated for ability to activate macrophage and natural killer cells, in vitro, using two independent measures of activation for each immune cell population. A standard series of exposure concentrations were tested for each herbal extract in a panel of four assays that evaluated macrophage phagocytosis, macrophage synthesis of interleukin-12, natural killer (NK) cell cytocidal activity (synthesis of granzyme B), and NK cell synthesis of interferon-gamma. Macrophage phagocytosis was stimulated by all three herbs tested: saw palmetto (up to 2.3-fold, P < .05), Echinacea (up to 3.6-fold, P < .01), and cat's claw (up to 4.7-fold, P < .01). Additionally, NK cell synthesis of interferon-gamma was stimulated by saw palmetto (up to 6.3-fold, P < .01) and Echinacea (up to 8.1 fold, P < .01) but not by exposure to cat's claw. None of the three herbs stimulated macrophage synthesis of interleukin-12 or NK cell synthesis of granzyme B. Comparison of the in vitro data with our earlier observations that cat's claw and Echinacea (but not saw palmetto) were each effective in reducing B16/F10 lung tumor colony formation in C57BL/6J mice suggests macrophage activation is the primary means by which these herbs modulate the immune system. Thus, macrophage activation (phagocytosis) may provide a potentially higher throughput method to identify herbal extracts with in vivo stimulatory effects.

Fertilization-induced changes in growth parameters and antioxidant activity of medicinal plants used in traditional Arab medicine

In response to increased popularity and greater demand for medicinal plants, a number of conservation groups are recommending that wild medicinal plants be brought into cultivation systems. We collected four medicinal herbs Cichorium pumilum, Eryngium creticum, Pistacia palaestina and Teucrium polium used in traditional Arab medicine for greenhouse cultivation to assess the effects of different fertilization regimes on their growth and antioxidant activity. Wild seedlings were collected and fertilized with either 100% Hoagland solution, 50% Hoagland solution, 20% Hoagland solution or irrigated with tap water. Plant height was measured and the number of green leaves and branches counted weekly. Thereafter, the aboveground parts of plants were harvested for preparing a water-soluble powder extracts of which antioxidant activity was measured by their ability to suppress the oxidation of beta-carotene. Of the fertilization regimes, we found either 20 or 50% Hoagland solution produced the most consistent response of the plant growth parameters. All powders prepared from the four wild growing plants inhibited oxidation of beta-carotene. Increasing the amount of fertilizer caused a significant concentration-dependent increase in antioxidant activity of the cultivated T. polium compared with the wild type. In contrast, increasing the amount of fertilizer caused a significant concentration-dependent reduction in the antioxidant activity of powders prepared from the cultivated E. creticum when compared with wild plants. Our results showed that cultivation success should not rely solely on parameters of growth but should incorporate assessment related to indices of therapeutic potential.