Cytokine production in leukocyte cultures during therapy with Echinacea extract

Eupatorium perfoliatum L.: phytochemistry, traditional use and current applications

ETHNOPHARMACOLOGICAL RELEVANCE

Eupatorium perfoliatum L. originates from North America, where it has been widely used since centuries by native Indians. Additionally extracts are used also in Europe as immunostimulating agent for treatment of fever and cold. The following review summarizes published data on phytochemistry, ethnopharmacological use, as well as clinical and preclinical data.

MATERIALS AND METHODS

Literature survey was performed via SciFinder(®) on papers and patents and by systematic research in ethnopharmacological literature at various university libraries.

RESULTS

The phytochemical composition of Eupatorium perfoliatum is described in detail for volatile oil, caffeic acid derivatives, flavonoids, sesquiterpene lactones, tannins, polysaccharides. Methods for analytical quality control, as well as specification for relevant lead structures can be deduced from published batch analysis. Preclinical studies indicate anti-inflammatory effects of ethanolic extracts, which can be correlated on a molecular level to eupafolin and sesquiterpen lactones. Antiplasmodial, antioxidative and immunomodulating activities are additionally discussed. Clinical data on the use of Eupatorium perfoliatum do not meet modern GCP requirements, but do indicate positive tendencies for use of ethanolic extracts for treatment of common colds.

CONCLUSION

While the postulated immunostimulating properties of Eupatorium perfoliatum have not been confirmed by in vitro data, animal-studies and in vitro experiments with plant extracts both indicate antiinflammatory effects beside antiplasmodial effect against Plasmodium falciparum. Such an antiinflammation caused by the ethanolic extracts can be correlated well with clinical symptoms related to diseases as common cold, rheumatism, athritis etc. These data also support the plausibility of the plant's traditional use by the North American indigenous population and early European settlers. In principle quality aspects of the herbal material have to be affirmed by establishing modern pharmacopoeial control methods to guarantee constant and reliable quality.

Caffeic acid derivatives from Eupatorium perfoliatum L

From the ethyl acetate soluble fraction of a methanol/water extract of the herb Eupatorium perfoliatum L. (Asteraceae) six caffeic acid derivatives have been isolated and identified by 1D- and 2D-NMR spectroscopic data. Besides the common quinic acid derivatives 5-caffeoylquinic acid (chlorogenic acid), 3-caffeoylquinic acid (neochlorogenic acid) and 3,5-dicaffeoylquinic acid, three up to now unknown depsides of caffeic acid with glucaric acid have been isolated: 2,5-dicaffeoylglucaric acid, 3,4-dicaffeoylglucaric acid, and 2,4- or 3,5-dicaffeoylglucaric acid.

Herbal products: active constituents, modes of action and quality control

An overview is given of the current position of medicinal herbs in general in relation to usage, market and production, types of pharmacological activity and how they differ from conventional drugs. The increasing importance of quality and manufactured products is also discussed. A more detailed consideration of these issues is given in relation to echinacea, valerian and St John's wort as these herbs are well studied, are market leaders and have widespread community usage.

Cytokine- and interferon-modulating properties of Echinacea spp. root tinctures stored at -20 degrees C for 2 years

Echinacea spp. phytomedicines are popular for treating upper respiratory infections. The purpose of this investigation was to examine the immunomodulatory properties of Echinacea tinctures from seven species after being stored at -20 degrees C for 2 years. Two experimental techniques were employed using human peripheral blood mononuclear cells (PBMC). In the first set of experiments, PBMCs were stimulated in vitro with tinctures alone and assayed for proliferation and production of interleukin-10 (IL-10), IL-12, and tumor necrosis factor-alpha (TNF-alpha). In the second set of experiments, subjects were immunized with influenza vaccine. PBMCs from vaccinated individuals were stimulated in vitro with Echinacea tinctures and influenza virus; cytokine production (IL-2, IL-10, and interferon-gamma [IFN-gamma]) was compared prevaccination and postvaccination. In the first experiments, (1) tinctures from E. angustifolia, E. pallida, E. paradoxa, and E. tennesseensis stimulated proliferation and tended to increase IL-10, (2) E. sanguinea and E. simulata stimulated only proliferation, (3) E. purpurea stimulated only IL-10, and (4) none of the extracts influenced IL-12 or TNF-alpha. In the second experiments, (1) tinctures from E. pallida, E. paradoxa, E. sanguinea, and E. simulata diminished influenza-specific IL-2, and (2) none of the extracts influenced influenza-specific IL-10 or IFN-gamma. For in vitro models using Echinacea, immune response may vary based on stimulus (Echinacea alone vs. Echinacea + recall stimulation with virus).

Dietary supplements in patients with cancer: Risks and key concepts, part 2

PURPOSE

The risks and key concepts regarding the use of dietary supplements in patients with cancer are described.

SUMMARY

There are six common characteristics of dietary supplements that must be addressed when used by patients with cancer. Clinicians must establish if the supplement is an antioxidant, is an anticoagulant or procoagulant, has immunosuppressive or immunomodulating properties, has hormonal properties, has known safety issues, and has known or theoretical drug interactions. These six characteristics of the dietary supplements commonly used by patients with cancer are reviewed to aid in the analysis of the scientific data and communication of the results with the patient or family members. A framework upon which clinicians can adequately help patients make informed decisions regarding the use of complimentary and alternative medicine and dietary supplements is also described. When evaluating the appropriateness of a supplement for use by a patient with cancer, clinicians must conduct a safety review (evaluate the six characteristics). If the supplement is considered safe, an efficacy review must be conducted, after which the clinicians can recommend the supplement's use, accept the patient's decision to use the supplement if no or inconclusive evidence exists, or discourage use if there is conclusive evidence supporting inefficacy. Available resources for locating information regarding dietary supplements are also discussed.

CONCLUSION

Counseling patients with cancer about dietary supplements requires a systematic thought process that considers the available theories and data, as well as the patients' views about the agents.

Echinacea species (Echinacea angustifolia (DC.) Hell., Echinacea pallida (Nutt.) Nutt.,Echinacea purpurea (L.) Moench): a review of their chemistry, pharmacology and clinical properties

This paper reviews the chemistry, pharmacology and clinical properties of Echinacea species used medicinally. The Echinacea species Echinacea angustifolia, Echinacea pallida and Echinacea purpurea have a long history of medicinal use for a variety of conditions, particularly infections, and today echinacea products are among the best-selling herbal preparations in several developed countries. Modern interest in echinacea is focused on its immunomodulatory effects, particularly in the prevention and treatment of upper respiratory tract infections. The chemistry of Echinacea species is well documented, and several groups of constituents, including alkamides and caffeic acid derivatives, are considered important for activity. There are, however, differences in the constituent profile of the three species. Commercial echinacea samples and marketed echinacea products may contain one or more of the three species, and analysis of samples of raw material and products has shown that some do not meet recognized standards for pharmaceutical quality. Evidence from preclinical studies supports some of the traditional and modern uses for echinacea, particularly the reputed immunostimulant (or immunomodulatory) properties. Several, but not all, clinical trials of echinacea preparations have reported effects superior to those of placebo in the prevention and treatment of upper respiratory tract infections. However, evidence of efficacy is not definitive as studies have included different patient groups and tested various different preparations and dosage regimens of echinacea. On the basis of the available limited safety data, echinacea appears to be well tolerated. However, further investigation and surveillance are required to establish the safety profiles of different echinacea preparations. Safety issues include the possibility of allergic reactions, the use of echinacea by patients with autoimmune diseases and the potential for echinacea preparations to interact with conventional medicines.

Changes in immunomodulatory properties of Echinacea spp. root infusions and tinctures stored at 4 degrees C for four days

BACKGROUND

Phytomedicinal preparations from members of the genus Echinacea are popular worldwide and frequently used to treat upper respiratory infections. With the increasing popularity of herbal medicines, many people are making their own Echinacea extracts at home and storing them at refrigerator (4 degrees C) temperatures. We tested the hypothesis that Echinacea extracts made using homemade methods change in immunomodulatory efficacy with storage at 4 degrees C over a 4-day period.

METHODS

Three extract types (50% ethanol tincture, cold water infusion, hot water infusion) from 5 different species (Echinacea angustifolia, E. pallida, E. purpurea, E. sanguinea, E. tennesseensis) were prepared. Four in vitro immune assays (monocyte secretion of TNF-alpha, IL-10, and IL-12; and peripheral blood mononuclear cell proliferation) using human blood were used to test extract efficacy at Days 1 and 4 post-extraction. Two statistical analyses, traditional ANOVA and several statistical models that account for endotoxin effects, were used.

RESULTS

Endotoxin was found to significantly impact immune outcomes only in 4-day old cold water infusions and not in all assays. Extracts showed the greatest stimulation in TNF-alpha assays. By extract type, 50% ethanol tinctures produced the most immune stimulation. By species, extracts from E. angustifolia extracts were the most efficacious in our assays; extracts from E. sanguinea showed the least activity overall.

CONCLUSIONS

Taken together, these results suggest that: (1) homemade Echinacea extracts are efficacious in modulating immune cell activity in vitro but that their properties change with time during storage at 4 degrees C; and (2) endotoxin effects from extracts may be important considerations in the analysis of immunobiological data.

Immune system effects of echinacea, ginseng, and astragalus: a review

Traditional herbal medicine provides several remedies for strengthening the body's resistance to illness through effects on immune system components. This review article examines 3 popular herbal immune stimulants that are often of interest to cancer patients. Echinacea, a native of North America, is widely used to prevent, or provide early treatment for, colds. Preclinical studies lend biological plausibility to the idea that echinacea works through immune mechanisms. Numerous clinical trials have been carried out on echinacea preparations: it appears that the extracts shorten the duration and severity of colds and other upper respiratory infections (URIs) when given as soon as symptoms become evident. However, trials of long-term use of echinacea as a preventive have not shown positive results. Ginseng has been studied in some depth as an antifatigue agent, but studies of immune mechanisms have not proceeded so far. Preclinical evidence shows some immune-stimulating activity. There have been several clinical trials in a variety of different diseases. Astragalus is the least-studied agent. There are some preclinical trials that show intriguing immune activity. The herbs discussed appear to have satisfactory safety profiles. Cancer patients may wish to use these botanicals to inhibit tumor growth or to boost resistance to infections. However, passive immunotherapy with herbs, with no mechanism to expose tumor antigens, is unlikely to be effective in inhibiting tumor growth. Although the margin of safety for these herbs is large, more research is needed to demonstrate the clear value of using herbs to improve resistance to infections.

Medicinal properties of Echinacea: a critical review

Preparations from Echinacea purpurea are among the most widely used herbal medicines. Most uses of E. purpurea are based on the reported immunological properties. A series of experiments have demonstrated that E. purpurea extracts do indeed demonstrate significant immunomodulatory activities. Among the many pharmacological properties reported, macrophage activation has been demonstrated most convincingly. Phagocytotic indices and macrophage-derived cytokine concentrations have been shown to be Echinacea-responsive in a variety of assays. Activation of polymorphonuclear leukocytes and natural killer cells has also been reasonably demonstrated. Changes in the numbers and activities of T- and B-cell leukocytes have been reported, but are less certain. Despite this cellular evidence of immunostimulation, pathways leading to enhanced resistance to infectious disease have not been described adequately. Several dozen human experiments--including a number of blind randomized trials--have reported health benefits. The most robust data come from trials testing E. purpurea extracts in the treatment for acute upper respiratory infection. Although suggestive of modest benefit, these trials are limited both in size and in methodological quality. Hence, while there is a great deal of moderately good-quality scientific data regarding E. purpurea, effectiveness in treating illness or in enhancing human health has not yet been proven beyond a reasonable doubt.

The peri-operative implications of herbal medicines

An increasing number of patients are taking herbal medicines such as echinacea, garlic, ginkgo biloba, ginseng, St John's Wort, valerian, ephedra, kava, grapefruit juice and ginger. Although these herbal medications are considered 'natural' products that may have some benefits, adverse effects such as increased bleeding tendencies and drug interactions are associated with their use. Surgeons and anaesthetists may be unaware of their patients' use of these medications because it is common for patients not to disclose their use of this form of medication, and both surgeons and anaesthetists often fail to enquire about their use. Anaesthetists and surgeons must be familiar with the effects of herbal medicines and should specifically enquire about the use of herbal medicines during pre-operative assessment. Currently available data suggest that all herbal medicines should be ceased 2 weeks before surgery.

Echinacea stimulates macrophage function in the lung and spleen of normal rats

Echinacea plant extract has been used for immunostimulation for many years but the evidence supporting its therapeutic potential is still controversial. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of preparations of Echinacea containing its components cichoric acid, polysaccharides and alkylamides in different concentrations. The rats were gavaged orally with these preparations, two times/day for 4 days. Phagocytic activity of alveolar macrophage was increased with increasing concentrations of the Echinacea components. A trend of increase in TNF-alpha and nitric oxide release by the alveolar macrophages following an in vitro stimulation with LPS was also evident. An enhanced release of cytokines (such as TNF-alpha and IFN-gamma) in response to Echinacea components, was also apparent in rat's spleen macrophage, but at higher concentrations. These results suggest that the Echinacea preparations containing optimal concentrations of cichoric acid, polysaccharides and alkylamides are potentially effective in stimulating an in vivo, non-specific immune response in normal rats.

Immunological and haematinic consequences of feeding a standardised Echinacea (Echinacea angustifolia) extract to healthy horses

This study was undertaken to compile new data on the efficacy of Echinacea in stimulating the immune system of the horse. Use of Echinacea is becoming widespread in horses, despite an absence of controlled laboratory research into its effectiveness or safety. This paper documents results of a double-blind, placebo-controlled, cross-over trial investigating the effect of standardised Echinacea extract on 8 horses. Animals were supplemented with Echinacea or placebo for 42 days, and their response to supplements recorded. Treatment with Echinacea increased phagocytic ability of isolated neutrophils, boosted peripheral lymphocyte counts and appeared to stimulate neutrophil migration from peripheral circulation into the tissues. Echinacea supplement also increased the size and concentration of peripheral red blood cells, and the concentration of haemoglobin and packed cell volume. It was concluded that Echinacea effectively stimulates equine immunocompetence, and the plant extract behaves, in equine subjects, as a haematinic agent, i.e. one which improves the quality of blood by increasing haemoglobin levels and the number of erythrocytes and which, by virtue of their effects on oxygen transport cells, are considered to improve parameters of exercise physiology and performance.

Alkylamides of Echinacea purpurea stimulate alveolar macrophage function in normal rats

Echinacea plant extract is widely used for the prevention and the treatment of upper respiratory tract infections. However, the active components in the herb, their optimal dosages and their in vivo effects are still undefined. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of various dose levels of three components, isolated and purified from Echinacea purpurea. The components were cichoric acid, polysaccharides and alkylamides. The rats were gavaged orally two times/day for 4 days with three different concentrations of each of the Echinacea components. Among the components, alkylamides at the dose level of 12 microg/kg body weight/day significantly increased the phagocytic activity as well as phagocytic index of the alveolar macrophages. The alveolar macrophages obtained from this group of rats also produced significantly more TNF-alpha and nitric oxide after an in vitro stimulation with LPS than any other active component or the control. None of the components at any concentration had any effect on the release of TNF-alpha, IFN-gamma and IL-2 by the splenocytes. These results suggest that the alkylamides are one of the active constituents of E. purpurea plant. At a dose level of approximately 12 microg/kg body weight/day they effectively stimulate alveolar macrophage function in healthy rats. The immunomodulatory effects of alkylamides appear to be more pronounced in lungs than in spleen.

Multiple immune functions in rats fed Echinacea extracts

This study evaluated acquired-immune functions representing the three major branches of the immune system in male rats fed a commercially available echinacea product. An additional comparison of effects on antibody formation in male and female rats was done using the commercial echinacea product and two echinacea tinctures marketed by local herbalists. In initial testing, we found no evidence of altered natural killer cell activity, T cell-mediated delayed-type hypersensitivity, or specific antibody formation in male rats given either a 225 mg/kg or 50 mg/kg of the commercial echinacea for 6 weeks. Antibody formation was significantly suppressed in female but not male rats given 250 mg/kg for 2 weeks of the commercial echinacea. The local products tested had no effect on antibody formation. We concluded that our study provided no supporting evidence for immunostimulatory activity by the echinacea preparations we examined and, in fact, may be immunosuppressive under some conditions.

Augmentation of natural killer cell activity in vivo against tumour cells by some wild plants from Jordan

Twelve aqueous extracts prepared from Jordanian plants that are currently used in traditional medicine to treat various types of cancer were tested in mice for their augmentation of natural killer cells in vivo in generating cytotoxicity against YAC tumour targets. After 1 week of oral administration of aqueous extracts of fresh Nigella sativum (N.s.) seeds and Allium sativum (A.s.) bulbs significant augmentation of splenic natural killer (NK) cells (62.3% +/- 6.4% and 52.6% +/-5.4% cytotoxicity, respectively), was obtained in comparison with spontaneous activity (24.5% +/- 1.6%) at 200:1 effector:target ratio. Onopordum acanthium (O.a.) stem and leaves and Allium cepa (A.c.) bulbs showed intermediate augmentation (38.6% +/- 3.8% and 30.6% +/- 3.4% cytotoxicity, respectively) while the rest showed insignificant augmentation activity. The fresh aqueous extract of a mixture of the plants with high and intermediate activity showed little insignificant augmentation activity (72.7% +/- 6.7% cytotoxicity) of NK cells compared with that obtained with each plant alone.

Inflammation and Native American medicine: the role of botanicals

There is a growing interest in medicinal botanicals as part of complementary medicine in the United States. In particular, both physicians and consumers are becoming aware of the use of herbals by Native American societies; many botanicals sold today as dietary supplements in the United States were used by Native Americans for similar purposes. Yet, these supplements represent only a small number of the >2500 different plant species from vascular taxa, and >2800 species from all taxa, known to have been prized for their medicinal properties by the indigenous inhabitants of the North American continent. We review some of the studies of the immunomodulatory activities of botanicals used by native peoples of North America, the bioactive constituents responsible for those activities, and the mechanisms by which these constituents might modulate the immune system. We focus particularly on 3 species of purple coneflower (ECHINACEA:) because of the widespread use of purple coneflower in the United States to boost immunity and prevent upper respiratory infections. Seven of the 10 most common botanicals sold in the United States were used extensively by Native Americans. However, there are very few data to support such use and even less information about drug toxicity or interactions.

Augmentation of natural killer cell activity in vitro against tumor cells by wild plants from Jordan

Thirteen aqueous extracts prepared from Jordanian plants, that are currently used in traditional medicine to treat various types of cancer, were tested in mice for their ability to augment natural killer (NK) cell function in vitro in generating cytotoxicity against YAC tumor targets. Lymphoid cells at a concentration of 5x10(6)/ml were incubated in medium alone or in medium containing different dilutions of either plant extract or purified interferon alpha for 20 h and tested for NK activity. Maximum NK activity (62. 3%) was obtained at 1:50 dilution of Nigella sativum fresh aqueous extract, 48.5% at 1:100 dilution for Allium sativum (and 38.3% at 1:50 dilution for Onopordum acanthium. Fresh aqueous plant extracts appeared to be more potent than old dried aqueous extract or ethanolic extracts. NK augmentation by plant extracts using nylon wool non-adherent spleen cells was slightly higher than the whole spleen cells.

Medicinal herbs: drugs or dietary supplements?

The process of evaluating medicinal herbs is complex, and there is a need to carefully define a research strategy that addresses a solution to safe and efficacious herbal products. Notwithstanding the immense value of distilling the pharmacological activity of an herb into a chemical suitable for drug development, another approach is to develop a standardized herbal extract that yields consistent pharmacological activity. However, it frequently is forgotten that even in an extract several active ingredients contribute to the pharmacological action. Sufficient evidence exists to suggest that extracts of medicinal herbs, once isolated in their pure state, can produce pharmacological effects that differ significantly from that of the whole herb. This article discusses a research-based strategy that may be suitable for validating, in part, the putative health benefits of medicinal herbs. Additionally, the body of scientific evidence that underpins the pharmacological activity of several herbs is reviewed briefly.

Increased production of antigen-specific immunoglobulins G and M following in vivo treatment with the medicinal plants Echinacea angustifolia and Hydrastis canadensis

A number of immunomodulatory effects have been attributed to the medicinal plants Echinacea angustifolia and Goldenseal (Hydrastis canadensis); however, little is known about whether treatment with these plants can enhance antigen-specific immunity. We investigated the antigen-specific in vivo immunomodulatory potential of continuous treatment with Echinacea and Goldenseal root extract over a period of 6 weeks using rats that were injected with the novel antigen keyhole limpet hemocyanin (KLH) and re-exposed to KLH after the initial exposure. Immunoglobulin production was monitored via ELISA continuously over a period of 6 weeks. The Echinacea-treated group showed a significant augmentation of their primary and secondary IgG response to the antigen, whereas the Goldenseal-treated group showed an increase in the primary IgM response during the first 2 weeks of treatment. Our results suggest that medicinal plants like Echinacea or Goldenseal may enhance immune function by increasing antigen-specific immunoglobulin production.

An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid

OBJECTIVE

To analyze the effects of certain herbs on sperm DNA and on the fertilization process.

DESIGN

Prospective comparative study.

SETTING

Clinical and academic research environment.

PATIENT(S)

Donor sperm specimens.

INTERVENTION(S)

Zona-free hamster oocytes were incubated for 1 hour in saw palmetto (Serenoa repens), echinacea purpura, ginkgo biloba, St. John's wort (Hypericum perforatum), or control medium before sperm-oocyte interaction. The DNA of herb-treated sperm was analyzed with denaturing gradient gel electrophoresis.

MAIN OUTCOME MEASURE(S)

Oocyte penetration and integrity of the sperm BRCAI exon 11 gene.

RESULT(S)

Pretreatment of oocytes with 0.6 mg/mL of St. John's wort resulted in zero penetration. A lower concentration (0.06 mg/mL) had no effect. High concentrations of echinacea and ginkgo also resulted in reduced oocyte penetration. Exposure of sperm to echinacea purpura and St. John's wort resulted in DNA denaturation. In contrast, saw palmetto and ginkgo had no effect. Sperm exposed to 0.6 mg/mL of St. John's wort showed mutation of the BRCA1 exon 11 gene.

CONCLUSION(S)

High concentrations of St. John's wort, echinacea, and ginkgo had adverse effects on oocytes. Saw palmetto had no effect. The data suggested that St. John's wort, ginkgo, and echinacea at high concentrations damage reproductive cells. St. John's wort was mutagenic to sperm cells.

Inhibition of human sperm motility by specific herbs used in alternative medicine

PURPOSE

Our purpose was to analyze sperm motility parameters in the presence of herbs.

METHODS

Washed sperm were incubated in either saw-palmetto (Serenoa repens, Permixon Sabal serrulatum), echinacea purpura, ginkgo biloba, St. John's wort (Hypericum perforatum), or control medium. Parameters were measured on a Hamilton-Thorn analyzer after 1, 4, 24, and 48 hr at 37 degrees C.

RESULTS

Sperm motility was inhibited at the high concentration (0.6 mg/mL) of St. John's wort. Curvilinear velocities and beat cross frequencies also decreased, but not hyperactivation. High-concentration saw-palmetto, echinacea, or gikgo inhibited motility at 24 and 48 hr.

CONCLUSIONS

A potent inhibition of sperm motility was seen in St. John's wort unrelated to changes in pH. Furthermore, sperm viability was compromised in St. John's wort, suggesting a spermicidal effect. Metabolic changes were observed in saw-palmetto-treated sperm. High-concentration echinacea purpura interfered with sperm enzymes. Ginkgo did not have an antioxidant effect on sperm motility.