What herbal tea is good for allergies
P-glycoprotein, verapamil, digoxin, ginkgo biloba, eucommia ulmoides, houttuynia cordata, rubus suavissimus S. Lee
Q—I own arthritis, so a friend of mine bought me a book on herbal remedies that claim they can relieve my swollen joints. When I asked my doctor about using the herbs, he said not to, that I could poison myself. What do you think? I thought every natural products and herbs were excellent for you.
A—Natural is not necessarily safe. Herbal preparations or even overuse of vitamins amounts to self-medication, and the results can be disastrous.
Additionally, numerous people attempt to cure serious health problems with
herbal preparations that may not work, and thus they delay seeking medical assist for a serious but treatable condition that can be helped if caught in time.
Herbal remedies to relieve arthritis may indeed contain substances to relieve inflammation.
These natural concoctions may also contain dangerous steroids and other contaminants, including mercury, arsenic, camphor, lead and carcinogens.
There has been a surge recently in the marketing of herbal teas and other »natural products» for self-medication.
Ginseng is now used in teas, sodas, even candies and is regarded as useful in treating several health problems.
Unfortunately, ginseng can affect glucose metabolism, elevate blood pressure and produce an estrogen effect.
Those who overmedicate themselves with ginseng can suffer with diarrhea, nervousness, insomnia and increased motor and cognitive activity. Most of these symptoms will vanish when ginseng is discontinued.
Chamomile tea is extremely favorite too. It`s touted as soothing, calming and excellent to drink before going to bed.
Many people, however, are allergic to this tea and don`t realize it is the cause of their flare-up of allergies.
A single cup of chamomile tea can cause an outbreak of hives and respiratory troubles.
Chamomile is in the same family as ragweed, aster and chrysanthemum, and anyone who knows they are allergic to pollens from those plants should stay away from chamomile tea.
Bee pollen is another natural product that has caused allergic reactions in numerous people. Vitamin companies are marketing bee pollen as a product that enhances athletic performance. This has not been substantiated. Other herbal teas are said to work as natural laxatives, but the package directions don`t tell how numerous cups to drink and how much would be too much.
In large doses, laxative teas containing senna and goldenseal may produce hypotension, respiratory depression and seizures.
Fortunately, most of the health problems caused by herbal remedies can be relieved by simply refraining from using the concoction. Sometimes, however, a substance must be taken to clear your system of the toxic substance.
Clearly, your best bet is to consider an herbal remedy a type of medicine and, as you did, enquire your doctor before taking it.
Now, I am certain numerous of you will feel that I am merely taking the usual
»medical» line with this response, for numerous of you may own had a excellent result with a given preparation or herb.
But when the situation is looked at from the point of view of dependable proof or valid statistics, the conclusions are less positive.
I must therefore advise on the basis of research I own confidence in and feel is reliable.
Herbal teas such as those made from Houttuynia cordata own been consumed for generations for health promotion. Herbal teas contain numerous ingredients, and there is concern that herbal teas can affect the pharmacokinetics of drugs. In this study we examined the effect of herbal teas on drug permeability. We used the human colon carcinoma cell line Caco-2 as a model to study the permeability of two drugs across the intestinal cell membrane.
We quantified of the quantity of digoxin and verapamil passed from apical to basal membranes of Caco-2 cells with and without extracts (1 mg/mL or 10 mg/mL) of four diverse teas (Rubus suavissimus S. Lee, Ginkgo biloba, Houttuynia cordata, and Eucommia ulmoides). These extracts were made with boiling water and dried. For our experiments, the dried extracts were resuspended in water. Our results showed that extracts from Rubus suavissimus S.
Lee, Houttuynia cordata, and Eucommia ulmoides at a concentration of 1 mg/mL or 10 mg/mL did not affect digoxin permeability from apical to basal membranes of Caco-2 cells. However, an extract from Ginkgo biloba at a concentration of 10 mg/mL significantly increased permeability of digoxin and verapamil. Though this concentration is higher than that of typical tea preparations, Ginkgo biloba extract may exert this effect by inhibiting drug export P-glycoprotein (P-gp) since both digoxin and verapamil are known to be transported by P-gp.
Findings regarding interactions between functional foods and medicines will be dependent on each medicine.
For example, approximately 40 functional foods modulate the effects of warfarin . However, the information available regarding interactions between functional foods and medicines is limited . To our knowledge, medical manuals rarely mention foods that can interact with medicines, other than the well-documented examples of grapefruit juice (GFJ) [15,16] and St.
John's wort (Hypericum perforatum.) . Among four kinds of teas used in this study, only Ginkgo biloba has been reported to interact with medicines .
The concentrations of extracts for normal drinking is mg/mL, thus the effective concentration of extracts used in this study, 10 mg/mL (Figure 1), is times higher than the concentration of extracts consumed in normal tea drinking. Eucommia ulmoides, Houttuynia cordata, and Rubus suavissimus S.
Lee did not significantly affect the levels of digoxin transport from apical to basal membranes (Figure 1B, C, D). Therefore, our results show that consumption of herbal tea prepared in normal concentrations should not affect the transport of drugs by P-gp.
In contrast, Ginkgo biloba extract increased digoxin permeability from the apical to basal membrane in a dose-dependent manner (Figure 1A). Ginkgo biloba extract also increased verapamil permeability (Figure 2). Thus, Ginkgo biloba extract may exert this effect by inhibiting export by P-gp on the apical side.
These results are in accord with those of Wang et al. , who showed that flavonoids in Ginkgo biloba inhibited the function of P-gp . The effect of Ginkgo biloba extract on P-gp may be negligible, because the effective concentration (10 mg/mL) is greater than the concentration ( mg/mL) of typical tea preparations.
Inhibition and induction of the metabolic enzyme CYP can also affect the pharmacokinetics of treatment with these medications.
This should be of concern since CYP3A4 is associated with the metabolism of numerous drugs. It is well known that there is overlap in the substrate specificities of CYP3A4 and P-gp . Thus, substrates of P-gp might significantly affect pharmacokinetics. GFJ affects the function of CYP3A4 and P-gp . In addition, catechins in green tea (Camellia sinensis) affect the function of CYP3A4 and P-gp in vitro . Moreover, it has been reported that an extract of Ginkgo biloba inhibited the function of CYP3A4 and P-gp [19, 22].
However, a clinical study in Korea has shown that pharmacokinetics of cilostazol was not affected significantly when used with Ginkgo biloba . In addition, herbs are used as alternative medicine in % of patients treated for cancer in Germany, and it has been evaluated that Ginkgo biloba can be used with drugs safely . Thus, the foods that contain ingredients that can inhibit metabolic enzymes and/or drug transport proteins in vitro may not affect pharmacokinetics.
It is necessary to examine the effects of the chronic intake of functional foods, even if single consumption does not affect pharmacokinetic parameters.
For example, dietary supplement ingredients to rats for four weeks affected the maximum concentration in blood digoxin levels (Cmax) and the area under the blood concentration-time curve (area under the curve, AUC) . It has been reported that chronic exposure of cancer cells to kaempferol significantly increased glutathione S-transferase activity and reduced the effect of anticancer agents, although this was an in vitro study .
In conclusion, since the concentrations of tea extracts (10 mg/mL) used in this study were times higher than the concentration for normal drinking, the effects of these four teas on the absorption of drugs can be disregarded.
However, it is still significant to examine the effects of chronic intake of herbal teas on both pharmacokinetics and effects of drugs in vivo.
Materials and methods
Cultures of the human colon carcinoma cell line Caco-2 were obtained from ATCC (Manassas, VA, USA) and were maintained in DMEM supplemented with 10% FBS, units/mL penicillin, and μg/mL streptomycin at 37°C under 5% CO2. To form a monolayer of CaCo-2 cells, 1 × 105 cells were plated into well Transwell plates with pore size of µm (Corning, Corning, NY, USA) for 21 days at 37°C under 5% CO2. The culture medium was changed every days.
Digoxin and verapamil were obtained from SIGMA-ALDRICH (St.
Louis, MO, USA) and Wako (Osaka, Japan), respectively. Dried products ( g) in tea Ginkgo biloba (Kenko Foods, Yokohama, Japan), Eucommia ulmoides (Kobayashi Pharmaceuticals, Osaka, Japan), Houttuynia cordata (Honzo, Nagoya, Japan), or Rubus suavissimus S. Lee (Honzo, Nagoya, Japan) were extracted by incubation with mL of boiling water at °C for 5 min.
The extracts were vacuum-concentrated to a volume of 20 mL, and 1 mL of each vacuum-concentrated solution was evaporated to dryness. The evaporation residue was weighed to calculate the concentrations of extracts of herbal teas. The vacuum-concentrated extracts of each herbal tea was prepared to be 1 mg/mL or 10 mg/mL in Hanks’ balanced salt solution containing 10 mM HEPES (pH ) (Figs. 1, 2).
Quantifications of digoxin and verapamil
Digoxin (final conc. 2 µM) or verapamil (final conc. 20 µM) was added to the apical chamber in the absence or presence of herbal tea extract. After 2 h, 1 mL of the medium from the basal chamber was collected.
mL of mM phosphate buffer (pH ) and 1 mL of an ethyl acetate/hexane/dichloromethane (, v/v) mixture were added. After 10 minutes of shaking, samples were centrifuged (10, × g, 4°C, 10 minutes). A volume of mL of the upper organic layer was transferred to a tube and evaporated to dryness under airflow at 40°C.
The evaporated residues were dissolved in µL of water/ CH3CN (, v/v) mixture and used as samples for HPLC quantification.
Digoxin (Figure 1) was quantified by HPLC (Shimazu, SPD-M20A) with a mm × φ mm, 3 μm ODS column (Unison UK-C18, Imtakt) with a flow rate of mL/min using water/CH3CN (); absorbance at nm was monitored. Verapamil (Figure 2) was quantified by HPLC with a flow rate of mL/min using mM AcONH4/CH3CN (); absorbance at nm was monitored.
Figure 1. Effect of herbal tea extracts on digoxin permeability. Values are mean ± S.E. n = 4 for each treatment.
Significant difference (*: p < vs control, Williams’ test)
Results of multiple observations are presented as means ± SEM. One-way analysis of variance (ANOVA) followed by the Williams’ test was used for multiple comparisons. p < was considered significant.
In developed countries, the incidence of lifestyle diseases has risen.
Increasing interest in health promotion is reflected in rising sales of functional foods and supplements. The global market for vitamin and mineral supplements and functional foods was estimated in to be worth approximately USD billion . Although the majority of supplement sales were those of vitamins and minerals, a large proportion are functional supplements containing herbs. Herbal teas own been consumed traditionally for protection against disease.
The efficacy and effectiveness of ingredients of the herbal teas own been extensively studied, and the effectiveness of herbal teas on hypertension , inflammation [3,4], allergies , and improvements of brain activity  has been documented.
Use of herbal teas for the general purpose of health maintenance does not seem to pose health risks, but concern has arisen regarding potential drug interactions with consumption of herbal teas .
It has been reported that more than 80% of patients take some helpful of supplements, with half of those taking supplements other than vitamins and minerals . Potential interactions between supplements and drugs own not been adequately studied .
Herbal teas contain medicinal compounds that could interact with other medicines. For example, some herbal medicines contain furanocoumarin that inhibits P-glycoprotein (P-gp), which exports drugs from cells. Furanocoumarin also inhibits cytochrome P (CYP) 3A4, a metabolic enzyme.
Furanocoumarin affects the pharmacokinetics parameter of P-gp substrate drugs . It has been shown that licorice root, commonly used as a sweetener, also inhibits P-gp [11,12].
In this study, we investigated the effects of extracts of Ginkgo bioba. Eucommia ulmoides, Houttuynia cordata, and Rubus suavissimus S. Lee on the permeability of the drugs digoxin and verapamil using the human colon carcinoma cell line Caco-2 as a model of intestinal absorption of drugs.
We evaluated the effects of extracts of herbal teas on drug permeability using Caco-2 cell monolayers from the intestinal tract. We examined the effects of each tea on the transport by P-gp by measuring the quantity of digoxin and verapamil that crossed the treated monolayer.
First, we examined the effects of herbal tea extracts on digoxin permeability from the apical side to the basal side of the Caco-2 cell monolayer.
The concentration of each concentrated extract was as follows: Ginkgo biloba, 90 mg/mL; Eucommia ulmoides, 30 mg/mL; Houttuynia cordata, 50 mg/mL; Rubus suavissimus S. Lee, 50 mg/mL. Digoxin ( nmol) alone or in combination with 1 mg/mL or 10 mg/mL of the Ginkgo biloba, Eucommia ulmoides, Houttuynia cordata, or Rubus suavissimus S. extracts was added to the buffer on the apical side.
The quantity of digoxin transported to the basal side was quantified (Figure 1): digoxin alone, nmol (%); digoxin with 1 mg/mL of an extract of Ginkgo biloba, nmol (%); digoxin with 10 mg/mL of an extract of Ginkgo biloba, nmol (%) (Figure 1A). Thus Ginkgo biloba increased digoxin permeability in a dose-dependent manner. However, the other three kinds of teas did not significantly affect digoxin transport (Figure 1B, C, D).
We also investigated the effect of Ginkgo biloba extract on verapamil transport. Verapamil (10 nmol) alone or in combination with 1 mg/mL or 10 mg/mL of Ginkgo biloba extract was added to the buffer solution on the apical side, and then the quantity of verapamil transported to the basal side was quantified (Figure 2).
The quantities of verapamil in the basal side were as follows: verapamil alone, nmol (%); verapamil with 1 mg/mL of Ginkgo biloba extract, nmol (%); verapamil with 10 mg/mL of Ginkgo biloba extract, nmol (%). Verapamil transport was significantly increased in the presence of 10 mg/mL of Ginkgo biloba extract.
Figure 2. Effect of Ginkgo biloba extract on verapamil permeability. Values are mean ± S.E. n = 3 for each treatment. Significant difference (*: p < vs control, Williams’ test)