Two different chemical compounds, related closely to one another.  Regulation of the one has virtually NOTHING to do with regulation of the other, actually-- and the two legislative streams leading to that regulation come from very different places, which our guest has conflated above.  Briefly:


pseudoephedrine-- the active ingredient in (former) formulations of Sudafed, also a handy precursor which is just one good chemical reduction away in the synthesis of methamphetamine, which is why it is tightly controlled in some states (including mine, where it is now prescription-only)

ephedrine-- a natural product that was regulated (basically pulled from the market, actually) because of growing concern about it's connection with heat-stress deaths and cardiac events leading to deaths. 

Neither is an antihistamine per se.  The former is an alpha-adrenergic agonist with good bioavailability but mostly decongestant activity.

Both are classified as sympathomimetic amines, meaning that if anything, they can mimic some of the actions of epinephrine (ephedrine considerably more potent in its action there than pseudoephedrine, btw, and both FAR, FAR less so than other biogenic amines like dopamine, norepinephrine, or epinephrine itself-- I mention that because I seriously do NOT want this post to be interpreted as ma huang being a substitute for epinephrine-- it is not.).

Both increase blood pressure, and have bronchodilatory effects.  These effects are FAR more marked with ephedrine than pseudoephedrine.

Not the same compound-- though now that I've said that, take a look at the chemical structures below-- they are REALLY similar, so it's a natural mistake to think that they ARE the same if you aren't a chemist or pharmacologist by training and know that chirality at the carbon centers here can make for all of the activity.  BUT-- not antihistamine, either one of them.






If you're curious to know just HOW much like epinephrine they are, take a look at all three side-by-side in the bottom row here:
[spoiler]
[/spoiler]

And now, our old friend diphenhydramine (benadryl) which IS an antihistamine:

(Sorry-- large image again) [spoiler][/spoiler]

Quote from: CMdeux on April 27, 2013, 04:42:06 PM
There are materials that contain naturally occurring analogs of known drugs which impact second messengers in the allergic cascade, or affect the systems impacted.

Ephedrine, for example, is a very useful bronchodilator.  Unfortunately, it is also an herbal remedy that comes with some hefty side effects, including risks so significant that it is no longer legal in the US.

Herbals are NOT regulated like drugs.  But here's the problem... if they are effective, then they ARE, in a functional sense... in every sense, actually-- drugs.  They just happened to be packaged with a lot of UNKNOWN inactive ingredients.   

General points well-taken, but ephedrine is only illegal in diet / appetite control drugs.

Regulation of ephedrine (Sudafed, etc.) owes to the use of ephedrine in the manufacture of methamphetamines, not anything inherent to the ingredient's effect on people's health. (And may I say that is intensely annoying.)

I have had naturopaths recommend some of those things for my formerly quite severe seasonal allergies.  None of it made a dent in my constant sneezing.  Also, I used to high dose vit c all the time.  I also eat a ton of veggies and fruit and none of that seemed to help.  You know what helped?  In the past I lived in a very polluted place where there were very few trees and hardly any grass.  My allergies vanished!  lol!  I think it is possible some of those things might help some people who have the most extremely mild of symptoms but maybe they don't.  I haven't ever found anything natural that helped other than the neti pot, air cleaner, allergy-proof covers on pillows, mattresses, getting rid of allergenic pets, hard wood floors, no drapery, get rid of dust catchers, etc. 

It's interesting, I'll say that for it.

But there are some concerning misconceptions/scientifically inaccurate statements in the piece that make me think that much of the advice therein is probably of questionable value.  It reads as though it was written by someone with a painfully spotty understanding of biochemistry and pharmacology, for starters. 

Bioavailability is notoriously low for MANY of the compounds noted, and for any biological activity, concentrations must be high.  Ergo... the food isn't a reasonable source of a biologically active compound.


Vitamin C (ascorbate) is not an "antihistamine" to the best of my knowledge.  If it were, then why do I not need less Zyrtec when I vitamin-C load for other reasons?  Chemically, if anything, ascorbates should prevent the oxidation of histamine, therefore PROMOTING extended allergic reactions... though there are far better agents for maintaining a reducing atmosphere, if one were trying to do so.    Not that I think that will work outside of in vitro studies, either, fwiw.   


There are materials that contain naturally occurring analogs of known drugs which impact second messengers in the allergic cascade, or affect the systems impacted.

Ephedrine, for example, is a very useful bronchodilator.  Unfortunately, it is also an herbal remedy that comes with some hefty side effects, including risks so significant that it is no longer legal in the US.

Herbals are NOT regulated like drugs.  But here's the problem... if they are effective, then they ARE, in a functional sense... in every sense, actually-- drugs.  They just happened to be packaged with a lot of UNKNOWN inactive ingredients.   

Needless to say if you are allergic to any of these foods, stay away from them.

I just found it interesting:

http://www.buzzle.com/articles/natural-antihistamine.html

Nutrients and Herbs with Antihistamine Properties

Natural antihistamines not only relieve the symptoms of an allergy, but can also reduce the frequency of future episodes of allergies by strengthening the immune system. A few nutrients with great antihistamine properties are mentioned below.

Vitamin C

The most important nutrients that have been found to possess strong antihistamine properties are in vitamin C. It is a well-known antioxidant that fights against the free radicals, boosts the immune system, and relieves the symptoms of allergies. It is also believed to reduce the sensitivity to particular allergens, so as to manage allergic conditions in the future. That's why it can be termed as one of the best antihistamines available. A few of the best vitamin C-enriched foods are:
Bananas
Pineapples
Papayas
Strawberries
Gooseberries
Guavas
Cantaloupe
Kiwifruit
Oranges and clementines
Kohlrabi
Bell peppers
Red and green chili peppers
Herbs (parsley and thyme)
Broccoli
Brussels sprouts
Cauliflower
Mustard greens
Kale
Garden cress
Though pineapple, banana, citrus fruits, strawberry, papaya, and kiwi fruit, are good sources of vitamin C, which has antihistamine properties, these foods are also known to stimulate the production of histamine by the mast cells. Some individuals can also be allergic to pineapple, which however, is not a very common food allergy.

Basically, every individual reacts in a unique way to excess histamine in the body and foods that trigger its production. Some individuals may be able to eat pineapple and papaya safely, while others may experience an adverse reaction. So, if you have any type of allergy or histamine intolerance, you will have to find out your own trigger foods and then reduce or avoid their consumption.

Another vitamin that can help control allergic reactions is vitamin A. Our body can prepare vitamin A from the plant pigment carotenoids, which have strong antioxidant properties. Carotenoids can be widely found in mangoes, carrots, sweet potatoes, papayas, and bell peppers.

Omega-3 Fatty Acids

Omega-3 fatty acids are also very helpful in reducing various allergic reactions. They are known for their anti-inflammatory properties, and are found in the following food items:
Salmon (cold water fish)
Flaxseed oil
Canola oil
Grass-fed meat
Hemp seeds
Flavonoids

Quercetin and pycnogenol are flavonoids that impart the rich colors to certain flowers, fruits and vegetables. Both quercetin and pycnogenol can inhibit the release of histamine by the mast cells, and hence, control flare ups. Quercetin can be found in red wine, broccoli, capsicum, berries, red onions, garlic, tea, and red apples. On the other hand, pycnogenol is largely extracted from the bark of the French maritime pine. Apart from being natural antihistamines, both quercetin and pycnogenol are powerful antioxidants.

Apart from these vitamins and nutrients, an enzyme, known as bromelain has anti-inflammatory properties, and can facilitate the proper absorption of quercetin and pycnogenol. Bromelain enzyme can be found in pineapple. Minerals that work as natural antihistamines are magnesium citrate, calcium citrate, and selenium. Another antihistamine is L-histidine, which is an amino acid that can inhibit over-secretion of histamine.

Herbs

For a long time, herbs have been known to cure a number of ailments, and some of them can prove quite beneficial for allergies too. They are enriched with compounds that can prevent or lower the secretion of histamine. For instance, green tea contains the compounds quercetin and catechin, that possess antihistamine properties. Similarly, herbs like basil, fennel, echinacea, reishi, chamomile, Ginkgo biloba, spirulina, ginger, garlic, butterbur, and licorice root, can also be used as natural remedies for allergies.

These natural antihistamines can not only reduce the severity of allergy, but can manage the condition in the long run too. Therefore, including the foods that possess antihistamine properties in the daily diet can prove quite effective to reduce the frequency of flare-ups in the future. As far as herbs are concerned, avoid their excessive use, or consult a herbalist or health care professional to know more about their appropriate dosage. Some herbs and foods can produce adverse effects in certain medical conditions, and also if they are taken along with some medications. Be sure to consult your physician before taking any herb or food for therapeutic purposes.


http://www.livestrong.com/article/134112-foods-that-act-as-antihistamine/Flavanoids

Flavanoids
Colorful fruits and vegetables such as blueberries, strawberries, tomatoes, sweet potatoes and bell peppers are rich in flavanoids, says Buzzle.com. These flavanoids act like antihistamines and also contain carotenes, which promote anti-inflammatory activity. According to McVitamins.com, garlic and onions act in the same way to "retard the inflammatory reactions of allergies."


Vitamin A

Fruits and vegetables are also full of vitamin A, which can help control allergic reactions. This is found most potently in spinach, mangoes, carrots, tomatoes and green leafy vegetables. Eat fruits and vegetables as fresh and as raw as possible for the best results.


Bromelain

According to Buzzle.com, pineapple is one of the best natural antihistamines as it contains an enzyme called bromelain, "which has anti-inflammatory properties, and can facilitate proper absorption of quercetin and pycnogenol."