Quercetin as a potential anti-allergic drug: which perspectives?

[forvictoria]

http://www.ncbi.nlm.nih.gov/pubmed/21625024
Abstract

Flavonoids polyphenolic compounds that exert many anti-inflammatory and anti-microbial effects, and exhibit an anti-allergic action. Quercetin is a flavonoids that recently has raised many issues and shown evidence about its action as a potential drug to allergy. A Chinese herbal formula, known as Food Allergy Herbal Formula (FAHF) has been related with blocking of anaphylaxis to peanuts (PNA) in mouse models. Quercetin appears to possess the same potential of FAHF as a safe anti-allergic substance but it opens only a wide perspective, at the moment, due to several complex issues that hamper the possibility to use natural medicine and phytochemicals as true drugs.

http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/dietandnutrition/quercetin

Description

Quercetin is a type of plant-based chemical, or phytochemical, known as a flavonoid (see also Phytochemicals). Good sources include apples, onions, teas, red wines, and many other foods. Quercetin is also available as a dietary supplement.

How is it promoted for use?

Quercetin is said to have a number of uses, but most of these are based on early findings from laboratory studies. Some early studies have suggested quercetin has antihistamine properties, and it is often promoted to help control allergies and asthma. Some proponents claim it can help stabilize small blood vessels and may help protect against heart attacks and strokes.

[twinturbo]

I'll let CMdeux handle the pharmacology stuff--no, I'm counting on her and others to fact check on it, the beautiful bonus of community review.

However, on pharmacognosy, the TCM branch is where I live and breath to sort the voodoo from the clinical value. There is some legitimate benefit to follow up on FAHF-2 in that it most likely a symptom controller putting properly into perspective that symptom control does nothing to cure allergic disease, nor stop the allergic march, nor prevent further sensitization or re-sensitization. The clinical evidence thus far only shows symptom control and I would expect that if it had the effect further up the chain on mechanism we'd have heard some evidence of that by now.

So that's brings us to anti-allergic, whatever that would mean. To me that means root level mechanism otherwise we're still talking late symptom control.

Now, where did I get this information and how do I come by my burden of proof? Well, aside from being an established patient of Dr. Li in her offsite clinic through Mt. Sinai, my husband and I have further followed the most up to date Pan-Asian and Australasian allergy congress in Asia, it was held in Taiwan in November 2013 called APCAACI 2013 to be specific. In attendence were representatives in immunology and allergy research from Taiwan (not insignificant contribution - Xolair/anti-IgE), Hong Kong, Singapore, Korea, Japan, mainland China, Switzerland, Germany, Canada and United States. But there were PLENTY of Chinese researchers representing respective populations there. Which means there was plenty of research on populations where TCM is used.

Not a single presentation was on FAHF-2. For the entire 3-4 day congress no presentations on TCM were made. At least three of the individual researchers/clinicians were also attendees of Dr. Li's 2010 East-West Symposium on traditional herbal formulas for use in allergy and asthma.

Still, it's not a known, accepted, widely used formula there, nor any herbal formula really, and they do indeed have a rising epidemic of allergic disease but by geography and presentation in population it differs from other regions. Example: tropical as well as temperate dust mite sensitization correlates strongly with asthma.

In conclusion, thus far no herbal formula has shown efficacy on root level mechanisms and are likely late symptoms controllers similar to what we have in manufactured pharmaceuticals, but some show promise in stronger preventative side of anaphylaxis, a constellation of symptoms.

There has been nothing we've seen, read or heard first person directly out of the researchers mouths in English or Mandarin Chinese during presentation or that I've heard from the doctor who initiated the studies of FAHF-2 to indicate it would be anti-allergy as in a cure, or prevent sensitizing or re-sensitizing.

You will find many anecdotal stories of vague appreciation of Chinese herbal medicine as a great exotic wonder in Western media but please realize there are labs in Asia with scientists that both understand pharmacognosy as well as pharmacology and Western medicine as fully fledged scientists or doctors.

I am in full support for this sort of research to continue under the auspices of clinical conditions, but not at the cost of loss to discovery on root mechanism and unraveling the allergic march.

[forvictoria]

I'm not sure I follow your post, quercetin is a bioflavonoid not a Chinese herbal medicine.

[twinturbo]

This is an 'alt med' comparison is to FAHF-2.

Symptom controller, not effect on root mechanism or prevention of sensitization, or re-sensitization. If FAHF-2 is the example, the example itself falls short in the land and people such 'alt med' originates from. Therefore if it comparatively performs like FAHF-2 as a symptom controller it would not be anti-allergy. Anti-histamine? Possible or likely, in any case then the correct symptom control is applicable.

[forvictoria]

ahh ok I understand now and yes they are saying it has anti histamine properties, should be interesting to see what if anything comes of this.

[CMdeux]

Quercetin's bioavailability is so utterly low (as in, it almost ISN'T orally available at all) that I predict that it is mostly hype.  That's me.

I've worked on a related natural product whose cardiotonic properties (quite real and extremely robust/perplexing) were at one time speculated to (similarly) be "due to quercetin which is known to have ____, _____ and _____ properties."  Or if not quercetin, another "bioflavonoid" in the plant material.  This term has come to be used so much that it is almost meaningless in publications, I'm afraid-- it is basically the equivalent of someone waving their hands and saying "it's MAGIC" rather than identifying a mechanism.

Having done some isolation work, I'm not buying that either.  Most of these effects are really small, and cumulative or at best the result of plateauing doses to reach some blood maximum.  OR they can be the result of a number of smaller effects (from a cocktail of active components) which act in concert.  That is quite a real phenomenon-- it's the basis of FAHF-2, apparently.

The problem is that if you standardize a biological to some ingredient that IS NOT actually the "active" ingredient, then you may well get wildly fluctuating efficacy even in "standardized" preparations.

For example,  St.John's Wort, Hawthorn, etc. as opposed to Digoxin, valerian, etc.  Knowing which molecule(s) is actually having the desired effect is pretty crucial.

You can apply things to tissue culture systems and completely IGNORE bioavailability, by the way.  In Pharmacology/Pharmacognosy this is lamentably common practice, I'm afraid.   But it also means that the data thus obtained is mostly useless for predicting anything in whole organisms. 

Oh-- and human beings have an immune response which is notoriously difficult to adequately model when it comes to IgE-mediated responses, so that complicates things still further.