This is really bugging me! But, could bugs be the answer?
Quercetin is a member of the flavonoid group of compounds. These compounds occur naturally in plants, and have been shown to have properties that are beneficial to health.
Quercetin has been studied in several recent investigations to assess it’s ability to inhibit xanthine oxidase (XO). Both allopurinol and febuxostat work by XO inhibition.
Unfortunately, the quercetin studies are largely confined to laboratory experiments with occasional animal tests. Animal tests so far have not shown success, and this appears to be down to solubility of quercetin.
Just as I thought I had finished reviewing relevant research, I spotted a mention of quercetin buried deep in a study of large cabbage white caterpillars. So deep, that I cannot assess if quercetin is actually relevant, but it does not matter – the abstract is fascinating.
A comparison of extracts from the tronchuda cabbage (Portuguese kale) with extracts from caterpillers feeding off it reveals some startling chemistry. The caterpillar extract is far more effective than extracts from the plant on which it feeds. The authors of “Pieris brassicae Inhibits Xanthine Oxidase” conclude:-
This is the first time that an insect has been tested for its xanthine oxidase inhibitory capacity, which proved to be very high. These findings are interesting considering that they can be used by food or pharmaceutical industries to prevent the oxidation of their products, to increase the dietary supply of antioxidants, or for prevention of free radical-mediated diseases, namely, gout.
Grub up!
I have also read about quercetin and, in fact, have bought some bottles of quercetin+bromelain capsules. However, I have read that quercetin is insoluble in water which means that the human body can hardly absorb it. It is soluble in alcohol but it requires pretty large amounts of alcohol and this three times a day. Literature also says it is soluble in alkaline solution but I failed with solving quercetin powder in a solution I made from baking soda. Does this mean it is senseless taking quercetin?
I have read about quercetin chalcone (“Aller DMG”, “Allergy Support Plus”, “Quercenase”) which is water-soluble and wonder whether this helps. Could not find any information on the internet so far.
I’m bringing all the quercetin discussion here, prior to summarizing for new reference page(s)
This table is an extract from the USDA flavonoids database (release 2.1) showing all quercetin values (excluding zero values).
Quercetin and Red Wine
The study that mentioned red wine was “Flow injection determination of xanthine oxidase inhibitory activity and its application to food samples”, and the reference to red wine was so insignificant that I nearly discarded it as irrelevant. Then I read how several natural compounds compared to allopurinol as a xanthine oxidase inhibitor. Chief amongst these is quercetin, though it’s more effective cousin apigenin, is also very interesting.