From the Guidelines
Enzymatically modified isoquercitrin (EMIQ) is the most effective compound in demonstrating anti-allergic effects in mice, due to its superior suppression of histamine release and inhibition of allergic reactions at lower doses. The anti-allergic effects of enzymatically modified isoquercitrin, quercetin 3-O-glucoside, α-oligoglucosyl rutin, and quercetin in mice are attributed to their ability to inhibit mast cell degranulation and the release of inflammatory mediators like histamine, as well as suppress the production of inflammatory cytokines 1. Key points to consider include:
- EMIQ appears to be the most effective compound, showing superior suppression of histamine release and inhibition of allergic reactions at lower doses compared to the other compounds.
- Quercetin 3-O-glucoside and α-oligoglucosyl rutin also exhibit anti-allergic properties but typically require higher doses to achieve similar effects.
- Pure quercetin, while effective in theory, has limited bioavailability which reduces its practical effectiveness.
- The superior effect of EMIQ is likely due to its enhanced bioavailability and absorption in the intestinal tract compared to the other forms.
- These flavonoids represent promising natural compounds for managing allergic conditions, though their effects in mice may not directly translate to identical outcomes in humans. It is essential to note that while these compounds show promise, the current evidence is based on studies in mice, and more research is needed to confirm their effectiveness in humans, as highlighted by the guidelines for allergen immunotherapy 1.
From the Research
Anti-Allergic Effects of Enzymatically Modified Isoquercitrin and Related Compounds
The anti-allergic effects of enzymatically modified isoquercitrin (α-oligoglucosyl quercetin 3-O-glucoside), quercetin 3-O-glucoside, α-oligoglucosyl rutin, and quercetin have been studied in mice. The key findings are:
- Enzymatically modified isoquercitrin (EMIQ) exhibited a significant inhibitory effect on the murine ear passive cutaneous anaphylaxis (PCA) reaction 2.
- Quercetin 3-O-glucoside (isoquercitrin, IQC) and α-oligoglucosyl rutin (αOR) showed less or no anti-allergic effect compared to EMIQ 2.
- The water solubility of these substances may affect their biological activities, as IQC and quercetin cannot completely dissolve in water at the concentration used 2.
- Glycosyl conjugation of quercetin with specific sugar motifs is an effective strategy to improve the biological activity of quercetin in vivo 2.
Mechanisms of Action
The mechanisms of action of these compounds involve:
- Inhibition of histamine production and pro-inflammatory mediators 3.
- Regulation of the Th1/Th2 balance and decrease of antigen-specific IgE antibody releasing by B cells 3.
- Anti-inflammatory and immunomodulatory functions, making them suitable for the management of allergic diseases 3.
Related Studies
Other studies have investigated the anti-allergic effects of quercetin and its derivatives, including:
- Quercetin's potential as a safe anti-allergic substance, although its use is limited by complex issues 4.
- The anti-inflammatory activity of quercetin and isoquercitrin in experimental murine allergic asthma 5.
- The pharmacology, toxicology, and metabolism of isoquercitrin, including its higher bioavailability and chemoprotective effects compared to quercetin 6.