Herbs (Global Traditional) · European
Eyebright (Euphrasia officinalis) (Euphrasia officinalis)
Moderate Evidencebotanical2 PubMed Studies
Hermetica Superfood Encyclopedia
Eyebright (Euphrasia officinalis) contains phenolic compounds that provide antihistamine effects and aucubin which demonstrates antioxidant properties. Laboratory studies show antioxidant activity comparable to Trolox, though human clinical evidence remains limited.
Eyebright (Euphrasia officinalis) is a small herbaceous plant native to European temperate grasslands, featuring white or red flowers. The aerial parts (stems, leaves, flowers) are harvested during flowering and processed into extracts using water infusion, ethanolic extraction (typically 50% v/v ethanol), or water-glycerin methods.
No human clinical trials, RCTs, or meta-analyses have been conducted on eyebright according to the available research. WebMD explicitly states there is no good scientific evidence to support its traditional uses, with evidence limited to in vitro antioxidant assays and animal studies on isolated compounds like aucubin.
No clinically studied dosages exist due to lack of human trials. Traditional preparations include: tinctures (30-40 drops 2-5 times daily), teas, 4:1 extracts, and powdered aerial parts, though these lack standardization or clinical validation. Consult a healthcare provider before starting any new supplement.
Eyebright (Euphrasia officinalis) is used primarily as an herbal preparation (tea, tincture, or extract) rather than a food source, so macronutrient contribution is negligible. **Key bioactive compounds:** • **Iridoid glycosides:** aucubin (0.05–0.5% dry weight) and catalpol, responsible for anti-inflammatory and antioxidant effects; bioavailability is moderate as aucubin is hydrolyzed by gut flora to the active aglycone aucubigenin. • **Phenolic acids:** caffeic acid, ferulic acid, and chlorogenic acid (collectively ~0.3–1.2% dry weight); these contribute antihistamine-like and antioxidant activity; bioavailability of caffeic acid is moderate (~30–50% absorption in upper GI). • **Flavonoids:** luteolin, apigenin, quercetin glycosides, and rutin (estimated total flavonoid content ~0.5–1.5% dry weight); quercetin glycosides have ~20–50% oral bioavailability depending on sugar moiety. • **Tannins:** condensed and hydrolyzable tannins (~2–5% dry weight), providing astringent properties; poorly absorbed but may exert local effects on mucosal surfaces. • **Lignans:** minor quantities reported but not well quantified. • **Volatile compounds:** trace essential oil content (<0.1%). • **Minerals (per dry herb):** modest amounts of zinc (~20–35 µg/g), manganese (~30–80 µg/g), iron (~50–150 µg/g), and copper (~8–15 µg/g); however, actual intake from typical herbal doses (1–3 g dried herb per day) is nutritionally insignificant. • **Vitamins:** trace amounts of vitamin C and B-complex vitamins reported in fresh aerial parts, but quantities are too low to be meaningful at standard dosing. • **Fiber/Protein:** dried aerial parts contain ~8–12% crude protein and ~15–20% crude fiber, but given typical dose sizes (1–3 g/day), macronutrient contribution is effectively zero. **Bioavailability notes:** Most active compounds are delivered via aqueous infusion (tea) or hydroalcoholic extract; iridoid glycosides require intestinal enzymatic activation; flavonoid glycosides are better absorbed than aglycones in the small intestine; tannin content may reduce absorption of co-ingested minerals if consumed alongside food.
Eyebright's phenolic compounds including quercetin and caffeic acid derivatives inhibit histamine release from mast cells, reducing allergic responses. Aucubin, an iridoid glycoside, scavenges free radicals and upregulates antioxidant enzymes like superoxide dismutase. The tannins present also provide astringent effects through protein binding.
Current evidence for eyebright is limited to traditional use and laboratory studies, with no published human clinical trials available. In vitro studies demonstrate antioxidant capacity equivalent to Trolox using DPPH and ABTS radical scavenging assays. Animal studies in mice showed aucubin reduced oxidative stress markers, but these findings cannot be directly extrapolated to humans. Most eyebright research focuses on its traditional use for eye conditions rather than controlled clinical outcomes.
Eyebright is generally considered safe when used as a tea or supplement, though comprehensive safety data is lacking. Topical eye applications may cause irritation or infection risk if preparations are not sterile. No documented drug interactions exist, but antihistamine effects could theoretically enhance sedating medications. Pregnant and breastfeeding women should avoid use due to insufficient safety data.
