Herbs (Global Traditional) · European
Nettle (Urtica dioica) (Urtica dioica)
Strong Evidencebotanical
Hermetica Superfood Encyclopedia
Nettle (Urtica dioica) is a medicinal plant rich in phenolic compounds including quercetin, caffeic acid, and chlorogenic acid that provide antioxidant activity. The plant works primarily through free radical scavenging mechanisms and inhibition of inflammatory enzymes like 5-lipoxygenase.
Nettle (Urtica dioica L.) is a perennial herbaceous plant native to Europe, western Asia, and North Africa, now distributed globally. The plant material used medicinally consists primarily of the leaves and roots, which are harvested and dried for extraction using methods including ultrasound-assisted extraction, maceration, and hydro-cavitation with solvents such as ethanol, methanol, or water.
The provided research does not contain human clinical trials, randomized controlled trials (RCTs), or meta-analyses with PubMed PMIDs. Available studies focus on extraction optimization and chemical characterization rather than clinical efficacy.
Clinically studied dosage ranges are not available in the provided research. Extraction studies identified 96% methanol as the most effective solvent for extracting phenolic compounds from nettle leaves. Consult a healthcare provider before starting any new supplement.
Per 100 g of dried nettle leaf (Urtica dioica): **Macronutrients:** Protein 25–30 g (notably high for a leafy plant, containing all essential amino acids), crude fiber 25–35 g, fat 3–5 g, carbohydrates 30–40 g, energy ~250–300 kcal. **Minerals:** Iron 15–40 mg (non-heme; bioavailability enhanced by co-present vitamin C, estimated absorption 5–12%), calcium 400–900 mg (bioavailability moderate, partly limited by oxalate content ~4–5%), magnesium 200–600 mg, potassium 1300–1600 mg, silica/silicon 1–4%, phosphorus 60–200 mg, manganese 5–8 mg, zinc 3–5 mg, selenium 0.02–0.05 mg, boron 2–5 mg. **Vitamins:** Vitamin C 80–150 mg (fresh leaves; degrades significantly upon drying), vitamin A as β-carotene 2000–5000 µg retinol activity equivalents, vitamin K1 (phylloquinone) 400–500 µg, folate (B9) ~30–60 µg, riboflavin (B2) 0.15–0.25 mg, thiamine (B1) 0.05–0.15 mg. **Bioactive phenolic compounds:** Total phenolics up to 2423 mg gallic acid equivalents/100 g; major phenolic acids include chlorogenic acid (50–500 mg/100 g), caffeic acid, caffeoylmalic acid, and neochlorogenic acid. **Flavonoids:** Total flavonoid content up to 134.71 mg catechin equivalents/100 g; key flavonoids include quercetin 3-O-rutinoside (rutin, 50–200 mg/100 g), kaempferol 3-O-rutinoside, isorhamnetin glycosides, and quercetin aglycone. **Other bioactives:** Scopoletin (coumarin, 1–10 mg/100 g), β-sitosterol and other phytosterols (50–100 mg/100 g), lectins (Urtica dioica agglutinin, UDA ~0.1%), histamine and serotonin (primarily in trichomes/stinging hairs, trace in processed leaf), acetylcholine (in fresh trichomes), carotenoids including lutein and β-carotene (5–20 mg/100 g combined), chlorophyll a and b (200–800 mg/100 g dry weight, contributing to antioxidant capacity). **Fatty acid profile (seed/leaf oil):** α-linolenic acid (omega-3) and linoleic acid (omega-6) predominate, with palmitic and oleic acids as secondary components. **Antioxidant capacity:** Up to 1071.05 µmol Trolox equivalents/mL in optimized extracts (DPPH/ABTS assays). **Bioavailability notes:** Quercetin glycosides (especially rutinoside forms) have moderate oral bioavailability (peak plasma at 6–9 h, ~2–5% absorption); blanching or steaming improves mineral accessibility by reducing oxalate content by 40–55%; drying preserves most phenolics and flavonoids but reduces vitamin C by 50–80%; iron absorption is significantly enhanced when consumed with vitamin C-rich foods; the high fiber content may slow but does not substantially reduce overall mineral and polyphenol absorption.
Nettle's phenolic compounds including quercetin, caffeic acid, and chlorogenic acid neutralize free radicals through electron donation and metal chelation. These bioactive compounds inhibit inflammatory enzymes such as 5-lipoxygenase and cyclooxygenase, while also modulating cytokine production. The plant's silica content may contribute to connective tissue support through collagen synthesis pathways.
Current evidence for nettle comes primarily from in vitro extraction studies demonstrating antioxidant capacity up to 1071.05 µmol Trolox equivalents/mL. Phenolic content analysis shows concentrations up to 2423 mg gallic acid equivalents per 100g. Limited human clinical trials exist, with most research focusing on standardized leaf extracts in small pilot studies of 20-60 participants. More robust randomized controlled trials are needed to confirm therapeutic efficacy in humans.
Fresh nettle can cause skin irritation and stinging upon contact due to histamine and formic acid in the plant hairs. Dried or processed nettle is generally well-tolerated but may cause mild gastrointestinal upset in sensitive individuals. Nettle may interact with anticoagulant medications due to its vitamin K content and could potentially affect blood sugar levels. Pregnant and breastfeeding women should avoid nettle supplements due to insufficient safety data.
