Raspberry Leaf (Rubus idaeus)

Raspberry leaf (Rubus idaeus) contains high concentrations of polyphenolic compounds including ellagic acid and sanguiin H-6 that demonstrate antioxidant activity in laboratory studies. The antioxidant effects correlate specifically with catechin content in shoot extracts.

Origin & History

Raspberry leaf derives from Rubus idaeus (Rosaceae family), a perennial shrub native to Europe, North America, and Asia where leaves are harvested from shoots for medicinal use. It is typically produced by drying and milling the leaves or shoots, followed by extraction using water for teas or organic solvents to isolate polyphenols dominated by ellagitannins, phenolic acids, and flavonoids.

Historical & Cultural Context

The research dossier does not describe historical or traditional uses of raspberry leaf in any medicinal systems. While the plant is native to Europe, North America, and Asia, specific cultural or traditional applications are not documented in the provided results.

Health Benefits

• Antioxidant activity correlated with catechin content in shoot extracts (preliminary in vitro evidence only)
• No human clinical trials available to document specific health benefits
• Chemical analysis shows high polyphenol content including ellagic acid (155-394 mg/100g) and sanguiin H-6 (139-633 mg/100g)
• Traditional use suggested but not documented in available research
• Further clinical research needed to establish therapeutic benefits

How It Works

Raspberry leaf's antioxidant activity stems from its polyphenolic compounds, particularly ellagic acid (155-394 mg/100g) and sanguiin H-6 (139-630 mg/100g), which neutralize reactive oxygen species. The catechins in shoot extracts demonstrate free radical scavenging capacity in vitro through electron donation mechanisms. These compounds may also modulate inflammatory pathways, though specific receptor interactions require further investigation.

Scientific Research

The research dossier explicitly states that search results lack human clinical trials, RCTs, or meta-analyses on raspberry leaf (Rubus idaeus), with no PubMed PMIDs for such studies provided. Available data focus only on chemical composition and in vitro antioxidant activity correlated with catechin content in shoot extracts.

Clinical Summary

Currently, no human clinical trials have documented specific health benefits of raspberry leaf supplementation. Available research consists only of preliminary in vitro studies examining antioxidant capacity of plant extracts. Chemical analysis confirms significant polyphenol content, but translation to human health outcomes remains unestablished. More rigorous clinical research with standardized extracts and defined endpoints is needed to validate traditional uses.

Nutritional Profile

**Macronutrients (per 100g dried leaf, approximate):** Protein: 6–10 g; Fat: 1–3 g; Carbohydrates (including dietary fiber): 40–55 g; Dietary fiber: 15–25 g. **Key Minerals:** Manganese: 5–10 mg (high relative to many herbal teas); Iron: 3–7 mg; Calcium: 200–400 mg; Magnesium: 50–120 mg; Potassium: 500–900 mg; Phosphorus: 40–80 mg; Zinc: 1–3 mg. **Vitamins:** Vitamin C: 10–30 mg (fresh leaf; degrades significantly upon drying); traces of B-complex vitamins (B1, B2, B3, B6) and vitamin E (tocopherols). **Bioactive Polyphenolic Compounds:** Ellagitannins — Sanguiin H-6: 139–633 mg/100g (dominant ellagitannin, primary contributor to antioxidant capacity); Lambertianin C: present in significant but variable amounts. Ellagic acid (free and bound): 155–394 mg/100g. Flavonoids — Catechins (particularly (+)-catechin and (−)-epicatechin): detected in shoot extracts, concentrations variable; Quercetin glycosides (quercetin-3-O-glucuronide, quercetin-3-O-rutinoside): 10–50 mg/100g; Kaempferol glycosides: present in lower concentrations. Hydroxycinnamic acids — Chlorogenic acid and caffeic acid derivatives: 5–30 mg/100g. Gallotannins: minor amounts detected. **Other Compounds:** Fragarine (an alkaloid-like smooth muscle active compound, specific to Rubus idaeus leaves; concentration not precisely quantified in literature but traditionally considered pharmacologically relevant). Organic acids including citric and malic acid in trace amounts. **Bioavailability Notes:** Ellagitannins such as sanguiin H-6 are poorly absorbed intact in the upper GI tract; they are hydrolyzed to ellagic acid, which is further metabolized by gut microbiota to urolithins (urolithin A, B, C, D) — the actual bioactive metabolites with demonstrated systemic bioavailability. Urolithin production is highly individual ('metabotype'-dependent). Free ellagic acid itself has low oral bioavailability (~<1% in animal models) due to poor solubility and rapid conjugation. Catechins and quercetin glycosides have moderate bioavailability (10–30% depending on glycoside form); glucuronide conjugates of quercetin are relatively well absorbed. Mineral bioavailability (especially calcium and iron) may be reduced by the high tannin content, which chelates divalent cations. Preparation as an infusion (tea) extracts primarily water-soluble polyphenols, with estimated extraction efficiency of 30–60% for total phenolics depending on steeping time and temperature.

Preparation & Dosage

No clinically studied dosage ranges are available as human trials are absent. Chemical analyses report polyphenol concentrations in extracts (ellagic acid up to 394 mg/100g in brewed leaf tea after 20 min; sanguiin H-6 139-633 mg/100g in shoots), but no standardization or dosing for therapeutic use is specified. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Green tea, grape seed extract, pomegranate, quercetin, resveratrol

Safety & Interactions

Raspberry leaf is generally recognized as safe when consumed as food or tea in typical amounts. Pregnant women should consult healthcare providers before use, as traditional claims about uterine effects lack clinical validation. No specific drug interactions have been documented in clinical literature. Individuals with plant allergies should exercise caution, and standardized extract dosing guidelines have not been established through clinical trials.