Purple Coneflower (Echinacea purpurea)

Purple Coneflower (Echinacea purpurea) is not consumed as a food for macronutrient value; it is used primarily as a medicinal herb. Its therapeutic profile is defined by its bioactive phytochemical constituents rather than caloric or macronutrient content. Key bioactive compounds include: • Alkamides (Alkylamides): ~0.01–0.04% in dried root, ~0.001–0.01% in aerial parts; the most bioavailable immunomodulatory compounds, rapidly absorbed through oral mucosa and GI tract with high oral bioavailability (~50–75%); key compounds include dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides. • Caffeic acid derivatives: Cichoric acid (dicaffeoyltartaric acid) is the dominant phenolic, present at ~1.2–3.1% of dry weight in aerial parts and ~0.6–2.1% in roots; echinacoside (caffeic acid glycoside) at ~0.3–1.3% in roots (more abundant in E. angustifolia); caftaric acid at ~0.1–0.8%; chlorogenic acid at ~0.02–0.1%. Bioavailability of cichoric acid is moderate but subject to rapid enzymatic degradation. • Polysaccharides: Arabinogalactans and heteroxylans at ~1–4% of dry root weight; fucogalactoxyloglucans in aerial parts; these high-molecular-weight immunostimulating compounds have low oral bioavailability but may exert effects through gut-associated lymphoid tissue (GALT) and Peyer's patches. • Glycoproteins: ~1–2% of dry weight, containing arabinose-rich carbohydrate moieties; contribute to macrophage activation. • Polyacetylenes: Including pontica epoxide and other C13 acetylenic compounds at trace levels (~0.001–0.01%); found primarily in roots; some show antifungal and anti-inflammatory activity. • Flavonoids: Rutoside (rutin), quercetin, and kaempferol glycosides present at ~0.1–0.5% of aerial parts; contribute antioxidant capacity. • Essential oil (volatile compounds): ~0.05–0.3% of aerial parts; contains borneol, bornyl acetate, germacrene D, caryophyllene, and humulene. • Minerals (in dried herb): Potassium ~15–20 mg/g, calcium ~8–12 mg/g, magnesium ~2–4 mg/g, iron ~0.1–0.5 mg/g, zinc ~0.02–0.06 mg/g, selenium trace amounts. • Vitamins: Trace amounts of vitamin C (~2–5 mg/100g dried herb), small amounts of B-vitamins; not a significant dietary source. • Fiber: Crude fiber ~15–25% of dried aerial parts (not typically relevant as it is consumed as tea or extract, not bulk plant material). • Protein: ~10–15% crude protein in dried aerial parts (not consumed in nutritionally relevant quantities). • Bioavailability notes: Alkamides are the most pharmacokinetically favorable compounds, detectable in plasma within 20 minutes of oral dosing, with peak levels at ~30–60 minutes. Cichoric acid shows lower systemic bioavailability due to esterase degradation but is partially absorbed intact. Polysaccharides are largely not absorbed systemically but interact with immune cells in the gut mucosa. Ethanolic extracts preferentially concentrate alkamides and caffeic acid derivatives, while aqueous extracts (teas) favor polysaccharides and glycoproteins. Standardized commercial preparations typically guarantee alkamide content (≥0.25 mg/mL) and/or cichoric acid content (≥2.5 mg/mL) for quality assurance.