Eucommia (Eucommia ulmoides)

Eucommia ulmoides bark (Du Zhong) is not consumed as a food source for macronutrients but contains a well-characterized array of bioactive compounds. Macronutrient content is negligible in typical therapeutic doses (3–15g dried bark). Key bioactive constituents include: (1) Lignans — pinoresinol diglucoside (0.1–0.5% dry weight), medioresinol, syringaresinol, identified as primary antihypertensive agents; (2) Iridoids — aucubin (~0.07–0.12% dry weight) and geniposide, contributing to anti-inflammatory and renal-protective effects; (3) Chlorogenic acid — a hydroxycinnamic acid derivative present at approximately 0.5–1.2% dry weight, contributing antioxidant and vasodilatory activity; (4) Gutta-percha (trans-polyisoprene) — a unique rubber-like polymer comprising 6–10% of bark dry weight, biologically inert but structurally distinctive; (5) Flavonoids — quercetin and rutin detected at trace levels (<0.05% dry weight); (6) Phenylpropanoids — including coniferin and syringin; (7) Minerals — bark contains modest calcium (~180–220 mg/100g dry weight), potassium (~300–400 mg/100g dry weight), magnesium (~50–80 mg/100g dry weight), and trace zinc and iron; (8) Dietary fiber — approximately 20–30% of dry bark weight as structural polysaccharides, though not consumed in fiber-relevant quantities in herbal doses. Bioavailability notes: Pinoresinol diglucoside requires gut microbiome conversion to aglycone forms for absorption; chlorogenic acid has moderate oral bioavailability (~30%); iridoid glycosides show variable absorption dependent on gut flora; standardized extracts (often to 1% pinoresinol diglucoside or 5% total iridoids) are used in clinical preparations to ensure consistent dosing.