Tu Si Zi (Cuscuta chinensis)

Tu Si Zi (Cuscuta chinensis) is classified as a traditional Chinese medicinal herb rather than a dietary staple, so its value lies primarily in its bioactive compounds rather than conventional macronutrient content. Key constituents include: Flavonoids (kaempferol, quercetin, hyperoside, astragalin; total flavonoid content approximately 1.5–4.0% by dry weight), which serve as the principal antioxidant and hepatoprotective agents. Lignans (notably sesamin and related compounds, ~0.2–0.8%) contribute to hormonal modulation and reproductive support. Polysaccharides (cuscuta polysaccharides, approximately 5–12% of dried seed weight) are immunomodulatory and support kidney yang function. Phenolic acids (chlorogenic acid, caffeic acid; ~0.3–1.0%) provide additional antioxidant capacity. Carotenoids (including lutein and beta-carotene in trace amounts, ~0.01–0.05%) support retinal health and vision. Sterols (beta-sitosterol, ~0.1–0.4%) contribute to cholesterol modulation and anti-inflammatory effects. Alkaloids (trace amounts, <0.1%) have been identified but are not considered primary active constituents. Minerals: contains moderate levels of zinc (~15–30 mg/kg), selenium (~0.05–0.2 mg/kg), manganese (~20–50 mg/kg), iron (~80–150 mg/kg), and calcium (~500–1500 mg/kg) in dried seed form. Crude protein content is approximately 10–15% by dry weight. Crude fiber is approximately 8–14%. Fat content is roughly 3–6%, with fatty acids including linoleic acid and oleic acid. Vitamins: trace amounts of vitamin A precursors and vitamin E (tocopherols, ~2–5 mg/100g). Bioavailability notes: The flavonoid glycosides (such as hyperoside and astragalin) require hydrolysis by gut microbiota to release aglycones (quercetin, kaempferol) for absorption, resulting in moderate oral bioavailability (~15–30%). Polysaccharides are largely absorbed intact through Peyer's patches for immune activation. Decoction (traditional water extraction) enhances the release of water-soluble flavonoids and polysaccharides but may reduce heat-sensitive carotenoid content. Co-administration with lipid-containing herbs or foods can improve carotenoid and sterol absorption. Ethanol extraction yields higher concentrations of lignans and flavonoid aglycones compared to aqueous preparation.