Yuan Zhi (Polygala tenuifolia)

Yuan Zhi (Polygala tenuifolia) is not typically consumed as a food source, so standard macronutrient profiling (carbohydrates, fats, protein) is not clinically relevant. Its therapeutic value lies in its bioactive compounds, primarily concentrated in the root. Key bioactive constituents include: Triterpenoid Saponins (Onjisaponins): approximately 2–6% of dried root weight, including onjisaponin B, E, and F, and tenuifolin (a hydrolysis product). These are the primary neuroprotective and expectorant compounds, with moderate oral bioavailability that is enhanced by gut microbial hydrolysis converting saponins into active aglycones. Xanthones: notably polygalaxanthone III and 1,2,3-trihydroxy-6,7-dimethoxyxanthone, present at approximately 0.1–0.5% of dried root. These exhibit strong antioxidant and anti-inflammatory activity with relatively low oral bioavailability due to poor water solubility. Oligosaccharide esters (Tenuifolisides): including tenuifoliside A, B, and C, at approximately 0.5–2% of dried root, which contribute to neuroprotective and memory-enhancing effects and show moderate bioavailability. Polygalitol: a sugar alcohol present at roughly 1–2%, acting as a mild osmotic agent. 3,4,5-Trimethoxycinnamic acid (TMCA): approximately 0.05–0.2%, a key sedative and anxiolytic compound with good oral bioavailability due to its small molecular size and lipophilicity. BT-11 (Onjisaponin B-derived metabolite): a standardized extract marker shown to enhance acetylcholine activity and promote nerve growth factor (NGF) expression. Minerals: trace amounts of zinc, manganese, iron, and calcium are present but not in nutritionally significant quantities given typical dosing (3–10 g dried root/day in decoction). Vitamins and fiber: not present in therapeutically meaningful amounts. Bioavailability notes: Decoction (traditional preparation) enhances extraction of saponins and oligosaccharide esters. Honey-processing (zhi yuan zhi) is traditionally used to reduce gastrointestinal irritation from saponins and may modestly improve tolerability. Saponin bioavailability is significantly enhanced by intestinal microflora-mediated biotransformation; co-administration with lipid-containing preparations may improve xanthone absorption.