Gui Zhi (Cinnamomum cassia twig)

Gui Zhi (Cinnamomum cassia twig) is primarily valued for its bioactive phytochemical composition rather than macronutrient content. Key compounds include: **Essential Oil (1–2% of dry weight):** predominantly cinnamaldehyde (65–80% of volatile oil), coumarin (0.3–0.5%), eugenol (trace to 0.2%), and cinnamyl acetate (1–5%). **Diterpenes and Phenolic Compounds:** cinnzeylanine, cinnzeylanol, and various proanthocyanidins (oligomeric procyanidins, approximately 2–4% of dry weight), which contribute significant antioxidant activity. **Flavonoids:** including catechin, epicatechin, and quercetin derivatives at concentrations of approximately 0.5–1.5% dry weight. **Polysaccharides:** water-soluble polysaccharides comprising roughly 3–6% of dry weight, which may contribute to immunomodulatory effects. **Minerals (per 100 g dry twig):** calcium (~50–80 mg), potassium (~100–200 mg), magnesium (~15–30 mg), iron (~2–5 mg), manganese (~5–15 mg), and zinc (~1–3 mg). **Vitamins:** trace amounts of vitamin A precursors and B-complex vitamins, though concentrations are nutritionally negligible at typical medicinal doses. **Macronutrients (approximate per 100 g dry material):** carbohydrates ~60–70 g (largely structural fiber and polysaccharides), crude fiber ~20–30 g, protein ~3–5 g, fat ~1–2 g. **Coumarins:** coumarin content is a safety consideration; typical concentration is 3,000–5,000 mg/kg in cassia bark, with twig portions generally containing lower levels (~500–2,000 mg/kg). **Bioavailability Notes:** Cinnamaldehyde is rapidly absorbed in the gastrointestinal tract and metabolized to cinnamic acid, with an oral bioavailability estimated at 20–30%. Proanthocyanidins have relatively low bioavailability (5–10%) but exert local gastrointestinal effects. Water decoction (traditional preparation method) extracts primarily water-soluble polysaccharides, flavonoid glycosides, and a portion of the volatile oils; alcohol-based preparations improve extraction of cinnamaldehyde and lipophilic terpenes. Standard medicinal dosage is 3–9 g of dried twig per decoction, meaning actual intake of bioactive compounds per dose is: cinnamaldehyde ~30–180 mg, proanthocyanidins ~60–360 mg, polysaccharides ~90–540 mg, and coumarin ~1.5–18 mg.