Bi Xie (Dioscorea hypoglauca) (Dioscorea hypoglauca)

Bi Xie (Dioscorea hypoglauca) is a rhizomatous herb with a nutritional and phytochemical profile centered on steroidal saponins rather than classical macronutrients. Primary bioactive compounds include diosgenin (a steroidal sapogenin, approximately 0.3–1.2% dry weight), protodioscin, and dioscin, which are the principal pharmacologically active constituents. Starch content is relatively high as expected of a rhizome, estimated at 30–50% dry weight, serving as the primary carbohydrate source. Crude protein content is modest, approximately 3–6% dry weight, comprising various amino acids including glutamic acid and aspartic acid. Crude fiber content ranges from 5–10% dry weight, contributing to digestive support. Lipid content is low, generally under 2% dry weight. Micronutrients include potassium (estimated 400–600 mg/100g dry weight), calcium (approximately 50–100 mg/100g), magnesium (approximately 30–60 mg/100g), and trace amounts of iron and zinc. Phytosterols including beta-sitosterol and stigmasterol are present at low concentrations (0.05–0.2% dry weight). Polyphenolic compounds and flavonoids are present in minor quantities. Bioavailability of diosgenin and related saponins is notably enhanced through intestinal bacterial hydrolysis, converting glycosidic forms to aglycone forms for absorption. Comprehensive quantitative nutritional data remains limited in peer-reviewed literature, as the herb is used therapeutically rather than as a food source.