Gymnema sylvestre

Gymnema sylvestre leaves contain limited conventional macronutrients as it is used in concentrated extract form rather than as a food source. Primary bioactive compounds include gymnemic acids (a family of triterpenoid saponins, typically 25–75% concentration in standardized extracts, most commonly standardized to 25% gymnemic acids by HPLC), which are the principal active constituents responsible for taste suppression and glucose modulation. At least 9 identified gymnemic acid fractions exist (gymnemic acids I–VII, gymnemosides A–F). Additional bioactives include gurmarin (a 35-amino-acid polypeptide, ~4 kDa, found primarily in Indian varieties, directly responsible for sweet taste suppression at taste receptors), gymnemasaponins (pentacyclic triterpene glycosides), and gymnemasides. Minor constituents include flavonoids (quercetin, kaempferol derivatives), alkaloids (including conduritol A), resins, and tartaric acid. Mineral content of dried leaf includes calcium (~1.2–1.8 g/100g dry weight), magnesium (~0.3–0.5 g/100g), potassium (~1.5–2.0 g/100g), and iron (~15–25 mg/100g dry weight), though these are not clinically significant at supplemental doses (typically 200–800 mg extract/day). Crude fiber in dried leaf is approximately 12–18% dry weight. Protein content is approximately 6–10% dry weight but is not a meaningful dietary source. Bioavailability of gymnemic acids is moderate; they undergo hepatic metabolism and are partially excreted renally; onset of taste suppression occurs within 5–10 minutes of oral contact and lasts 15–90 minutes depending on concentration.