Goldenrod (Solidago virgaurea)

Goldenrod (Solidago virgaurea) is used primarily as a medicinal herb rather than a food source, so conventional macronutrient profiling (calories, protein, fat, carbohydrates) is not typically applicable at therapeutic doses. Its value lies in its bioactive phytochemical composition: Key Bioactive Compounds: • Flavonoids (1.0–3.5% of dried herb): Including rutin (quercetin-3-O-rutinoside, up to ~1.5%), quercitrin, astragalin, kaempferol-3-O-rutinoside, and isorhamnetin glycosides. These are the primary contributors to anti-inflammatory and antioxidant activity. Bioavailability of rutin is moderate; gut microbiota cleave the sugar moiety to release quercetin for absorption. • Saponins (approximately 2–6% of dried herb): Primarily triterpenoid saponins based on oleanolic acid and bayogenin aglycones, collectively referred to as virgaureasaponins (e.g., virgaureasaponin 1, 2, 3). These contribute to diuretic, antifungal, and anti-biofilm properties. • Phenolic acids (~0.5–1.5%): Including chlorogenic acid (up to ~0.7%), caffeic acid, and 3,5-di-O-caffeoylquinic acid (leiocarposide, approximately 0.3–1.0%). Leiocarposide is considered a marker compound with analgesic and anti-inflammatory properties. • Diterpenes: Clerodane-type diterpenes (e.g., solidagoic acids A and B) present in small quantities; contribute to anti-inflammatory effects. • Polysaccharides: Acidic heteroglycans and arabinogalactans present in the herb may contribute to mild immunomodulatory effects. • Essential oil (0.1–0.5%): Contains α-pinene, myrcene, germacrene D, limonene, and sabinene among others. • Tannins (~3–5%): Condensed tannins contribute to astringent and mild antimicrobial properties. Minerals (per dried herb, approximate): • Potassium: relatively high, contributing to the aquaretic (water-eliminating without excessive electrolyte loss) diuretic effect • Calcium, magnesium, and silicon: present in moderate trace amounts typical of herbaceous Asteraceae plants • Iron and manganese: trace quantities Vitamins: Not a significant source of vitamins at standard medicinal doses (typically 3–5 g dried herb per day as infusion, or 350–700 mg standardized dry extract). Bioavailability Notes: • Flavonoid glycosides (rutin, astragalin) require deglycosylation by intestinal enzymes or colonic microbiota before aglycone absorption; peak plasma levels of quercetin from rutin appear ~6 hours post-ingestion. • Saponins have generally low oral bioavailability (<5%) but exert local effects in the gastrointestinal and urinary tracts; renal excretion of metabolites may explain urinary tract activity. • Leiocarposide is hydrolyzed to its active aglycone in the GI tract; absorption kinetics are not well characterized in humans. • Aqueous extraction (traditional tea infusion) preferentially extracts flavonoid glycosides, phenolic acids, and polysaccharides; hydroethanolic extracts (40–60% ethanol) yield higher concentrations of saponins and diterpenes.