Petasites hybridus

Petasites hybridus (butterbur) is a medicinal herb rather than a dietary staple, so its nutritional profile is characterized primarily by bioactive compounds rather than conventional macronutrients. Raw rhizome contains approximately 80-85% water, with dry matter comprising roughly 10-15% carbohydrates (including inulin-type fructans and mucilages), 2-4% crude fiber, 1-2% protein, and <1% fat. Micronutrient content is modest: potassium (~300-400 mg/100g fresh weight), calcium (~40-60 mg/100g), magnesium (~15-25 mg/100g), and trace amounts of iron and zinc. The dominant bioactive compounds are sesquiterpene esters known as petasins: petasin and isopetasin (combined concentration 0.1-0.4% in raw rhizome dry weight; standardized commercial extracts such as Ze339 and Petadolex are typically standardized to ≥7.5 mg petasin per tablet). These petasins are lipophilic and demonstrate good oral bioavailability, with peak plasma concentrations reached within 1-2 hours post-ingestion. Pyrrolizidine alkaloids (PAs) including senecionine and integerrimine are present in raw plant material at potentially hepatotoxic concentrations (up to 0.5% dry weight) and must be removed in certified PA-free extracts (<0.08 mcg/daily dose per European regulatory guidance). Additional bioactives include flavonoids (isoquercitrin, astragalin; ~0.1-0.3% dry weight), caffeic acid derivatives, and volatile terpenoids. Petasin bioavailability is enhanced by lipid co-ingestion due to its lipophilic nature. Vitamin content is negligible from a nutritional standpoint.