Hermetica Superfood Encyclopedia
Legacy index-continuity record: the score and narrative are provisional and must not be represented as validated or human-approved.
Review flags: AWAITING_SEMANTIC_VALIDATION
Foxglove (Digitalis purpurea) contains cardiac glycosides including digoxin that strengthen heart muscle contractions by inhibiting sodium-potassium ATPase pumps. The raw plant is extremely toxic and only pharmaceutical preparations of isolated compounds are used medically.
Origin & History
Foxglove (Digitalis purpurea) is a biennial herbaceous plant native to western Europe, belonging to the Scrophulariaceae family, with leaves serving as the primary source for medicinal extracts. Extracts are typically obtained from dried leaves using methanolic or other solvent methods, yielding cardiac glycosides including digitoxin and related compounds as the main chemical constituents.
Research Narrative (Provisional)
Search results lack human clinical trials, RCTs, or meta-analyses specifically on Digitalis purpurea herb or extracts; evidence focuses on purified derivatives like digoxin. Two double-blind, placebo-controlled trials on digoxin (not raw herb) showed successful withdrawal in elderly patients with stable congestive heart failure and benefit in chronic heart failure patients with S3 gallop (sample sizes not specified in abstracts). No PubMed PMIDs for herb-specific RCTs were found.
Preparation & Dosage
Dosage guidance is withheld because the publication gate has not recorded adequate support for this profile.
Nutritional Profile
Foxglove (Digitalis purpurea) is not a nutritional food source and contains no meaningful macronutrient profile for dietary purposes. Its significance lies entirely in its bioactive secondary metabolites. Cardenolide cardiac glycosides are the primary compounds: digoxin (0.1–0.3% dry weight of leaves), digitoxin (0.2–0.4% dry weight), and gitoxin (trace to 0.1% dry weight). Digoxin concentration varies significantly by plant part — mature second-year leaves harvested before flowering contain the highest glycoside concentrations. Lanatoside C (a precursor glycoside) is present at approximately 0.1–0.2% dry weight. Secondary bioactives include digitalinum verum, gitaloxin, and odoroside. Flavonoids including luteolin and apigenin glycosides are present at low concentrations (estimated 0.5–1% dry weight total). Anthraquinones are absent. Saponins occur at trace levels. Mineral content includes potassium, calcium, and magnesium in amounts typical of leafy plants but nutritionally irrelevant given toxicity constraints. Crude fiber is present as with most leaves (~15–20% dry weight) but not bioavailable for human dietary use. Protein content is approximately 10–15% dry weight, again irrelevant due to toxicity. Bioavailability note: cardiac glycosides are highly bioavailable orally (digoxin ~70–80% absorption), which underpins both therapeutic utility and extreme toxicity risk — the therapeutic index is dangerously narrow with toxic dose only marginally above therapeutic dose.
Reported Mechanism (Provisional)
Foxglove's cardiac glycosides (digoxin, digitoxin) bind to and inhibit Na+/K+-ATPase pumps in cardiac cell membranes, increasing intracellular sodium levels. This leads to increased intracellular calcium through the sodium-calcium exchanger, resulting in stronger myocardial contractions (positive inotropy). The compounds also slow electrical conduction through the AV node, reducing heart rate.
Clinical Narrative (Provisional)
Purified digoxin from foxglove has demonstrated efficacy in heart failure patients in multiple randomized controlled trials, including the DIG trial with 6,800 participants showing reduced hospitalizations. Studies specifically examined patients with systolic heart failure and S3 gallop sounds. However, clinical evidence applies only to pharmaceutical-grade isolated compounds, not whole plant preparations. The raw herb lacks standardization and poses significant toxicity risks.
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