Yohimbe (Pausinystalia johimbe)

Yohimbe bark (Pausinystalia johimbe) is not consumed as a food source but rather as a pharmacologically active herbal preparation. Its value lies entirely in its bioactive alkaloid profile rather than macronutrient content. Primary Bioactive Alkaloid: • Yohimbine (indole alkaloid, alpha-2 adrenergic antagonist) — bark contains approximately 1–6% total alkaloids by dry weight, with yohimbine comprising roughly 10–15% of total alkaloid fraction, yielding approximately 1,000–15,000 mg/kg (0.1–1.5%) yohimbine in raw bark depending on source, age, and preparation method. Typical standardized extracts deliver 2–8 mg yohimbine per dose. Secondary/Related Alkaloids: • Corynanthine (rauwolscine/alpha-yohimbine) — approximately 0.1–0.5% of bark dry weight; acts as alpha-2 antagonist with slightly different receptor selectivity than yohimbine • Ajmalicine (raubasine) — approximately 0.05–0.3%; mild cerebrovascular vasodilator • Corynantheine — trace to 0.1%; mild alpha-adrenergic activity • Allo-yohimbine — trace amounts; stereoisomer of yohimbine with reduced potency • Dihydrocorynantheine — trace amounts • Pseudoyohimbine — trace amounts; weaker alpha-2 antagonism. Minor Constituents: • Tannins (condensed and hydrolyzable) — approximately 5–12% of bark dry weight; may affect GI absorption of co-consumed substances • Proanthocyanidins — variable amounts contributing to astringency • Plant sterols (beta-sitosterol, stigmasterol) — trace quantities • Saponins — minor amounts • Cellulose and lignin — bulk structural carbohydrates (not nutritionally relevant). Mineral Content (trace, per gram of bark): • Potassium, calcium, magnesium, iron, manganese — present in negligible nutritional quantities typical of tree bark matrices. Bioavailability Notes: • Oral bioavailability of yohimbine from raw bark is approximately 20–33%, with significant first-pass hepatic metabolism via CYP3A4 and CYP2D6 enzymes. • Peak plasma levels achieved in 45–90 minutes post-ingestion. • Half-life of yohimbine is approximately 0.5–2.5 hours (highly variable due to CYP2D6 polymorphisms — poor metabolizers may experience 3–5× higher plasma concentrations). • Tannins in raw bark may partially reduce alkaloid absorption compared to purified yohimbine HCl, though some evidence suggests the full-spectrum bark extract produces a more gradual absorption curve. • The presence of corynanthine and other alkaloids in whole bark may modulate the pharmacological profile compared to isolated yohimbine. • Alkaloid extraction efficiency increases substantially with ethanol-based preparations (70–90% ethanol) versus water decoctions (approximately 30–50% alkaloid recovery). • No significant macronutrient (protein, fat, carbohydrate), vitamin, or dietary fiber value — yohimbe bark is classified strictly as a pharmacological botanical, not a nutritional supplement.