A corynanthe-type indole alkaloid present in yohimbe bark (Pausinystalia johimbe) that shares the pentacyclic indole core of yohimbine. Functional studies in pithed rats show it acts as a preferential α₁-adrenoceptor antagonist (PMID:3021076). Marketed elsewhere (as raubasine) as a cerebral vasodilator; quantitative human receptor pharmacology and clinical PK are not characterised. It is also a potent inhibitor of human CYP2D6 (Ki ≈ 3.3 nM; GtoPdb, PMID:8487254), a potential basis for pharmacokinetic interactions.
Target Organ Systems
nervous
cardiovascular
Interactions
Dextromethorphan (caution): Dextromethorphan is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Dextromethorphan levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Metoprolol (caution): Metoprolol is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Metoprolol levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Atomoxetine (caution): Atomoxetine is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Atomoxetine levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Desipramine (caution): Desipramine is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Desipramine levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Nortriptyline (caution): Nortriptyline is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Nortriptyline levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Risperidone (caution): Risperidone is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Risperidone levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Aripiprazole (caution): Aripiprazole is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Aripiprazole levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Nebivolol (caution): Nebivolol is a CYP2D6 substrate; ajmalicine (raubasine) is a potent in-vitro CYP2D6 inhibitor (Ki 3.3 nM), so co-exposure could raise Nebivolol levels. In-vitro potency — clinically relevant at raubasine drug doses; from yohimbe, ajmalicine is a trace constituent.
Notes
PubChem CID 441975 (C21H24N2O3, MW 352.4). Present in yohimbe bark: PMID:23657953 (UPLC-IM-QTOF profile; "yohimbine or ajmalicine core structure") + PMID:25905738.