Rauwolfia alkaloids are a clinically important group of indole alkaloids derived from Rauwolfia serpentina and related species. For B. Pharm students, mastering key compounds — reserpine, ajmaline, ajmalicine (raubasine), deserpidine and rescinnamine — is essential to understand their pharmacology, mechanisms (VMAT inhibition, antiarrhythmic effects), therapeutic applications (antihypertensive, antipsychotic, antiarrhythmic), adverse effects (depression, sedation, nasal congestion) and drug interactions. This concise review emphasizes chemical classification, extraction, stability, pharmacokinetics, dosing and clinical implications to build both factual recall and applied reasoning. Focused learning of these alkaloids strengthens exam readiness and clinical decision-making. Answers are provided for self-assessment. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which part of Rauwolfia serpentina is the primary source of pharmacologically active alkaloids?
- Leaves
- Seeds
- Roots
- Flowers
Correct Answer: Roots
Q2. Rauwolfia alkaloids belong to which chemical class?
- Isoquinoline alkaloids
- Pyrrolizidine alkaloids
- Indole alkaloids
- Quinoline alkaloids
Correct Answer: Indole alkaloids
Q3. Which Rauwolfia alkaloid is best known for irreversible inhibition of vesicular monoamine transporters (VMAT)?
- Ajmaline
- Reserpine
- Ajmalicine
- Yohimbine
Correct Answer: Reserpine
Q4. The primary antihypertensive action of reserpine is due to:
- Direct vasodilation of arterioles
- Beta-adrenergic blockade
- Depletion of peripheral and central catecholamines
- Calcium channel blockade
Correct Answer: Depletion of peripheral and central catecholamines
Q5. Ajmaline is pharmacologically classified as which type of antiarrhythmic?
- Class I (sodium channel blocker)
- Class II (beta blocker)
- Class III (potassium channel blocker)
- Class IV (calcium channel blocker)
Correct Answer: Class I (sodium channel blocker)
Q6. Which clinical application is historically associated with reserpine?
- Management of diabetes mellitus
- Treatment of hypertension and certain psychoses
- Treatment of bacterial infections
- Management of asthma
Correct Answer: Treatment of hypertension and certain psychoses
Q7. A major central adverse effect of reserpine related to monoamine depletion is:
- Hypomania
- Depression
- Hyperactivity
- Insomnia
Correct Answer: Depression
Q8. Which of the following Rauwolfia alkaloids is commonly used as a vasodilator in cerebrovascular insufficiency?
- Deserpidine
- Ajmalicine (raubasine)
- Reserpine
- Rescinnamine
Correct Answer: Ajmalicine (raubasine)
Q9. Rescinnamine differs from reserpine mainly by:
- Being a beta blocker rather than an alkaloid
- Longer duration of antihypertensive action
- Having no effect on monoamines
- Being water-insoluble and inactive orally
Correct Answer: Longer duration of antihypertensive action
Q10. The biochemical precursor for most indole alkaloids in Rauwolfia is:
- Phenylalanine
- Tryptophan
- Tyramine
- Histidine
Correct Answer: Tryptophan
Q11. Which analytical method is most commonly used for simultaneous quantification of Rauwolfia alkaloids in extracts?
- Thin-layer chromatography only
- High-performance liquid chromatography (HPLC)
- Colorimetry using metallic salts
- Gravimetric analysis
Correct Answer: High-performance liquid chromatography (HPLC)
Q12. Deserpidine is best described as:
- An alpha-2 agonist from Rauwolfia
- An analogue of reserpine with antihypertensive activity
- A selective serotonin reuptake inhibitor
- A calcium channel blocker alkaloid
Correct Answer: An analogue of reserpine with antihypertensive activity
Q13. Which property best describes reserpine’s interaction with VMAT?
- Reversible competitive inhibition
- Irreversible inhibition leading to prolonged effect
- Enhances vesicular uptake of monoamines
- Blocks only serotonin uptake selectively
Correct Answer: Irreversible inhibition leading to prolonged effect
Q14. Which adverse effect is commonly seen early after starting reserpine therapy?
- Tachycardia
- Postural hypotension and nasal congestion
- Hyperglycemia
- Urinary retention
Correct Answer: Postural hypotension and nasal congestion
Q15. Which storage/handling precaution is important for reserpine-containing formulations?
- Store exposed to light for stability
- Keep in acidic, refrigerated conditions to prevent degradation
- Store at high temperature for activation
- No special precautions required
Correct Answer: Keep in acidic, refrigerated conditions to prevent degradation
Q16. Which clinical test uses ajmaline as a pharmacologic provocation?
- Vasovagal syncope stress test
- Brugada syndrome diagnostic test
- Orthostatic hypotension challenge
- AV nodal reentrant tachycardia induction
Correct Answer: Brugada syndrome diagnostic test
Q17. Which statement about ajmaline’s mechanism is correct?
- It blocks potassium channels predominantly
- It blocks cardiac sodium channels and slows conduction
- It stimulates beta-1 receptors in the heart
- It acts as a muscarinic receptor agonist
Correct Answer: It blocks cardiac sodium channels and slows conduction
Q18. Which of the following is a contraindication for reserpine therapy?
- Chronic obstructive pulmonary disease
- History of major depressive disorder
- Mild seasonal allergies
- Controlled hypothyroidism
Correct Answer: History of major depressive disorder
Q19. Which solvent is typically effective for initial extraction of Rauwolfia alkaloids from root powder?
- Distilled water only
- Nonpolar solvent like hexane only
- Alcoholic solvents such as ethanol or methanol
- Saturated brine solution
Correct Answer: Alcoholic solvents such as ethanol or methanol
Q20. Which effect is expected when reserpine is combined with other antihypertensive agents?
- Antagonism leading to hypertension
- Additive hypotensive effect
- No interaction at all
- Immediate tachyphylaxis
Correct Answer: Additive hypotensive effect
Q21. Which alkaloid is associated with fewer central nervous system depressive effects compared with reserpine?
- Reserpine
- Deserpidine
- Ajmaline
- Rescinnamine
Correct Answer: Deserpidine
Q22. Which pharmacokinetic feature explains reserpine’s long duration of action?
- Rapid renal excretion within hours
- Irreversible VMAT binding and slow catecholamine resynthesis
- Extensive first-pass metabolism making it inactive
- High plasma protein binding that is easily reversible
Correct Answer: Irreversible VMAT binding and slow catecholamine resynthesis
Q23. Which laboratory assay is most suitable to detect reserpine in plasma during pharmacokinetic studies?
- ELISA using monoclonal antibodies
- HPLC coupled with mass spectrometry (HPLC-MS)
- Total nitrogen estimation
- Flame photometry
Correct Answer: HPLC coupled with mass spectrometry (HPLC-MS)
Q24. A patient on reserpine develops parkinsonian symptoms; this is most likely due to:
- Direct blockade of peripheral dopamine receptors
- Central dopamine depletion from VMAT inhibition
- Excess dopamine release in basal ganglia
- Allergic reaction to the plant extract
Correct Answer: Central dopamine depletion from VMAT inhibition
Q25. Which structural feature is characteristic of many Rauwolfia alkaloids?
- Benzodiazepine ring system
- Indole nucleus derived from tryptamine
- Steroid nucleus
- Pyridine ring only
Correct Answer: Indole nucleus derived from tryptamine
Q26. Which of the following is an expected pharmacodynamic consequence of chronic reserpine therapy?
- Upregulation of VMAT expression within hours
- Reduced sympathetic tone and decreased heart rate and blood pressure
- Permanent increase in plasma catecholamines
- Immediate rebound hypertension after first dose
Correct Answer: Reduced sympathetic tone and decreased heart rate and blood pressure
Q27. In quality control of Rauwolfia roots, which contaminant is of particular regulatory concern?
- Heavy metals and microbial contamination
- Excessive simple sugars
- High fiber content
- Excess chlorophyll
Correct Answer: Heavy metals and microbial contamination
Q28. Which clinical monitoring parameter is most important when initiating reserpine therapy?
- Liver ultrasound every week
- Frequent blood pressure and mental status assessment
- Daily ECG for arrhythmias only
- Serum glucose monitoring hourly
Correct Answer: Frequent blood pressure and mental status assessment
Q29. Which statement about the solubility of Rauwolfia alkaloids is true?
- They are highly soluble in nonpolar solvents like hexane
- They form basic salts and are readily extractable with acidic aqueous solutions or alcohols
- They are insoluble in most organic solvents and only dissolve in water
- They are volatile gases at room temperature
Correct Answer: They form basic salts and are readily extractable with acidic aqueous solutions or alcohols
Q30. Which educational focus will best help a B. Pharm student integrate Rauwolfia alkaloid knowledge clinically?
- Memorizing plant morphology only
- Understanding chemical structure, mechanism, therapeutic use and adverse effects
- Studying only traditional uses without pharmacology
- Focusing solely on cultivation techniques
Correct Answer: Understanding chemical structure, mechanism, therapeutic use and adverse effects
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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