Herbs in oral care – neem and clove MCQs With Answer

Herbs in oral care are increasingly important in B. Pharm curricula because of their bioactive phytochemicals and clinical relevance. This concise overview emphasizes two key botanicals — neem (Azadirachta indica) and clove (Syzygium aromaticum) — highlighting antimicrobial, anti-inflammatory, analgesic, antioxidant actions and formulation roles in toothpaste, mouthwash, temporary dental cements, and mucoadhesive gels. Topics include active constituents (azadirachtin, nimbidin, eugenol), mechanisms of action, extraction and standardization (GC-MS, MIC), stability and compatibility, safety/adverse effects, and evidence from in vitro and clinical studies. Understanding these herbs supports rational formulation design and patient counseling. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which active constituent of clove is primarily responsible for its analgesic and antiseptic effects?

• Eugenol
• Thymol
• Menthol
• Azadirachtin

Correct Answer: Eugenol

Q2. Azadirachta indica is known for a major limonoid with insecticidal and antimicrobial activity. Which compound is this?

• Azadirachtin
• Quercetin
• Eucalyptol
• Eugenol

Correct Answer: Azadirachtin

Q3. What is the primary molecular mechanism by which eugenol produces local analgesia in dental applications?

• Blockade of voltage-gated sodium channels
• Inhibition of acetylcholinesterase
• Opioid receptor agonism
• Monoamine reuptake inhibition

Correct Answer: Blockade of voltage-gated sodium channels

Q4. Why is zinc oxide–eugenol a commonly used dental material in temporary restorations?

• It forms a chelate with zinc oxide producing a sealing paste
• It polymerizes to form a hard resin matrix
• It acts as a systemic analgesic when absorbed
• It neutralizes oral pH permanently

Correct Answer: It forms a chelate with zinc oxide producing a sealing paste

Q5. Which mechanism best explains neem’s antiplaque activity?

• Inhibition of bacterial adhesion and biofilm formation
• Systemic immunosuppression
• Stimulation of salivary proteases
• Neutralization of enamel minerals

Correct Answer: Inhibition of bacterial adhesion and biofilm formation

Q6. Which solvent is most commonly used to extract eugenol-rich fraction from clove buds for oral formulations?

• Ethanol
• Water
• n-Hexane
• Carbon tetrachloride

Correct Answer: Ethanol

Q7. The antimicrobial action of clove (eugenol) against oral pathogens is mainly due to which effect on microbial cells?

• Disruption of cell membrane integrity and increased permeability
• Inhibition of DNA gyrase only
• Chelation of essential metal ions exclusively
• Competitive inhibition of peptidoglycan synthesis

Correct Answer: Disruption of cell membrane integrity and increased permeability

Q8. Which cariogenic oral bacterium is frequently targeted and inhibited by neem and clove extracts?

• Streptococcus mutans
• Lactobacillus acidophilus
• Escherichia coli
• Staphylococcus aureus

Correct Answer: Streptococcus mutans

Q9. Which compound is commonly used as a standardization marker in quality control of neem extracts?

• Azadirachtin
• Salicylic acid
• Eugenol
• Caffeine

Correct Answer: Azadirachtin

Q10. What is a common adverse effect associated with topical use of eugenol in dental practice?

• Contact allergy and mucosal irritation
• Renal failure
• Hypertension
• Severe hypoglycemia

Correct Answer: Contact allergy and mucosal irritation

Q11. Which laboratory assay is standard for quantifying the minimum inhibitory concentration of neem or clove extracts against oral bacteria?

• MIC determination (broth microdilution)
• ELISA for antibodies
• Western blot for proteins
• Hemagglutination assay

Correct Answer: MIC determination (broth microdilution)

Q12. Eugenol belongs to which chemical class of plant secondary metabolites?

• Phenylpropanoids
• Alkaloids
• Cardiac glycosides
• Saponins

Correct Answer: Phenylpropanoids

Q13. Neem’s anti-inflammatory effects in periodontal contexts are mainly mediated by which action?

• Inhibition of inflammatory mediators (prostaglandins, cytokines)
• Direct opioid receptor activation
• Promotion of pro-inflammatory cytokines
• Induction of histamine release

Correct Answer: Inhibition of inflammatory mediators (prostaglandins, cytokines)

Q14. What is a major formulation stability concern when incorporating eugenol into oral care products?

• Volatility and oxidative degradation of eugenol
• Extreme water solubility causing leaching
• Crystallization at room temperature
• Polymerization into insoluble resin

Correct Answer: Volatility and oxidative degradation of eugenol

Q15. For sustained local action on oral mucosa, which dosage form is most appropriate for delivering neem or clove actives?

• Mucoadhesive gel
• Immediate-release tablet
• Standard mouthwash rinse
• Oral capsule for systemic absorption

Correct Answer: Mucoadhesive gel

Q16. Which statement best reflects clinical evidence comparing neem mouthwash to chlorhexidine for plaque control?

• Some clinical trials show neem mouthwash comparable to chlorhexidine in reducing plaque
• Neem mouthwash is universally superior to chlorhexidine in all studies
• No clinical trial has evaluated neem versus chlorhexidine
• Neem mouthwash causes systemic toxicity, so it cannot be compared

Correct Answer: Some clinical trials show neem mouthwash comparable to chlorhexidine in reducing plaque

Q17. Which class of phytochemicals in neem contributes significantly to its antioxidant activity?

• Flavonoids
• Polypeptides
• Steroid hormones
• Simple sugars

Correct Answer: Flavonoids

Q18. Zinc oxide–eugenol material is primarily indicated as which dental product?

• Temporary cement
• Definitive resin composite restoration
• Systemic antibiotic
• Anticariogenic varnish

Correct Answer: Temporary cement

Q19. Neem extracts can reduce cariogenicity by inhibiting which bacterial enzyme involved in glucan synthesis?

• Glucosyltransferase (GTF)
• DNA polymerase
• Lactate dehydrogenase
• ATP synthase

Correct Answer: Glucosyltransferase (GTF)

Q20. Which analytical technique is most suitable for qualitative and quantitative analysis of eugenol in clove oil?

• Gas chromatography–mass spectrometry (GC-MS)
• Atomic absorption spectroscopy (AAS)
• Polarimetry
• Viscometry

Correct Answer: Gas chromatography–mass spectrometry (GC-MS)

Q21. Why should eugenol-containing materials be avoided under resin-based permanent restorations?

• Eugenol inhibits polymerization of resin composites
• Eugenol strengthens resin bonding excessively
• Eugenol causes rapid resin polymerization
• Eugenol converts resins into soluble salts

Correct Answer: Eugenol inhibits polymerization of resin composites

Q22. Compared to lidocaine, topical eugenol used in dental pain is generally:

• Less potent with shorter duration of action
• More potent and longer lasting
• Equivalent in potency and duration
• Ineffective as an analgesic

Correct Answer: Less potent with shorter duration of action

Q23. Which major phytochemical group is abundant in neem bark and contributes to its biological effects?

• Limonoids (triterpenoids)
• Anthraquinones
• Cardenolides
• Cyanogenic glycosides

Correct Answer: Limonoids (triterpenoids)

Q24. What formulation strategy can reduce volatility and control release of clove oil in an oral product?

• Microencapsulation of clove oil
• Complete removal of oil and use of water only
• Dry heating at high temperature
• Adding strong acids to the formulation

Correct Answer: Microencapsulation of clove oil

Q25. Which oral complaint is clove oil traditionally used to relieve?

• Toothache (dental pain)
• Chronic otitis media
• Urinary incontinence
• Systemic hypertension

Correct Answer: Toothache (dental pain)

Q26. In microbiology reports, minimum inhibitory concentration (MIC) is most commonly expressed in which units?

• Micrograms per milliliter (µg/mL)
• Grams per liter (g/L)
• Moles per liter (M)
• Percent weight/volume (%)

Correct Answer: Micrograms per milliliter (µg/mL)

Q27. High concentrations of undiluted clove oil applied to oral mucosa can cause which adverse effect?

• Mucosal ulceration and severe irritation
• Permanent tooth enamel remineralization
• Systemic hypocoagulability
• Enhanced taste sensitivity

Correct Answer: Mucosal ulceration and severe irritation

Q28. Neem formulations have demonstrated inhibitory activity against which periodontal pathogen?

• Porphyromonas gingivalis (anaerobic gram-negative)
• Mycobacterium tuberculosis
• Clostridium difficile
• Human influenza virus

Correct Answer: Porphyromonas gingivalis (anaerobic gram-negative)

Q29. Which microscopic diagnostic feature is characteristic of clove bud powder in pharmacognostic analysis?

• Numerous oil cells/oleoresin-containing glands
• Simple unbranched trichomes only
• Calcium oxalate raphides exclusively
• Distinct lignified fibers with spiral thickening

Correct Answer: Numerous oil cells/oleoresin-containing glands

Q30. To improve oxidative stability of eugenol in an oral formulation, which additive is most appropriate?

• Tocopherol (vitamin E) antioxidant
• Sodium hypochlorite as oxidizer
• Hydrochloric acid for acidification
• High concentrations of hydrogen peroxide

Correct Answer: Tocopherol (vitamin E) antioxidant

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