Possible interactions between chemicals and herbs MCQs With Answer

This quiz collection focuses on possible interactions between chemicals and herbs relevant to herbal cosmetics, designed specifically for M.Pharm students. It highlights mechanistic details—such as phototoxicity, enzyme induction/inhibition, metal chelation, redox reactions, and formulation incompatibilities—that can alter safety, efficacy and stability of topical products. Questions cover common herb constituents (terpenes, polyphenols, coumarins, pyrrolizidine alkaloids), typical excipient and preservative interactions, and practical formulation strategies (stabilizers, encapsulation, heat inactivation, analytical testing). Use these MCQs to deepen understanding of how botanical ingredients interact chemically and biologically with cosmetic chemicals, and to guide rational formulation and risk assessment in phytocosmetic development.

Q1. Which herb-derived ingredient is most commonly associated with phototoxic reactions in topical cosmetics?

• Aloe vera
• Bergamot oil (contains bergapten)
• Chamomile
• Neem oil

Correct Answer: Bergamot oil (contains bergapten)

Q2. Which additive is most appropriate to stabilize ascorbic acid against metal-catalyzed oxidation in herbal formulations?

• Parabens
• EDTA (a chelating agent)
• Tocopherol
• Xanthan gum

Correct Answer: EDTA (a chelating agent)

Q3. Tannins present in many plant extracts may reduce percutaneous absorption of co-formulated actives mainly by which mechanism?

• Increasing skin pH
• Forming insoluble complexes with proteins and alkaloids (protein precipitation)
• Acting as strong surfactants
• Generating free radicals that degrade actives

Correct Answer: Forming insoluble complexes with proteins and alkaloids (protein precipitation)

Q4. Oxidation of which terpene commonly found in citrus oils leads to formation of strong skin sensitizers on storage?

• Linalool
• Limonene
• Cineole
• Geraniol

Correct Answer: Limonene

Q5. St. John’s wort (Hypericum perforatum) is known for causing drug interactions due to which primary biochemical effect?

• Inhibition of monoamine oxidase A
• Induction of CYP3A4 and P-glycoprotein expression
• Direct covalent binding to drugs
• Chelation of divalent metal ions

Correct Answer: Induction of CYP3A4 and P-glycoprotein expression

Q6. Anthocyanin-rich botanical extracts may show unstable coloration in a cosmetic product primarily because they are sensitive to which factor?

• Microbial contamination only
• pH changes (color shift with pH)
• Shear during mixing
• Presence of nonionic surfactants

Correct Answer: pH changes (color shift with pH)

Q7. Saponin-containing herbal extracts can interact with surfactants in a formulation to produce which likely outcome?

• Complete neutralization of fragrance
• Increased foaming and potential skin irritation
• Fixed discoloration to a permanent brown
• Enhanced preservative efficacy

Correct Answer: Increased foaming and potential skin irritation

Q8. Which traditional herbal remedy contains pyrrolizidine alkaloids and poses a risk of hepatotoxicity when co-used with hepatotoxic chemicals?

• Chamomile
• Comfrey (Symphytum officinale)
• Aloe vera
• Green tea

Correct Answer: Comfrey (Symphytum officinale)

Q9. The blackening or brown discoloration observed in some tannin-containing herbal formulations is most commonly caused by interaction with which contaminant?

• Sodium chloride
• Ferric (iron) ions
• Isopropyl alcohol
• Sorbitol

Correct Answer: Ferric (iron) ions

Q10. Many essential oil terpenes (e.g., menthol, limonene) act as penetration enhancers by which primary mechanism?

• Forming permanent covalent bonds with keratin
• Disrupting stratum corneum lipid packing to increase permeability
• Increasing skin hydration by binding water molecules
• Raising the pH of the skin surface

Correct Answer: Disrupting stratum corneum lipid packing to increase permeability

Q11. Which botanical extract contains glabridin and is known to inhibit tyrosinase activity, potentially interacting with other depigmenting actives?

• Rosemary
• Licorice (Glycyrrhiza glabra)
• Neem
• Aloe vera

Correct Answer: Licorice (Glycyrrhiza glabra)

Q12. Furocoumarins (e.g., bergapten) cause phototoxicity by which photochemical mechanism when present in topical products?

• UVA-mediated formation of DNA adducts and crosslinks
• Direct thermal denaturation of collagen
• Neutralization of UV filters
• Chelation of sunscreen actives

Correct Answer: UVA-mediated formation of DNA adducts and crosslinks

Q13. Which factor commonly associated with botanical extracts most strongly reduces the efficacy of standard cosmetic preservatives?

• Low viscosity of the final product
• High organic load (high concentration of plant solids and sugars)
• Presence of volatile fragrance only
• Use of opaque packaging

Correct Answer: High organic load (high concentration of plant solids and sugars)

Q14. Browning of fresh herbal aqueous extracts due to polyphenol oxidase can be minimized in processing by which method?

• Adding more sugar
• Heat inactivation (blanching or pasteurization) to denature enzymes
• Lowering storage temperature to -80°C without treatment
• Adding fragrance oils

Correct Answer: Heat inactivation (blanching or pasteurization) to denature enzymes

Q15. Which class of green tea constituents is primarily responsible for strong metal chelation and antioxidant interactions in formulations?

• Caffeine alkaloids
• Catechins (polyphenols)
• Essential oils
• Polysaccharides

Correct Answer: Catechins (polyphenols)

Q16. Willow bark extract contains salicylates; co-application with other salicylate-containing cosmetics can increase the risk of which systemic effect?

• Hypertension
• Systemic salicylate exposure and potential salicylate toxicity
• Hypoglycemia
• Renal calcification

Correct Answer: Systemic salicylate exposure and potential salicylate toxicity

Q17. Which herbal supplement commonly implicated in enhanced bleeding risk might interact with topical or systemic anticoagulants if absorption occurs?

• Ginkgo biloba
• St. John’s wort
• Licorice
• Green tea (in normal cosmetic doses)

Correct Answer: Ginkgo biloba

Q18. To detect chemical incompatibilities between a botanical extract and an active cosmetic ingredient during development, which analytical approach is most appropriate?

• Forced degradation/stress testing with HPLC analysis
• Only organoleptic (smell/taste) testing
• Simple visual inspection after 24 hours
• Measuring refractive index only

Correct Answer: Forced degradation/stress testing with HPLC analysis

Q19. When high levels of polyphenolic antioxidants in an extract consume oxidizing preservatives (e.g., peroxides) this interaction is best described as what?

• Chelation reaction
• Redox (antioxidant–preservative) reaction leading to preservative depletion
• Physical adsorption only
• pH buffering

Correct Answer: Redox (antioxidant–preservative) reaction leading to preservative depletion

Q20. Which formulation strategy most effectively minimizes direct chemical interactions between a reactive botanical extract and co-formulated actives or preservatives?

• Add the extract last without further processing
• Microencapsulation or liposomal encapsulation of the extract
• Increase water activity of the product
• Reduce cosmetic viscosity only

Correct Answer: Microencapsulation or liposomal encapsulation of the extract

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