Question

The oil of Cymbopoganflexuosus contains one of the following

• A. Citral
• B. Alpha-Terpienol
• C. Alpha pinene
• D. Nerol

Hint:

Citral is a key component of lemongrass oil, known for its lemon-like fragrance and used in various fragrance and flavor products.

Answer 1

The Correct Option is A

Step 1: Understanding the oil composition.
Cymbopogan flexuosus, also known as lemongrass, is a plant known for its essential oil, which is rich in citral. Citral is a mixture of two isomers, geranial and neral, and gives the oil its characteristic lemon-like fragrance.
Step 2: Analyzing the options.
(A) Citral: Correct — The oil from Cymbopogan flexuosus is rich in citral, making it an important compound used in perfumery and aromatherapy.
(B) Alpha-Terpienol: This compound is typically found in other essential oils, not in Cymbopogan flexuosus.
(C) Alpha pinene: Alpha pinene is found in pine and other coniferous trees, not in lemongrass oil.
(D) Nerol: Nerol is a compound found in some essential oils but is not a major component of Cymbopogan flexuosus.
Step 3: Conclusion.
The correct answer is (A) Citral as it is the primary component of Cymbopogan flexuosus oil.

Answer 2

We can identify the compound by first grouping these four terpenoid-type chemicals by structure, then matching each to its known plant source.

1. Citral: Citral is an acyclic monoterpene aldehyde (a mixture of the geranial and neral isomers) that gives lemongrass oil its sharp lemon-like smell; lemongrass is the common name for Cymbopogon flexuosus, so this matches the plant in question directly.
2. Alpha-Terpineol: This is a monoterpene alcohol with a lilac-like odour, more typically associated with pine oil and eucalyptus-type oils, not the defining constituent of lemongrass oil.
3. Alpha pinene: This is a bicyclic monoterpene hydrocarbon that is the chief constituent of turpentine from pine and other conifers, structurally and botanically unrelated to lemongrass oil.
4. Nerol: Nerol is a monoterpene alcohol found in small amounts in oils like rose and neroli oil; it is chemically related to citral (citral is essentially its oxidised aldehyde form) but is not itself the main constituent reported for Cymbopogon flexuosus.

Matching the compound to its known botanical source, lemongrass oil (from Cymbopogon flexuosus) is characterised chemically by its high citral content.

Therefore, the correct answer is Citral.