Question

Etoposide and Teniposide are the semi-synthetic derivatives of:

• A. Podophyllotoxin
• B. Digoxin
• C. Vincristine
• D. Taxol

Hint:

Podophyllotoxin is a precursor for the synthesis of key anticancer drugs like Etoposide and Teniposide, which work by inhibiting DNA synthesis in rapidly dividing cells.

Answer 1

The Correct Option is A

Semi-synthetic drugs start from a natural lead compound that is then chemically modified to improve its properties, so identifying the plant source behind etoposide and teniposide answers this question.

1. Podophyllotoxin: Isolated from Podophyllum species, this lignan compound binds tubulin in its natural form, but its high toxicity ruled it out as a drug on its own. Chemists attached a glucopyranoside sugar group to make etoposide, and a thienylidene glucoside group to make teniposide, both of which shift the mechanism toward inhibiting topoisomerase II and allow the drugs to be used safely as chemotherapy agents.
2. Digoxin: This is a steroid glycoside from foxglove used for cardiac conditions, unrelated in both source plant and mechanism to etoposide and teniposide.
3. Vincristine: This vinca alkaloid is a natural product used directly as a chemotherapy drug, not a starting material that gets converted into etoposide or teniposide.
4. Taxol: Sourced from yew bark, taxol works through a microtubule-stabilising mechanism that is unrelated to the topoisomerase inhibiting, podophyllotoxin derived drugs in question.

Given that both etoposide and teniposide are made by modifying podophyllotoxin, the correct answer is Podophyllotoxin.