Question

Which of the following statement/s are correct regarding the alkylating agents as anticancer agents:
A. They get converted into highly nucleophilic anions and bind to the nitrogen atom of guanine intercalating the DNA strands
B. Cyclophosphamide and busulfan belong to this class 
C. They inhibit the DNA synthesis by inhibiting the DNA polymerase enzyme 
D. They inhibit the DNA supercoiling by irreversibly inhibiting the DNA topoisomerase enzyme 
Choose the correct answer from the options given below:

• A. A, B and D only are correct
• B. Only B is correct
• C. Only A and B are correct
• D. All A, B, C and D are correct

Answer 1

The Correct Option is B

To evaluate the given statements regarding alkylating agents as anticancer agents, we need to understand the mechanism of action of these agents and identify which statements are factually accurate.

1. Statement A suggests that alkylating agents get converted into highly nucleophilic anions and bind to the nitrogen atom of guanine, intercalating the DNA strands. This is incorrect. Alkylating agents form highly electrophilic intermediates (not nucleophilic) that form covalent bonds primarily with nucleophilic sites on DNA, such as the N7 position of guanine, but they do not intercalate DNA strands.
2. Statement B states that cyclophosphamide and busulfan belong to this class. This is correct. Both cyclophosphamide and busulfan are well-known alkylating agents used in chemotherapy.
3. Statement C claims that alkylating agents inhibit DNA synthesis by inhibiting the DNA polymerase enzyme. This is incorrect. Alkylating agents primarily act by directly binding to DNA and causing cross-links, which can distort DNA and prevent replication, but they do not specifically inhibit DNA polymerase enzymes.
4. Statement D suggests that alkylating agents inhibit DNA supercoiling by irreversibly inhibiting DNA topoisomerase enzyme. This is incorrect. The inhibition of DNA topoisomerase and affecting supercoiling is characteristic of other classes of drugs, such as topoisomerase inhibitors, not alkylating agents.

Based on this analysis, the only correct statement is B. Therefore, the right option is:

• Only B is correct