The Quran was written by Muhammad long after the New Testament was written (di nga lang na-distribute widely dahil wala pang publishing house noon

) I would say the Quran was not based on the OT but rather, the muslims believed in the prophets, leaders, kings, etc of the OT. The Quran has its own teachings and doctrines, some contrary to the OT, some adhering to it. Most of it is its defense of its principles and teachings, kaya nga tawag nila sa mga "unbelievers" ay infidels. Also it will never be based on the OT mainly because di ba nga galit na galit sila sa mga Jews?
The NT on the other hand also was not based on the OT, but rather it's the fulfillment of what was not achieved - salvation.