U.S. oil tumbled 5.56 percent after a sharp rise in U.S. gasoline inventories.
The yen rose on Tuesday as traders sought safety in the low-risk currency on anxiety about sluggish global growth.
The dollar weakened against a basket of currencies on Wednesday after the release of the FOMC minutes from its December meeting.
Oil fell on fears about China's economic growth and a stronger U.S. dollar, returning some of the gains triggered by Middle East tensions.
Gold added to an overnight price surge, as geopolitical tension in the Middle East and a global stock market rout triggered safe-haven bids.
U.S. stock index futures pared losses to point to flat to higher open as oil struggled for gains amid pressure from jittery Chinese markets.
Gold hit a seven-week high, extending gains for a third session, as persistent concerns over the Chinese economy battered stock markets.