The Bombay Stock Exchange benchmark Sensex fell over 229 points in early trade today on weak global cues. The Sensex was trading at 17,550, down by over 140 points when reports last came in. Similarly the Nifty of National stocks exchange was down by over 42 points to quote at 5265.Stock brokers said sentiment on the domestic bourses was dampened as US stocks tumbled overnight after downgrading of ratings for Greece and Portugal. The downgrading has raised doubts about euro-zone economic stability.The US Dow Jones Industrial Average ended 1.99 per cent down in Tuesday's trading. In morning trade today, Japan's Nikkei plunged 2.47 per cent and Hong Kong's Hang Seng down 1.46 per cent.