The Bombay Stock Exchange benchmark Sensex has shed almost 169 points in the opening trade today, on profit-booking and a weak trend in Asia.The 30-share barometer, which had gained 268.49 points in Monday's session, fell by 168.71 points or 0.87 per cent to 19,236.39 level at the outset of trade, with oil and gas, auto, banking, realty and technology sector stocks leading the fall.Similarly, the wide-based National Stock Exchange index Nifty declined by 56.10 points or 0.96 per cent to trade below 5,800 mark at 5,773.90.