At the pre-opening bell, the frontline index S&P BSE Sensex opened in green with a gain of 116.95 points or 0.17%. On the sectoral front, metals jumped 0.17%, power zoomed by 0.30% and auto soared by 0.13%. Meanwhile, Alembic Pharmaceuticals Ltd, Aarti Drugs Ltd and Zydus Wellness Ltd emerged as the top gainers of BSE in the pre-opening session today.