Phytochemical investigation of the ethanolic extract of leaves of Polyalthia longifolia var. pendula has led to the isolation of seven clerodane diterpenoids and five alkaloids. (-)-14, 15-bisnor-3, 11 E-kolavadien-13-one (1), (-)-16-oxocleroda-3,13(14) E-dien-15-oic acid (2), (-)-16α-hydroxycleroda-3,13 (14) Z-dien-15,16-olide (3), (+)-(4→2)-abeo-16(R/S)-2, 13 Z-kolavadien-15, 16-olide-3-al (4), (-)-3β, 16α-dihydroxycleroda-4(18), 13(14) Z-dien45,16-olide (5), (-)-3, 12 E-kolavadien-15-oic acid-16-al (6), (-)-labd-13 E-en-8-ol-15-oic acid (7), liriodenine (8), (-)-anonaine (9), (+)-isoboldine (10), (-)-asimilobine (11) and hordenine (12) have been isolated. This is the first report of 1, 6 and 10 from this plant species while 12 is reported for first time from this genus. Clerodane derivatives 1-7 were evaluated for their antimicrobial activity. Diterpene 3 was found to be most potent agent with MIC value of 6.25 μg/mL against Staphylococcus aureus and Sporothrix schenckii.