Pimarane Diterpenoids from Aerial Parts of and Their Antimicrobial Activity.

The ethyl acetate fraction obtained from aerial parts of was subjected for isolation of new bioactive compounds, which enabled isolation of five new pimarane-type diterpenoids, namely, 3 8 12, 18-tetrahydroxy pimar-15-ene 7 8 12, 18-tetrahydroxy pimar-15-ene 3 8 11 12, 18-pentahydroxy pimar-15-ene 12 acetoxy, 8 3, 18-trihydroxy pimar-15-ene and 3 acetoxy, 8 12 18-trihydroxy pimar-15-ene along with nine known compounds. The structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new pimarane diterpenoids were examined for antimicrobial activity against Gram-negative and Gram-positive bacteria strains. Among them, the compound 3 8 12, 18-tetrahydroxy pimar-15-ene was most effective, exhibiting minimum inhibitory concentration (MIC) values of 15.62 µg/mL against , 31.25 g/mL against , 62.5 g/mL against , and 125 g/mL against .