ent-rosane and labdane diterpenoids from Sagittaria sagittifolia and their antibacterial activity against three oral pathogens.

Seven new ent-rosane diterpenoids, sagittines A-G (1-7), together with one new labdane diterpene, 13-epi-manoyl oxide-19-O-alpha-l-2',5'-diacetoxyarabinofuranoside (8), were isolated from the whole plant of Sagittaria sagittifolia. The structures and relative configurations of 1-8 were characterized using spectroscopic means, chemical methods, and X-ray crystallography. Compounds 1-4 exhibited antibacterial activity against the oral pathogens Streptococcus mutans ATCC 25175 and Actinomyces naeslundiis ATCC 12104, with MIC values between 62.5 and 125 microg/mL. Compound 5 was active against only A. naeslundiis ATCC 12104, with an MIC value of 62.5 microg/mL.