<i>e</i><i>nt</i>-Rosane and Labdane Diterpenoids from <i>Sagittaria </i><i>s</i><i>agittifolia</i> and Their Antibacterial Activity against Three Oral Pathogens

Abstract

Seven new ent-rosane diterpenoids, sagittines A−G (1−7), together with one new labdane diterpene, 13-epi-manoyl oxide-19-O-α-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 μg/mL. Compound 5 was active against only A. naeslundiis ATCC 12104, with an MIC value of 62.5 μg/mL.