The alkaloid berberine isolated from C.
rhizoma (Ranunculacea) showed bactericidal activity
against oral bacteria, with greatest activity against A.
actinomycetemcomitans (MIC = 13 μgmL-1) and P.
gingivalis (MIC = 20 μgmL-1), although much less
activity was observed against Lactobacillus and
Streptococcus species. Berberine also inhibited the
collagenase activity of A. actinomycetemcomitans and
P. gingivalis.