The inhibitory effects of five berberines alkaloids (BAs) from rhizoma ofCoptis chinensis Franch,a traditional Chinese medicinal (TCM) herb,on Bacillus shigae(B.shigae)growth were investigated by microcalorimetry.The power-time curves of B.shigae with and without BAswere acquired;meanwhile,the extent and duration of inhibitory effects on the metabolism wereevaluated by growth rate constants (k1,k2),half inhibitory ratio (IC50),maximum heat output(P_(max)),and peak time (t_p).The values of k1 and k2 of a shigae in the presence of the five BAsdecreased with the increasing concentrations of BAs.Moreover,P_(max) was reduced,and the value oft_p increased with increasing concentrations of the five drugs.The inhibitory activity varied withdifferent drugs.IC50 of the five BAs was respectively 75 mu g/mL for berberine,90 ng/mL forcoptisine,115 mu g/mL for palmatine,220 mu g/mL for epiberberine,and 400 mu g/mL forjatrorrhizine.The sequence of antimicrobial activity of the five BAs:berberine > coptisine >palmatine > epiberberine > jatrorrhizine.The functional groups methylenedioxy at C2 and C3 on phenylring improve antimicrobial activity more strongly than methoxyl at C2 and C3 on phenylring.However,the effect of bacteriostasis is not significant with methylenedioxy or methoxyl at C9and C10 on phenyl ring.
YAN Dan1,2,3, JIN Cheng1, XIAO XiaoHe1 & DONG XiaoPing2 1 Institute of Chinese Medicine, 302 Hospital of People’s Liberation Army, Beijing 100039, China
