43antibacteria role. Here, we report that ART can serve as a novel bNOS inhibitor to
synergize antibiotics for more effective antibacterial effects. The combined use of
ART with antibiotics might decrease the dosage of antibiotics, and increase their
bactericidal efficiency. On the other hand, we also expected that ART could inhibit
CAT to elevate the H 2 O 2 level for maximizing bacterial apoptosis.
5.2.2 Results and Analysis
4.2.2.1 Induction and Suppression of NO Production in Bacteria
To induce the endogenous NO in bacteria, we cultured the G+ bacterium Bacilus
licheniformis under oxidative stress conditions including hypoxia and cold, from
which we investigated the influence of ART on oxidative stress-induced NO pro-
duction. Consequently, ART was found to substantially mitigate the production of
NO from B. Licheniformis under the oxidative stress condition. A gradual increase
of NO production was noticed in bacterial cultures standing without agitation at
the room temperature (as the hypoxia group) or without agitation at 4 °C (as the
hypoxia + cold group). High levels of NO were measured in both treatments,
whereas the control has only a negligible NO level. Accordingly, hypoxia and
cold-triggered NO can be repressed by ART and l-NMMA (Fig. 4.1).
Fig. 4.1 Induction of NO production in B. licheniformis upon acclimatization to oxidative stress
and suppression of oxidative stress-inducible NO. ART artemisinin; l-NMMA NG-monomethyl-
l-arginine monoacetate; NO nitric oxide. Double asterisks (**) represent very significant differ-
ence from the control (P < 0.01); Double pound signs (##) represent very significant difference
from the hypoxia + cold group (P < 0.01)
4.2 In Vitro Examination for ART Suppressing ...