Purpose: To evaluate the antidiarrhea and antioxidant properties of honokiol extracted from
Magnoliae officinalis
cortex (bark of
Magnolia officinalis), an important medical material in traditional Chinese
medicine, for treating diseases such as diarrhea and thrombotic stroke.
Methods: The antidiarrhea activity of honokiol was investigated using castor oil-induced diarrhea as
well as neostigmine-induced increase in small intestine transit in mice. In castor oil-induced diarrhoea
test, mice received honokiol (25, 50 and 100 mg/kg BW) orally once daily for 1 day and the mice’
droppings were observed. In small intestine transit test, mice received honokiol (25, 50 and 100 mg/kg
BW) orally once daily for 4 days and the percentage distance travelled by charcoal meal was noted to
determine. For the determination of anti-oxidant activity, with 50 mg/kg vitamin E as positive control, the
mice were administered with 25, 50 or 100 mg/kg honokiol orally and daily for 14 days. The activity and
gene expression of antioxidative enzymes as well as antioxidant status were monitored to assess the
antioxidant potential of honokiol.
Results: All doses of honokiol showed (p < 0.001) significant inhibitory activity against castor oil-induced
diarrhea when compared with model control (diarrhea Index, 1.10 vs. 1.39)-. Honokiol at all
doses also reduced neostigmine-stimulated small intestinal transit by approximately 16 % in comparison
with -neostigmine control group-(59.0 % vs. 70.1%). Compared with control (no honokiol), the activities
of catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) in the
plasma (CAT, 7.31 vs. 13.21 U/mL; GSH-Px, 439.6 vs. 608.9 U/m; T-SOD, 82.2 vs. 109.8 U/mL) and
liver (CAT, 7.73 vs. 14.39 U/mg; GSH-Px, 167.6 vs. 202.7 U/mg; T-SOD, 44.3 vs. 53.9 U/mg) were
significantly enhanced by honokiol (p < 0.01). CAT and GSH-Px gene expressions were also
significantly enhanced by honokiol (p < 0.05), compared with control (no honokiol) (CAT, 0.32 vs. 0.39;
GSH-Px, 4.49 vs. 5.80). Additionally, total antioxidant capacity was increased by 60 % with 100 mg/kg
honokiol.
Conclusion: The results provide some justification for the use of
Magnoliae officinalis cortex as an
antidiarrheal remedy in Chinese traditional medicine. The fact that honokiol also enhanced both the
non-enzymatic and enzymatic antioxidant defense systems, suggests its potential as a natural
antioxidant.
